LECROY 9400A Operating
THE LeCROY MODEL 9400A
DIGITAL OSCILLOSCOPE
North
American
Headquarters:
LeCROY Corporation
700 Chestnut
Ridge Road
Chestnut
Ridge,
NY 10977-6499
U.S.A.
Tel: 914-578 6097
European Headquarters:
LeCROY S.A.
2, rue Pr~-de-la-Fontaine
Case postale 341
1217 Meyrin 1 / Geneva
Switzerland
Tel: 41-22-719-21-11
Serial Number
January 1990
TABLE OF CONTENTS
Page Number
Section
I. GENERAL INFORMATION
Technical Data Sheet
1.1
1.2
1.3
1.4
1.5
1.6
2.
2-1
2-1
2-2
2-3
2-3
2-3
2-3
Safety Information
Operating Voltage
Switching on the 9400A
3-1
3-1
3-2
DISPLAY LAYOUT
4.1
4.2
4.3
4.4
4.5
4.6
5.
Introduction
9400A Architecture
ADCs and Memories
Trigger
Automatic Calibration
Display
Manual and Programmed Control
INSTALLATION
3.1
3.2
3.3
4.
I-I
i-I
1-2
1-2
1-2
1-3
PRODUCTDESCRIPTION
2.1
2.2
2.3
2.4
2.5
2.6
2.7
3.
Warranty
Assistance and Maintenance Agreements
Documentation Discrepancies
Service Procedure
Return Procedure
Initial Inspection
Menu Field
Time and Frequency Field
Trigger Delay Field
Abridged Front Panel Status Field
Displayed Trace Field
Message Field
4-1
4-2
4-2
4-2
4-2
4-3
MANUAL OPERATION
5.1
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
5.1.6
5.1.7
Front-panel Controls
5-1
Vertical
Time Base
Trigger
Displaying Traces
Display Control
Screen Adjustments
Cursors
5-1
5-4
5-6
5-12
5-12
5-1
5-15
ii
5-18
5.2 Menu Controls
6.
5.2.1
5.2.2
5.2.3
5.2.4
5.2.5
5.2.5.1
5.2.5.2
Store Menu
Panel Status Menu
Memory Status
Storage and Recall of Front Panel Setups
Special Modes
Auto-store Mode
Common Expand Mode
5-18
5-20
5-22
5-24
5-25
5-25
5-26
5.2.6
5.2.7
RS-232-C Setup
Plotter Setup
5-26
5-28
REAR PANEL CONTROLSAND CONNECTORS
6.1
6.2
6.3
6.4
6.5
7.
Fuse Protection
Accessory Power Connectors
Battery Pack
GPIB and RS-232-C Port Selection
Plotter Connector
6-1
6-1
6-1
6-1
6-2
REMOTEOPERATIONS
7.1
7.2
7.3
7.4
7.4.1
7.4.2
7.4.3
7.4.4
7.4.5
7.4.6
7.4.7
7.4.8
7.4.9
7.5
7.6
7.6.1
7.6.2
7.6.3
7.6.4
7.6.5
7.6.6
7.6.7
7.6.8
7.6.9
7.6.10
Programmed Control
RS-232-C Ports
GPIB Port (Option OP02 only)
C~IB and RS-232-C Command Format
Introduction
Compound Commands
Command Format
Answers from the 9400A
Flushing of 9400A Output Buffer
Command Synchronization with Data Acquisition
Character Strings
Prompt
Errors and Adapted Values
7-1
7-1
7-2
7-3
7-3
7-4
7-4
7-5
7-6
7-6
7-7
7-7
7-8
7-8
7-11
Data Block Transfers
Commands
Notation
Acquisition Parameter Commands
Display Commands
Plotter Commands
Transfer Commands
Other Remote Commands
Communication Format Command
Status Byte and Mask Register Commands
GPIB Interface Message Interpretation
RS-232-C Only Commands
iii
7-11
7-12
7-15
7-20
7-22
7-30
7-31
7-34
7-38
7-39
7.7
7.8
7.9
7.10
8.
7-43
7-47
7-48
7-50
7.10.1
Waveform Data in 8-bit Format
7.10.2
Waveform Data in 16-bit Format
7.11
Use of the Service Request (SRQ) Interrupts
7-50
7-52
7-52
7.11.1
7.11.2
7-52
7-55
Service Request in GPIB
Service Request in RS-232-C
BASIC 9400A WAVEFORM MEASUREMENTS AND OPERATING PROCEDURES
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
8.10
8.11
8.12
8.13
8.14
8.15
9.
Binary Format of Waveform Descriptors
Format of Trigger Time(s)
Data Addressing Conventions
Interpretation of Waveform Data Values
Repetitive Signal Acquisition
Single Shot Acquisition
Trace Expansion - Expand A/B
Sequential Recording of Single Events in
Segmented Memory
Slow Signal Recording
Window Triggering
Storing and Recalling Front Panel Setups
Signal Storage in Memories C, D
Redefinition Function - Expand Memories C, D
Auto-Store in Memory C, D
Common Expand Mode
Remote Control Via RS-232-C Port
Remote Control Via GPIB (Option OP02 Only)
Making a Plot when the Computer, the 9400A,
and the Plotter are All Connected Together
on a GPIB Bus (Option OP02 Only)
Configuring the Parallel Polling (Option 0P02 0nly)
8-1
8-3
8-5
8-6
8-8
8-9
8-9
8-10
8-11
8-12
8-13
8-14
8-18
8-19
8-20
GETTING THE MOST OUT OF YOUR 9400A
9.1
9.2
9.3
9.4
Front Panel Controls
Accurate Amplitude Measurements
Accurate Time Measurements
Auto-calibration
9-1
9-1
9-3
9-4
I0. WPOI WAVEFORM PROCESSING OPTION
I0.i
10.2
10.2.1
10.2.2
10.2.3
10.2.4
10.2.5
10.2.6
Processing Capabilities
Setting up a Waveform Processing Function
Manually
Summed Average
Continuous Average
Extrema
Arithmetic
Functions
Smoothing
I0-i
10-2
10-3
10-4
10-5
10-6
10-6
10-6
iv
10.3
10.4
10.5
10.6
11.
Remote Control of Waveform Processing Functions
Additional Values in the Descriptors of
Processed Waveforms
Vertical Scaling Units
Index of Topics
Fast Fourier
Waveform Processing
(WP02, V 2.06FT)
ii.i
11.2
11.3
11.4
11.4.1
11.4.2
11.5 FFT Application
11.5.1
11.5.2
11.5.3
11.6
11.7
11.8
11.9
ii. I0
II-I
11-3
11-4
11-7
11-7
Descriptors
of
Hints
Some practical suggestions
Relationships of 9400A FFT output waveforms to
the FFT computation steps
Computation Speed of FFT
FFT 9400A Glossary
Errors and Warnings
Table of Nyquist Frequencies
References
Index of Topics
Appendix
10-13
10-15
10-17
Option
Processing
Capabilities
Modification
to WP01 Functions
FFT Processing
Examples
Remote Control
of FFT Processing
Remote Commands
Additional
Values in the
FFT Processed
Waveforms
10-8
11-9
ii-ii
II-ii
11-12
11-15
11-16
11-21
11-22
11-29
11-30
44 43 42
LeCroy9400A
STORE
©
~
40 39
100Ms/s
DUAL 175MHz OSCILLOSCOPEsG,/s
I
45
SELECT
VERT GAIN
PosmoN
...~+
©
"~I .EOEF,
NE
©
REFERENCE
TRACKING
38
TIME MAGNIFIER
+
POSITION
(
ON
46
0
3
0
4
0
5
0
6
36
O
CHANNEL 1
OFFSET
47
CHANNEL 2
OFFSET
(p:
5V
LEVEL
VOLTSIDIV
5mY
5V
5mV
"°
TIIIS’n
COUPLING
I
ilEAny
MODE
LFREJ
8
0
9
49
0
I
10
11
INTENSITY
©
12
GRIDINTENSITY
©
13
DUAL GRID
o
14
REMOTE
CURSOR MEASUREMENTMODE
VOLTAGE
ON
15
TIME
SOURCE
CIAll
17
9400A FRONTPANEL
Figure1.1
HIS
.~--;-- 0
OC
DC
UNE
HD
~,1,0
I
.,,o, ~0
I...
,oo,, ~0
I,.,.
250 V pk MAX
250 Y pk MAX
PROBECALIBRATOR
i
POWER
EJ[TIIO
ON
EXTERNAL
250 V pk MAX
@
MARKER
18
T 0
c.,~
GND
o o o
16
SLOPE
6ND
6110
0
loll
0’ ~0 ""’
IIIOUll ~0
I’
\
©
34
33
32
31
,, 1"0 ,.,-1"0
7
0
35
+ <..- .->-
HFRF.J
SCREEN
DUMP
DELAY
/
-~ -.,~+
©I
VOLTSIDIV
48
0
37
INTERLEAVED
SAMPLING
2
0
DIFFERENCE
I
19
!10
21
22
23
24
25
26
30
29
28
27
51
52
53
54
55
9400A REAR PANEL
Figure1.2
56
57
DIGITAL OSCILLOSCOPE
175 MHz BANDWIDTH,
100 Ms/s, 5 Gs/s
LeCroy
MODEL 9400A PORTABLE
DUAL-CHANNEL OSCILLOSCOPE
9400A
High Bandwidth and
Precision
For instant hardcopiesthe 9400A’sscreendump
feature sendsdata
directly to the DPgO01
8-pendigital plotter.
A widerangeof oscilloscopeaccessoriesincluding cameras
anda
scope
cart (pictured)areavailablefor the 9400A.
ORDERING INFORMATION
Oscilloscope and Options
Oscilloscope Accessories(cont’d)
Code
9400A/G
9400AOP01
9400AOP03
9400AWP01
9400AWP02
9400AMS01
9400AIM01
9400CS01
Description
Digital Oscilloscope
High-precisionOption
Printer Optionfor 9400A/G
Waveform
ProcessingOption
FFTProcessingOption (requires 9400AWP01)
MassStorageand RemoteControl Package,includingan IBMlap-top controller, interface,cables
andsoftware
GPIBInterface for IBM-PCC
computers
CalibrationSoftware
Oscilloscope Accessories
OM9400A
SM9400A
Operator’sManual
Service Manual
CAg001
CA9002
CS9400
DPg001
94XX-FC
OC9001
P9010
Pg010/2
P9011
P9100
RM9400
SGg001
Tcg001
TC9002
TC9003
automatically
connects
youto yourlocal salesoffice.
WORLDWIDE
Australia:Scient. DevicesPty, Ltd, (03) 579-3622
Austria: Dewetron
Elektr. Messger&te
GmbH,
(0316) 391804
Benelux:LeCroyB.V. "31~4902-89285
Canada:
RayonicsSci. Inc., W.Ontario, (416) 736-1600
E. Ontario/Manitoba,(613) 521-8251
Quebec,(514) 335-015
W. Canada,(604) 293-1854
Denmark:
Lutronic Aps, (42) 459764
Finland:LabtronicOY,(90) 847144
France:LeCroySad(1) 69073897
Germany:
LeCroyGmbH,
(06221) 49162,(North) (0405)
LeCroy
Innovators in Instrumentation
¯ High-resolution Display
Camera
(using Polaroid film) andHood
CameraAdapter (35mm)with Hood
CertifiedCalibration
Digital Plotter, 8-penA4size
Front Cover
OscilloscopeCart
10:1 OscilloscopeProbe
10:1 OscilloscopeProbewith 2 mcable
10:1/1:1 OscilloscopeProbe
100:1 OscilloscopeProbe
AdapterKit for RackMounting
High-voltageProtector
Transit Case
ProtectiveCover
Transit Casefor 9400AandMassStorage
US SALES OFFICES
1-800-5-LeCroy
¯ Long Memories
Greece:
Hellenic S/RLtd., (01) 7211140
India: ElectronicEnt., (02) 4137096
Israel: Ammo,
(03) 453157
Italy: LeCroySrl, Roma
(06) 302-9646,Milano(02) 2940-5634
Japan:ToyoCorp., (03) 2790771
Korea:Samduk
Science& Ind., Ltd., (02) 46804914
Mexico:NucleoelectronicaSA, (905) 56936043
NewZealand:E.C. GoughLtd., (03) 798-740
Norway:AvantecAS, (02) 630520
Portugal:M.T.Brandao,Lta¯, (02) 691116
Spain:AnadigIngenierosSA, (01) 43324
Switzerland:LeCroySA(022) 71921
Sweden:MSSAB, (0764) 68100
Taiwan:
Topward
El. Inst., Ltd., (02) 6018801
United Kingdom:LeCroyLtd., (0235) 33 114
LeCROY CORPORATE
HEADQUARTERS
700 ChestnutRidge Road
ChestnutRidge, NY10977-6499
Telephone:(914) 425-2000
TWX:(710)577-2832
Fax: (914) 425-8967
LeCROY EUROPEANHEADQUARTERS
2, rue Pr~de-la-Fontaine
P.O.Box341
1217Meyrin1-Geneva,Switzerland
Telephone:(022) 71921 11 Telex: 41 90
Fax: (022) 78239
Copyright @March1990. LeCroyis the registered trademarkof LeCroyCorporation. All rights reserved. Information in this publication supersedesall earlier versions. Specifications subject
to changewithout notice,
TDS011/004
¯ Signal Processing and FFT
¯ Mass Storage
gnalaveraging
improves
the signal-to-noiseratio andincreasessensitivity andvertical resolu¯ Above,a functiongeneratorsignal is averaged
40 timesto showthe details of a perturbation
p trace).
~(t
QTHE COMPLETE TEST
O AND MEASUREMENT
SYSTEM
The LeCroy 9400A Digital Oscilloscope is a powerful general-purpose
tool for waveform recording and analysis. Combining ease of use with a
comprehensive range of measurementand processing capabilities,
it enables extremely precise measurements.
The LeCroy 9400A provides 1 75 MHz bandwidth, 100 megasamples/sec
8-bit ADCs, + 2 % DC accuracy (+ 1% optional),
32K memory per channel, and up to 192Kof waveformstorage memory¯It is fully program mable
over RS-232-Cor GPIB interfaces. Plotter drivers enable color archiving
via a wide range of digital plotters.
FEATURES
SPECIFICATIONS
Transient recording - With a sampling rate of 100
megasamples/sec,the 9400Ais an extremely powerful
transient recorder. Long 32K data point acquisition
memories, combined with a continuously adjustable
trigger (from 100%pre-trigger to 10,000 divisions
post-trigger at any time-basesetting), ensurethat rare
events cannot be missed. Both channels are sampled
simultaneouslyso that exact time correlation is maintained between channels.
High bandwidth and precision - Two independent
channels, each with 175 MHzbandwidth and a highperformance 8-bit ADC, handle input signals with
better than +2%DCaccuracy (_+1% optional). The
9400Afeatures sampling rates of 100 megasamples/
sec for transient events. Long memories and a
versatile cursor system (including voltage, time and
cross-hair cursors), give time measurements
with an
accuracyof_+0.02%of the time-basesetting, and resolution of +0.002%
full scale.
Full programmability - All the 9400A’s front-panel
controls are fully programmablevia the two RS-232-C
interface ports or the GPIBport. A single push-button
initiates a screen dumpfor accurate color hard copies
of the display via a wide rangeof digital plotters. The
GPIB comes complete with LeCroy "MASP"software
offering computercontrol and massstorage on any PC
compatible with the IBM® standard.
High-resolution display-The 9400A’s large display
screenproducesbright, stable, razor-sharp pictures of
your signal underany repetition rate conditions. Very
accurate signal comparisonsare possible as up to four
waveforms(live, expandedor processed) can be displayed simultaneously on the high-resolution screen
(1024 x 1024pixels).
Signal processing - The waveform processing options extend the applications of the 9400Ato high
bandwidthsignal characterization, as well as mathematical and spectral analysis. The routines include
averaging (summed
and continuous), smoothing, integration, differentiation,
square, square-root, full
arithmetic, FFT spectral analysis, and Extremamonitoring.
Long memories-Thelong 32K acquisition memories
of the 9400ADigital Oscilloscope capture waveforms
with high fidelity. At similar time-base settings, the
9400A’s long memoriesallow sampling rates up to 25
times faster than that of instruments which have only
1K of acquisition memory(see graph below). Faster
sampling rates ensure higher single-shot bandwidth
as well as significantly reducing problemscausedby
undersampling and aliasing. The 9400A’s long memories allow displayed waveformsto be expandedup to
100times to showthe finest signal details.
>-
Massstorage and remote control - A sophisticated
massstorage and remote control packageis available
to assist users involved in automatedand computeraided testing. Convenientportability for field applications is also provided by a lap-top computer.
SINGLE- SHOT BANDWIDTH ( NYQUIST
FREQUENCY )
Vs.
\\
\
"’,
~"r-
I \
10
\
\
,\
\
5
\
\
\
\ \ ""i
\
1
0.5
\
Offset: _+ 8 divisions in 0.04 division increments.
DCaccuracy: Standard < + 2%, optional _< + 1%.
Noise: _< 0.45% RMS.
Bandwidthlimiter (- 3 dB): 30 MHz.
Maxinput voltage: 250 V (DC + peak AC) at 1 M~, 5 V
(500 mW)or _+ 10V peak AC at 50
VERTICALDIGITAL SECTION
ADCs:Oneper channel, 8-bit flash.
Conversionrate: Up to 100 megasamples/sec
for transient
signals, up to 5 gigasamples/sec
for repetitive signals, simultaneously on both channels.
Aperture uncertainty: + 10 psec.
Overall dynamicaccuracy(typical): Sine waveapplied to
the BNCinput for RMScurve fit at 80%full scale. The accuracy measurement
includes the front-end amplifier, sample
& hold and ADC.
Nyquist
50.0 100.0
1.0
10.0
175.0
41.9
41.9
41.9
37.1
29.9
7.0
7.0
7.0
6.2
5.0
\
\
10n
5On 100 n
500n
I LI
.U
10 ~
50tJ
ioo~
TIME
%
\
1-
,,soo~,,.1~
BASE
¯
.=
SETTING
(sec/div)
bandwidth is a function
of sampling rate. Long memories enable higher sampling rates at equal time-base
settings.
Above, the 9400A
is compared to oscilloscopes
with 1K (dotted line)
and 512 points (dashed line)
of memory. At slower time-base settings,
the single-shot
the 9400A, expressed as Nyquist frequency,
is typically
25 times higher than in oscilloscopes
with 1K memory and 50 times higher than
only 512 points.
Roll for slowly-changingsignals from 500 msec/div to
100 sec/div;
Sequence
for capturing transients in segmentedmemories
of 8, 15, 31,62,125 or250 blocks.
Trigger
Sources: CHAN1,CHAN2,LINE, EXT, EXT/10.
Slope: Positive, negative, window.
Coupling:AC, LF RE J, HFRE J, DC.
Modes:
Sequence:
stores multiple events in segmentedacquisition memories.
Auto:automatically re-arms after each sweep.If no trigger occurs, oneis generatedat 2 Hzrepetition rate.
Normal:re-arms after each sweep.If no trigger occurs
after 2 sec, the display is erased.
Single (hold): holds display after a trigger occurs. Rearmsonly whenthe "single" button is pressedagain.
Pro-trigger: Adjustable in 0.2%increments, to 100%.
Post-trigger delay: Adjustable in 0.02 division increments
up to 10,000divisions.
External trigger input: 1M~, < 30pE 250Vmax., + 2V in
EXT, + 20V in EXT/10.
Rate: > 200 MHz.
SELF TESTS
Auto-calibration: Performed every 20 minutes or wheneve
the gain or time-base parameters are changed;provides
accuraciesof:
DCgain: + 2%(+ 1%optional) of full scale;
Offset: + 0.5%of full scale (50~ only);
Time: 20 psec RMS.
During the warming-upperiod, auto-calibration is carried OL
at 1 minuteintervals unlessthe oscilloscopeis in single or
sequencetrigger mode.
DISPLAY
Acquisition memories,Channels1 and 2: Two, 32K 8-bit
word memories(64K total) which can be segmentedinto
15, 31,62, 125 or 250 blocks.
Reference memories,C and D: Two, 32K, 16-bit word memories (64K total) which can store two acquired and/or
processed waveforms.
Function memoriesE and F (optional): Two32K, 16-bit
word memories(64K total) for waveformprocessing.
Glitch detection: Permanentglitch detection for events
clown to 0.04%of the time-base setting, 10 nsec minimum.
CRT:12.5 ×17.5 cm(5 x 7 inches); magneticdeflection; vec
tor graphics system.
Resolution: 1024 x 1024 addressable points.
HORIZONTALSECTION
Screendump:Single or multi-pen digital plotters are menu
selected. The 9400Asupports the HP 7400series, as well a,
the Tektronix 4662, Philips PM8151, GraphtekWX4638/6.
and compatible models. Screen dumpsare activated by a
front-panel push-button.
\
\
Single-shot
(solid
line)
bandwidth of
in those with
Bandwidth(- 3 dB):
@50 ~: DC- 175 MHzat 10 mV/div, up to 225 MHz
at 1V/div;
DC- 150 MHzat 5 mV/div.
@1 M~ AC: < 10 Hz - 100 MHztypical.
@1 M~ DC: DC - 100 MHztypical.
Single shot: DC- 50 MHz(Nyquist).
Input impedance: 1 M~//50 pF and 50 ~ +_ 1%.
Channels:Two; standard BNCconnector inputs.
Sensitivity range: 5 mV/div to 1 V/div at 50 ~ impedance
and 5 mV/div to 5 V/div at 1 M~impedance;detents at
1-2-5, 1 : 2.5 continuouslyvariable.
Input frequency
(MHz)
Signal-to-noise
ratio (dB)
Effectivebits
TIME BASE SETT[NG
100 L
50
VERTICAL ANALOGSECTION
Time Base
Range:2 nsec/div to 100 sec/div.
Accuracy:Better than + 0.002 %of the time-base setting.
Interpolator resolution: 10 psec.
Acquisition
Modes
Random
Interleaved Sampling(RIS) for repetitive
from 2 nsec/div to 2 ~sec/div;
signals
Single shot for transient signals andrepetitive signals from
50 nsec/div to 200 msec/div;
Grid: Internally generated;separateintensity control for gric
and waveforms.Single and dual grid mode.
Expansion:Dual zoomhorizontal expansion operates simu
taneously on live, stored and processedwaveforms,
expandingup to 100times. Vertical expansionfrom 0.4 up tc
2 times for non-processedwaveforms,up to 10 times for
processed waveforms.
Cursors:Twotime cursors give time resolution of _+ 0.2%c
full scale for unexpanded
traces; up to +_ 0.002%for expanded traces. The correspondingfrequency information is alsc
provided. Twovoltage cursors measurevoltage differences
to 0.2%of full scale for eachtrace.
A cross-hair marker measuresabsolute voltage versus
signal groundas well as the time relative to the trigger.
DIGITAL OSCILLOSCOPE
175 MHz BANDWIDTH,100 Ms/s,
LeCroy
5 Gs/s
MODEL 9400A PORTABLE
DUAL-CHANNEL OSCILLOSCOPE
9400A
¯
High Bandwidthand
Precision
¯ Long Memories
¯ High-resolution Display
¯ Signal Processing and FFT
¯ Mass Storage
"ignal averaging
improves
the signal-to-noiseratio andincreasessensitivity andvertical resoluin. Above,a functiongeneratorsignal is averaged
40 timesto showthe details of a perturbation
(toptrace).
THE COMPLETE TEST
AND MEASUREMENT
SYSTEM
TheLeCroy9400ADigital Oscilloscopeis a powerful general-purpose
tool for waveform
recordingandanalysis. Combining
easeof usewith a
comprehensive
rangeof measurement
andprocessingcapabilities, it enables extremelyprecise measurements.
The LeCroy9400Aprovides 175 MHzbandwidth, 100 megasamples/Sec
8-bit ADCs,+ 2 %DCaccuracy(+ 1%optional), 32Kmemory
per channel, andup to 192Kof waveform
storagememory.
It is fully programmable
over RS-232-C
or GPIBinterfaces. Plotter drivers enablecolor archiving
via a widerangeof digital plotters.
FEATURES
Transientrecording- With a samplingrate of 100
megasamples/sec,
the 9400Ais an extremelypowerful
transient recorder. Long32Kdata point acquisition
memories,combinedwith a continuously adjustable
trigger (from 100%pre-trigger to 10,000divisions
post-triggerat anytime-base
setting), ensurethat rare
events cannotbe missed. Both channelsare sampled
simultaneously
so that exacttimecorrelation is maintained betweenchannels.
High bandwidthand precision - Twoindependent
channels, each with 175 MHzbandwidthand a highperformance8-bit ADC,handle input signals with
better than +_2%DCaccuracy(.-_1% optional). The
9400Afeatures samplingrates of 100 megasamples/
sec for transient events. Long memoriesand a
versatile cursor system(including voltage, time and
cross-hair cursors), give time measurements
with an
accuracyof__0.02%
of the time-basesetting, andresolution of _+0.002%
full scale.
Full programmability- All the 9400A’sfront-panel
controls are fully programmable
via the two RS-232-C
interface ports or the GPIBport. A single push-button
initiates a screendump
for accuratecolor hardcopies
of the displayvia a widerangeof digital plotters. The
GPIBcomescomplete with LeCroy"MASP"software
offering computercontrol and massstorageon anyPC
compatiblewith the IBM® standard.
High-resolution
display- The9400A’slarge display
screenproduces
bright, stable, razor-sharppicturesof
your signal underanyrepetition rate conditions.Very
accuratesignal comparisons
are possibleas up to four
waveforms
(live, expanded
or processed)can be displayedsimultaneouslyon the high-resolution screen
(1024x 1024pixels).
Signal processing- The waveformprocessing options extendthe applications of the 9400Ato high
bandwidthsignal characterization, as well as mathematical and spectral analysis. Theroutines include
averaging(summed
and continuous),smoothing,integration, differentiation, square,square-root, full
arithmetic, FFTspectral analysis, andExtremamonitoring.
LongmemoriesThe long 32Kacquisition memories
of the 9400ADigital Oscilloscopecapture waveforms
with highfidelity. At similar time-basesettings, the
9400A’slong memories
allow samplingrates up to 25
timesfaster than that of instrumentswhichhaveonly
1K of acquisition memory
(see graph below). Faster
samplingrates ensurehigher single-shot bandwidth
as well as significantly reducingproblemscausedby
undersampling
and aliasing. The9400A’slong memories allow displayedwaveforms
to be expanded
up to
100timesto showthe finest signal details.
SINGLE-SHOT
Massstorageandremotecontrol - A sophisticated
massstorageand remotecontrol packageis available
to assist users involved in automatedandcomputeraidedtesting. Convenient
portability for field applications is also providedby a lap-top computer.
BANDWIDTH (NYQUIST
Vs. TIME BASE SETTING
FREQUENCY)
100
50
\
\
l0
-
\
\
\
5 -
\
\
\
\
\
\
\
0.5 --
\
\
\
\
\
1On
50n
lO0n
SOOn
Ip
5p
10FI
%.
\
"¯
50H
TIME
BASE
(sec/div
Single-shot
(solid
line)
bandwidth of
in those with
\
SETTING
)
bandwidth is a function
of sampling rate. Long memories enable higher sampling rates at equal time-base
settings.
Above, the 9400A
is compared to oscilloscopes
with 1K (dotted line) and 512 points (dashed line) of memory. At slower time-base settings,
the single-shot
the 9400A, expressed as Nyquist frequency,
is typically
25 times higher than in oscilloscopes
with 1K memory and 50 times higher than
only 512 points.
SPECIFICATIONS
VERTICAL
ANALOG SECTION
Bandwidth(- 3 dB):
@50 ~2: DC- 175 MHzat 10 mV/div, up to 225 MHz
at 1V/div;
DC- 150 MHzat 5 mV/div.
@1 M(2 AC: < 10 Hz- 100 MHztypical.
@1 M(~ DC: DC- 100 MHztypical.
Single shot: DC- 50 MHz(Nyquist).
Input impedance:1 M~2//50 pF and 50 ~-2 + 1%.
Channels:Two; standard BNCconnector inputs.
Sensitivity range: 5 mV/div to 1 V/div at 50 (2 impedance
and 5 mV/div to 5 V/div at 1 M~)impedance;detents at
1-2-5, 1 : 2.5 continuouslyvariable.
Offset: + 8 divisions in 0.04 division increments.
DCaccuracy: Standard _< + 2%, optional _< _+ 1%.
Noise: < 0.45% RMS.
Bandwidthlimiter (- 3 dB): 30 MHz.
Maxinput voltage: 250 V (DC + peak AC) at 1 M~2, 5 V
(500 mW)or _+ 10V peak AC at 50 (~.
VERTICAL DIGITAL SECTION
ADCs:Oneper channel, 8-bit flash.
Conversionrate: Up to 100 megasamples/sec
for transient
signals, up to 5 gigasamples/sec
for repetitive signals, simultaneously on both channels.
Apertureuncertainty: _+ 10 psec.
Overall dynamicaccuracy(typical): Sine waveapplied to
the BNCinput for RMScurve fit at 80%full scale. The accuracy measurement
includes the front-end amplifier, sample
& hold and ADC.
Input frequency
(MHz)
Signal-to-noise
ratio (dB)
Effectivebits
Nyquist
50.0 100.0
1.0
10.0
175.0
41.9
41.9
41.9
37.1
29.9
7.0
7.0
7.0
6.2
5.0
Acquisition memories,Channels1 and 2: Two, 32K 8-bit
word memories(64K total) which can be segmentedinto
15, 31,62, 125 or 250 blocks.
Reference memories,C and D: Two, 32K, 16-bit word memories (64K total) which can store two acquired and/or
processed waveforms.
Function memoriesE and F (optional): Two32K, 16-bit
word memories(64K total) for waveformprocessing.
Glitch detection: Permanentglitch detection for events
downto 0.04%of the time-base setting, 10 nsec minimum.
HORIZONTAL SECTION
Time Base
Range:2 nsec/div to 100 sec/div.
Accuracy:Better than + 0.002 %of the time-base setting.
Interpolator resolution: 10 psec.
Acquisition
Modes
Random
Interleaved Sampling(RIS) for repetitive
from 2 nsec/div to 2 #sec/div;
signals
Singleshotfor transient signals andrepetitive signals from
50 nsec/div to 200 msec/div;
Roll for slowly-changing signals from 500 msec/div to
100 sec/div;
Sequence
for capturing transients in segmentedmemories
of 8, 15, 31,62, 125 or 250 blocks.
Trigger
Sources: CHAN1,CHAN2,LINE, EXT, EXT/10.
Slope: Positive, negative, window.
Coupling: AC, LF RE J, HF REJ, DC.
Modes:
Sequence:
stores multiple events in segmentedacquisition memories.
Auto: automatically re-armsafter each sweep.If no trigger occurs, oneis generatedat 2 Hzrepetition rate.
Normal:re-arms after each sweep.If no trigger occurs
after 2 sec, the display is erased.
Single (hold): holds display after a trigger occurs. Rearmsonly whenthe "single" button is pressedagain.
Pre-trigger: Adjustable in 0.2% increments, to 100%.
Post-trigger delay: Adjustable in 0.02 division increments
up to 10,000divisions.
External trigger input: 1M,(2, < 30pF, 250Vmax., _+ 2V in
EXT,4- 20Vin EXT/10.
Rate: > 200 MHz.
SELF TESTS
Auto-calibration: Performed every 20 minutes or whenever
the gain or time-base parameters are changed; provides
accuraciesof:
DCgain: + 2%(+ 1%optional) of full scale;
Offset: + 0.5%of full scale (50~ only);
Time: 20 psec RMS.
During the warming-upperiod, auto-calibration is carried out
at 1 minuteintervals unlessthe oscilloscopeis in single or
sequencetrigger mode.
DISPLAY
CRT:12.5 x17.5 cm(5 x 7 inches); magneticdeflection; vector graphics system.
Resolution: 1024 x 1024 addressable points.
Grid: Internally generated;separateintensity control for grid
and waveforms.Single and dual grid mode.
Expansion:Dual zoomhorizontal expansion operates simultaneously on live, stored and processedwaveforms,
expandingup to 100 times. Vertical expansionfrom 0.4 up to
2 times for non-processedwaveforms,up to 10 times for
processed waveforms.
Screendump:Single or multi-pen digital plotters are menu
selected. The 9400Asupports the HP7400 series, as well as
the Tektronix 4662, Philips PM8151, Graphtek WX4638/6,
and compatible models. Screen dumpsare activated by a
front-panel push-button.
Cursors:Twotime cursors give time resolution of + 0.2%of
full scale for unexpanded
traces; up to + 0.002%for expanded traces. The correspondingfrequency information is also
provided. Twovoltage cursors measurevoltage differences
to 0.2%of full scale for eachtrace.
A cross-hair marker measuresabsolute voltage versus
signal groundas well as the time relative to the trigger.
For instant hardcopiesthe 9400A’sscreendump
feature sendsdata
directly to the DP9001
8-pendigital plotter.
A widerangeof oscilloscopeaccessoriesincluding cameras
anda
scopecart (pictured)areavailablefor the 9400A.
ORDERING INFORMATION
Oscilloscope and Options
Oscilloscope Accessories(cont’d)
Code
9400A/G
9400AOP01
9400AOP03
9400AWP01
9400AWP02
9400AMS01
9400AIM01
9400CS01
Description
Digital Oscilloscope
High-precisionOption
Printer Optionfor 9400A/G
Waveform
ProcessingOption
FFTProcessingOption (requires 9400AWP01)
MassStorageand Remote
Control Package,includinganIBMlap-topcontroller, interface, cables
andsoftware
GPIBInterface for IBM-PCC
computers
CalibrationSoftware
Oscilloscope Accessories
OM9400A
SM9400A
Operator’sManual
ServiceManual
CA9001
CA9002
CS9400
DP9001
94XX-FC
OC9001
P9010
P9010/2
P9011
P9100
RM9400
SG9001
TC9001
TC9002
TC9003
Camera
(using Polaroidfilm) andHood
CameraAdapter (35mm)with Hood
CertifiedCalibration
Digital Plotter, 8-penA4size
Front Cover
OscilloscopeCart
10:1 OscilloscopeProbe
10:1 OscilloscopeProbewith 2 mcable
10:1/1:1 OscilloscopeProbe
100:1OscilloscopeProbe
AdapterKit for RackMounting
High-voltageProtector
Transit Case
ProtectiveCover
Transit Casefor 9400AandMassStorage
US SALES OFFICES
1-800-5-LeCroy
automatically
connects
youto yourlocal salesoffice.
WORLDWIDE
Australia:Scient. DevicesPty, Ltd, (03) 579-3622
Austria: DewetronElektr. Messger~teGmbH,
(0316) 391804
Benelux:LeCroyB.V. "31-4902-89285
Canada:
RayonicsSci. Inc., W. Ontario, (416) 736-1600
E. Ontario/Manitoba,(613) 521-8251
Quebec,(514) 335-015
W.Canada,(604) 293-1854
Denmark:
Lutronic Aps, (42) 459764
Finland:LabtronicOY,(90) 847144
France:LeCroySad(1) 69073897
Germany:
LeCroyGmbH,
(06221)49162,(North) (0405)42713
LeCroy
Innovators in Instrumentation
Greece:
Hellenic S/RLtd., (01) 7211140
India: ElectronicEnt., (02) 4137096
Israel: Ammo,
(03) 453157
Italy: LeCroySrl, Roma
(06) 302-9646,Milano(02) 2940-5634
Japan:ToyoCorp., (03) 2790771
Korea:Samduk
Science& Ind., Ltd., (02) 46804914
Mexico:NucleoelectronicaSA, (905) 56936043
NewZealand:E.C. GoughLtd., (03) 798-740
Norway:AvantecAS, (02) 630520
Portugal:M.T.Brandao,Lta., (02) 691116
Spain:AnadigIngenierosSA,(01) 43324
Switzerland:LeCroySA(022) 71921
Sweden:MSSAB, (0764) 68100
Taiwan:
Topward
El. Inst., Ltd., (02) 6018801
UnitedKingdom:
LeCroyLtd., (0235) 33 114
LeCROY CORPORATE
HEADQUARTERS LeCROY EUROPEANHEADQUARTERS
700 ChestnutRidge Road
2, rue Pre-de-la-Fontaine
ChestnutRidge, NY10977-6499
P.O.Box341
Telephone:(914) 425-2000
1217Meyrin1-Geneva,
Switzerland
TWX:(710)577-2832
Telephone:(022) 71921 11 Telex: 41 90
Fax: (914) 425-8967
Fax: (022) 78239
Copyright (~ March1990. LeCroyis the registered trademarkof LeCroyCorporation. All rights reserved. Information in this publication supersedesall earlier versions. Specifications subject
to changewithout notice.
TDS 011/004
In single-shotapplicationsthe 9400A’ssmoothing
routinescan be
usedto remove
high-frequency
noise fromtransients.
Anapparentnoisesignal (top trace) is averaged
over 400times
(middle)to reveala low amplitude
clock signal. FFTanalysis(lower)
showsthe clock frequencyto be 1.02 MHz.
MASS STORAGE9400AMS01
ambiguous
checkof the 9400A’sspecifications. If instrumentstraceable to a standardare used, the calibration will
be traceable to the samestandard.
Optional dual floppy-disk storage system mountedexternally
on the oscilloscope.
Controller: PC01programmablecontroller with LCDdisplay
and full-size keyboard.
Medium:
720 kilobyte, 3 1/2 inch flexible diskettes.
Bustransfer rate: 220kilobytes/sec over National Instruments TMGPIB interface model 80400-50.
Dimensions: 6.9 x 31.2 x 40.5 cm;
2.7 x 12.3 x 15.9 inches.
Weight:6 kg, 13 Ibs.
For further information refer to the massstorage data sheet.
CALIBRATION SOFTWAREAND SYSTEMS
9400CSO1 "CALSOFT"
Test andcalibration softwarepovidinga convenientandun-
Computerrequired: Any computer compatible with the
IBM-PC standard.
Tests: A comprehensive
series of tests include internal,
bandwidth,linearity, noise, rise time/overshoot,sinefit, time
baseandtrigger.
Presentation of results: Results of the calibration check are
fully documented
on hard copy, or can be archived on hard
disk or diskette.
"CALSOFT"
systems: Various system configurations including 9400CS01,signal generators, power supplies, and a
computerwith accessories and fixtures are quoted on request.
Training: User training classes on service and maintenance
of the 9400series oscilloscopes, as well as calsoft operation
are scheduledregularly.
CERTIFIED CALIBRATIONCS9400
Certified traceable calibration to NBSor any other national
standard is obtained by specifying CS9400whenordering
the 9400A.
A lap-top IBM-PCC
is usedto provide massstorageandremote
control (9400AMSO
1) for field andautomated
testing applications.
by optional firmware packages. Theseinclude FFT spectrum
analysis, arithmetic functions, integration, differentiation,
square root, square, averaging (continuous and summation)
and smoothing, as well as Extremamonitoring.
For additional information refer to data sheets WP01
and
WP02.
Timeand cross-hair cursors indicate Hz and dB or volt values when an FFT spectrum analysis is made.
Menus:
Standard:Waveformstorage; acquisition parameters;
memorystatus; store/recall front-panel configurations,
RS-232-Cconfiguration; plotter setup.
Optional: (WP01/WP02)
averaging, arithmetic, functions,
extrema, smoothing, FFT and frequency domain averaging.
120
110
REMOTE CONTROL
100
All the front-panel controls, including variable gain, offset
andposition controls (not cursor positioning), andall the internal functions are programmable.
RS-232-Cports: Two: for computer/terminal control and
plotter connection. Asynchronousup to 19200baud.
GPIBport: (IEEE-488).Configuredas talker/listener for
computercontrol and fast data transfer; 400 kilobytes/sec
maximum.ASCII or binary. The address switches are on the
rear panel.
It includes LeCroy MS02(MASP)IBM-PC-basedsoftware
for massstorage andremotecontrol applications. For further
details on MASP
software, please refer to the MS01/02data
sheet.
90
80o
60=
50,t, 0~
\
\
\
30=
PROBES
20=
Probecalibration: 976 Hz square wave, 1 V p-p +_ 1%.
Standardprobes: Twomodel P9010, xl0 attenuating passive probes with 10 M~input impedancein parallel with a
5.5 pF capacitance.
Probepower:Twopower outlets on the rear panel provide
_+ 15 V and + 5 V DCfor active probes.
Temperature:
5 to 40°Crated; to 50°C operating.
Humidity: 80%
EMI Immunity:The 9400Acomplies with the following standards: IEC 801, VDE0871, FCCPART15 and SEV.
Safety standards:The 9400Acomplies with the following:
IEC-348, ASE3453 and VDE0411.
Powerrequired: 110 or 220 V AC, 48 to 65 Hz, 200 W.
Battery backup:NiCd batteries maintain front-panel settings for 6 months minimum.
0h
10
50
t00
5o
u
/
20
/
u
® 10
u3
uJ
5-
2 ____
t
of
WAVEFORMPROCESSING9400AWP01, AND
9400AWP02
Routines are called and set up via menus.Extensive signal
processing in both time and frequency domainsis provided
50000
5000 10000
RECORDLENGTH (no. of points)
i
OPTIONS FOR THE 9400A
500 1000
WithoptionWPO
1 installed, the 9400A
becomes
a fast signal a verager
(both summation
andcontinuous).A s manyas 100,000points/secare
averaged
with record lengthschosenby the user up to a maximum
of
32,000.Thegraphabovedisplays the relationship betweenrecord
length andthe number
of signals/secaveraged.
F-
Dimensions:(HWD)19.2 x 36.5 × 46.5 cm,
(7 1/2 x 14 3/8 x 18 3/8 inches).
Weight: 14 kg (30 Ibs) net, 20 kg (44 Ibs) shipping.
Warranty:2 years.
\
10=
GENERAL
9400AOP01
: _+ 1%DChigh-precision option. A certificate
traceability is providedwith this option.
9400AOP03:
Printer drive for HP 2225Think Jet.
\
70=
~
,5
J
.2
50
125
J
250
J
625
/
1250
/
2500
6250
12500
25000
RECORDLENGTH (Points)
FFTexecution
timeas a functionof recordlength,includingwindow
calculationsanddisplaygeneration,is expressed
in the graphabove.
WAVEFORMPROCESSING PACKAGE
INCLUDING
AVERAGING,
INTEGRATION,
DIFFERENTIATION
LeCroL
WP01 WAVEFORM
PROCESSING
FIRMWARE
FORMODEL9400A DIGITAL OSCILLOSCOPE
9400AWP01
¯ Averaging
- Summation
andContinuous
¯ Arithmetic
- including
Addition,
Subtraction,
andMultiplication
Functions
-including
Integration,
Differentiation,
andSquare
Root
Extrema
Mode
- Storage
of
Extreme
Positive
andNegative
Values
¯ Smoothing
- Reduction
of
Noise
onSingle
Events
erform complex measurement sequences with ease. Above, a damped sine wave (top)
s~raining different
mathematical functions together, the WP01waveform processing package
ed (middle) and then integrated (bottom) allowing RMSmesurements to be calculated.
FOR SIGNAL
¯ CHARACTERIZATION
AND ANALYSIS
The LeCroy WP01WaveformProcessing Firmware Packageoffers powerful
routines that extend the use of the 9400Ato signal characterization, mathematical analysis, and post-processing of single events. Orderedas an
option, or retrofitted, WP01
allows for further extensionsof the 9400A’sprocessing capabilities with other firmware packages.
The LeCroy 9400A provides 175 MHzbandwidth, 100 megasamples/sec
8-bit ADCs,+2%DCaccuracy (+1% optional), 32K memoryper channel,
and up to !92K of waveformstorage memory.It is fully programmableover
RS-232-C
’or opti0rlal GPIBinterfaces. Plotter drivers enablecolor archiving
via a wide rangeof digital plotters.
FEATURES
Extensive Signal Averaging- Twooperation
modes:
¯ Summationaveraging up to 1,000,000 waveforms
¯ Continuous averaging with weighting factors up
to 128.
Averages up to 100,000 words/see in summation
mode.
Offset Dithering- Improvesthe vertical resolution
for low-noise measurements
by several bits in
summationaveraging mode.Reducesthe effect of
ADC
differential non-linearities.
Artifact Rejection- Rejects waveformsthat
exceed the dynamic range of the ADCto ensure
statistical validity of summed
averageresults.
"Extrema"Mode- Keepstrack of time and amplitude drift by storing extremepositive and negative
values, such as glitches, over a programmable
numberof sweeps.
PowerfulArithmetic- Processesaddition, subtraction, multiplication or division on pairs of waveforms stored in the 9400A’smemorylocations
CH1,CH2, C, D and E. Waveformdata can be normalizedby additive or multiplicative constants.
Complex
Functions- Computesintegration, differentiation, square, squareroot and negation on
single waveformsstored in the 9400Amemorylocations CH1, CH2,C, D and E. Waveformdata can be
multiplied by constants.
Smoothing- Allows two smoothing modesto
reduce unwantednoise on single events:
¯ Meanvalue smoothing downto 50 segments
¯ N-point smoothingwith up to 9-point filter.
Vertical Expansion- Provides vertical scale expansion by a factor of up to 10 in signal averaging
mode.
Chainingof Operations- Automatically chains two
operations.
Example: F(E) = Average (CH1-CH2).
An indefinite numberof operations can be performedsequentially, either manuallyor via remote
control.
Remote
Control - Controls remotely all front-panel
settings, as well as all waveformprocessingoptions
via either GPIBor RS-232-Cinterfaces.
ColorArchiving- Copiesscreen in color using a
widerangeof digital plotters.
FUNCTIONALDESCRIPTION
WP01,an optional waveformprocessing firmware
packagefor the 9400ADigital Oscilloscope, is optimizedfor processingsignals in real time. The
powerful 68000-basedsystem permits rapid representation of processedresults such as averages,
differentiations, multiplications, integrations and
smoothing of waveforms.
Waveformoperations can be performed on live or
stored signals, or a combinationof both. Theyare
selected through simple menus,and it is even possible to chain themand computefor examplethe integral of the multiplication of two traces, or averagethe
difference of CH1and CH2.
WP01includes an additional 512 kilobytes random
access memoryfor accumulation, computation and
waveformbuffering. It permits the accumulationof up
to 1,000,000 waveformsof 32000points each.
All processing occurs in waveformmemoriesE and F
which maybe displayed on the screen by pressing
FUNCTION
E, F buttons. Wheneverone of the FUNCTIONSE or F or their expansions (EXPAND
A or B)
turned on, the corresponding waveformprocessing is
executedand the result displayed.
SIGNAL AVERAGING
WP01offers two powerful, high-speed signal
averaging modesto improve signal-to-noise ratio and
provide more accurate measurements.Averaging
increases the dynamicrange by several bits, allowing
the sensitivity to reach#Volts.
Summed
averagingconsists of the repeated addition,
with equal weight, of recurrencesof the selected
source waveform. Wheneverthe required numberof
waveformsis reached, the averaging process will
stop. The total numberof waveformsto be accumulated can be selected between10 and 1,000,000
sweepsin a 1-2-5 sequence.Signals exceeding the
dynamicrange of the 9400A’s 8-bit ADCat any point
maybe automatically rejected to ensure valid summed
averagingresults.
The user mayalso chooseto ,,dither,, the programmableoffset of the input amplifier. Dithering uses
slightly different portions of the ADCfor successive
waveforms
so that the differential non-linearities are
averaged.As a result, in a low-noise application, the
measurementprecision and dynamic range are
improved.
Continuousaveraging, sometimescalled exponential
averaging, consists of the repeated weighted average
of the source waveformwith the previous average.
This modeof averaging is a continuous process. The
effect of previous waveformsgradually tends to zero.
Relative weighting factors can be chosenfrom 1:1 to
1:127. This averagingmodeis most useful for setting
up measurements
or observing noisy signals that
changewith time.
EXTREMAMODE
Trackingrare glitches or monitoringsignals drifting in
time and amplitude is madeeasy with the unique
EXTREMA
mode. The computation of extrema consists
of a repeated comparisonof recurrences of the source
waveformwith the accumulated extrema waveform.
Whenevera given data point of the new waveform
exceedsthe existing data point of the accumulated
extremawaveformit replaces it. In this waythe maximumand/or minimumenvelope of all waveformsis
accumulated up to a maximum
of 1,000,000 sweeps.
ARITHMETIC
WP01
also offers basic arithmetic operations such as
addition, subtraction, division, andmultiplication.
Thesearithmetic functions can be performed on two
source waveformson a point by point basis. Different
vertical gains and offsets of the two sourcesare automatically taken into account. However,both source
waveformsmust have the sametime-base setting. The
first waveformmaybe multiplied by a constant factor
and offset by a constant.
MATHEMATICALFUNCTIONS
Mathematicalfunctions such as negation, square,
squareroot, integral and differentiation are performed
on a single source waveform. The waveformmaybe
multiplied by a constant factor and maybe offset by a
constant. Arithmetical and mathematicalfunctions may
be chained by using memoryC and D.
SMOOTHING
WP01provides two types of smoothing to decrease
signal noise of single transient acquisitions.
Meanvalue smoothing
divides the acquired signal
into a chosen numberof segmentsand then generates the smoothedwaveformin which each displayed
point correspondsto the meanvalue of "n" points
contained in the corresponding segment. The number
of segments can be between 50 and 32000. Mean
value smoothingtakes all digitized points on the
screen into account.
N-point smoothingapplies a moving average of N
points symmetrically placed around each of the 50 to
32000selected points for display.
Eachselected point Yk is replaced in the smoothed
waveformby a processed point Y’k corresponding to:
(N-1)/2
C(n) Y(k+n)
Y’ (k) =
n= -(N-1)/2
where,in caseof a 3-point filter,
N -- 3; C1 --- 1/4; Co -- 1/2; C1 = 1/4
The numberof points N can be selected to be 3, 5, 7
or 9.
SPECIFICATIONS
SUMMATION AVERAGING
Numberof sweeps:10 to 1,000,000 can be selected
in a 1-2-5 sequence.
Numberof points averagedover CH1, CH2:50to
32000in 10 steps.
Offset dithering: up to 6 LSBsmaybe chosen.
Artifact Rejection: ON/OFF
Theoretical signal-to-noise improvement
achievable:
57 dB.
Vertical expansion: 10 times maximum.
Maximum
sensitivity: 500/~V/div after vertical
expansion.
CONTINUOUS AVERAGING
Number
of sweeps:infinite.
Weighting
factors selectable:1:1, 1:3, 1:7, 1:15, 1:31,
1:127.
Number
of points averaged:50 to 32000in 10 steps.
Vertical expansion:10 times maximum.
Maximum
sensitivity: 500/JV/div after vertical
expansion.
AVERAGING SPEED
The figures below assumethat the display time
betweentriggers is negligible:
recordlength
(= of points)
32000
25000
12500
6250
2500
1250
625
250
125
50
summation
(sweeps/sec)
3
4
6
13
32
51
73
100
112
118
In interleaved samplingmode,the averaging speedis
reduced as moresignals are required to complete a
displayed waveform.
WAVEFORMARITHMETIC
Addition, subtraction, multiplication, and ratio can be
performed on two live waveformsfrom CH1and CH2,
or from stored waveformsin memoriesC, D and E.
Example: E = CH1 - CH2
F = CH2* D
F=CH1 +E
Numberof points processed:from 50 to 32000 can
be selected in 10 steps.
Multiplicative constants:from 0.01 to 9.99 can
be selected in steps of 0.01.
Additive constant:from - 9.99 to 9.99 divisions can
be selected in steps of 0.01.
Vertical expansion:2 times maximum.
Typical executiontime for 1250 points: 600 msec.
WAVEFORM FUNCTIONS
Integration, differentiation, square,squareroot,
negation(invert).
Examples: E=./’ CH1dt
F = - CH2
E= dD
dt
Numberof points processed:from 50 to 32000 can
be selected in 10 steps.
Multiplicative constants:from 0.01 to 9.99 can be
selectedin steps of 0.01.
Additive constant:from -9.99 divisions to 9.99
divisions can be selected in steps of 0.01.
Vertical expansion:2 times maximum.
Typical executiontime for 1250points:
400-1000 msec.
MEAN VALUE SMOOTHING
Numberof adjacent blocks processed:50 to 32000in
10 steps,
Number
of points per block: varies with the time base
and the numberof blocks selected,
Typical executiontime for 1250 points: 700 msec.
N-POINT SMOOTHING
Filter coefficients with weightingfactors for successive
data points:
3 point - (1:2:1) 1/4
5 point - (1:4:6:4:1) 1/16
7 point - (1:6:15:20:15:6:1)1/64
9 point- (1:8:28:56:70:56:28:8:1) 1/256.
Number
of points processed: 50 to 32000in 10 steps.
Vertical expansion:2 times maximum.
Typical execution time of 1250 points: 500 msec.
Numberof sweeps:selected in a 1-2-5 sequence
from 1 up to 1,000,000.
Number
of points processed: 50 to 32000in 10 steps.
Glitches as short as 10 nsec or 0.04%of the timebase setting are displayed.
Vertical expansion:2 times maximum.
Typical executiontime for 1250points: 300 msec.
CHAINING OF OPERATIONS
Twofunctions can be automatically chained using
functions E and F.
Example: E = CH1 - CH2
F = summedaverage of E
Manualchaining using memoryC and D for
intermediateresults maycontinueindefinitely.
REMOTE CONTROL
All front-panel controls and WaveformProcessing
functions are fully programmable
via either the
9400A’s GPIBor RS-232-Cinterfaces. Simple Englishlike mnemonics
are used.
EXTREMA MODE
Logs all extremevalues of a waveformover a programmable number of sweeps. Maximaand minima
are displayed separately by ROOFand FLOOR
traces.
STORED FRONT PANELS
Upto 7 front-panel setups, including WP01menus,
can be stored and recalled by the menubuttons at
the left side of the 9400Ascreen.
The+_ 1 V amplitude sine wavein channel1 (upper trace) is squared
(function E: 1 * 1, lower trace) andthen integrated (functions F:IE).
Thevalue of the integral betweenthe two cursors is 4.00 pV2s. the
RMSvalue can be calculated with the formula RMS=
1/2 = 0.707V.
( 1_. ,/" V2dt)I/2 In this case:RMS
= (1. 414V2s)
8ps
At
A fast negativegoing signal at 5 nsec/div (upper trace) recorded
Random
Interleaved Samplingmodeis inverted and stored in
memory
C (lower trace). Integral and differential are shown
function E andfunction F. Thearea underthe inverted curve is
measured
by first defining the area with the time cursors and then
readingthe valueof C, In this case:11.44nVs.
LeCroy
Innovators in Instrumentation
LeCROY CORPORATEHEADQUARTERS
700 Chestnut Ridge Road
Chestnut Ridge, NY 10977-6499
Telephone:(914) 578-6097
800-5-LeCroy(532 769)
TWX:(710) 577-2832
Fax: (914) 425-8967
LeCROY EUROPEANHEADQUARTERS
Route du Nant-d’Avri1101
P.O. Box 341
1217 Meyrin 1-Geneva,Switzerland
Telephone:(022) 823355 Telex: 419058
Fax: (022) 823915
Othersales and service representativesthroughoutthe world.
Copyright© January1989LeCroyis the registered trademarkof LeCroyCorporationAll rights reserved¯ Informationin this publication supersedes
all earlier versions. Specifications subject to change
withoutnotice
TDS013/QO2
FAST FOURIER PROCESSINGPACKAGE
25,000 POINT TRANSFORMS,
SPECTRAL
AVERAGING
LeCroy
WP02 SPECTRUMANALYSIS FIRMWARE
FOR MODEL9400A DIGITAL OSCILLOSCOPE
9400AWP02
¯ 50to 25,000
pointFFTs
over
Two
Channels
Simultaneously
¯ Frequency
Resolution
from
1 Milli-Hzto 50MHz
¯ Upto 5 GS/sec
Sampling
Rate
¯ Time
andFrequency
Domain
Averaging
Wide
selection
of FFTDisplay
Formats
andWindow
Functions
~nodulated
signal (top trace) is analyzed
in the frequency
domain
usingthe 9400A’s
FFT
~cessingcapability whichprovidespower(middle)andmagnitude
(lower) information.
5idelobes6 kHzfromthe fundamental
frequency
are clearly visible.
FREQUENCYDOMAIN
MEASUREMENTS
AND ANALYSIS
The WP02Spectrum Analysis Firmware Package brings powerful FFT
routines to extend the capabilities of the 9400ADigital Oscilloscope into
frequency domain measurementand analysis. It is available as an option,
or maybe retrofitted.
The LeCroy 9400A provides 175 MHz bandwidth, 100 megasamples/sec
8-bit ADCs, +2% DC accuracy (+__1% optional),
32K memory per channel,
and up to 192K of waveform storage memory. It is fully programmable over
RS-232-Cor optional GPIB interfaces. Plotter drivers enable color archiving
via a wide range of digital plotters.
FEATURES
LongRecordTransforms- Extremely long record
FFTs(up to 25,000 points) provide significant
signal-to-noise ratio improvementon single
phenomena.
FrequencyDomainAveraging- Averages up to
200 FFTresults to reduce base-line noise and
allows analysis of phase-incoherentand nontriggerable noisy signals.
WideBandFrequencyDomainAnalysis - Covers
wide DCto 175 MHzbandwidth with high
resolution in the frequencydomain.
Time DomainAveraging- Can increase the
dynamic range up to 72 dB or more when
averagingreal-time signals prior to FFTexecution.
Offset dithering helps to improve dynamicrange
and reduces ADCnon-linearity effects.
High SamplingRates - Up to 5 gigasamples/sec
effectively eliminatesatiasing errors.
BroadSpectrumCoverage- Executes FFTs over
record lengths as long as 25,000 data points
giving up to 12,500 spectral componentsat almost
any samplingrate.
Dual Input Channels- Both input channels can be
analyzed simultaneously to allow comparisonof
independent signals for common
frequencydomaincharacteristics.
Fast Processing- FFTsare processed and
displayedrapidly, e.g. a 1,250 point waveformis
transformedin less than 1.75 sec, a 50 point
waveformwithin 300 msec.
Versatile Display Formats- Frequency-domain
data maybe presented as magnitude, phase, real,
imaginary, log-power, Iog-PSD(power spectral
density); and all maybe selected via menuoptions
after signal capture.
StandardWindow
Functions- Rectangular for
transient signals; von Hann(Harming) and
Hamming
for continuous waveformdata; Flattop for
accurate amplitude measurements;BlackmanHarris for maximum
frequency resolution.
User-definable Window
Functions- Specially
defined windowfunctions can be loaded over GPIB
and stored in the 9400A’s reference memories.
CalibratedVertical Scaling- Flattop truncation
windowprovides precisely calibrated vertical
scaling for all spectral components.
FrequencyCursors- Cursors give up to 0.008%
frequency resolution and measurepower or
voltage differences to 0.2%of full scale.
AutomaticDCSuppression- DCsignal
componentsmaybe suppressed automatically
prior to FFTexecution (menuselected).
Full Documentation
- The 9400ADigital
Oscilloscope status in the FrequencyDomainis
fully documentedon one comprehensivedisplay
page specifying Nyquist frequency, numberof
points, vertical scaling, windowfunction, etc.
Chainingof Operations- Chains two operations
automatically, e.g. Function F = FFTof
(CH1 X CH2). Any numberof operations may
performedsequentially, either manuallyor via
remotecontrol.
Full Remote
Control- All front-panel settings and
waveformprocessing functions are programmable
via GPIBand/or RS-232-Cinterfaces. Acquired
and processed waveforms can be downloadedto a
computerand can later be retrieved and displayed
on the 9400A.
ColorArchiving- Provides color hard copies of
the screen, using a wide range of digital plotters.
FFT BRINGS STRONGSPECTRALANALYSISCAPABILITIES
TO THE 9400A
POWERFUL PERFORMANCEIN A WIDE RANGE
OF APPLICATIONS
The versatility and performanceof the WP02-FFT
packagewith the 9400Amakeit an ideal tool for a
variety of applications suchas:
Electronic engineering- As a very high performance
spectrumanalyzer it is extremely useful for measuring
phasenoise, characterizing filters, amplifier bandwidth
roll-off, or harmonic
distortion.
Communications
- The FFTanalyzer is ideal for
characterizing HFlinks, modems
and data links, cable
TV, PCM,fiber optics, etc.
Acousticdevices- Covers the entire audio spectrum
in one FFT operation from 25 kHz downwardswith
2 Hz resolution.
Preventive maintenancesystems- With a motion
transducer (accelerometers/velocity and/or
displacement transducers), the 9400AWP02
package
can be used to analyze the vibration signatures of
rotating and reciprocating machineryfor early
detection of wear or damage.
Non-destructivetest engineering- The high
bandwidth and sampling rate of the 9400A, together
with its long memories,makeit a valuable instrument
for ultrasound non-destructive testing. "Long record
FFTs"provide unprecedentedspectral resolution,
henceimprovedcharacterization of the material under
test, and muchshorter measuringtimes.
X-(FFT(2))
.2MHz10mY
Ch 1 20 mV ~
T/dry20 ~s Ch 2>~]mV
Trlg-1.56dLv+ CHAN2 =
A 2 MHzsignal is frequency modulatedwith a 99 kHzsine wave. To
improvethe signal-to-noise ratio on the phase-incoherentFMsignal,
spectral averagingof 64 spectra is used(bottomtrace). Thepart
the spectrumat the right-hand side is the 2nd harmonicof the carrier
with sidebands.
Longrecords allow higher samplingrates, to reducealiasing. A
110 kHzsquare wave is recorded over 1250and 6250points with
samplingrates of 200 and 40 nsec/point respectively. Thebottom
trace, a short record transform, has considerablealiasing whereas
the longer record transform(top) is alias-free.
TheFFT menudocumentsall the relevant parameters.
LeCroy
Innovators in Instrumentation
LeCROY CORPORATE HEADQUARTERS
700 Chestnut Ridge Road
Chestnut Ridge, NY 10977-6499
Telephone: (914) 425-2000
TWX:(710) 577-2832
Fax: (914) 425-8967
LeCROY EUROPEAN HEADQUARTERS
2, rue [email protected]
P.O. Box 341
1217 Meyrin 1-Geneva, Switzerland
Telephone: (022) 719 21 11 Telex: 41 90
Fax: (022) 782 39
Other sales and service representatives throughoutthe world.
[email protected]
is the registeredtrademark
of LeCroy
Corporation.
All rights reserved,informationin this publicationsupersedes
all earlier versions.Specificationssubject
to change
withoutnotice.
TOS013/003
FUNCTIONAL DESCRIPTION
FOURIER PROCESSING
Fourier processing is a mathematicaltechnique
which permits a time-domain waveformto be
described in terms of frequency-domainmagnitude
and phase, or real and imaginary spectra. In spectral analysis, a waveformcan be sampledand digitized, then transformedby a discrete Fourier transform (DFT). Fast Fourier Transformsare a set of
algorithms used to reduce the computation time
(by better than a factor of 100 for a 1000point
FFT) neededto evaluate a DFT. Theprincipal
advantageof the FFTis the rapidity with whichit
can analyze large quantities of waveformsamples.
In effect, using standard measurement
techniques,
it converts a time-domaininstrument into digital
spectrumanalyzer.
The WP02Fast Fourier Processing Packageenhances
the outstanding features of the LeCroy9400ADigital
Oscilloscope. It provides high resolution, wide-band
spectrumanalysis capabilities along with sophisticated windowfunctions and fast processing.
FFT AND THE LeCROY 9400A DIGITAL
OSCILLOSCOPE
In FFT mode, the 9400Aprovides measurementcapabilities superior to those of common
swept spectrum
analyzers.
In particular, it is nowpossible to performspectral
analysis on continuous and single events at an economicprice. Andit enables users to obtain time and
frequency values simultaneously and to compare
phases of the various frequency componentswith
each other. Rather than the commonlyused "power of
two" record lengths the routines used in the WP02
packagefeature decimal record lengths, which can be
selected in a 1-2-5 order. Resulting spectra are therefore also calibrated in convenientdecimal Hertz
values.
TheFFT’s digital nature ensureshigh accuracy, stability and repeatability. Theseare strongly supportedby
the 9400A’s superb DCand dynamic accuracy specifications, such as standard +2%,optional 4-1%, DC
accuracy, high effective-bit count and increased resolution through signal averagingand dithering.
With the 9400A, signals maybe acquired and processed simultaneously using Channels1 and 2. This is
particularly useful whenlooking for common
frequency-domain
characteristics in both signals or for
characterization of networks.
IMPROVED RESOLUTION
The Fast Fourier Transformcalculates equally-spaced
frequency componentsfrom DC to the full 9400A
bandwidth.By lowering the samplingrate, it is possible to makemeasurements
with 1 milli-Hertz resolution up to 12,5 Hz (Nyquist). By increasing the sampling rate to 5 gigasamples/sec(200 psec/point)
Random
Interleaved Sampling mode,the widest resolution becomes50 MHzand the Nyquist frequency
2.5 GHz... comfortably abovethe highest frequency
componentsrecordable by the 9400A,thus virtually
eliminatingaliasing effects.
VERSATILE WINDOWFUNCTIONS
The WP02-FFT
software provides a selection of windowfunctions, designed to minimize leakage and to
maximizespectral resolution of single and non-cyclic
events. Theseinclude the familiar rectangular or
unmodifiedwindowtypically used for transient events,
the von Harm(Planning) and Hammingwindowsfor
continuoussignals, and, in addition, Flattop and
Blackman-Harris windowsfor more precise amplitude
(power) measurements
or strong suppression of side
lobes respectively.
Furthermore, user-defined windowfunctions maybe
loaded onto the 9400Avia the GPIBinterface. Through
multiplication, they modify the acquiredsignal followed by FFT in an automatedfashion.
SPECIFICATIONS
VERTICAL ANALOG SECTION
Inputs: two; BNCconnectors.
Sensitivity: 5 mV/divto 1 V/div at 50 £~ impedance
and 5 mV/div to 5 V/div at 1 M£) impedance;detents
at 1-2-5, variable 1:2.5.
DCaccuracy:standard <_ _+ 2%; optional _< _+ 1°.
Bandwidth
(-3 dB):
@50 (5: DC- 175 MHzat 10 mV/div, up to
225 MHzat 1 V/div;
DC- 150 MHzat 5 mV/div.
@1M~2AC: 10 Hz-100 MHztypical
@1M~ DC: DC-100 MHztypical
Bandwidth
limiter: 30 MHz(-3 dB).
Input impedance:
1 M£~//50pF and 50 £2
characteristic.
Maximum
input: 250 V (DC + peak AC) at 1 M~
5 V DC(500 mW)or 4- 10 V peak ACat 50 ~2.
Offset: _+ 8 divisions in 0.04-division increments.
MEMORIES
Acquisition memory:
32K x 8 bits per channel
(CH1 and CH2).
Referencememory:
32K x 16 bits per reference
memory(C and D).
Functionmemory:32Kx 16 bits per function memory
(E andF).
The content of the acquisition and function memories
can be stored in reference memoriesC and D.
Recordlength selection for FFT
Function memoriesE and F only: 50-25000data
points in 9 steps in 1-2-5 sequence.Recordlengths
are selected by decimationafter signal acquisition.
This implies that the Nyquist criterion can be adjusted
and optimizedafter signal acquisition and prior to FFT
execution.
REMOTE
CONTROL
All front-panel
controls and WP01and WP02
processing functions are fully programmable via the
9400A GPIB and RS-232-C interfaces.
Simple
English-like
mnemonicsare used.
STORED
Blackman-Harris
FRONT PANELS
Up to 7 front-panel setups, including WP01and WP02
menu settings can be stored and recalled by the
menubuttons at the left side of the 9400A screen.
WP02-FFT
INSTALLATION
A WP02-FFTpackage may be retrofitted
to a LeCroy
9400A Digital Oscilloscope. The WP01Signal
Processing hardware and software is a prerequisite
for installation of WP02.
Flattop
Hamming
Longrecordsgive widefrequencyspan.FFTof 1000Hzsineamplitudemodulated
squarewave,recordedover 25,000points,
showsharmonicsup to 25 kHz. Expansion
showssidebandsat 10 Hz
and-30.1 dB.
ORDERING
vonHann(Hanning)
Thesumof two 1 V p-p sinusoidsof 500kHzand527.5kHzis
digitized over2,500points andtransformed
to the frequency
domain.
4 different window
functionsareappliedto indicatetheir effect on
leakagesuppression
andspectralresolution.Thevertical scalefactor
is 10dB/div,80dBm
full scale.
INFORMATION
Oscilloscope and Options
Description
Code
Digital Oscilloscope
9400A
9400AOP01 High-precisionoption (+_ 1%DCaccuracy)
processingoption
9400AWP01 Waveform
9400AWP02 Fast Fourierprocessing
option(requires
9400AWP01
)
9400AMS01 Massstorageandremotecontrol package,
includinganIBMlap-topcontroller, interface,
cablesandsoftware
9400AIM01 GPIBinterface for IBM-PCC
computers
Oscilloscope
Accessories
OM9400A Operator’sManual
SM9400A Service Manual
Camera
(using Polaroidfilm) andHood
CA9001
CA9002
Cameraadapter (35 mm)with Hood
CS9400
CertifiedCalibration
DP9001
Digital Plotter, 8-penA4size
OC9001
OscilloscopeCart
RM9400
AdapterKit for RackMounting
SG9001
High-voltage
protector
TC9001
Transit Case
TC9002
ProtectiveCover
FREQUENCY
Frequencyrange: DCto > 175 MHz.
Frequencyresolution: 1 mHzto 50 MHz.
Nyquist frequencyrange: 25 mHzto 2.5 GHz.
Frequency
scale factors; 5 mHz/divto 500 MHz/divin
1-2-5 sequence.
Frequencyaccuracy:0.008%at center lobe.
Horizontalexpansion:up to 100 times.
Cursors:Differential (arrows) and absolute (crosshair)
provide frequency and related amplitude measurements.
AMPLITUDE AND PHASE
General
Amplitudeaccuracy:see windowfunctions table below.
Signal overflow:A warningindication is provided at
the top of the 9400Adisplay whenthe input signal
exceeds the ADCrange.
DCsuppression: selected via the menu(ON/OFF),
removesDCcomponentprior to FFT execution.
Cursors:Horizontal bars provide differential amplitude
measurements.
Numberof traces: Time domain and frequency
domaindata can be displayed simultaneously (up to
4 traces).
Spectrum Display Formats and Scaling
Realspectrum,in V/div, zero baseline at 0 div (center
of screen).
Imaginaryspectrumin V/div, zero base line at 0 div.
Powerspectrum in dBm.
Powerspectral density in dBm.
FrequencyDomainAveragingup to 200 spectra for
power, PSDor magnitude.
Logdisplay applies to powerand PSDspectra in
10, 5, 2 or 1 dB/div; 80 clB display range.
Markersat left edgeof screen give absolute dBm
reference (0 dBmis 1 mWinto 50 ~).
Phase
Phaserange: + 180 degrees to - 180 degrees.
Phaseaccuracy:___ 5 degrees.
Phasescale factor: 50 degrees/div.
Zerobaseline: 0 div (center of screen).
Calibrated Vertical Expansion
All spectra formats, up to 10 times, in 1-2-5 sequence.
Window Functions
Selected in menu:Rectangular, von Hann(Hanning),
Hamming,Flattop, Blackman-Harris and user
definable. The table belowgives filter passband
shapeand resolution:
FILTER PASS BAND AND RESOLUTION
Filter band.
widthat Highest Scallop Noiseband6dB
sidelobe Loss
width
Window
type
(freq. bins) (dB) (dB at bin) (freq. bins)
Rec--13
3.92
1.0
tangular
1.21
1.42
1.5
von Hann 2.00
--32
Hamming 1.81
--43
1.78
1.36
2.96
Flattop
1.78
--44
0.01
1.13
1.71
Blackman. 1.81
--67
Harris
Definitions
Filter bandwidthat -6dB characterizes the frequency
resolutionof the filter.
Highestside lobe indicates the reduction in leakage
of signal componentsinto neighboring frequency bins.
Scallop loss gives amplitude accuracy of the
magnitude spectrum.
Noise bandwidthis the bandwidthof an equivalent
rectangularfilter.
FFT EXECUTION TIME
FFTexecution times, including windowcalculations
and display generation, are provided in the graph
below:
/
z.c
/
,_0
v
LU
5-
X
L~
u_
jJ
/
/
/
/
m
50
125
250
625
1250
2500
6250
12500
25000
RECORDLENGTH (Points)
WP01 SIGNAL AVERAGING/ARITHMETIC
PROCESSING
(Prerequisite
for WP02)
Summation
averaging: 10-1,000,000 signals.
Continuous
averaging:infinite numberof signals,
weightingfactors 1, 3, 7, 15, 63, 31,127.
Waveform
arithmetic: +, -, *, +.
Waveform
functions:integration, differentiation,
square, squareroot, negation(inversion).
Smoothing:
1-, 3-, 5-, 7-, 9-point filters.
Extrema:records extreme values (envelopes) over
programmablenumber of sweeps.
CHAINING OF OPERATIONS
Twofunctions can be automatically chained using
functions E and F.
Examples: fnE = CH1* CH2
fnF = FFTof fnE
fnE = FFT of CH1
fnF = Integral fnE
Manualchaining using memoriesC and D for
intermediateresults maycontinue indefinitely.
SECTION I
GENERAL INFORMATION
I.I
Warranty
LeCroy
warrants
its oscilloscope
products
to operate
within
specifications under normal use, and services them for a period of two
years from the date of shipment. Spares, replacement parts and repairs
are warranted for 90 days. Software is thoroughly
tested but is
supplied "as is" with no warranty of any kind covering detailed
performance. Accessory products not manufactured by LeCroy are covered
solely by the warranty of the original equipment manufacturer.
In exercising this warranty, LeCroy will repair or, at its option,
replace any product returned to the Customer Service Department or an
authorized service facility within the warranty period, provided that
the warrantor’s examination discloses that the product is defective due
to workmanship or materials, and that the defect has not been caused by
misuse, neglect, accident or abnormal conditions or operation.
The purchaser is responsible for the transportation
and insurance
charges arising from the return of products to the servicing facility.
LeCroy will return all in-warranty
products with transportation
prepaid.
This warranty is in lieu of all other warranties, expressed or implied,
including but not limited to any implied warranty of merchantability,
fitness, or adequacy for any particular purpose or use. LeCroy shall
not be liable for any special, incidental, or consequential damages,
whether in contract, or otherwise.
1.2
Assistance
and Maintenance
Agreements
Answers to questions concerning installation, calibration, and use of
LeCroy equipment are available from the Customer Service Department,
700 Chestnut Ridge Road, Chestnut Ridge, New York 10977-6499, U.S.A.,
(914)578-6097, and I01 Route du Nant drAvril, 1217 Meyrin i, Geneva,
Switzerland, (41)22/782-33-55, or your local field engineering office.
LeCroy offers a selection of customer support services. For example,
maintenance agreements provide extended warranty and allow the customer
to budget maintenance costs after the initial two year warranty has
expired. Other services requested by the customer such as installation,
training, on-site repair, and addition of engineering improvements are
made available through specific Supplemental Support Agreements.
General Information
I-i
1.3
Documentation
Discrepancies
LeCroy is committed
to providing
state-of-the-art
instrumentation
and
is continually
refining
and improving
the performance
of its products.
While physical
modifications
can be implemented
quite
rapidly,
the
corrected
documentation
frequently
requires
more time
to produce.
Consequently,
this
manual
may not agree
in every
detail
with
the
accompanying
product.
There may be small discrepancies
in the values
of
components
for the purposes
of pulse
shape,
timing,
offset,
etc.,
and,
occasionally,
minor
logic
changes.
Where any such inconsistencies
exist,
please
be assured
that
the unit
is correct
and incorporates
the
most up-to-date
circuitry.
1.4
Service
Procedure
Products
requiring
maintenance
should
be returned
to the Customer
Service
Department
or authorized
service
facility.
If under warranty,
LeCroy will
repair
or replace
the product
at no charge.
The purchaser
is only responsible
for the transportation
charges
arising
from return
of the goods to the service
facility.
For all LeCroy products in need of repair after the warranty period,
the customer must provide a Purchase Order Number before any equipment
which does not operate correctly can be repaired or replaced. The
customer will be billed for the parts and labor for the repair as well
as for shipping.
1.5
Return
Procedure
To determine
your nearest
authorized
service
facility,
contact
the
factory
or your field
office.
All products
returned
for repair
should
be identified
by the model and serial
numbers and include
a description
of the defect
or failure,
name and phone number of the user,
and,
in
the case of products
returned
to the factory,
a Return
Authorization
Number (RAN).
The RAN may be obtained
by contacting
the Customer
Services
Department
in New York on 914-578-6059,
in Geneva
on
(022) 782-33-55
or your nearest
sales
office.
Return shipments should be made prepaid. LeCroy will not accept C.O.D.
or Collect Return Shipments. Air-freight is generally recommended.
Wherever possible, the original shipping carton should be used. If a
substitute carton is used it should be rigid, and should be packed such
product is surrounded with a minimum of four inches of
that the
excelsior or a similar shock-absorbing material. In addressing the
shipment, it is important that the Return Authorization Number be
displayed on the outside of the container to ensure its prompt routing
to the proper department within LeCroy.
General Information
1-2
1.6
Initial
Inspection
It is recommended that the shipment be thoroughly inspected immediately
upon delivery to the purchaser. All material in the container should be
checked against the enclosed Packing List. LeCroy cannot accept
responsibility for shortages in comparison with the Packing List unless
notified promptly. If the shipment is damaged in any way, please
contact the factory or local field office immediately.
General Information
1-3
SECTION 2
PRODUCTDESCRIPTION
2.1
Introduction
The LeCroy 9400A is a high-performance digital oscilloscope suited to
research and to test and measurement applications.
It is used to
capture, analyze, display and archive electrical waveforms in fields
such as electronic engineering, physics research, automated testing and
measurement, telecommunications, electromagnetic pulse and interference
measurement, LIDAR technology and ultrasonics research.
2.2
9400A Architecture
The 9400A has been built around the powerful 68000 microprocessor which
is used by the unit to perform computations and control oscilloscope
operation.
Att~uator
AC
Amplifier
5omple 4.
hold
Offsel Gain
AOC
Acqulsition
memory
Processor +
interfaces
....
r15112C
""
!
9400A BLOCK DIAGRAM
Figure 2.1
Product Description
2-1
All front panel rotary
knobs and push buttons
are constantly
monitored
by the internal
processor,
and front
panel
setups
are rapidly
reconfigured
via the unit’s
internal
16-bit
bus. Data are quickly
processed
according
to the selected
front
panel
setups,
and are
transferred
to the acquisition
memory for direct
waveform display
or
stored in the 9400A’s reference
memories.
The 68000 controls
the unit’s
two RS-232-C ports
which are used to
directly
interface
the 9400A to a digital
plotter,
remote terminal
or
other slow-speed
device and also controls
GPIB (IEEE-488)
operation
when the 9400A is equipped with the I/O option,
OP02.
2.3
ADCs and Memories
The 9400A’s two identical input channels are equipped with a
I00 megasample/second (megasample/sec), 8-bit ADC and a 32 kiloword
acquisitionmemory (See Figure 2.1). This dual ADC architectureensures
absolute amplitude and phase correlation, maximum ADC performance for
both single and dual channel acquisition modes, large record lengths
and high time resolution.
The 9400A’s two 32K acquisition memories simplify transient capture by
providing very long waveform records that capture waveform features
even when trigger timing is uncertain. In addition, very accurate time
measurement is made possible by a digitally controlled zoom providing
an expansion factor of up to I00 times the time base speed.
The 9400A oscilloscope
is capable of acquiring
and storing
repetitive
signals
at a Random Interleaved
Sampling rate of 5 gigasamples/second
(gigasamples/sec).
An exclusive
high-precision
time digitizing
technique
enables measurement of repetitive
signals
to a bandwidth of
175 MHz at an effective
measuring interval
of 200 psec.
The 9400A’s very low aperture
uncertainty
of 10 psec assures precision
measurements over its entire
range as indicated
by the table below:
Overall*
Input
dynamic accuracy
Frequency
Signal-to-noise
Effective
bits
(MHz)
Ratio
(typical),
1
RMS sine
wave curve
fit
10
50
100
175
(dB) 41.9
41.9
41.9
37.1
29.9
7.0
7.0
7.0
6.2
5.0
* including the front-end amplifier,sample and hold and ADC
9400A PERFORMANCE
Table 2.1
Product
2-2
Description
2.4
Trigger
The 9400A’s digitally-controlled trigger system offers facilities such
as pre-trigger recording, bi-slope and window triggering, sequence and
roll modes in addition to the standard operating modes of Auto, Normal
and Single (Hold). The trigger source can be external or can be either
of the two inputs, and the coupling is selected from AC, LF REJect,
HF REJect and DC.
2.5
Automatic
Calibration
The 9400A has an automatic calibration facility that ensures overall
vertical accuracies of ± 2% (optionally ± 1%) and ± 20 psec RMS for the
unit’s crystal-controlled time base.
The time base is calibrated each time the 9400A’s time base control is
adjusted
to a new TIME/DIV
setting;
vertical
gain and offset
calibration take place each time the front panel fixed gain control for
either CHAN i or CHAN 2 is adjusted to a new VOLTS/DIV setting.
Calibration of both channels also takes place each time the BANDWIDTH
LIMIT push button is pressed.
Further information
on automatic
Section 9.4, "Auto-calibration".
2.6
calibration
may
be found
in
Display
The 9400A’s large 12.5 cm x 17.5 cm (5 x 7 inches) screen displays
analog waveforms with high precision and serves as an interactive,
user-friendly interface via a set of screen-oriented
push buttons
located immediately to the left and right of the CRT.
The oscilloscope displays up to four waveforms, while simultaneously
reporting the parameters controlling signal acquisition. In addition,
the screen presents internal status and measurement results, as well as
operational, measurement, and waveform analysis menus.
A hard copy of the 9400A’s screen is available via the unit’s dedicated
plotter port.
2.7
Manual and Programmed
Control
The 9400A’s front panel layout and operation will be very familiar to
users of analog oscilloscopes. The interactive software menus assist in
quickly utilizing the recording and processing capability of the 9400A
to its full potential.
Product Description
2-3
The 9400A has also been designed for remote control operation in
automated testing and computer aided measurement applications. The
entire measurement process, including dynamic modification of front
panel settings and display organization, can be controlled via the rear
panel RS-232-C and optional GPIB (IEEE-488)
ports. GPIB control
enables direct interfacing between the 9400A and a host computer at
data transfer rates of up to 400 kilobytes/sec.
The LeCroy 9400A is capable of storing up to seven front panel setups
which may be recalled either manually or by remote control, thus
ensuring rapid oscilloscope front panel configuration. When the power
is switched on, the 9400A’s front panel settings are the same as when
it was last used.
Product
2-4
Description
SECTION 3
INSTALLATION
3.1
Safety Information
The 9400A has been designed to operate from a single-phase power source
with one of the current-carrying
conductors (neutral conductor)
ground (earth) potential. Operation from power sources in which both
current-carrying conductors are live with respect to ground (such as
phase-to-phase on a tri-phase system) is not recommended, as the 9400A
is equipped with over-current protection for one mains conductor only.
The 9400A is provided with a three-wire electrical cord containing a
three-terminal
polarized plug for mains voltage and safety ground
connection. The plug’s ground terminal is connected directly to the
frame of the unit. For adequate protection against electrical hazard,
this plug must be inserted into a mating outlet containing a safety
ground contact.
3.2
Operating
Voltage
Prior to powering up the unit, make certain that the mains voltage for
your area corresponds to the mains voltage value appearing in the
window of the selector box at the rear of the 9400A.
The operating voltage for the 9400A is either 115 V or 220 V at 48 to
62 Hz. Switching from one mains voltage to another is not possible. If
the mains voltage appearing in the window differs from that used in
your area contact the nearest LeCroy sales office or distributor.
*CAUTION*
If a 9400A set for 115 V is plugged into a 220 V power source, severe
damage can occur. Before powering up the unit, ensure that the corect
line voltage has been set.
Installation
3-i
3.3
Switching
on the
9400A
Switch on the 9400A by setting the POWER switch (26) to the
position.An auto-calibration takes place and the grid is displayed
after approximately 15 seconds.
Note that the 9400A is reset to the configuration it was in prior being
to switched off.
Installation
3-1
SECTION 4
DISPLAY LAYOUT
The 9400A’s CRT area is divided between the centrally located grid and
six other fields. Traces from the acquisition or reference memories are
displayed on the grid. A dual grid system is also available by pressing
push button 14 (see Figure 1.1). The six fields are used to display
such information as interactive menu queries and responses, current
acquisition
parameters,
relative and absolute time and voltage
measurements, and messages to assist the user.
°.
..
DISPLAY LAYOUT
Figure 4.1
4.1
Menu Field (I)
This field is divided into nine sub-fields associated with menu keys
2-10. Each field may display the name of a menu or perform an operation
when the related menu key is pressed. The lowest field and related
Return push button (i0) are used to restore the higher menu level.
Display Layout
4-1
4.2
Time and Frequency
Field
(II)
When the Marker cursor is activated by pressing push button (18), this
field displays the time difference between the Marker cross-hair and
the point of triggering (common for all displayed traces).
When the Time cursors
are activated
by pressing
push button
(17),
two
readings
are indicated.
The left-hand
reading
indicates
the time
interval
between the Reference
and Difference
arrowhead
cursors,
while
the right-hand
reading
indicates
the frequency
corresponding
to 1/(Time
interval).
Trigger Delay
Field
(III)
This
field
indicates
one of the two trigger
delay
modes.
In the
pre-trigger
mode, an upward-pointing
arrow
appears
below the bottom
line
of the
trace
display
grid,
as shown
in Figure
4.1.
It is
adjustable
from 0 to 10 divisions,
corresponding
to a 0 to 100Z
pre-trigger
setting.
In the post-trigger
mode, this
arrow is replaced
by a leftward-pointing
arrow next to the post-trigger
indication
(in
decimal
fractions
of a second)
at the bottom of the grid.
The maximum
post-trigger
setting
corresponds
to 10000 screen
divisions.
4.4
Abridged
Front
Panel
Status
Field
(IV)
This is a short-form display of the data acquisition parameters, and is
updated whenever the 9400A’s front panel controls are manipulated. This
field indicates vertical sensitivities, input couplings, time base and
trigger conditions.
See Section
the absolute
4.5
Displayed
5 for
value
Trace
a detailed
of input
Field
list
offset).
of front
panel
parameters
(including
(V)
The Displayed Trace field is associated with push buttons 45-50. The
data displayed in this field are the identity of the displayed trace,
and the current time base and sensitivity settings for the acquired
signal, as well as an indication of the position of the VAR sensitivity
vernier (28). The symbol ">" appears when the vernier is not in the
detent position (i.e. not in the fully clockwise position). Whenever
Measurement Cursors (16, 17, 18) are activated, absolute or relative
waveform voltage data are displayed in this field.
A frame
formed
around
one of the upper
six
signal
sources
in the
Displayed
Trace field
indicates
which of the traces
is to be acted upon
during
manipulation
of the various
display
controls
((39)
through
(43).
Display
Layout
4-2
4.6
Message Field (VI)
Messages
appearing
in field (Vl) indicate
the 9400A’s
current
acquisition status or report improper manipulation of the front panel
controls. The following figure illustrates a typical message displayed
in the Message field.
Channel1
5~e 20mV
Channel 2
5~ .5 V
Ch~ 20mV
T/dlv 5~m 012 .5 V ~
Trig S.O8dtv+CHAN ~
EXAMPLE of MESSAGE FIELD DISPLAY
Figure 4.2
********
*NOTE*
********
In the following sections, Roman numerals in parentheses refer to the
display field numbering scheme in Figure 4.1. Arabic numerals relate to
the numbering scheme used to refer to front and rear panel controls and
connectors in Figures i.I and 1.2.
Display Layout
4-3
SECTION 5
MANUALOPERATION
5.1
Front-Pmlel
5.1.1
Vertical
Controls
Input Connectors (21) - BNC type connectors are used for both CHAN
and CHAN 2 signal inputs as well as the external trigger connector.
The maximum permissible input voltage is 250 V (DC + peak AC).
Signal Coupling and Input Impedance (22) - Selects the method used
couple a signal to the vertical amplifier input.
Possible selections: AC, GND, or DC with I M~ impedance
DC with 50 ~ impedance
In the AC position, signals are coupled capacitively, thus blocking the
input signal’s DC component and limiting the lower signal frequencies
to < i0 Hz.
In the DC position, all signal frequency components are allowed to pass
through, and the input impedance may be chosen to be I M~ or 50 ~. The
user should note that with I M~ input impedance the bandwidth is
limited to I00 MHz. The maximum dissipation into 50 ~ is 0.5 W, and
signals will automatically be disconnected whenever this occurs. A
warning LED (OVERLD) lights when an overload condition is detected. The
input coupling LED (22) is simultaneously switched to GND. The overload
condition is reset by removing the signal from the input and selecting
a 50 ~ input impedance again.
VOLTS/DIV (27) - Selects the vertical sensitivity factor in a 1-2-5
sequence. The sensitivity range is from 5 mV to 5 V/div at I M~ input
impedance and from 5 mV to I V/div at 50 ~ impedance (when the VAR
vernier (28) is in the detent position, i.e. turned fully clockwise).
Manual Operation
5-1
Menu
C~’1 5mVll
T/d:l.v .2jJ Ch2.5 V Trlg
.2O V - ~ =
DISPLAY of VERTICAL SENSITIVITY PARAMETERS
in the ABRIDGED PANEL STATUS FIELD
Figure 5.1
The VOLTS/DIV setting for CHAN 1 and CHAN 2 is displayed, along with
signal input coupling and various other data, in the Abridged Panel
Status Field (IV), see Figure 4.1. It may be modified either manually
or via remote control, and is immediately updated.
Whereas acquisition control settings displayed in the Abridged Panel
Status Field (IV) are immediately updated upon manual or remote modifications of the VOLTS/DIV or TIME/DIV settings, the control settings in
the Displayed Trace field (V), corresponding to the conditions under
which the waveform was stored, are updated with every trigger.
I:h.....d.
t
.IJ~ IluN
ChmrmL
2
.e~, v
.~L V~
T/dlv’JiOn..
Oh2
.2Y ,,
Trl~i- .20V - EXTSENSITIVITY DATA DISPLAYED in the ABRIDGED PANEL
STATUS FIELD and in the DISPLAYED TRACE FIELD
Figure 5.2
Manual Operation
5-2
VAR (28) - Verniers provide continuously variable sensitivity within
the VOLTS/DIV settings and extend the maximum vertical sensitivity
factor to up to 12.5 V/div. Variable sensitivity settings are indicated
by the ">" symbol in the lower portion of the Abridged Front Panel
Status field and the calibrated value appears in the Total V/div field
of the Panel Status menu (See Section 5.2.2). (Minimum sensitivity
achieved by rotating the vernier counter-clockwise.)
VERTICAL OFFSET (32) - This control vertically positions the displayed
trace. The maximum offset is ± 1 grid height (± 8 divisions) from the
center of the screen, and is manually adjustable (or programmable)
0.04 division increments.
A pair of upward- or downward-pointing
double-shaft
arrows indicates when the trace has been positioned
outside the grid, as shown in Figure 5.3.
w
ir
UPWARD and DOWNWARD POINTING, DOUBLE SHAFT ARROWS
INDICATING THAT CHANNEL 1 and 2 ARE OFF SCREEN
Figure 5.3
PROBES - Two Model P9010 passive probes are supplied with the 9400A.
These probes have I0 M~ input impedance and 6 pF capacitance. The
system bandwidth
with P9010 probes is DC to I00 MHz in 1M~ DC
coupling, and < I0 Hz to I00 MHz in AC coupling. Active FET probes
(Tektronix models P6201, P6202a and P6230) may be powered via probe
power connectors on the rear panel.
Manual Operation
5-3
PROBE CALIBRATION (19,
20) Tocal ibrate the
to the CHAN 1 or CHAN 2 BNC connector
grounding
alligator
clip
to the front
oscilloscope
and the tip to lug (19).
P901 0 Prob e, conn ect it
(21).
Connect
the probe’s
panel
ground
lug (20)
of the
Adjust
the 9400A’s front
panel controls
as described
in Section
8.1.
In
case of over- or undershooting
of the displayed
signal,
it is possible
to adjust
the P9010 Probe by inserting
the small screwdriver,
supplied
with
the probe
package,
into
the trimmer
on the probe’s
barrel
and
turning
it clockwise
or counter-clockwise
to achieve
an optimal
square
wave contour.
BANDWIDTHLIMIT (50) Byset ting the
BAND~rlDTH LIMI T butt on to O N t he
bandwidth
can be reduced
from 175 MHz to 30 MHz (-3 dB). Bandwidth
limiting
may be useful
in reducing
signal
and system
noise
or
preventing
high-frequency
aliasing
for single-shot
events
at time bases
below 50 ~sec/division.
5.1.2
Time Base
TIME/DIVISION (36) This control se lects th e time pe r division in a
1-2-5 sequence from 2 nsec to 100 sec. The time base is displayed in
the Abridged Panel Status field (IV) as well as in the Displayed Trace
field (V). The time bas~ is crystal-controlled and features an overall
-~.
accuracy better than I0
SAMPLING MODES
Three sampling modes are possible with the 9400A depending
time-base setting selected by the user. They are:
*
*
*
on the
Random Interleaved Sampling (RIS)
Single Shot (SS)
Roll Mode
Random Interleaved Sampling (RIS)
At time-base settings from 2 to 20 nsec/div, the 9400A automatically
uses the RIS mode for signal acquisition. Repetitive waveforms and a
stable trigger are required. Waveforms can be digitized with sampling
intervals as small as 200 psec for an equivalent sampling rate of up
to 5 gigasamples/sec.
Manual Operation
5-4
Between the 50 nsec and 2 psec/div range of time base settings, the
user may select the RIS acquisition mode by pressing the INTERLEAVED
SAMPLING button (37).
Single Shot
For time base settings from 50 nsec to 200 msec/div the 9400A records
the waveform in a single acquisition.
Sampling rates up to
i00 megasamples/sec are possible in the Single Shot mode.
Roll
From 500 msec to I00 sec/div, the 9400A samples continuously. Each
digitized point updates the display, resulting in a trace moving from
right to left similar to that produced by a strip-chart recorder.
TIME BASE
SAMPLING RATE
TIME/POINT
(TIME/DIV)
RIS
2.0
5.0
i0.0
20.0
50.0
0.I
0.2
0.5
1.0
2.0
5.0
I0.0
20.0
50.0
0.i
0.2
0.5
1.0
2.0
5.0
I0.0
20.0
50.0
0.I
0.2
nsec
nsec
nsec
nsec
nsec
~sec
~sec
psec
psec
~sec
psec
psec
psec
Bsec
msec
msec
msec
msec
msec
msec
msec
msec
msec
sec
sec
200
200
200
200
200
200
200
200
400
800
psec
psec
psec
psec
psec
psec
psec
psec
psec
psec
DISPLAYED RECORD
LENGTH (Points)*
SS
I0.0
I0.0
i0.0
i0.0
I0.0
I0.0
I0.0
i0.0
I0.0
20.0
40.0
80.0
0.2
0.4
0.8
2.0
4.0
8.0
20.0
40.0
80.0
nsec
nsec
nsec
nsec
nsec
nsec
nsec
nsec
nsec
nsec
nsec
nsec
psec
psec
~sec
psec
Hsec
psec
~sec
psec
~sec
RIS
SS
I00
250
500
I000
2500
5000
10000
24000
24800
25000
---
50
I00
200
500
i000
2000
5000
i0000
20000
25000
25000
25000
25000
25000
25000
25000
25000
25000
25000
25000
25000
Manual Operation
5-5
TIHE BASE
SA}4PLING RATE
TIME/POINT
(TIME/DIV)
RIS
SS
DISPLAYED RECORD
I.RNCTH (Points)*
RIS
SS
ROLL NODE
0.5
1.0
2.0
5.0
I0.0
20.0
50.0
I00.0
sec
sec
sec
sec
sec
sec
sec
sec
---
0.2
0.4
0.8
2.0
4.0
8.0
20.0
40.0
msec
msec
msec
msec
msec
msec
msec
msec
-------
25000
25000
25000
25000
25000
25000
25000
25000
Note: When the 9400A is remotely read out, the entire memory content of
32,000 words is available at all time base speeds for single shot and
roll modes. 24,000 samples are available for all RIS settings except at
I and 2 psec/div, when 24,800 and 25,000 samples respectively are
available.
LIST of SAMPLING MODES, SAMPLING RATE,
and DISPLAYED RECORD LENGTH
Table 5.1
5.1.3
Trigger
EXTERNAL Trigger
Input (24) - This BNC connector input accepts
external trigger signal of up to 250 V (DC + peak AC). Input impedance
is 1M~ in parallel with < 30 pF. The triggering frequency is >200 MHz.
Trigger SOURCE (23) - Selects the trigger signal source as follows:
CHAN 1 - Selects the Channel i input signal.
CHAN 2 - Selects the Channel 2 input signal.
LINE - Selects the line voltage powering the oscilloscope in order
to provide a stable display of signals synchronous with the power
line.
Manual Operation
5-6
EXT - With the Trigger
SOURCE set to EXT, a signal
applied
to the
BNC connector
labeled
EXTERNAL can be used to trigger
the scope
within
a range of ± 2 V.
EXT/IO - With the Trigger SOURCE set to EXT/10, a signal applied
to the BNC connector labeled EXTERNAL, can be used to trigger the
scope within a range of ± 20 V.
Trigger
trigger
COUPLING (30)
circuit:
- Selects
AC Trigger
- Signals
rejected
and frequencies
the
type
of
are capacitively
below 60 Hz are
LF REJ - Signals
are coupled
network.
DC is rejected
and
attenuated.
The LF REJ trigger
high frequencies
is desired.
signal
coupling
coupled;
attenuated.
to
DC levels
the
are
via a capacitive
high-pass
filter
signal
frequencies
below 50 kHz are
mode is used whenever
triggering
on
BF RBJ - Signals
are DC-coupled
to the trigger
circuit
and a
low-pass
filter
network
attenuates
frequencies
above 50 kHz. The
HF REJ trigger
mode is used when triggering
on low frequencies
is
desired.
DC - All of the signal’s frequency components are coupled to the
trigger circuit. This coupling mode is used in the case of high
frequency bursts, or where the use of AC coupling would shift the
effective trigger level.
LEVBL (33)
a trigger.
Trigger
generate
The trigger
range
± 5 screen
-
is
divisions
SLOPE
circuit.
- with
with
EXT as trigger
± 20 V with
the
level
of
the
signal
required
as follows:
None (zero-crossing)
± 2 V with
Adjusts
CHAN 1 or CHAN 2 as trigger
LINE as trigger
source
source
source
EXT/IO as trigger
source
(25) Se lects th e si gnal ed ge us ed to act ivate the
POS - Requires
a positive-going
edge
NEG - Requires
a negative-going
edge.
of the
trigger
trigger
signal.
Manual Operation
5-7
(POS/NEG)
a positive-
- Permits
"window"
or negative-going
triggering,
i.e.
triggering
on either
signal
edge, whichever
occurs
first.
When the POS/NEG trigger
slope
is selected,
the Trigger
LEVEL
control
(33) is turned
counter-clOckwise
for bi-slope
triggering
at base
line
level.
Turning
the Trigger
LEVEL control
(33)
clockwise
generates
a variable
amplitude
trigger
window which is
symmetrical
with respect
to the center
of the screen
(internal
trigger
source)
and to ground
(external
trigger
source).
When
using
an internal
trigger
source,
the
user
may produce
an
asymmetrical
window by offsetting
the base line
with respect
to
ground via Vertical
OFFSET control
(32).
In the window triggering mode no trigger will occur while the
signal remains within the window. A signal which exceeds the
pre-selected limits will generate a trigger and the signal is
stored into the memory, as shown in the following figure.
Parml
STATUS
¯
M
WINDOW TRIGGERING
Figure 5.4
In the above figure the trigger level is ± 3 divisions as indicated in
the Abridged Panel Status field.
Manual Operation
5-8
Trigger
MODE (29)
- Selects
SINGLE (HOLD) - Selected
the
mode of
using
the
trigger
lower
operation
button
as follows:
(29).
In this
mode the
9400A digitizes
until
a valid
trigger
is
received.
After
the waveform
has been acquired
and displayed,
no
further
signals
can be acquired
until
the SINGLE (HOLD) button
has
been pressed
again
to re-arm
the trigger
circuit
in preparation
for the next trigger
signal.
This type of acquisition
provides
a
simple
means of recording
a wide variety
of transient
events.
When the 9400A is in the Random Interleaved Sampling (RIS) mode,
sufficient
number of triggers must be obtained to complete
waveform
reconstruction,
after which the waveform
will be
displayed. No further signals can be acquired until the SINGLE
(HOLD) button has been pressed again.
When the 9400A is in the Roll mode (~ 500 msec/div), pressing the
SINGLE (HOLD) button causes data acquisition to immediately halt
and the display to freeze.
NORM- Selected
using
button
(29).
When in the normal
(NORM) trigger
mode, the 9400A continuously
digitizes
the input
signal.
Whenever a valid
trigger
is received,
the acquired
waveform is displayed
on the CRT, digitization
starts
again
and the trigger
circuit
is re-armed.
If no subsequent
trigger
is received
within
2 seconds,
previously
acquired
waveforms
are erased
from the screen.
The absence
of a valid
trigger
will thus result
in a blank screen.
To retain the last acquired waveform indefinitely in the NORM
mode, the 9400A’s Auto-store feature is used. Auto-store can be
called via the Special Modes menu described in Section 5.2.5.
When the 9400A is in the RIS mode, a sufficient number (typically
200) of valid triggers is required for each display of a complete
waveform.
In the Roll mode (~ 500 msec/div), the 9400A samples the input
signals continuously. Each point is immediately updated on the
display. This results in a trace which moves from right to left
across the CRT. In the NORM mode, triggers are ignored. The only
way to halt data acquisition is to select the SINGLE (HOLD) mode
or switch the 9400A into AUTO mode and provide a trigger.
Manual Operation
5-9
AUTO - Selected using button (29).
This mode resembles the NORM mode, except that it automatically
generates an internal trigger and forces a waveform to appear on
the screen whenever the selected trigger is not present for more
than 500 msec. When the 9400A auto-triggers, the display usually
moves in time as the trigger is not time-correlated with the input
signal.
Auto trigger can not be used when the 9400A is in the RIS mode.
When the 9400A is in the Roll mode (> 500 msec/div), it samples
input signals continuously. In the AUTO mode any valid trigger
will halt data acquisition once the trigger delay requirements
have been satisfied.
SEO_NCE - Selected using the upper button (29).
Sequence triggering enables the 9400A’s acquisition memories to be
partitioned into up to 250 segments.
Possible settings are: 8, 15, 31, 62, 125, or 250 segments.
Waveform acquisition in SEONCE mode is particularly useful in the
case of short-lived or echoed signals, such as those typically
encountered in RADAR, SONAR, LIDAR and NMR.
In this mode, the time base setting determines the total duration
(TIME/DIV x I0) of each segment. Changing the number of required
segments does not change the time base; it only affects the number
of digitized points (record length) per segment. The number
data points per division is shown in the Acquisition Parameters
display, called by pressing Panel STATUS button (2).
The display is only updated after a sufficient number of sweeps
has been acquired. If less than the required number of triggers is
available the SEQNCE acquisition may be aborted by pushing the
SEQNCE button (29) again.
The 9400A then completes the missing sweeps by auto-triggering a
sufficient number of times while setting its input coupling
temporarily to GND. Thus the artificially completed sweeps will
appear on the display as GND lines.
Manual Operation
5-10
Number of Segments
Points/Seg~nent
8
15
31
62
125
250
2501
2001
i001
497
241
I01
SEQUENCE TRIGGER MODE
NUMBER OF SEGMENTS VS. RECORD LENGTH (TIME BASE: 20 usec)
Table 5.2
Neither the CHAN 1 nor CHAN 2 display is updated when the 9400A is
in the SINGLE or SEQNCE trigger mode, i.e. when no further data
are acquired. Vertical positioning of the displayed trace may
nevertheless be modified via the OFFSET control (32). The VAR
vernier (28) also remains active. However, no other parameter
modifications, such as vertical sensitivity or time changes, will
alter the display of a currently acquired waveform in CHAN 1 or
CHAN 2.
Of course, all parameters may be modified during this time by
manipulating
the appropriate
front panel controls, but such
modification - indicated by parameter changes in the Abridged
Front Panel Status field (IV) - will only be used when acquiring
the next trace.
Whenever the 9400A is in the NORM or AUTO trigger mode, data are
continuously
acquired and the display rapidly updated. All
modifications in acquisition parameters are thus followed quickly
by subsequent
waveform
acquisition
which results in their
appearing to the user as changes to the CHAN 1 or CHAN 2 display.
TRIG’D and READY LEDs (31) - The TRIG’D LED indicates Whenever the
digitizing has stopped (normally after a valid trigger). The READY LED
indicates that the trigger circuit has been armed and the 9400A is
currently digitizing input signals. Upon receiving a valid trigger
signal, it will continue digitization until the trigger conditions have
been satisfied and will then display the acquired waveform.
DELAY (34) - Adjusts the degree of pre- or post-trigger delay when
recording signals in the acquisition memories. Delay operation is via a
single continuously rotating knob. Turning this knob slowly allows
minute adjustment of the trigger point; turning it quickly results in
rapid trigger point movement. The DELAY control enables pre-trigger
adjustment, displayed in %. Pre-trigger adjustment up to 100% full
scale, and post-trigger adjustment up to i0,000 divisions in 0.02
division increments are available.
Manual Operation
5-11
The pre-trigger indicator is displayed by an upward pointing arrow on
the bottom graticule line; the post-trigger indicator is displayed in
decimal fractions of a second, preceded by a leftward-pointing arrow,
in the left-hand corner of the Trigger Delay field (III).
ZERO (35) - Resets the trigger delay from previously set positions
the leftmost graticule line (i.e. 0.0% Pre-trigger position).
5.1.4
Displaying
Traces
Up to four different waveforms (out of a total of eight) may
simultaneously displayed. Whenever a trace is displayed by pressing one
of the TRACE ON/OFF buttons ((46)-(49)), the corresponding waveform
will appear on the screen together with a short description in the
Displayed Trace field (V). When several signals are being displayed
simultaneously,
buttons (46)-(49) can be used as convenient trace
identifiers by repeatedly pressing one of these buttons and simply
seeing which of the displayed traces is turned ON and OFF by this
operation.
EXPAND A, B buttons (46) - Turn the displayed expansion of a waveform
ON or OFF. The expanded portion of the waveform is displayed on the
source trace as an intensified region. The default settings are;
EXPAND A operates on CHANNEL 1 and EXPAND B operates on CHANNEL 2. They
may be changed to allow expansion on any other source trace, by using
the REDEFINE button (48).
MEMORY C, D buttons (47) - Turn the display of a waveform in reference
Memories C or D ON or OFF. Acquired data may be stored into these
memories via the STORE button (I), as described in Section 5.2.1.
FUNCTION E, F buttons (48) - If your 9400A is equipped with a waveform
processing firmware option, pressing these buttons will turn the
display of a computed waveform ON or OFF. The type of computation may
be defined by pressing the REDEFINE button (45). See WPOI Waveform
Processing Option, Section I0.
CHANNEL I, 2 buttons (49) - Turn the display of signals applied
either of the input connectors (21) ON or OFF. Recording of data into
CHAN 1 and CHAN 2 acquisition memories always occurs simultaneously and
irrespective of whether the trace display is ON or OFF.
5.1.5
Display
Control
Displayed traces may be modified
waveform acquisition.
within
certain
limits
following
are controlled
by the VERTICAL and
The CHAN 1 and CtlAN 2 traces
Base controls ((27), (28), (32) and (36), (37), respectively).
Manual Operation
5-12
Time
Six traces, EXPAND A, B (46), MEMORY C, D (47), and FUNCTION E, F
are controlled by the Display Control knobs and buttons (39)-(45).
one trace is controllable at a time. The identity of the controlled
trace is indicated
by a rectangular
frame around the waveform
descriptor in the Displayed Trace field (V).
Whenever more than one of the six traces listed above are currently
displayed, the frame may be moved to the next trace by pressing the
SELECT button (44).
Horizontal POSITION knob (39) - Horizontally positions an expanded
waveform and the intensified
region along the source trace. This
control is activated only after the EXPAND A and/or B buttons (46) have
been pressed to display the expanded trace. The Horizontal POSITION
knob allows the user to scroll continuously
through a displayed
waveform. However, if the source trace was recorded in sequence mode
(i.e. a number of sequentially
acquired
traces was stored in
partitioned memory blocks), the movement of the Horizontal POSITION
knob will be discrete allowing any single segment to be selected.
The Horizontal POSITION control affects only EXPAND A, B.
Vertical POSITION knob (40) - Vertically repositions the trace.
RESET button (41) - Serves to reset previously adjusted VERT GAIN,
Vertical and/or Horizontal POSITION to the following default values:
VERT GAIN
-
Same as the original trace
Vertical POSITION
-
Same as the original trace
Horizontal POSITION
-
Center of the original trace
In the Common Expand mode (See Section 5.2.5.2), this button is used
synchronize the two intensified regions of EXPAND A and B.
VERT GAIN knob (42) - Turning the knob clockwise allows vertical
expansion by a factor of up to 2.5. Counterclockwise rotation allows
vertical contraction by a factor of up to 2.5. If the vernier knob is
not in the detent position it is possible to achieve vertical expansion
by a factor of up to 5.
Pressing RESET (41) returns gain
control to a mid-range plateau
corresponding to a gain of I. If the 9400A is equipped with WP01, the
vertical gain is increased from 2.5 to I0 for averages, mathematics and
functions.
Manual Operation
5-13
TIME MAGNIFIER knob (43) - This control horizontally expands waveforms
up to I00 times.
Overall timing accuracy is improved at higher magnification factors,
since the expand function is controlled digitally and makes use of the
scope’s high number of recorded data points. This control has no effect
on MEMORY C, D or FUNCTION E, F.
SELECT button (44) - Chooses one of the traces - EXPAND A through
FUNCTION F - to be controlled via Display Control knobs and buttons
((39)-(45)). The selected trace is indicated by a rectangular
around the waveform descriptor in the Displayed Trace field (V).
Pressing the SELECT button (44) moves the rectangle to the next
displayed trace in a rolling sequence.
REDEFINE button (45) - Used to redefine the identity of the selected
waveform. EXPAND A, B traces may be redefined to be the expansion of
CHAN 1 or CHAN 2, MEMORY C or D or FUNCTION E or F (for 9400A’s
equipped with the Waveform Processing Option).
Pressing the REDEFINE button (45) calls a menu on the left-hand side
the screen enabling selection of the desired source redefinition. When
the button corresponding to this redefinition is pressed, EXPAND A or B
will be temporarily selected as the new source trace until subsequent
redefinition is performed. The default signal sources are CBAN I for
EXPAND A and CHAN 2 for EXPAND B.
It is not possible to redefine Memories C and D; Function E and F may
only be redefined
if your 9400A is equipped
with the Waveform
Processing Option. For scopes with this option installed, see Section
l0 which deals with the Waveform Processing Option.
5.1.6
Screen Adjustments
INTENSITY knob (12) - Adjusts the intensity of the displayed trace and
all alphanumeric readouts and messages. The INTENSITY control may be
adjusted in either manual or remote control mode.
GRID INTENSITY knob (13) - Controls grid and graticule
independently of displayed trace intensity.
intensity
DUAL GRID button (14) - This button switches between single and dual
grid modes. The dual grid is useful when displaying multiple traces, in
which case the CHAN I display is permanently assigned to the upper grid
and CBAN 2 to the lower grid. All other displayed traces may be
repositioned anywhere on the screen via the Vertical POSITION control
(4O).
Manual Operation
5-14
SCREEN DUMP button (II) - Dumps the contents of the screen to
on-line digital plotter via the 9400A’s rear panel RS-232-C interface
port or optional GPIB port to provide color or monochrome hard copy
archiving of the display. All of the screen illustrations included in
this manual were produced using the SCREEN DUMP function.
5.1.7
Cursors
Cursor measurementscan be made simultaneouslyon up to 4 traces on the
9400A’s CRT.
HARKER Cursor button (18) - Pressing this button generates a
cross-hair marker for precise time measurements relative to the point
of triggering, as well as absolute voltage measurements along the
displayed waveform irrespective of the vertical offset of the trace
displayedon the grid.
Note that setting the marker cursor to 0 time interval provides a
visual indicationof the trigger point.
r
/
/ \
/
\/
/ \
/ \
f
/
\
\
\
/
\
\
v
I
!
!
/
/
."--
i-i-l
.
, .
-
:
..
." :
. .
i :
, ..
!
I
I I
"
I
I
i Y_i i ,
I
I
.-
’+:
:
:
..
!!: .:
J i,+-l,.
~).
1.
-4.2 mY
Channel 2
.2mV
Ch 1>.2 V ~
T/dlv .Snm Ch2 20mYffi
Trig .00 dlv + CHN~1"
DISPLAYED TRACES SHOWING MARKER CURSOR,
INTERVAL BETWEEN TRIGGER POINT and CURSOR, as
well as ALPHANUMERIC
READOUT of the AMPLITUDE of the TRACES
Figure
5.5
Manual Operation
5-15
TIME Cursors button (17) - Generate a downward-polnting
and
upward-pointing arrow on the currently displayed traces, permitting
accurate differential time, voltage and frequency measurements. Time
cursors are displayed as follows:
Maln
M~u
/,.k
A
#
....
j---l--i-i::-\~
~......
,! t /
/
,7.....t.......
!......
/ ........
t,.....
I .....7 E1.....f
.7.......
/ t / " t l ........
/
t
....1......
-’~-/-i tIi
i
iii iii i
I,,,
.......
t ChannQ1
Jig mV 1
p
At 1.78,m
F 588.1Hz
Ch I.>.2 V ~
T/div .5ms Ch2 20mY =
Trig .00 dlv + CHN~~.~
DISPLAYED TRACE SHOWING TIME CURSORS,
their VOLTAGE DIFFERENCE their TIME DIFFERENCES
and the CORRESPONDING FREQUENCY.
Figure 5.6
Note: Measurement resolution
(I0 divisions).
with Time cursors is 0.2Z of full scale
In the case of expanded traces, time cursors are displayed on the
trace, providing up to ×100 higher resolution measurement (0.002E
maximum, depending on the setting of TIME MAGNIFIER control(43)).
Use of the waveform expansion facility is therefore
ensure the most accurate time measurements.
recommended
Manual Operation
5-16
to
VOLTAGE Cursors button (16) - Generates two linear cursor bars which
provide accurate differential
voltage measurements
when adjusted
vertically on the currently displayed waveform. The REFERENCE and
DIFFERENCE controls (38) serve to position the Reference and the
Difference cursor bars.
Voltage cursor bars are displayed as follows:
R
A
A
A
-I~ -I-I......
-I~
......
A.....
A........
II I~ I
....,....I...~...
I...~...
....1’..../ .......\
~ll \J
....~.......
~......
--V
V-....i::--VV
¯
.I.
I-
Q14.>.2
V "
T/oiLy .2meCh22C)mV
Tr’J.o .CX) dlv÷ CHNq
1
DISPLAYED TRACE SHOWING REFERENCE and DIFFERENCE VOLTAGE
CURSORS, and ALPHANUMERIC READOUT of TRACE AMPLITUDE
Figure 5.7
Note that measurement resolution
full scale (8 divisions).
with the VOLTAGE cursors is 0.2% of
case of Time and Voltage
CURSOR POSITIONING
knobs (38) - In the
cursors, the REFEP~NCE control adjusts the Time and Voltage Reference
cursor to the point used as measurement
reference. The DIFFERENCE
control is then adjusted to move the Difference cursor to the desired
position along the trace.
The + Marker cursor is moved along the displayed waveform by means of
the REFERENCE cursor positioning knob alone.
Pressing the TRACKING button causes the Difference cursor to track the
Reference cursor at a fixed interval as determined by the DIFFERENCE
control (in the case of Voltage and Time cursors).
Manual Operation
5-17
5.2
Menu Controls
After the Main Menu key (2) has been pressed, any one of the 9400A’s
interactive menus may be selected by pressing buttons (2)-(10). Figure
5.8 shows the available menus as they appear on the 9400A. To obtain a
given menu, press the button adjacent to the menu desired.
Isls
,,,.
,,,,|,,,, ¯ ,,,,|,,,,,,,,,.,,,,|,,,,l,,,,a,,,,,
T/dlv. 2 nil Ch2
TrJ.g .20 cllv - CHN~
t :
9400A Main Menu and RELATED MENU KEYS
Figure 5.8
5.2.1
Store
Menu
Using the STORE button (I), it is possible
the waveforms currently in the 9400A’s
reference Memories C and/or D.
to store
acquisition
either
or both of
memories
into
To store the currently acquired waveform, first stop the acquisition by
pressing the SINGLE (HOLD) button (29). Once acquisition has stopped,
press button (I) and respond to the messages displayed to the left
the screen. The options are shown in Figure 5.9.
Manual Operation
5-18
St, ore
Trooe
1 ->
HImC
Ch~2 ->
FunoE->
HmC
FunoF ->
Chon1. ->
HImD
Chart2->
FunoE ->
I’kmD
FunoF ->
Chl 50mYI
T/dtv .2me Ch250mV
+LINE .
TPLQ --
Ret,ul-n/
Conoel
STORE TRACE MENU
Figure 5.9
Pressing buttons (2), (3), (6) or (7) causes an identical copy
displayed waveform (or waveforms) to be stored into reference Memories
C and/or D.
If
acquisition is taking place when the store button (I) is pressed,
the user is prompted with the message:
STOP ACQUISITION IN ORDER TO STORE
Manual Operation
5-19
5.2.2
Panel
Status
Menu
The Panel Status menu provides a complete report of front panel control
settings and permits on-screen adjustment of acquisition parameters.
PLOTTING
PANEL STATUS MENU
Figure 5.10
Vertical parameters:
Fixed
V/dtv
The current
control
(27)
is indicated.
Total
setting
with the
of the front
panel
Vertical
Sensitivity
VAR vernier
in the fully
clockwise
position
V/div
The current
setting
of the front
panel
Vertical
Sensitivity
control
(27) plus the additional
sensitivity
range (up to x 2.5
the Fixed
V/div setting)
is provided
by turning
the VAR vernier
(28) counterclockwise.
Manual Operation
5-20
Trigger
parameters:
Delay
In Figure 5.10 the indicated trigger delay is 10% Pre, meaning
that when in Main Menu the Delay arrow is positioned one division
to the left of the center
of the grid. In the case of a
post-trigger delay setting9 this would be indicated in decimal
fractions of a second (i.e. + 4.00 msec).
Level
The trigger level indicated in Figure 5.10 is displayed in terms
of grid divisions. The 9400A displays the current trigger level
setting in divisions when in the internal trigger mode. It
displays the setting in Volts when in the external trigger mode.
Time/point
Indicates the time between digitized points for the corresponding
time base setting.
Points/div
This parameter indicates the number of digitized
division on any non-expanded waveforms displayed.
# Segments
for
points per
SEQNCE
This parameter indicates the number of segments selected for
sequential acquisition. On-screen modification of this parameter
is possible by pressing the Modify # Segments button (4) to change
the indicated segment number from 8 to 250 in a rolling sequence.
Set CHAN 1 Attenuator
(6) and set CHAN 2 Attenuator (7)
allow the user to enter probe attenuation factors of I0, i00 and
I000.
Press the Return key (10) to list the available menus.
For information concerning the other parameters displayed on the Panel
Status menu, see Section 5.1.
Manual Operation
5-21
5.2.3
Memory Status
The Panel Status menu displays acquisition parameters for waveforms to
be acquired after receiving a trigger signal. On the other hand, the
Memory Status menu displays all acquisition parameters for waveforms
currently stored in the various memories of the 9400A.
The annotation used for Memory Status is similar to that of the Panel
Status menu. Pressing the Memory Status button (3) displays the Memory
Status menu in Figure 5.11.
v 2,0OFT
ItDtORYSTATUS
Ch t+2
STATUS To¢.ol V/dlv
OPP~#.
Coupltr~-LLml~,
llk~ GI.D
Time(F’meq)/dlv
STATUS TO:’|lpr~ + ~d.tv
rFun£~1
TrLg-Deloy
Tr-I.m~l + Slq:~
Tr~_~i-__.-~e
÷ Ca:x~
I1mory LIIt~
Rm}or’d-Type
EJO.O
mV
.0 mV
~ t HO,0:1=
.5 me
~00 rm, ~
9.8X Pre
.OOcRv, +
04AN 1, DC
-~)00,2E(X)O
SINi~
150.0mY
.0 mV
AC1 HI}, OFF
.5 me
200 I’m, 2500
9.8X Pr~
.OOcRv, +
CHAN~, []C
-;~X), 2EO00
5INIEE
PLOTTII~
MEMORY STATUS CHAN 1 and CHAN 2
Figure 5.11
Pressing button (2),
(3) or (4) while in the memory status menu
display the acquisition parameters of waveforms stored in acquisition,
expansion
and storage
memories respectively.
Manual Operation
5-22
V 2.08FT
Ch t+2
STATUS
F~p~m
l~m Gto
STATUS
Fun E+F
Plmory C
~moryo
50OIV
4000mV
13(3600,OFF
.2mo
80rm, 2500
.4ZI:Me
50.0 mV
.OmV
DOEO
O, OFF
.Eme
200 no, 2500
.OXPre
-20.0 V , EXT/IO, DC
-~000,260(X)
5INGLE
LINE , 13C
0,26000
SINGLE
A~Cl)
t252, 20
5
TRACE A,
B EXPAND STATUS MENU
Figure 5.12
V 2.08FT
ItEI’IORYSTATUS
Ch t+2
STATUS
~xp A+8
I~m C+D
STATUS
Fun E+F
MmmryC
5OO
iiV
4000mV
DCEOO, OFF
.2mo
80rm, L:~O0
.4ZI:Me
LXHE , 13C
0,26000
5[NGI.[
A~(l)
t252,20
1
Hm.ory D
50.OmV
.OmV
DCEO0, OFF
.6me
2CX3rm, 2500
.OXPre
-20.OV , E~T/tO, OC
-7(XX),26000
5INGLE
PLOTTING
MEMORY STATUS C and D
Figure 5.13
Manual Operation
5-23
The indication in the upper right-hand corner of Figures 5.12, 5.13,
5.14 corresponds to the software version implemented in the scope.
5.2.4
Storage
and Recall
of Front
Panel
Setups
Pressing the Store PANEL or Recall PANEL buttons ((4) and (5),
respectively) enables storage or recall of up to seven different front
panel acquisition parameter settings.
SP~m’e
Parml
-> Pa’ml5
STORE
-> I%:’ml2
,,,, ........
:::.::::.::::,
-> I::-ml 9
STORE
-> I:(a’ml 4 ..........................
-> I:m-ml5
STORE
-> Pa-ml8
-> I:onel 7
STCI~
Return
STORE and RECALL FRONT PANEL SETUP MENUS
Figure 5.14
Once you have obtained
the Store PANEL menu by
buttons (2) through (8)
Press the Return button
normal scope operation.
a satisfactory front panel setup, simply call
pressing button (4); then press any one of the
to store this front panel setup where required.
(10) to go back to the Main Menu and continue
Manual Operation
5-24
To recall a previously stored front panel setup, press the Recall PANEL
button (5) while in the Main Menu. A list of the seven stored front
panel setups which are available will be displayed. Press the button
((2) through (8)) which corresponds to the desired setup, and the
panel settings will automatically
be configured according to the
acquisition parameters recalled.
5.2.5
Special
Nodes (7)
¯ :q~IALMODES
AUTO-STORE
OFF
In ~ and AUTO,the oeollloeoope moybe Por-o~ to
o,k~mc~loolly
etxx,e oneor both ~tm’lnell In olt,~’me
mmory
C or O oPtm,p.j.m ooqutmltton o4’ ~¢h tKMBwLo~downtim dJ.mplayrq:m~lt;lon
Mod.CommonPOP,,. lhJ.m modw
r’~be, ell’me a ~ opm-c~iont.d¢~ oe muchas 200 me.
COPItONE~N~D
OFF
ktwnON, thehoplzont~l
poeitlan
and time.mgnlFler
oor~roiknd:eao~ on bothexpandmd
tPoo~ A ANDB
PoPo olmult~neoue
horizontal
ooan. The vertloal
arxJpaml~lon
remainIndivldua11y
aor~rolled.
Return
PLOTTING
SPECIAL MODES MENU
Figure 5.15
5.2.5.1
Auto-store
Mode
Pressing the Special Modes button (7) while in the Main Menu allows the
user to automatically store - following acquisition - CHAN I or CHAN 2
into the unit’s two reference memories.
Pressing the Modify Auto-store button (2) allows the user to choose
from among the following possible storage modes: CHAN I into Memory C
or D; CHAN 2 into Memory C or D, or, alternatively, CHAN I into Memory
C and CHAN 2 into Memory D.
Manual Operation
5-25
This is a useful feature for very low repetition rate signals acquired
in the NORMAL trigger mode. Subsequent
display of the selected
reference memory provides the user with a lasting waveform display
which can be studied long after the originally acquired signal has been
erased. In the NORMAL trigger mode the CHAN 1 and CHAN 2 displays are
automatically erased after a two second interval to warn the user that
a proper trigger is not available.
5.2.5.2 Common Expand Mode
Section 5.1.4 discusses independent expansion of single traces to
display a magnified portion of the waveform from CHAN 1 and/or CHAN 2,
Memories C and/or D, or of Function E and/or F if the 9400A is equipped
with WPOI Waveform Processing
firmware.
However, in certain
applications, it is convenient to be able to move the intensified
region along two different traces simultaneously. This is the purpose
of the Common Expand mode.
In this mode it is possible to either synchronize the intensified
regions of the two source signals, or to maintain a fixed time interval
between them, in which case the intensified regions for each trace will
move horizontally at a fixed interval. (See Section 8.11 for an example
of intensified regions shifting on two traces expanded in the Common
Expand mode).
In the Common Expand mode, when the user is examining two expansions at
a fixed interval (he may re-synchronize them by pressing the RESET
button (41)) both expansions are shifted to the center of the grid.
Turning the Horizontal
POSITION control (39) until both of the
intensified regions move off the screen will also re-synchronize them.
In the Common Expand mode, only the Horizontal
POSITION control (39)
and TIME MAGNIFIER control (43) act simultaneously on the intensified
regions on both the EXPAND A and B signal source, while the VERT GAIN
control (42) and Vertical POSITION control (40) act independently
each expanded waveform.
Note that when the Common Expand mode is called,
magnification factor applies to both A and B expansion.
5.2.6
RS-232-C
the EXPAND A
Setup (8)
Two RS-232-C ports are available on the rear panel of the 9400A
permitting remote oscilloscope operation and data transfer, as well as
convenient plotter interfacing.
Manual Operation
5-26
When in the main menu, pressing RS-232-C SETUP button (8) calls
interactive menu enabling configuration of both of the 9400A’s RS-232-C
ports
for a particular
application.
Parameters
for
the
plotter-dedicated RS-232-C port (57) are displayed in the lower portion
of the screen, while those for the remote RS-232-C port (56) are
presented in the upper portion of the screen.
RS~32 - RemOte c~nbrol port
Saud r’~e: !~
C~ro~er Length Cblt6):
Parity:
norm
Number oF stop bits: I
I~wioue
VALUE
Nex~
RS232 - Plotterport
Baud rate: 9600
CharooterLength Cblt~):
Parity:
none
Number oP etop bite: I
RS-232-C SETUP MENU
Figure 5.16
To modify any of the parameters displayed, first select the field to be
modified. The rectangular frame around parameter values indicates the
currently selected field. Pressing the Previous FIELD button (2) will
cause the frame to move towards the top of the list, whereas pressing
the Next FIELD button (3) will move the frame downwards.
Following field selection, the current value of the field may be
modified by pressing either the Previous (6) or Next VALUE (7).
Baud rate is selected from a set of values in the range ii0 through
19,200 baud. The possible settings of character length are 6, 7, and 8;
parity, none, even or odd; and number of stop bits, I and 2.
Manual Operation
5-27
5.2.7
Plotter
Setup
(9)
The 9400A has been designed to permit direct interfacing
of the
oscilloscope with four of the most popular plotters via the rear panel
RS-232-C dedicated plotter port or the optional GPIB (IEEE-488) port.
When the 9400A is connected to a plotter via the GPIB port, with no
host computer in the configuration,
the oscilloscope’s rear panel
thumb-wheel switch must be set to the Talk Only mode (address > 31
decimal) and the plotter to the Listen Only mode.
Plotter setup configuration is similar to configuration of the RS-232-C
ports (see Section 5.2.6 above).
PLOTTER
Plobt~w’: IHE~-ETTPACKARD
7+70Aomoompob~hlol
Plobbempore: RS292
Plob speed: NORHN.
NuMbem
oF Installed
PPovlouo
VALUE
Next;
pane: Z
PLOTSIZE
PopemeLze: A4 (ISO) - USIt°/8.5"
The plot; amea w111 be 1~ bhon: 22gram ¯ 1BO~
Reb~Pn
PLOTTING
PLOTTER SET-UP MENU
Figure 5.17
Manual Operation
5-28
The user can choose the following parameters:
Plotter Type:
HP7470A (or compatible), Philips PM8151
(or compatible),Tektronix or Graphtec FP 5301
Plotter Port:
RS-232-C or GPIB (IEEE-488)
Plot Speed:
Normal or Low Speed
Number of
Installed Pens:
I to9
Plot Size:
ISO
A5
(US 8.5" x 5.5"), ISO
A4 (US
8.5"),IS0 A3 (US 17" x ii") or non-standard
Non-standard:
In the case of non-standard paper sizes, the size of
the grid square can be chosen between 0 to 99.9 mm in
0.I mm steps; lower left corner position from 0 to
999 mm (for both X and Y coordinates) in I mm steps.
ii"
* If GPIB is selected by no GPIB board is installed (basic 9400A), the
instrument may lock up when the screen dump button is pressed.
Manual Operation
5-29
SECTION 6
REAR PANEL CONTROLSAND CONNECTORS
6.1
Fuse
Protection
The power supply of the 9400A is protected against short circuits and
overload by means of a T(slow) 1.6/ 250 V fuse for units which can
operate on 220 V or 115 V mains voltage (switch selected) or a T (slow)
3.15/ 250 V fuse for units operating only on 115 V mains voltage. The
fuse is located under the 115 to 220 V mains voltage selector drum
cover.
6.2
Accessory
Power
Connectors
(51)
Two LEMO RA 0304 NYL connectors have been provided to permit use of FET
type probes with the 9400A. These connectors provide output voltages of
+ 5 V, ± 15 V and GND connection, suitable for most FET probes.
The maximum output current per connector must be limited to 150 mA for
each of the three voltages.
6.3
Battery
Pack (52)
The battery pack consists of two KR 15/51, 1.2 V rechargeable NiCd
batteries enabling retention of front-panel setups for 6 months in case
of power failure or whenever the 9400A is switched off. The battery
pack is automatically recharged during operation.
The battery pack can be accessed by pressing the plastic latch at the
top of the cover and pulling it downward and toward the user.
6.4
GPIB and RS-232-C Port Selection (54)
The 9400A’s rear panel thumbwheel switch is used to set addresses for
programmed or remote oscilloscope operation. Any one of addresses 31-99
selects the RS-232-C port. Addresses 0-30 define the 9400A’s address
when using the optional GPIB (IEEE-488) port.
GPIB and RS-232-C pin assignments
panel next to each connector.
are clearly indicated on the rear
Rear Panel Controls and Connectors
6-1
6.5
Plotter
Connector
(57)
In addition to the RS-232-C port (56) used for remote 9400A operation,
a second RS-232-C port (57) has been incorporated to facilitate direct
interfacing of the 9400A with a digital plotter. Plotters are used for
hard copy archiving of displayed waveforms and other screen data. Pin
assignments for the plotter connector are identical to those of the
remote RS-232-C port (56).
While a plotter unit connected to the 9400A’s RS-232-C port can be
computer controlled from a host computer via the optional GPIB port,
the oscilloscope’s on-board digital plotter drivers permit hard copies
to be made without an external computer.
Plotter
connector
20
6
1
7
This
assignments:
Description
Pin #
2
3
4
5
pin
T x D
RxD
RTS
CTS
DSR
GND
SIG GND
Transmitted Data (from the 9400A)
Received Data (to the 9400A)
Request To Send (always on) (from the 9400A)
Clear To Send (to the 9400A)
When TRUE, the 9400A can transmit.
When FALSE, transmission stops.
Used for 9400A output hardware handshake.
Data Terminal Ready (from the 9400A)
Always TRUE.
Data Set Ready (to the 9400A)
Protective Ground
Signal Ground
corresponds
to
DTR
a DTE (Data
Terminal
Rear
6-2
Equipment)
configuration.
Panel Controls and Connectors
SECTION 7
REMOTE OPERATIONS
7.1
Progr.mmed
Control
Most of the front panel and internal functions of the 9400A can be
remotely controlled using a set of high-level, English-like commands
and mnemonics. For example, a command followed by <?> tells the scope
to transfer to the host computer the value of the control setting
defined by the command. It is thus possible to read the complete status
of the instrument by repeated queries. It is also possible to save the
entire status of the instrument in binary format with a single command.
The 9400A’s remote control facility
allows complex measurement
procedures and instrument setups, a particularly useful feature in
experimental and automated testing environments.
The 9400A can be programmed via the rear panel RS-232-C port interfaced
with a computer terminal or a computer. Remote control is also possible
via GPIB (IEEE-488 bus) if the 9400A has been fitted with the option
OP02. In this case data transfer rates are relatively faster.
To help users who wish to remotely control the Models 9400 (125 MHz
bandwidth) and 9400A (175 MHz bandwidth) oscilloscopes, LeCroy have
published the following application notes which are available on
request:
ITI 002: Linking the LeCroy 9400 to an IBM R PC-AT via the RS-232-C
Asynchronous Interface.
ITI 005: Linking the LeCroy 9400 to an IBM PC-AT via GPIB.
ITI 006: Linking the LeCroy 9400 to an HP 9000 Model 216 controller.
7.2
RS-232-C Ports (56 and 57)
The 9400A has two RS-232-C ports. One is available for computer or
terminal controlled oscilloscope operation, the other for plotter
interfacing. The RS-232-C ports provide an asynchronous data transfer
rate of up to 19,200 baud.
Remote Operations
7-1
RS-232-C
Pin Assignments
The remote RS-232-C pin Assignments (indicated on the rear panel) are
as follows:
Description
Pin #
2
3
4
5
TxD
RxD
RTS
CTS
2O
DTR
6
1
7
DSR
GND
SIG GND
Transmitted Data (from the 9400A)
Received Data (to the 9400A)
Request To Send (always on) (from the 9400A)
Clear To Send (to the 9400A)
When TRUE, the 9400A can transmit.
When FALSE, transmission stops.
It is used for the 9400A output hardware handshake.
Data terminal ready (from 9400A). If the software
Xon/Xoff handshake is selected it is always TRUE.
Otherwise (hardware handshake) it is TRUE when the
9400A is able to receive characters and FALSE when the
9400A is unable to receive characters.
Data Set Ready (to the 9400A)
Protective Ground
Signal Ground
This corresponds to a DTE (Data Terminal Equipment) configuration.
Although descriptions vary slightly, pin assignments for the dedicated
plotter interface (Section 6.6) are identical to those for the remote
RS-232-C connector above.
7.3
GPIB Port
(Option
OP02 only)
(55)
The 9400A’s GPIB interface (optional) complies with IEEE-488 (1978)
standards, and is intended to provide high-speed data transfer in
either the ASCII or binary format between the 9400A and the computer to
which it is interfaced. The maximum data transfer rate, depending on
the controller used, may be as high as 400 kilobytes/sec.
GPIB Port
Selection
(54)
As mentioned in Section 6.5, the 9400A’s rear panel thumbwheel switch
is used to set addresses
for programmed
or remote oscilloscope
operation. Addresses 0-30 define the 9400A’s address when using the
GPIB (IEEE-488) port; using any one of addresses 31-99 selects the
RS-232-C port. The thumbwheel is read at power ON only. Whenever the
GPIB address is changed, the power must be turned off and on again.
GPIB functions are clearly indicated on the rear panel next to the GPIB
connector.
Remote
7-2
Operations
GPIB Functions
The following is a list of the various
9400A’s rear panel GPIB connector:
AHI
SHI
L4
T5
SRI
RL2
DCI
DTI
PP1
CO
E2
7.4
7.4.1
functions
provided via the
Complete Acceptor Handshake
Complete Source Handshake
Partial Listener Function
Complete Talker Function
Complete Service Request Function
Partial Remote/Local Function
Complete Device Clear Function
Complete Device Trigger
Parallel Polling: remote configuration
No Controller Functions
Tri-state Drivers
GPIB and RS-232-C Command Format
Introduction
All the remote control commands apply equally to communication via the
GPIB and RS-232-C ports. (Note that GPIB commands should not be used
when Option 0P02 is not fitted in the 9400A.) Certain functions,
however, which are part of the GPIB standard (such as Device Clear or
Group Execute Trigger) must be implemented as separate commands for the
RS-232-C interface
(see Section 7.6.10).
The command syntax
compatible
with IEEE Recommended
Practice
for Code and Format
Conventions (IEEE Standard 728-1982).
In GPIB, the predefined control commands, such as Device Clear, Group
Execute Trigger, Set Remote or Set Local, are part of the device driver
commands. Therefore the 9400A only has English-like commands for these
functions in RS-232-C inferfacing applications. The user must consult
the manual for his GPIB-interface driver in order to determine the form
of these special commands.
Commands are formed of easy-to-read, unambiguous English words, with
abbreviations
(typically 2 to 4 characters) being used to achieve
higher throughput. Short and long formats may be freely substituted for
one another.
The execution of certain commands depends on whether the 9400A is in
the REMOTE or LOCAL state.
Remote Operations
7-3
When the 9400A is in LOCAL:
- All the front panel controls are active.
- Reading the 9400A by remote control is possible.
- The status byte masks (see MASK command) and the communications
protocol (see COMM command) may be written, status bytes may
cleared.
When the 9400A is in REMOTE:
- All the front-panel controls are deactivated, except the two
display intensity controls and the left-hand side menu buttons.
- All the remote commands are executed.
- A special command (SCREEN) exists to deactivate the front panel
display intensity controls and allows them to be set remotely.
7.4.2
Compound Commands
One or several commands can be
with <END>. In GPIB transfers,
(End of Information). In this
RS-232-C transfers, <END> is a
<CR>.
sent to the 9400A in a message ending
<END> is the line which marks the EOI
case, <END> is <;>,<CR> or <LF>.
user-selectable string; the default is
Where multiple commands are used to compose a message, each command is
separated from the following one with a <;>, a <CR> or a <LF> or with
any combination of these characters.
Example:
TRIG SLOPE POS; TIME/DIV 50 NS <END>
represents 2 commands where <;> is used to separate them.
Commands are executed only after <END> is received. Exceptions to this
rule are mentioned later (see Section 7.4.6).
7.4.3
Command Format
Simple commands consist of a header, indicating the desired operation.
The header is usually followed by one or more parameters used to
describe the desired operation in greater detail.
HEADER (<SPACE>, <,> or <=>) Parameter i, Parameter 2, etc.
Remote Operations
7-4
The header may be separated from Parameter 1 by either a space, comma,
equals sign or any combination of these. Parameters MUST be separated
from one another using a comma.
Headers and key-word parameters may be transmitted using either the
full or an abridged format. Both upper and lower case characters are
valid and may be used interchangeably.
Numbers must be in accordance with ANSI X3.42-1975 standards and may be
transmitted as integers, or in scientific notation, with or without
exponents. Waveform data values, however, can only be transferred as
integers (8- or 16-bits). Suffixes are optional (but acceptable only
when specifically mentioned).
Example:
The following commands are all legal ways of setting the vertical
gain of CHANNEL i to I00 mV/div:
CHANNEL 1VOLT/DIV .I
CHANNEL 1VOLT/DIV,IO0 MVOLT
CIVD=IOOE-03 VOLT
CIVD I00 MV
The expression <i00 MV> is considered as a single parameter with a
suffix; therefore no comma is allowed to separate them. The space
separating the parameter value and the suffix is optional.
7.4.4
Answers from the
9400A
As well as specifying a new parameter setting, it is also possible to
query the 9400A in order to obtain a current value. Such queries are
always indicated by a question mark.
Example:
TIME/DIV ?
instructs the 9400A to transmit a character
its current time base value.
string representing
Answers from the 9400A are sent in a message followed by
(see COMM TRAILER command) and <END>.
the TRAILER
Remote Operations
7-5
Example:
When set to I00 nsec/div, the answer to the query would be:
TD 100E-09<CR><LF><END>,
where <CR><LF> is the default TRAILER, and
<END> = another <CR>, when using RS-232-C (unless modified with
the command RS CONF).
= EOI-line ACCOMPANYING <LF>, when using GPIB.
If the 9400A generates
multiple
responses
to a single message
containing queries, it will send a separate response for each query.
7.4.5
Flushing of the 94OOA’s Output Buffer
When the 9400A generates an answer to a query or outputs a data stream
in response to a transfer command, the host computer should read the
data. If it fails to do so, the 9400A may become blocked when trying to
output data (this does not occur with a response of less than 80
characters, since the output is buffered).
~henever the 9400A receives a new command message, upon detection of
the <END> of this message, it flushes the output buffer of all
responses due to the previous command message. If the 9400A detects a
new <END> from a new command message while still treating a previous
command message, it aborts those (previous) commands which generate
output data, but not the new commands. The 9400A assumes that the user
is not interested in the answers to previous commands since he is
sending another command message rather than reading the responses.
7.4.6
Command Synchronization with Data Acquisition
Some remote commands cannot be executed at all times, e.g. it is not
possible to read channel 1 or channel 2 while the oscilloscope is armed
and waiting for a trigger, since the memories of the two channels are
continuously being written into.
The user can avoid such situations
entirely
by only executing
single-shot acquisitions (TRIG MODE SINGLE) and by checking that bit
of status byte 4 (TRIGGERED bit) is set to one (indicating that
acquisition is complete) before sending the READ command.
Another way is to send the command to read channel 1 or channel 2. The
9400A automatically
defers the execution of this command until a
waveform has been acquired. It is thus possible to also read waveforms
while the instrument
is in the trigger modes NORM or AUTO, i.e.
practically "on-the-fly".
Remote Operations
7-6
Execution of the command is also deferred when using some other remote
control commands,
in particular
the command STORE channel I or
channel 2, and the special command WAlT whose sole purpose is to force
such a synchronization. (See Section 7.6.6 "Other Remote Commands".)
7.4.7
Character
Strings
Strings
may be displayed (see MESSAGE and KEY commands), sent to
plotter
(see the TRANSMIT command) or used as Prompt (see COMM PROMPT
command).
The string
must
be delimited by string delimiters. The
is
<"> and may be changed
(see the
default
string
delimiter
COMMSTRDELIM command).
Example:
COMM STRDELIM 47; MSG /OKAY/
Defines </> (decimal ASCII 47)
display OKAY on the screen.
The TRANSMIT command also outputs
decimal ASCII using a \nnn format.
as the string delimiter and will
characters
that are specified
in
Example:
TRANSMIT "\B27AB"
Can be used to transmit to the plotter the character ESC (decimal
ASCII 27) followed by <A> and <B>.
If
the backslash character <\> is to be transmitted along with other
characters, then <\\> is to be used.
Example:
TRANSMIT "AI\\A2"
Instructs the 9400A to transmit the string AI\A2 to the plotter.
Note:
"\nnn" or "\\" represent only one character of the ASCII string count.
7.4.8
Prompt
The 9400A may generate a PROMPT (see COMM-PROMPT command) when
decodes the <END> message in a command message. This PROMPT will be put
into a message as is done with all other 9400A responses (see Section
7.6.7 7)).
Remote Operations
7-7
7.4.9
Errors
and Adapted
Values
When it treats a command, the 9400A checks its validity. The list of
errors is presented in Section 7.6.8 (ERROR status byte).
In general:
- A SYNTAX ERROR is produced when the structure of a command is
wrong, or if a command, a key-word parameter or a suffix is not
recognized.
- A SEMANTIC ERROR is produced when the
wrong combination of parameters or if
not valid.
command is composed of a
a numerical parameter is
- An ENVIRONMENT ERROR is produced when the command, although it
is valid, cannot be accepted, the 9400A not being in the state
to do so.
When an error is detected, the corresponding code is loaded into status
byte 6, and the bit # 5 of status byte 1 is set.
Some commands cause bit 0 of status byte i (VALUE ADAPTED bit) to
set when the 9400A detects a numerical value or a parameter out of
range. The value is always modified to the closest legal value.
7.5
Data Block Transfers
Data (9400A setup values, waveform values, waveform descriptor) are
transferred between the 9400A and the Host Computer (see the READ or
SETUP commands, Section 7.6.5) or between the Host and the 9400A (see
WRITE or SETUP commands) in one or several blocks. Data blocks are
never contained within a read or write command, but are always
separate. This section explains only the overall block structure. For
the interpretation of the data, see Section 7.10.
Examples:
Reading a waveform from channel i of the 9400A:
- Host sends the command READ,CHANNEL 1.DATA<END> to 9400A.
- 9400A responds with one (or several) data
formats described below, and terminates
<END>.
blocks in one of the
with <TRAILER> and
Remote Operations
7-8
Thus, the overall command sequence and data structure is the same
as for queries.
Sending a new setup block to the 9400A:
- Host sends the command SETUP<END> to 9400A.
- Host sends the data blocks to the 9400A. Each data block is
composed of a preamble, the data, an optional postscript and
<END>.
Here, the setup data cannot be directly
command, but must be separated by <END>.
appended
to the setup
Several block formats are available for read and write; they are
distinguished from each other by the preamble. The command COMM FORMAT
selects the format.
Format A: GPIB only, binary format, no checksum.
Preamble:
#Abb where bb is the number of data values that will be
sent (2 binary bytes).
Data:
One binary byte for each 8-bit value, two binary bytes
for each 16-bit value.
Postscript: None.
Format L: GPIB or RS-232-C, ASCII format.
Preamble:
#L<count>, where <count>
that will be sent.
is
the number of data values
Data:
<data>, where <data> are data values in ASCII.
Postscript: None.
<count> and <data> are in the same format but do not necessarily have
the same number of characters. However, <count> is always treated as a
WORD (16 bits), whereas <data> may be chosen as a BYTE (8 bits) or
WORD. The choice of formats (see COMM FORMAT command) is the following:
BYTE (8 bits value)
WORD
(16 bits value)
HEX:
xx (2 hex digits)
xxxx
(4 hex digits)
UNSIGNED FIXED:
nnn (3 decimal digits)
nnnnn
(5 decimal digits)
UNSIGNED SHORT:
,n (I to 3 decimal digits) ,nnnnn (I to 5 decimal
digits)
Remote Operations
7-9
The HEX and UNSIGNED
FIXED are fixed size formats,
whereas
UNSIGNED SHORT is a variable size format. Therefore, it requires commas
to separate the values.
Examples:
HEX format:
#LOOOA0102030405060708090A
UNSIGNED FIXED: #L...I0..I..2..3..4..5..6..7..8..9.10
Each dot represents a space
character
UNSIGNED SHORT: #L,10,1,2,3,4,5,6,7,8,9,10
Note:
The conversion type and the size must be fixed before reading
writing data.
Data transfers via RS-232-C can only be made in ASCII formats.
AND
If the host computer allows only small amounts of data to be sent or
read, the transfer may be partitioned into several blocks of the
selected format. The maximum length of each block is determined by the
COMM BLOCKSIZE command. The length includes all bytes or characters of
the -block as well as characters which may compose the <TRAILER> and
<END>.
The transfer will be structured as follows:
Ist Block
-- <TRAILER><END> -- 2nd Block -- <TRAILER><END> -- ....
.... -- Last Block -- <TRAILER><END> -- END block -- <TRAILER><END>
Where the END block is:
#I
When reading data from the 9400A, the exact form of
determined by the command COMM TRAILER. <END> is:
<END> = <CR> when using RS-232-C
RSCONF).
=
(unless
modified
the TRAILER is
with the command
EOI ACCOMPANYING the last character of TRAILER, when in GPIB.
If the 9400A receives another command message, terminated with <END>,
while sending data, the transfer is aborted and status byte 6 (ERROR)
is set to the value i.
Data may be lost if the readout sequence is interrupted with a Serial
Poll or by the untalk command.
Remote Operations
7-10
Thus, the overall command sequence and data structure is the same
as for queries.
Sending a new setup block to the 9400A:
- Host sends the command SETUP<END> to 9400A.
- Host sends the data blocks to the 9400A. Each data block is
composed of a preamble, the data, an optional postscript and
<END>.
Here, the setup data cannot be directly
command, but must be separated by <END>.
appended
to the setup
Several block formats are available for read and write; they are
distinguished from each other by the preamble. The command COMM FORMAT
selects the format.
Format A: GPIB only, binary format, no checksum.
Preamble:
#Abb where bb is the number of data values that will be
sent (2 binary bytes).
Data:
One binary byte for each 8-bit value, two binary bytes
for each 16-bit value.
Postscript: None.
Format L: GPIB or RS-232-C, ASCII format.
Preamble:
#L<count>, where <count>
that will be sent.
Data:
<data>, where <data> are data values in ASCII.
is the number
of data values
Postscript: None.
<count> and <data> are in the same format but do not necessarily have
the same number of characters. However, <count> is always treated as a
WORD (16 bits), whereas <data> may be chosen as a BYTE (8 bits) or
WORD. The choice of formats (see COMM FORMAT command) is the following:
BYTE (8 bits value)
WORD
(16 bits value)
HEX:
xx (2 hex digits)
xxxx
(4 hex digits)
UNSIGNED FIXED:
nnn (3 decimal digits)
nnnnn
(5 decimal digits)
UNSIGNED SHORT:
,n (I to 3 decimal digits) ,nnnnn (I to 5 decimal
digits)
Remote Operations
7-9
The HEX and UNSIGNED
FIXED
are fixed size formats,
whereas
UNSIGNED SHORT is a variable size format. Therefore, it requires commas
to separate the values.
Examples:
HEX format:
#L000A0102030405060708090A
UNSIGNED FIXED: #L...I0..I..2..3..4..5..6..7..8..9.10
Each dot represents a space
character
UNSIGNED SHORT: #L,I0,I,293,4,5,6,7,8,9,10
Note:
The conversion type and the size must be fixed before reading
writing data.
Data transfers via RS-232-C can only be made in ASCII formats.
AND
If the host computer allows only small amounts of data to be sent or
read, the transfer may be partitioned into several blocks of the
selected format. The maximum length of each block is determined by the
COMM BLOCKSIZE command. The length includes all bytes or characters of
the -block as well as characters which may compose the <TRAILER> and
<END>.
The transfer will be structured as follows:
st
i
Block
-- <TRAILER><END> -- 2nd Block -- <TRAILER><END> -- ....
.... -- Last Block -- <TRAILER><END> -- END block -- <TRAILER><END>
Where the END block is:
#I
When reading data from the 9400A, the exact form of
determined by the command COMM TRAILER. <END> is:
<END> = <CR> when using RS-232-C
RS_CONF).
=
(unless modified
the
TRAILER is
with the command
EOI ACCOMPANYING the last character of TRAILER, when in GPIB.
If the 9400A receives another command message, terminated with <END>,
while sending data, the transfer is aborted and status byte 6 (ERROR)
is set to the value I.
Data may be lost if the readout sequence is interrupted with a Serial
Poll or by the untalk command.
Remote Operations
7-10
7.6
Commands
7.6.1
Notation
In this section the following notation is used to explain the commands.
However, these symbols must not be sent to the 9400A as part of a
command.
[
<
to
]
denotes the range of a numerical value.
>
denotes the choice of parameters.
The options are listed vertically.
)
denotes the abridged format of a keyword.
denotes a separator which may be <,> or a space or <=>.
The last two are only acceptable between the header and
the first parameter~ not between parameters.
indicates commands which can be executed in REMOTE
Queries (terminated with a <?>) are always allowed.
only.
** indicates commands which can only be executed in REMOTE when
the display intensity controls have also been set to REMOTE.
Example:
TIME/DIV (TD) , < ?
< [ 2 NS to I00 S ] >
"TIME/DIV" is the long format of the
time base.
command for controlling the
"TD" is the short form equivalent of
be used at all times.
"TIME/DIV". Either form may
The comma is the separator between the header and the first
parameter. It may be replaced by a space or by an equal sign <=>,
or by any combination of these. Note that subsequent parameters
MUST be separated from each other by commas only.
The parentheses < > show that the choice of the first (and only)
parameter is either <?> or a time base value in the range of
2 nsec to I00 sec.
The asterisk <*> indicates that this command can only be executed
when the 9400A is in the REMOTE state. However
the query
¯ , can be executed at any time.
"TIME/DIV7,,
Remote Operations
7-11
7.6.2
Acquisition
Parameter
Commands
, <?
>
< [ 2 NS to I00 S ] >
i) TIME/DIV (TD)
Other available suffixes are: US (Bsec, microseconds) and MS (msec,
milliseconds).
The 9400A sets the VALUE ADAPTED bit:
- if an out-of-range value is given.
- if a value outside the incremental steps of i, 2, 5 is given.
Examples:
TD = ?
TD 20 US
TIME/DIV 12 MS
Instructs the 9400A to send the current time base
value.
Sets the 9400A to 20 Bsec per division.
Sets the 9400A to I0 msec; since the value is
modified from 12 msec to I0 msec, the VALUE ADAPTED
bit in status byte 1 is set.
2) INTERLEAVED (IL)
, <?
< ON
< OFF
>
>
>
*
*
Enables or disables Interleaved Sampling.
The 9400A sets the ENVIRONMENT ERROR:
- if ON command is sent while the time base is greater than 2 US.
- if OFF command is sent while the time base is less than 50 NS.
3) TRIG DELAY
(TRD)
Positive format:
Negative format:
, < ?
< [ 0.00 % to i00.00 %
< [ -0.04 NS to -I000000
] >
S ] >
pre-trigger.
post-trigger delay.
Valid delay v~ues correspond to 0 to i0000 time base divisions in
steps of 1/50
of a division. If the TIME BASE is changed, the
delay remains the same or may change just slightly due to rounding,
provided that it does not exceed I0000 divisions.
Note:
In the case of post-trigger delay, the remote value is negative
while the corresponding value displayed on the screen is positive.
Remote Operations
7-12
The 9400A sets the VALUE ADAPTED bit:
- if a positive out-of-range value is given.
- if a negative value corresponding to more than i0000 divisions is
given.
4) TRIG LEVEL (TRL) , < ?
, < [ -5.00 DIV to 5.00 DIV ] >
when the oscilloscope
internal
trigger
CHANNEL_2).
is set
sources
, < [ -2.00 V to 2.00 V ]
>
when the oscilloscope
trigger source.
, < [ -20.0 V to 20.0 V ]
when the oscilloscope
trigger source.
is set
to one of the
(CHANNEL_I or
to in
the
EXT
>
is set
to the
EXT/10
When the oscilloscope is set to LINE trigger source, this command
has no meaning and no error will be reported. In the case of POS_NEG
triggering, only a positive value is meaningful.
The 9400A sets the VALUE ADAPTED bit:
- if an out-of-range value is given.
The 9400A sets the ENVIRONMENT ERROR:
- if the DIV suffix is sent instead of V or if the V suffix is sent
instead of DIV.
5) TRIG COUPLING (TRC)
6) TRIG MODE (TRM)
, <
<
<
<
<
?
AC
DC
LF REJ (LF)
HF-REJ (HF)
>
>
>
, <
<
<
<
<
?
SEQNCE (SE)
AUTO (AU)
NORM (NO)
SINGLE (Sl)
>
>
>
>
>
*
*
*
*
*
*
*
*
The 9400A sets the ENVIRONMENT ERROR:
- if SEQNCE is sent while the 9400A is in Interleaved Sampling.
7) TRIG SOURCE (TRS) , < ?
< CHANNEL i (CI)
< CHANNEL-2 (C2)
>
< LINE (eI)
>
< EXT (EX)
< EXT/IO (E/IO) >
Remote Operations
7-13
*
*
*
*
*
8) TRIG SLOPE (TRP)
9) SEGMENTS (SEG)
>
?
>
POS (P0)
>
NEG (NE)
POS NEG (PN)
*
*
*
>
>
>
>
>
>
>
*
*
*
*
*
*
, <
<
<
<
, <?
<8
< 15
< 31
< 62
< 125
< 250
Indicates or selects the number of segments for waveforms acquired
in SEONCE mode.
, <?
>
< [ 5.000 MV to 12.500 V ] >
i0) CHANNEL 1 VOLT/DIV (CIVD)
CHANNEL 2 VOLT/DIV (C2VD)
The range of the Volts/div setting is limited
division in the case of 50 Q coupling.
to 2.5 Volts per
Note that this value corresponds to the 9400A input gain. It does
not take probe attenuation factors into account.
The 9400A sets the VALUE ADAPTED bit:
- if an out-of-range value is given.
Examples:
CHANNEL_2_VOLT/DIV,500 MV
CIVD=.5
C2VD 120 MV
ii) CHANNEL 1 ATTENUATION (CIAT)
CHANNEL 2 ATTENUATION (C2AT)
Sets channel 2 to 500 mV/div
Sets channel 1 to 500 mV/div
Sets channel 2 to 120 mV/div by
choosing I00 mV/div fixed gain and
setting the variable gain to the
required value.
, <?
< i
< I0
< i00
< I000
>
>
>
>
>
Indicates or selects the attenuation factor of the probe.
12) CHANNEL 1 OFFSET (CIOF)
CHANNEL 2 OFFSET (C20F)
, <?
>
< [ -8.00 DIV to 8.00 DIV ] >
The 9400A sets the VALUE ADAPTED bit:
- if an out-of-range value is given.
Remote Operations
7-14
*
*
*
*
, <?
< AC 1 MOHM (AIM)
< DC 1 MOHM (DIM)
< GND
< DC 50 OHM (D50)
13) CHANNEL I COUPLING (CICP)
CHANNEL 2 COUPLING (C2CP)
,
14) BANDWIDTH (BW)
>
>
>
>
>
*
*
*
*
<?
>
< ON >
< OFF >
*
*
15) STOP
Stops the acquisition of a signal. This command may be used to
return the 9400A from the "armed" state to the "triggered" state,
when the trigger is absent. It generates records similar to those
produced in the AUTO trigger mode.
It is also useful to stop a SEQNCE acquisition when the number of
triggers available is insufficient to fill all sweeps. Upon receipt
of the STOP command, the 9400A displays the artificially completed
sweeps as GND lines.
7.6.3
Display Commands
i) DUAL
-
GRID
(DG)
, <
< ON >
< OFF >
*
*
Examples:
Instructs the 9400A to display dual
grids.
Instructs the 9400A to display a
single grid of 8 x i0 squares.
DUAL GRID ON
DG OFF
2) TRACE CHANNEL I (TRCI)
TRACE-CHANNEL-2 (TRC2)
TRACE-EXPAND A (TREA)
TRACE-EXPAND-B (TREB)
TRACE-MEMORY-C (TRMC)
TRACE-MEMORY-D (TRMD)
TRACE-FUNCTION E (TREE)
TRACE-FUNCTION-E (TREE)
, <?
< ON
< OFF
>
>
>
*
*
The 9400A sets the ENVIRONMENT ERROR:
- i~h 4 traces are already ON, and a command is received
5 trace ON.
to turn a
Remote Operations
7-15
Examples:
TRCI ?
TRMC = OFF
3) SELECT (SEL)
Instructs
the 9400A to send a message,
indicating whether the display of channel I is
on or off.
Instructs the 9400A to turn the display of
memory C off.
, <?
< EXPAND A (EA)
< EXPAND-B (EB)
< MEMORY-C (MC)
< MEMORY-D (MD)
< FUNCTION E (FE)
< FUNCTION-F (FF)
>
>
>
>
>
>
>
*
*
*
*
*
*
Selects a display trace, similar to the front panel control.
Thereafter, the commands VERT GAIN, VERT POSITION, TIME_MAGNIFIER,
HOR POSITION and REDEFINE will-be applied to the SELECTed trace.
The 9400A sets the ENVIRONMENT ERROR:
- if the SELECTed trace is OFF.
>
4) VERT GAIN (VG) , < ?
< [ 1.000 to 2.500 ] >
ii
ii
ii
ii
II
II
II
II
I
VERT GAIN is applied to the SELECTed trace. This command instructs
the 9400A to modify the display gain (not the acquisition gain) by
factor of up to 2.5.
II
II
II
Remote Operations
7-16
Adj us tment
Reduce
Manually
Signal
Size
Increase
Signal
Size
Turn the Vert. Gain knob
anti-clockwise.
Turn the Vert. Gain knob
clockwise.
Notice that a ">" symbol
appears in the window* on
9400A screen.
Notice that the volts
value in the window*
changes,
e.g.
".5 V"
changes to "> .2 V"
Read the exact V/div in
the memory STATUS menu.
Read the exact
V/div in
the memory STATUS menu.
Enter the command "VG ?"
The response is a value between i and 2.5.
Query
Exact V/div = response x value indicated in the
select window on 9400A screen.
Remote
Control
I
Enter "VG" followed by a
value between I and 2.5
to attenuate the signal
up to 2.5 times.
Not possible
I
* assumes that cursors are not being used
The 9400A sets the VALUE ADAPTED bit:
- if an out-of-range value is given.
The 9400A sets the ENVIRONMENT ERROR:
- if the SELECTed trace is OFF.
5) VERT POSITION (VP)
>
, <?
< [ -16.00 DIV to 16.00 DIV ] >
VERT POSITION is applied to the SELECTed trace. This command
instructs
the 9400A to modify the display position (not the
acquisition offset) of the selected trace by up to ± 16 divisions,
relative to the original position at acquisition.
Remote Operations
7-17
The 9400A sets the VALUE ADAPTED bit:
- if an out-of-range value is given.
The 9400A sets the ENVIRONMENT ERROR:
- If the SELECTed trace is OFF.
6) TIME MAGNIFIER
(TM) , < ?
< [ 0 to6 ] >
TIME MAGNIFIER is applied to the SELECTed trace. It may only be
applTed to traces EXPAND A or EXPAND B.
The value 0 corresponds
to no expansion.
Each increment of I
corresponds to the next lower time base value (relative to the
original trace). The value 6 therefore allows an expansion by
factor of I00.
The 9400A sets the VALUE ADAPTED bit:
- if an out-of-range
positive value
generate a semantic error.
is given.
Negative values
The 9400A sets the ENVIRONMENT ERROR:
- if the SELECTed trace is OFF.
- if the SELECTed trace is neither EXPAND A nor EXPAND B.
>
7) HOR POSITION (HP) , <
, < [ 0.0000 DIV to i0.0000 DIV ] >
when the source trace corresponds to a single
waveform
(acquired
in single shot or with
INTERLEAVED ON).
, < [ 1 to max ] >
when the source trace corresponds to multiple
waveforms (acquired in SEQNCE).
The parameter
indicates
the number of the
sequence to be displayed. "max" depends on the
selected number of segments (see SEGMENTS).
HOR POSITION will be applied to the SELECTed trace. It may only be
applied to traces EXPAND A or EXPAND B. The parameter in the range
0 to I0 divisions corresponds to The CENTER of the intensified
region on the original
trace. The smallest possible step is
0.0004 div.
The 9400A sets the VALUE ADAPTED bit:
- if an out-of-range value is given (Interleaved Sampling or Single
Shot).
- if a positive out-of-range value is given (SEQNCE). Negative
zero values generate a semantic error.
Remote Operations
7-18
The 9400A sets the ENVIRONMENT ERROR:
- if the SELECTed trace is OFF.
- if the SELECTed trace is neither EXPAND A nor EXPAND B.
8) REDEFINE (RDF)
, <
<
<
<
<
?
CHANNEL I (Cl)
CHANNEL-2 (C2)
MEMORY C (MC)
MEMORY-D (MD)
>
>
>
>
>
*
*
*
*
Redefines
the source of the SELECTed
trace to
or MEMORY_D. The SELECTed
CHANNEL 2, MEMORY_C,
EXPAND A or EXPAND B.
be CHANNEL i,
trace must be
The 9400A sets the ENVIRONMENT ERROR:
- if the SELECTed trace is OFF.
- if the SELECTed trace is neither EXPAND A nor EXPAND B.
9) MESSAGE (MSG)
, <String to be displayed>
The string may be up to 43 characters in length. The message is
the Message
Field above the graticule
(see
displayed
in
Section 4.6).
Example:
MESSAGE "Apply probe to Jll.5, then press READY"
Instructs the 9400A to display the
string delimiters " on the line above
The push button READY does not exist
of 9 soft keys may be defined as such
message between the
the graticule.
on the 9400A, but any
with the command KEY.
i0) KEY , < [I to 9] > , <String to be displayed>
The string is displayed in the Menu Field (see Section 4.1) next
the soft key selected with the first parameter. The string may be up
to Ii characters in length.
Examples:
KEY 3,!READY!
Instructs the 9400A to display the message "READY" next to
the third (from the top) soft key on the left hand side
the graticule. This command is only accepted if the string
delimiter has been changed from the default value <"> to
<!> with the command COMM STRDELIM=33. The default value
<"> = 34 (see Section 7.6.7).
Remote Operations
7-19
KEY l, "Restart"
Instructs the 9400A to display the message "Restart" next
to the first soft key. Here, the default string delimiter
is used.
11)
SCREEN (SCR)
, <?
>
< REMOTE (RM)
< LOCAL (LC)
*
*
or
SCREEN (SCR) , < ON
< OFF
**
**
>
or
SCREEN (SCR) , < INTENSITY (INT)
> , [0 to
< GRID INTENSITY (GI)>
**
**
"?" allows the user to know the status of the screen.
"REMOTE" and "LOCAL" select the control mode of the screen.
When the 9400A is set to REMOTE, the screen remains under LOCAL
control allowing the operator to adjust the display intensity. The
screen itself must be put into the REMOTE state using the command
SCREEN (SCR) , <ON> before the commands marked with "**" are valid.
"ON" and "OFF" turn the screen ON an OFF respectively.
When the 9400A is being used to capture transients automatically
without a user looking at the display, the display may be turned
off. This improves the response time of the instrument since display
generation, which may take up to I00 msec, is suppressed.
"INTENS" and "GRID INT" set the display intensity.
The 9400A sets the VALUE ADAPTED bit:
- if a value greater than 170 is given.
7.6.4
Plotter
Commands
i) PLOTTER (PT)
,
<?
>
or
PLOTTER (PT)
, <name> , <port> , <speed> , <pens>
Remote Operations
7-20
<name>
=
<
<
<
<
<port>
=
< RS232 (RS)
< GPIB (SP)
<speed>
<pens>
GRAPHTEC (GR)
HEWLETT PACKARD (HP)
PHILIPS (PH)
TEKTRONIX (TEK)
>
>
>
>
< NORMAL SPEED (NS)
< LOW SPEED(LS)
=
[ 1 to 9 ]
Configures the 9400A for a predefined plotter.
Examples:
PLOTTER HP,RS,NS,2
Configures
the 9400A for a Hewlett-Packard
plotter,
connected to the RS-232-C plotter port, running at normal
speed, with 2 pens. This is how the 9400A must be
configured
for the HP7470 and HP7475 or compatible
plotters.
PT,GR,GP,LS,4
Configures the 9400A for a Graphtec FP5301 or compatible
plotter, connected through GPIB, running at low speed (for
plotting on transparencies), with 4 pens.
2) PLOT SIZE (PS)
,
<? >
< A5 >
< A4 >
< A3 >
*
*
*
Configures the 9400A to plot onto a predefined paper size.
AS=
A4=
A3 =
148 mm by 210 mm, compatible with U.S. 5 1/2" by 8 1/2"
210 mm by 297 mm, compatible with U.S. 8 1/2" by II"
297 mm by 420 mm, compatible with U.S. ii" by 17"
or
PLOT SIZE (PS) , NON STANDARD (NSTD) , <grid> , <x> ,
Configures the 9400A to plot onto a non-standard paper size.
<grid>
=
[ 00.0 MM to 99.9 MM ]
Remote Operations
7-21
<x>
=
[ 0 MM to 999 MM
]
[ 0 MM to 999 MM
]
<y>
<grid> is the size (length of a side) of the standard square
within the 8 times I0 squares grid.
<x>,<y> are the positions of the lower left hand corner of the
graticule with respect to the origin of the plotter.
The 9400A sets the VALUE ADAPTED bit:
- if an out-of-range
positive value
generate a semantic error.
is given.
Negative values
*
3) SCREEN DUMP (SD)
Instructs the 9400A to dump the screen display onto the plotter.
4) TRANSMIT (TX) , <String to be transmitted to the plotter>
Instructs the 9400A to transmit a character string to the plotter.
The string may be up to 43 characters in length and may include
commands such as "paper advance" or "print string". This enables the
user to add comments to a plot, or generate multiple plots by remote
control.
The 9400A sets the ENVIRONMENT ERROR:
- if the 9400A is controlled through GPIB and if the plotter access
port is the GPIB port.
7.6.5
Transfer Comm~,ds
i) STORE
(STO)
, [ 1 to
instructs the 9400A to store the current front panel configuration
in one of 7 non-volatile storage areas for later recall.
or
STORE (STO)
, < CHANNEL 1 (CI) > , < MEMORY C (MC)
< CHANNEL-2 (C2) > < MEMORY-D (MD)
instructs
the 9400A to store the waveform
and the waveform
descriptor of either Channel 1 or 2 into reference memories C or D.
Notes:
If the 9400A receives a command to store Channel 1 or 2 while it is
acquiring data, the execution of the command is delayed until the
trigger has arrived.
Remote Operations
7-22
No message will be displayed
performed.
on the screen when the operation
is
2) RECALL (REC) , [ 1 to
instructs the 9400A to recall one of 8 front-panel configurations
stored in non-volatile memory. The value "8" corresponds to the
default setup.
3)
SETUP
(SU)
or
SETUP (SU)
*
The first form permits the complete setup to be read in internal
data representation. Transmission format depends on the selected
forms by the COMM FORMAT command. The setup data block corresponds
to 257 binary bytes.
The second form permits setup data to be sent to the 9400A in the
same form as they were read from the 9400A. This command must be
terminated
with <END>, i.e. it must be the last of a list of
commands. The data transferred to the 9400A must be contained in a
separate block (see Section 7.5).
Note:
The serial port parameters can not be transmitted. In particular, if
the transfers are by RS-232-C, modification of the serial port
parameters by this command would bring about some strange results.
The 9400A sets the VALUE ADAPTED bit:
- if a data value in the block is incorrect. The DEFAULT setup will
be used in this case.
The 9400A sets the INVALID BLOCK ERROR:
- if the received block(s) is incorrect.
4) READ (RD)
, <
<
<
<
CHANNEL I.DESC
CHANNEL-2.DESC
MEMORY C.DESC
MEMORY D.DESC
(CI.DE)
(C2.DE)
(MC.DE)
(MD.DE)
transfer the descriptor of the indicated waveform from the 9400A to
the host computer. See Section 7.7 for the format of this data
block.
or
Remote Operations
7-23
READ (RD)
, <
<
<
<
CHANNEL1.DATA
CHANNEL 2.DATA
MEMORY C.DATA
MEMORY-D.DATA
(CI.DA) > , <Parameter list>
(C2.DA) >
(MC.DA)
(MD.DA)
<Parameter list> = <intval> , <# values> , <addr> , <sweep #>
transfer the data values of the indicated waveform from the 9400A to
the host computer. An explanation of the optional parameter list is
given below.
or
READ (RD)
, <
<
<
<
CHANNEL 1.TIME
CHANNEL-2.TIME
MEMORY C.TIME
MEMORY-D.TIME
(CI.TI)
(C2.TI)
(MC.TI)
(MD.TI)
transfer the trigger time(s) of the indicated waveform from the
9400A to the host computer. See Section 7.8 for the format of this
data block.
or
READ (RD)
, <
<
<
<
CHANNEL I.* (CI.*) > , <Parameter list>
CHANNEL-2.* (C2.*)
MEMORY C.* (MC.*)
MEMORY-D.* (MD.*)
transfer ALL visible data of the indicated waveform from the 9400A
to the host computer. Data are transferred in the order descriptor,
data, time(s).
<Parameter list> = <intval> , <# values> , <addr> , <sweep #>
<intval>
= [ 1 to
16000
Interval between data points to be
read, for example:
I = read all points
4 = leave out 3 of 4 data values
]
<# values>= [ 0 to 32000 ]
Number of data values to read
<addr>
Address
of first
data
relative to the left hand
the screen
= [ -32000 to 32000 ]
<sweep #> = [ 0 to 250 ]
Sweep number in SEQNCE
numbered from
1 to max. # sweeps
0 = read all sweeps
point
side of
waveforms,
Remote Operations
7-24
The parameter list is optional. Any omitted parameter
default value:
<intval>
<# values>
<addr>
<sweep #>
=
=
=
=
is set to a
i, i.e. leave no values out
# values on the screen
address of left-most value on the screen
0, i.e. read all sweeps
Thus, the omission of all parameters results in all the data values
on the screen being read. A detailed explanation
of the data
addressing conventions is given in Section 7.9.
If the user does not specify the number of data values, READ DATA
transfers are executed over the number of data values displayed on
screen + i, i.e. if the screen shows nominally 25000 data values,
25001 values are transferred.
Data formats:
- The descriptor (.DESC), the data (.DATA) and the time(s)
(.TIME) are each transmitted as a single block unless
maximum block size has been specified with the command
COMM BLOCKSIZE.
- When all data are read (.*), they are transmitted as three
blocks in the order: descriptor, data, time(s).
- When all sweeps of a SEQNCE data record are read (sweep #
0), each sweep is transmitted as a separate block.
- The parameter <# values> applies to the number
values per sweep in the case of SEQNCE data.
of data
Note:
If the 9400A receives a command to read CHANNEL I or CHANNEL 2 while
it is acquiring data, the execution of the command will be-delayed
until the TRIGGER has arrived.
The 9400A sets the VALUE ADAPTED bit:
- if <intval> is greater than 16000 (it is adapted to 16000).
- if <# values> corresponds to too large a value (it is adapted to
the number corresponding to the last accessible value).
- if <addr> is out of range (it is adapted to the nearest legal
address).
- if <sweep #> is higher that the selected number of sweeps (it is
adapted to the last sweep number).
Remote Operations
7-25
Examples:
READ,CI.DE
Instructs
the 9400A to transmit the
waveform descriptor of Channel 1 in the
format described in Section 7.7. If the
9400A
is armed
and waiting
for a
trigger, the execution is deferred until
the waveform is acquired.
READ,MC.DA
Instructs the 9400A to transmit all data
values of Memory C which would appear on
the screen, but no descriptor or trigger
time(s).
READ,MC.DA,,,-7000
Instructs the 9400A to transmit all data
points of Memory C, starting
-7000
(invisible) points before the left hand
side of the screen, up to the last value
at the right hand side.
READ,CI.DA,5,100,1000
Instructs the 9400A to transmit I00 data
values of Channel i, starting
i000
values to the right of ~e beginning of
the screen. Only every 5 data value is
transmitted, i.e. 4 out of 5 values are
omitted.
READ,MD.DA,,,,5
Instructs the 9400A to transmit all data
values of sweep #5 from the SEQNCE data
record in memory D. If memory D is not a
SEONCE record, the last parameter is
ignored,
and the command
would be
interpreted as READ,MD.DA, resulting in
the transmission of all (visible) data
of the memory D.
READ,CHANNEL 2.*
Instructs
the 9400A to transmit the
waveform descriptor, data and time(s)
Channel 2. This is the most complete
(and safest) way to archive the visible
part of a waveform. The host computer
can restore the complete waveform in
memories C or D with the command WRITE
MC.*, followed by the transmission of
the data records.
Remote Operations
7-26
READ,CHANNEL_2.*,,,-32000 Instructs
the 9400A to transmit the
waveform descriptor, data and time(s)
Channel 2, including all invisible data
values on the left-hand
side of the
screen. The address -32000 is
usually
out
of range,
but
the
9400A
automatically
adapts to the
closest
legal value. This complete data record
is restored in memory C with the command
WRITE MC.*,,,-32000.
5) WRITE (WT)
, < MEMORY C.DESC
< MEMORY-D.DESC
(MC.DE)
(MD.DE)
*
*
transfer the waveform descriptor from the host computer to the
indicated
memory location of the 9400A. This command must be
followed by the descriptor block(s). The 9400A checks the limits
each parameter transmitted. If any value is out of range, or the
number of values transmitted is incorrect, the entire descriptor
block is considered invalid and is discarded.
WRITE (WT) , < MEMORY C.DATA (MC.DA) > , <Param.list>
< MEMORY-D.DATA (MD.DA)
*
*
<Parameter list> = <intval> , <# values> , <addr> , <sweep #>
transfer data values from the host computer to the indicated
memory location of the 9400A. This command must be followed by the
data value block(s). See the READ command for an explanation
<Parameter list>.
or
WRITE (WT) , < MEMORY C.TIME (MC.TI)
< MEMORY-D.TIME (MD.TI)
*
,
transfer trigger time(s) from the host computer to the indicated
memory location of the 9400A. This command must be followed by the
trigger time block. If the number of values transmitted
is
incorrect, the entire block is discarded.
When transferring WRITE DATA without specifying the number of data
values, the nominal number + i data values must be sent to the 9400A
(25000 + 1 data values for example). This additional value may
needed for the generation of the last displayed point at the right
hand side of the screen.
or
WRITE (WT) , < MEMORY C.* (MC.*) > , <Parameter list>
< MEMORY-D.* (MD.*)
Remote Operations
7-27
*
*
<Parameter llst> = <intval>,<# values>,<addr>,<sweep #>
transfer ALL data from the host computer to the indicated memory
location of the 9400A. This command must be followed by the data
blocks in the order: descriptor, data, trigger time(s).
See the READ command for an explanation of <Parameter list>.
In general, the 9400A decodes and checks each WRITE command it receives
and verifies the optional parameters. If it receives a WRITE command
for a complete waveform ( WRITE xx.*), the parameters are only checked
after the DESCRIPTOR block has been transmitted.
If the <intval>
parameter is not I, intermediate points will be computed with a linear
interpolation.
DESCRIPTOR values are checked for consistency after the entire block
has been received. If an error is detected, the entire block is
discarded and the invalid data block has no effect on the currently
stored descriptor. The same is true for the time block.
However the waveform DATA values are directly stored into the final
buffer during transmission. If an error occurs during the transfer, the
data memory might be only partially filled with the new data.
The 9400A sets the VALUE ADAPTED bit:
- if a numerical parameter had to be modified during checking.
- if less or more DATA values have been received than were indicated by
the numerical parameters (after checking) and only if the number
DATA values is not greater than the number of values remaining until
the end of the sweep buffer.
The 9400A sets the INVALID BLOCK ERROR if an error in a block has been
detected, i.e. if:
- The preamble is incorrect (is not #A, #L or #I)
- The preamble number (indicating how many values the block has)
greater than the number of values that are allowed (SETUP,
DESCRIPTOR or TIME) or greater than the number of values remaining
until the end of the sweep buffer (DATA).
- The number of received values does not correspond to the number in
the preamble.
- In the case of ASCII blocks (#L format), there are characters which
are neither separator characters (",", CR or LF) nor digits.
- In the case of ASCII blocks, a value is greater than 255 (BYTE or
bits transfer) or greater than 65535 (WORD or 16 bits transfer).
- Other errors:
- Too many or too few values have
or TIME).
been received (SETUP, DESCRIPTOR
Remote Operations
7-28
READ,CHANNEL
5) WRITE (WT)
2.*,,,-32000
Instructs the 9400A to transmit the
waveform descriptor, data and time(s)
Channel 2, including all invisible data
values on the left-hand side of the
screen. The address -32000 is usually
out
of range,
but
the
9400A
automatically
adapts to the
closest
legal value. This complete data record
is restored in memory C with the command
WRITE MC.*,,,-32000.
, < MEMORY C.DESC
< MEMORY-D.DESC
(MC.DE)
(MD.DE)
*
*
transfer the waveform descriptor from the host computer to the
indicated
memory location of the 9400A. This command must be
followed by the descriptor block(s). The 9400A checks the limits
each parameter transmitted. If any value is out of range, or the
number of values transmitted is incorrect, the entire descriptor
block is considered invalid and is discarded.
WRITE (WT) , < MEMORY C.DATA (MC.DA) > , <Param.list>
< MEMORY-D.DATA (MD.DA)
*
*
<Parameter list> = <intval> , <# values> , <addr> , <sweep #>
transfer data values from the host computer to the indicated
memory location of the 9400A. This command must be followed by the
data value block(s). See the READ command for an explanation
<Parameter list>.
or
*
*
WRITE (WT) , < MEMORY C.TIME (MC.TI)
< MEMORY-D.TIME (MD.TI)
transfer trigger time(s) from the host computer to the indicated
memory location of the 9400A. This command must be followed by the
trigger time block. If the number of values transmitted
is
incorrect, the entire block is discarded.
When transferring WRITE DATA without specifying the number of data
values, the nominal number + I data values must be sent to the 9400A
(25000 + 1 data values for example). This additional value may
needed for the generation of the last displayed point at the right
hand side of the screen.
or
WRITE (WT) , < MEMORY C.* (MC.*) > , <Parameter list>
< MEMORY-D.* (MD.*)
Remote Operations
7-27
*
*
<Parameter list> = <intval>,<# values>,<addr>,<sweep #>
transfer ALL data from the host computer to the indicated memory
location of the 9400A. This command must be followed by the data
blocks in the order: descriptor, data, trigger time(s).
See the READ command for an explanation of <Parameter list>.
In general, the 9400A decodes and checks each WRITE command it receives
and verifies the optional parameters. If it receives a WRITE command
for a complete waveform ( WRITE xx.*), the parameters are only checked
after the DESCRIPTOR block has been transmitted. If the <intval>
parameter is not i, intermediate points will be computed with a linear
interpolation.
DESCRIPTOR values are checked for consistency after the entire block
has been received. If an error is detected, the entire block is
discarded and the invalid data block has no effect on the currently
stored descriptor. The same is true for the time block.
However the waveform DATA values are directly stored into the final
buffer during transmission. If an error occurs during the transfer, the
data memory might be only partially filled with the new data.
The 9400A sets the VALUE ADAPTED bit:
- if a numerical parameter had to be modified during checking.
- if less or more DATA values have been received than were indicated by
the numerical parameters (after checking) and only if the number
DATA values is not greater than the number of values remaining until
the end of the sweep buffer.
The 9400A sets the INVALID BLOCK ERROR if an error in a block has been
detected, i.e. if:
- The preamble is incorrect (is not #A, #L or #I)
- The preamble number (indicating how many values the block has)
greater than the number of values that are allowed (SETUP,
DESCRIPTOR or TIME) or greater than the number of values remaining
until the end of the sweep buffer (DATA).
- The number of received values does not correspond to the number in
the preamble.
- In the case of ASCII blocks (#L format), there are characters which
are neither separator characters (",", CR or LF) nor digits.
- In the case of ASCII blocks, a value is greater than 255 (BYTE or
bits transfer) or greater than 65535 (WORD or 16 bits transfer).
- Other errors:
- Too many or too few values have
or TIME).
been received (SETUP, DESCRIPTOR
Remote Operations
7-28
READ,CHANNEL
5) WRITE (WT)
2.*,,,-32000
Instructs the 9400A to transmit the
waveform descriptor, data and time(s)
Channel 2, including all invisible data
values on the left-hand
side of the
screen. The address -32000 is usually
out
of range,
but
the
9400A
automatically
adapts to the
closest
legal value. This complete data record
is restored in memory C with the command
WRITE MC.*,~,-32000.
, < MEMORY C.DESC
< MEMORY D.DESC
*
*
(MC.DE)
(MD.DE)
transfer
the waveform
descriptor
from the host
computer
to the
indicated
memory location
of the
9400A.
This
command must be
followed
by the descriptor
block(s).
The 9400A checks the limits
each parameter
transmitted.
If any value
is out of range,
or the
number of values
transmitted
is incorrect,
the entire
descriptor
block is considered
invalid
and is discarded.
WRITE (WT) , < MEMORY C.DATA (MC.DA) > , <Param.list>
< MEMORY D.DATA
(MD.DA)
*
*
<Parameter list> = <intval> , <# values> , <addr> , <sweep #>
transfer
data
values
from the host
computer
memory location
of the 9400A. This command must
data
value
block(s).
See the READ command for
<Parameter
list>.
to the indicated
be followed
by the
an explanation
or
WRITE (WT)
, < MEMORY C.TIME
< MEMORY D.TIME
(MC.TI)
(MD.TI)
*
*
transfer
trigger
time(s)
from the host
computer
memory location
of the 9400A. This command must
trigger
time
block.
If the
number
of values
incorrect,
the entire
block is discarded.
to the indicated
be followed
by the
transmitted
is
When transferring WRITE DATA without specifying the number of data
values, the nominal number + I data values must be sent to the 9400A
(25000 + 1 data values for example). This additional value may
needed for the generation of the last displayed point at the right
hand side of the screen.
or
WRITE (WT) , < MEMORY C.* (MC.*) > , <Parameter list>
< MEMORY D.* (MD.*)
Remote
7-27
Operations
*
*
<Parameter list> = <intval>,<# values>,<addr>,<sweep #>
transfer
ALL data
from the host
computer
to the indicated
memory
location of the 9400A. This command must be followed by the data
blocks in the order: descriptor, data, trigger time(s).
See the READ command for an explanation of <Parameter list>.
In general, the 9400A decodes and checks each WRITE command it receives
and verifies the optional parameters. If it receives a WRITE command
for a complete waveform ( WRITE xx.*), the parameters are only checked
after the DESCRIPTOR block has been transmitted. If the <intval>
parameter is not i, intermediate points will be computed with a linear
interpolation.
DESCRIPTOR values are checked for consistency after the entire block
has been received. If an error is detected, the entire block is
discarded and the invalid data block has no effect on the currently
stored descriptor. The same is true for the time block.
However the waveform DATA values are directly stored into the final
buffer during transmission. If an error occurs during the transfer, the
data memory might be only partially filled with the new data.
The 9400A sets the VALUE ADAPTED bit:
- if a numerical parameter had to be modified during checking.
- if less or more DATA values have been received than were indicated by
the numerical parameters (after checking) and only if the number
DATA values is not greater than the number of values remaining until
the end of the sweep buffer.
The 9400A sets the INVALID BLOCK ERROR if an error in a block has been
detected, i.e. if:
- The preamble is incorrect (is not #A, #L or #I)
- The preamble number (indicating how many values the block has)
greater than the number of values that are allowed (SETUP,
DESCRIPTOR or TIME) or greater than the number of values remaining
until the end of the sweep buffer (DATA).
- The number of received values does not correspond to the number in
the preamble.
- In the case of ASCII blocks (#L format), there are characters which
are neither separator characters (",", CR or LF) nor digits.
- In the case of ASCII blocks, a value is greater than 255 (BYTE or
bits transfer) or greater than 65535 (WORD or 16 bits transfer).
- Other errors:
- Too many or too few values have
or TIME).
been received (SETUP, DESCRIPTOR
Remote Operations
7-28
-
The string beginning with a character other than "#" is received
while the 9400A expects a block.
Such an error happens if the 9400A, previously configured to work
without the END block (#I), receives less data than expected,
followed by a command.
Too many blocks have been received.
-
If the 9400A detects an error while receiving
data
remaining values in the block, as well as the following
purged until END block (#I) or a command is received.
blocks, any
blocks are
When a command is received instead of a block, block transfer
aborted, but the command will be decoded like any other command.
is
When a block is received without being preceded by the WRITE command,
the block will be purged and syntax error ii will be produced (Invalid
Header).
Note: Block data must end with a legal Trailer such as <CR>, <LF> or
<CRLF>.
6) INSPECT (INS)
, <
<
<
<
CHANNEL 1.LIMIT
CHANNEL-2.LIMIT
MEMORY C.LIMIT
MEMORY-D.LIMIT
(CI.LI)
(C2.LI)
(MC.LI)
(MD.LI)
instructs the 9400A to return a character string containing
lower and upper address limits of the current waveform,
the
or
INSPECT (INS)
, <
<
<
<
CHANNEL I.NSWEEPS
CHANNEL-2.NSWEEPS
MEMORY C.NSWEEPS
MEMORY-D.NSWEEPS
(CI.NS)
(C2.NS)
(MC.NS)
(MD.NS)
instructs the 9400A to return a character string containing
number of sweeps (in averaging and extrema),
the
or
INSPECT (INS)
, < MEMORY C.INTVAL
< MEMORY-D.INTVAL
(MC.IV)
(MD.IV)
instructs the 9400A to return a character string, containing the
interval between data points used by a waveform processing function.
This value may be used as the <intval> parameter in the readout of
such waveforms if the user wishes to read only the computed data
points and none of the interpolated points.
Remote Operations
7-29
7.6.6
Other
Remote Commands
1) CALIBRATE (CAL)
forces
input
the 9400A to do a calibration
channels
at the current
gain
of the interpolator
and bandwidth
settings.
and of both
or
CALIBRATE (CAL)
,
<? >
< ON >
< OFF >
*
*
allows automatic calibration (ON), disables automatic calibration
See
(OFF), or queries the state of the automatic calibration.
Section 9.4 for the conditions under which the 9400A calibrates
itself.
2) PROBE CAL (PC)
, [ 0.000V to 5.000V ]
, < AC >
< DC >
This command permits generation of a square signal (AC) with
period of 1.024 msec, or a continuous (DC) level at the specified
voltage at the probe test output.
When the 9400A returns to LOCAL, the default calibrator signal of 1
V (AC) is generated.
The 9400A sets the VALUE ADAPTED bit:
- if a positive out-of-range value is given.
3) AUTO STORE (AS) , ? >
<[0toS]
>
This command allows the user to query the 9400A on its AUTOSTORE
state or setting of the AUTOSTORE mode:
O:
i:
2:
3:
4:
5:
AUTOSTORE off
automatic storage of CHANNEL 1
automatic storage of CHANNEL-1
automatic storage of CHANNEL-2
automatic storage of CHANNEL-2
automatic storage of CHANNEL-1
and of CHANNEL 2 into MEMORY-D
into
into
into
into
into
MEMORY C
MEMORY-D
MEMORY-C
MEMORY-D
MEMORY-C
Remote
7-30
Operations
4) CALL
HOST (CH)
, <
< ON >
< OFF >
This command may be executed even while the 9400A is in LOCAL. When
the CALL HOST mode is set, the 9400A (only while it is in LOCAL)
displays -the message "Call Host" next to the soft key #7 of the
Main Menu. Whenever this soft key is pressed it will generate a
service request (SRO), provided that the masks of status byte 3 and
status byte 1 are correctly set (see Section 7.6.8). The purpose
this command is to allow the operator in an ATE setup (Automatic
Test Engineering) to call the host computer even while the 9400A is
in LOCAL mode, i.e. while the operator is permitted to change the
9400A front panel settings.
5) IDENTIFY
(ID)
Request for identification message. "?" may be omitted.
The 9400A will send the message "LECROY 9400A - V xxxxxx",
"xxxxxx" is the software version number.
where
6) WAIT
When the 9400A is acquiring a signal, the WAIT command stops any
command interpretation until the oscilloscope has been triggered.
7.6.7
Communication
Format Command
i) COMM HEADER (CHDR)
, < OFF
>
< SHORT (SHO)
< LONG (LG)
Defines the header format in the 9400A character strings in response
to queries. Options are no header, short or long formats. The
default is SHORT. When the header is OFF, the suffixes of the
dimensioned parameters are also suppressed.
2) COMM TRAILER (CTRL)
, <
<
<
<
CRLF
CR
LF
OFF
>
>
>
>
Defines the trailer format in the 9400A character
strings in
response to queries. OFF is only possible in RS-232-C control. The
default is CRLF.
Note:
In remote
control
E0I line set.
through
GPIB,
the
last
character
is
sent
with
Remote Operations
7-31
the
The 9400A sets the ENVIRONMENT ERROR:
- if command is CTRL OFF, while controlling via GPIB.
3) COMM HELP (CHLP)
, < OFF
>
< REM PORT (RPO)
< PLOT PORT (PeO)
Allows a HELP feature for the setup of remote control programs to be
turned on. When the HELP feature has been turned on, the 9400A
transmits character strings reflecting the message exchange between
the host computer and the oscilloscope to the REMOTE or to the
PLOTTER RS-232-C ports. These HELP messages can be viewed on a
normal display terminal.
4) COMM FORMAT (CFMT),A,
<BYTE>
<WORD>
Or
COMM FORMAT (CFMT),L,
<BYTE>,<HEX>
<WORD>,<UNSIGNED_FIXED(UFIX)>
or
COMM_FORMAT(CFMT),L,
<BYTE>,<UNSIGNED_SHORT(USHO)>,<COMMA>
"
"
"
<WORD>,
<CR>
<LF>
<CRLF>
Selects a block transfer format, as described in Section 7.5. In
RS-232-C remote control, only format L is available.
BYTE is for 8-bit data.
WORD is for 16-bit data. This format is normally used for 16-bit
data being read from Memory C, Memory D, Function E or Function F.
Raw data in Channel 1 and Channel 2 are always 8-bit data. It is
possible to read raw or processed data as 16-bit words. Raw data
have the measured
8-bit value in the most significant
byte
(transmitted
first), and zero in the least significant
byte
(transmitted after).
HEX results in 2 hexadecimal digits for each 8-bit value and in 4
hexadecimal digits for 16-bit value.
UNSIGNED
data.
FIXED uses 3 digits for BYTE data and 5 digits for WORD
UNSIGNED SHORT uses only as many digits as required but separates
data values with a sign. The last parameter selects the separator
between numbers.
The default is <COMMA>.
Remote
7-32
Operations
Example:
With "COMM FORMAT L,BYTE,UNSIGNED_SHORT,CRLF", a block will be:
#L
2
123
34
Whereas with "COMM_FORMAT L,BYTE,UNSIGNED_SHORT" it is:
#L,2,123,34
The 9400A sets the ENVIRONMENT ERROR:
- if the A format is selected while the 9400A is controlled through
RS-232-C.
5) COMM BLOCKSIZE (CBLS) -i
The data is transmitted in one block only, and
block (#I) is neither sent nor received.
the END
COMM BLOCKSIZE (CBLS) ,
The data is transmitted in one block only. The END block
(#I) will be sent and must be received. This is the
default block size.
COMM BLOCKSIZE (CBLS) , 40to 32000 ]
The data is transmitted in one or more blocks. The END
block (#I) will be sent and must be received with the
purpose of marking the end of the block transfer.
This command selects the maximum block size for data block transfers
(READ,WRITE,SETUP).
The specified block size includes all data
bytes, including preamble and postscript.
The 9400A sets the VALUE ADAPTED bit:
- if the numerical parameter is positive but less than 40 (it will
be adapted to 40) or if it is greater than 32000 (it will
adapted to 32000).
6) COMM STRDELIM (CSDE) , [ to127]
Defines the ASCII character that the 9400A recognizes as a string
delimiter. The default is the character <">, whose decimal value is
34.
Remote Operations
7-33
7) COMM PROMPT (CPRM) , < OFF
< prompt string >
Defines the 9400A prompt string which may be up to I0 characters
long. The default is OFF. This feature simplifies interactive
programming of the 9400A. When set, the host computer must read the
9400A after every command, even when no response is normally
expected. The 9400A responds either with the prompt string alone or
with its response, followed by the prompt, indicating that it is
ready for another command.
Summary of COMM default values:
COMM HEADER
COMM-TRAILER
COMM-HELP
COMM-FORMAT
:
COMM BLOCKSIZE :
COMM-STRDELIM :
COMM-PROMPT
7.6.8
Status
Byte
and Mask Register
SHORT
CRLF
OFF
GPIB: A format, BYTE
RS232: L format, BYTE, UFIX,COMMA
0
" (Decimal value: 34)
OFF
Commands
The 9400A contains a Main Status Byte (STB I) and 5 additional status
bytes, numbered from 2 to 6. Each status byte has an associated mask
register, also numbered from i to 6. The purpose of the status bytes is
to keep track of the internal conditions of the 9400A. The user can use
2 methods of staying informed:
- The status bytes can be read at any time, one by one or in a
single block, with or without simultaneous clearing. This method
ignores all mask registers. The host computer program is required
to continue testing a status bit of interest, e.g., bit #0 of the
OPERATION COMPLETE status byte (STB 5) after the SCREEN_DUMP
command.
- The user can configure the 9400A to generate an interrupt to the
host computer upon the occurrence of one or several conditions.
The user must demask the bit(s) of the status byte which
corresponds
to the condition(s),
by setting l’s into the
corresponding
bit of the mask in question. In addition, the
corresponding bit in the Main Status Byte (STB I) must also
demasked in order to allow the generation of the Service Request.
This method is much more efficient timewise, but requires a more
complex setup. In addition, the host computer must be configured
to handle an interrupt by the GPIB SRQ-line. See Section 7.11 for
more explanations and examples.
Remote Operations
7-34
Status bytes are cleared
command STB, but not with
by a Device Clear command.
a Device Clear command, or
Main Status
Byte
(except STB 4) when reading them with the
TSTB. They are also cleared on POWER ON and
Mask registers are cleared on POWER ON, with
by writing 0 into them.
(STB 1):
DI0 # Bit
# Associated
(1-8)
(0-7)
data
DIO-I
DIO-2
DIO-3
0
1
2
DIO-4
3
DIO-5
DIO-6
DIO-7
DIO-8
4
5
6
7
Significance
(to generate
none
STB 2
STB 3
STB
an SRQ)
VALUE ADAPTED
unspecified
SOFTKEY PRESSED or
CALL TO HOST
INTERNAL STATE has
CHANGED
OPERATION COMPLETE
ERROR detected
RQS (request for service)
MESSAGE READY
4
STB 5
STB 6
none
none
If one of the bits DIO-I to DIO-6 or DIO-8 becomes
1 and the
corresponding bit is set in the Main Mask register (MASK I), the RQS
bit is set to i, and a service request (SRQ) is generated if it is not
already pending. The bits associated with the lower status bytes (STB
to 6) are only set inside STBI if their masks allow the propagation of
the bits to STB1 (see description of the individual status bytes
below).
VALUE ADAPTED: set if a value associated with a remote control
command is out of range, and adapted to the closest legal value.
Bit I (DIO-2): reserved.
SOFTKEY PRESSED: set if one of the 9 soft keys (in REMOTE) or
the key CALL TO HOST (in LOCAL) has been pressed. The last key
only active after being setup by the command CALL HOST. The
identity of the soft key is coded in the SOFTKEY PRESSED status
byte (STB3).
INTERNAL STATE CHANGE: set if an internal state within the 9400A
has changed. The identity of the internal state is recorded in the
INTERNAL STATE status byte (STB 4).
OPERATION COMPLETE: set if an operation in the 9400A has been
completed. The associated OPERATION COMPLETE status byte (STB5)
contains the information about which operation has been completed.
ERROR: set if an error condition has been detected.
The error is coded in the associated ERROR status byte (STB 6).
Remote Operations
7-35
RQS: GPIB RQS bit,
indicating
if
a service
MESSAGE READY: set
to indicate
that
transmission
to the remote controller.
request
a message
is
is
pending.
ready
for
STB 2:
This status byte is unused and has no significance. However, it exists
and has an associated mask. The commands STB, MASK and TSTB act on all
6 status bytes or masks, including STB 2.
SOFTKEYPRESSED Status
Byte
(STB 3):
This status byte contains the coded value of the most recently pressed
soft key. Whenever the MASK 3 is non-zero, and the code in STB 3 is set
to a non-zero value, the SOFTKEY PRESSED bit (DIO-3) in STB I is set.
Codes:
O: No soft key pressed.
i - 9: One of soft keys I - 9 pressed (in REMOTE)
I0: CALL TO HOST soft key pressed (in LOCAL)
INTERNAL STATE Status Byte (STB 4):
This status byte contains status bits, reflecting the internal state of
the 9400A. Since the internal states cannot be directly controlled,
reading this byte does NOT reset it. Whenever a bit of this status byte
gets set, and the corresponding bit in MASK 4 is also set, the INTERNAL
STATE bit (DIO-4) in STB 1 is set.
Bits:
O:
1:
2:
3:
TRIGGERED:
cleared when the 9400A is armed, i.e.
acquiring data, and set when the 9400A is triggered,
i.e. not acquiring data.
0VERLOADI: set when channel 1 is in overload, reset
otherwise.
OVERLOAD2: set when channel 2 is in overload, reset
otherwise.
FIRST SEQNCE sweep triggered
Note:
Overloads are cleared by removing the overloading signal from the input
and by returning the input coupling to 50 Q. Overloads never occur with
1Mg coupling.
OPERATION COMPLETE Status Byte (STB 5):
This status byte contains status bits reflecting the identity of the
operation which has been completed. Whenever a bit of this status byte
gets set, and the corresponding bit in MASK5 is also set, the OPERATION
COMPLETE bit (DIO-5) in STBI is set.
Remote Operations
7-36
t
Bits:
Set when a screen dump (in REMOTE only) is finished
Set when calibration is done (in REMOTE only)
Average END
O:
2:
3:
ERRORStatus
Byte (STB 6):
This status byte contains the coded value of the most recently detected
error. The individual bits have no well defined meaning. Whenever MASK
6 is non-zero, and the code in STB 6 is set to a non-zero value, the
ERROR bit (DIO-6) in STBI is set.
Code:
No error
Not all 9400A responses have been read upon receipt of a
new command string, terminated with <END>. Output buffer
has been flushed.
0:
I:
Syntax errors:
i0:
II:
12:
13:
14:
15:
20:
30:
40:
50:
60:
I00:
i)
STB
,
Invalid separator or too many parameters
Invalid header
Invalid number format
Invalid keyword
Invalid block
2 or more strings in the same command
Command permission error; REMOTE only command has been
received while the 9400A is in LOCAL, or SCREEN control
command has been received while SCREEN control is LOCAL
The 9400A has received a command for an option that is
not installed
Semantic error: false number of parameters or false
parameter in a command
Environment error: the 9400A is not set to the proper
status to accept the received command (trace OFF, false
format...)
Descriptor error; an inconsistency has been detected in
the data received with a WRITE descriptor command
Command not yet implemented
[ I
to
6
?
]
Reads the contents of one of the 6 status bytes and clears it. STBI
is the Main Status Byte. STB 4 is not cleared.
or
STB
,
?
Reads all 6 status bytes in the order I to 6 and clears them (except
STB 4).
Remote Operations
7-37
2)
MASK
, [ 1 to
6 ] ,
Reads the contents of one of the 6 mask registers. Mask register 1
is the mask register corresponding to the Main Status Byte.
or
MASK
,
?
Reads the contents of the 6 mask registers in the order 1 to 6.
or
MASK
, [ 1 to 6 ] , [ 0 to 255 ]
Sets the contents of one of the 6 mask registers to a decimal value
between 0 to 255.
3)
TSTB
, [ 1 to
6 ] ,
Reads the contents of one of the 6 status bytes but does not clear
it. Status Byte 1 is the Main Status Byte.
or
TSTB
,
?
Reads the contents of all status bytes in the order 1 to 6, but does
not clear them.
7.6.9
GPIB Interface
Message Interpretation
I) Device clear: DCL (GPIB hexa code: 14) or SDC (GPIB hexa code:
Clears the input and output buffers, terminates plotting and data
transmission.
All the status bytes, except STB 4, and all the
corresponding masks as well as the SRQ line are reset.
THIS COMMMAND IS IMMEDIATELY EXECUTED.
2) Trig: GET (GPIB hexa code:
Re-arms the oscilloscope. Valid only in SINGLE or SEONCE mode and
only when the 9400A is in REMOTE.
3) REMOTE/LOCAL commands:
If the 9400A receives a command to go into REMOTE or go back to
LOCAL while it is acquiring a signal, the front panel REMOTE LED
doesn’t change, although the internal state as well as the display
will change.
Remote Operations
7-38
7.6.10 RS-232-C
Only Commands
The following commands are only valid when the 9400A is controlled via
the RS-232-C ports. <ESC> stands for the ASCII ESCAPE character.
I) RS CONF , <duplex> , <endl> , <end2> , <echo> , <delay>
Configures the RS-232-C remote control protocol.
<duplex>
= [0
to
127]
<endl>
<end2>
= [0
= [0
to
to
127]
127]
<echo>
<delay>
If 0, it selects full duplex mode,
otherwise selects half duplex mode.
The number represents
the decimal
ASCII value of the trigger (or talk)
character.
Selects <END> message string of 1 or
2 characters in length, as it will be
used in commands sent to the 9400A.
In transfers from the 9400A to the
host computer,
messages
or data
blocks are terminated with <TRAILER>
(as
defined
with the command
COMM TRAILER), followed by <END>.
Default: <CR>.
= [0 to 127]
Selects the echo character
(in half
duplex only). If zero, no echo mode
is selected.
Default: no echo character.
[0 to 60,000]
Selects the delay before talk in msec
(half duplex only).
Default: 0 msec.
The 9400A sets the VALUE ADAPTED bit:
- if an out of range positive value is given for the delay.
The 9400A may be configured to work either in full duplex mode or in
half duplex mode. Full duplex mode may be selected if the host computer
does not echo the characters it receives from the 9400A and if it is
able to store the received characters in a buffer. In half duplex mode,
the host computer tells the 9400A to talk by sending a trigger
character to the 9400A.
In full duplex mode, the 9400A sends its message(s) immediately.
Remote Operations
7-39
In half duplex mode, after it has received the trigger character, and
the selected delay has elapsed the 9400A sends its messages one at a
time until <END> message. It needs a trigger for each message. If the
host echoes received characters, echo mode must be selected. In that
case, the 9400A discards any received characters (except those of
Device Clear Command) until it receives the <echo> character.
The 9400A may be configured for Half Duplex mode in two situations:
a) If the computer which controls the 9400A through
port, does not support full duplex communication
data flow between
the 9400A and itself in
simultaneously (e.g. if the port on the computer
one direction at a time).
the RS-232-C Remote
and cannot support
both directions
can only be open in
b) If the computer, which controls the 9400A, echoes characters
receives from the 9400A (the port acting as a terminal port).
In the first case, the 9400A can be configured
sequence of commands:
<ESC>
COMM TRAILER OFF
RS CONF 9,13,10,0,0
it
with the following
disables echoing of characters received by the
9400A.
disables trailer.
selects half duplex mode with <TAB> (decimal9)
as a talk character, <CR> <LF> (decimal 13 and
i0) as <END> message string, no echo character
and no turnaround delay.
Whenever the computer interrogates the 9400A to get one or
responses, or to get one more blocks of data, it sends the
followed by <CR> (optional) and <LF> and then by <TAB>. <TAB>
9400A into the talker mode and instructs the 94OOA to send one
or one block of data to the computer. To get more information
blocks, <TAB> must be re-sent.
several
command
puts the
response
or more
Example:
The computer wants to know time base and bandwidth limit settings.
Computer sends:
9400A answers:
Computer sends:
9400A answers:
TIME/DIV ?; BANDWIDTH ?<CR><LF><TAB>
TIME/DIV 2.00E-O3<CR><LF>
<TAB>
BANDWIDTH ON<CR><LF>
The characters
which put the 9400A into a talker mode and the
characters of the <END> message string must not be the same. If they
were, <END> would purge the second part of the output.
Remote Operations
7-40
If turnaround delay is necessary, i.e. if a certain amount of time is
necessary between the time the 9400A receives the trigger character and
the time it sends the first character, the last parameter of the
RS CONF must be non-zero.
Example: RS CONF 9,13,10,0,I000
with a turnaround delay of 1 second.
The turnaround delay is given in msec, therefore the value of I000
corresponds to 1 sec. Note that during this delay the 94OOA may appear
as dead.
In the second case, i.e. when the controller echoes characters,
9400A can be configured with the following sequence of commands:
<ESC>
COMM TRAILER OFF
RS CONF 9,13,10,10,0
the
disables echoing of characters received by the
9400A.
disables trailer.
selects half duplex mode with <TAB> (decimal9)
as trigger (or talk) character, <CR> <LF>
(decimal 13 and I0) as <END> message string,
<LF> as echo character
and no turnaround
delay.
Whenever the controller interrogates the 9400A to get one or several
responses or to get one or more blocks of data, it sends the command
followed by <CR> (optional) and <LF> and then by <TAB>. This last
character instructs the 9400A to send one response or one block of
data. To get more information or more blocks <TAB> must be re-sent.
Example:
The computer wants to get the setup configuration. If the 9400A has
been configured to sends blocks of data in hex format in blocks of 300
characters, the computer will receive 3 blocks.
Computer sends:
SU ?<CR><LF><TAB>
#L .......<CR><LF>
9400A answers:
Each character including <LF> will be echoed by the computer.
<TAB>
Computer sends:
#L .......<CR><LF>
9400A answers:
Each character including <LF> will be echoed by the computer.
<TAB>
Computer sends:
#1<CR><LF>
9400A answers:
#1<CR><LF> will be echoed by the computer.
Notice that <LF> is used both as the last character of <END> message
string and as the <ECHO> character. Character strings (except <ESC>
string for DEVICE CLEAR and <ESC>, <ESC>, <ESC>, <ESC>) will be lost if
sent between <TAB> and <LF>.
In both cases, if a service request has been activated, the string will
be sent only when the trigger character is received.
Remote Operations
7-41
In both cases, DEVICE CLEAR ( <ESC>C ) resets the RS-232-C remote port
to the DEFAULT setting, i.e.:
- ECHO ON
- full duplex mode with <CR> as <END> message string.
- Overwrite mode if the output buffer becomes full.
2) RS SRQ
, [0 to 127] , [0 to 127] , [0 to 127]
Defines a 3-character service request (SRO) string that is sent
the 9400A each time the RQS bit (bit 6) of the Main Status Byte
(STB I) is set to i. A null character (value O) terminates
string, i.e. a string of 1 or 2 characters may be defined by setting
the rest of the characters to O. If the first character is set to
null (value 0), the default string is selected. Default is the bell
(value 7). If half duplex mode is selected, the transmission of this
string may be delayed until the trigger character has been received.
The 9400A appends <END> to the SR0-string, but not the <TRAILER>.
3) <ESC>
Selects DTR / CTS hardwire handshake protocol.
THIS COMMMAND IS IMMEDIATELY EXECUTED.
4) <ESC>
Selects XON (ASCII DCI character)
handshake protocol. (DEFAULT)
/ XOFF (ASCII DC3 character)
THIS COMMAND IS IMMEDIATELY EXECUTED.
5) <ESC>[
The 9400A does not echo characters received.
THIS COMMMAND IS IMMEDIATELY EXECUTED.
6) <ESC>]
The 9400A echoes characters received. (DEFAULT).
THIS COMMMAND IS IMMEDIATELY EXECUTED.
7) <ESC>
When its output buffer is full, the 9400A stops until more space is
created in the output buffer (i.e. until the host computer has read
some characters).
THIS COMMMAND IS IMMEDIATELY EXECUTED.
Remote Operations
7-42
8) <ESC>
If the output buffer becomes full, the 9400A overwrites
character. (DEFAULT).
the last
THIS COMMMAND IS IMMEDIATELY EXECUTED.
9) <ESC>
Sets the 9400A to REMOTE.
I0) <ESC>
Sets the 9400A to LOCAL.
II) <ESC>
The 9400A executes a DEVICE CLEAR command, clears the input and
output buffers, all the status bytes except STB 4, and all the
corresponding
masks. It then terminates
plotting
and data
transmission
and resets the RS-232-C REMOTE port to DEFAULT
setting.
THIS COMMMAND IS IMMEDIATELY EXECUTED.
12) <ESC>
The 9400A executes a TRIGGER command (see Section 7.6.9).
7.7
Binary Format of Waveform Descriptors
The waveform descriptor contains all information needed to correctly
interpret the waveform data. In addition, there are some values that
apply only to some records, in particular to waveforms that are the
result of data processing.
The descriptor contains 8-bit values, 16-bit values and 32-bit integer
values. There are no floating point values. Multi-byte values are
always transferred
with the most significant
byte first. In the
following list, each parameter is identified by its (decimal) address
relative to the beginning of the descriptor, and by the number of bits.
Data values shown are always in decimal.
Note: The first 4 bytes are header information
IEEE-488 specifications. The 5th byte is POS O.
in agreement
Remote Operations
7-43
with
Pos Size
8-bit
Meaning
Fixed vertical gain, coded as an integer.
22 = 5 mV/div
23 = i0 mV/div
24 = 20 mV/div
25 = 50 mV/div
.......
31 = 5 V/div
Values below 22 and above 31 may occur on processed data
records. See Section 7.10.1 for an example of how data
values are converted to volts in processed data records.
8-bit
Variablevertical gain, in units of 0.005 of unity.
0 = gain of 0.4,
120 = gain of 1.000.
See Section 7.10.1 for an example of how data values are
converted to volts in processed data records.
Unused
2
16-bit
4
16-bit
Vertical offset in units of 0.04 of the vertical
deflectionfactor, i.e. 0.04 V/div.
0 = - 8 div
25 = - 7 div
50 = 6
div
.....
225 = 1 div
200 =
0 div
250 =
2
div
.....
400 =
8 div
See Section 7.10.i for an example of how data values are
convertedto volts in processed data records.
6
8-bit
Input channel couplingat acquisition.
1 = Ground
0 = DC, 50 Q
3 = Ground
2 = DC, 1M~
4 = AC, [email protected]
7
8-bit
Attenuation of external probe (must have been set up
manually or by remote control)
0 = *i
1 = *i0
2 = *100
3 = *1000
This value is already
absorbed into the fixed vertical
gain (position
0), it serves only as a reminder here.
8
8-bit
Bandwidth limit at acquisition.
0 = off
1 = on
9
8-bit
Time base at acquisition,coded as an integer.
4 = 2 nsecldiv
5=
5 nsec/div
6 = 10 nsecldiv
7 = 20 nsec/div
.....
34 = 20 sec/div
35 = 50 sec/div
36 = 100 sec/div
Remote Operations
7-44
8) <ESC>
If the output
buffer
becomes full,
character.
(DEFAULT).
the
9400A overwrites
the last
THIS COMMMAND IS IMMEDIATELY EXECUTED.
9) <ESC>
Sets the 9400A to REMOTE.
I0) <ESC>
Sets the 9400A to LOCAL.
11) <ESC>
The 9400A executes a DEVICE CLEAR command, clears the input and
output buffers, all the status bytes except STB 4, and all the
corresponding
masks. It then terminates
plotting
and data
transmission
and resets the RS-232-C REMOTE port to DEFAULT
setting.
THIS COMMMAND IS IMMEDIATELY EXECUTED.
12) <ESC>
The 9400A executes a TRIGGER command (see Section 7.6.9).
7.7
Binary Format
of Waveform Descriptors
The waveform descriptor contains all information needed to correctly
interpret the waveform data. In addition, there are some values that
apply only to some records, in particular to waveforms that are the
result of data processing.
The descriptor contains 8-bit values, 16-bit values and 32-bit integer
values. There are no floating point values. Multi-byte values are
always transferred
with the most significant
byte first. In the
following list, each parameter is identified by its (decimal) address
relative to the beginning of the descriptor, and by the number of bits.
Data values shown are always in decimal.
Note: The first 4 bytes are header information
IEEE-488 specifications. The 5th byte is POS 0.
in agreement
Remote Operations
7-43
with
Pos Size
8-bit
Heaning
Fixed vertical gain, coded as an integer.
23 = i0 mV/div
22 = 5 mV/div
25 = 50 mV/div
24 = 20 mV/div
.......
31 = 5 V/div
Values below 22 and above 31 may occur on processed data
records. See Section 7.10.1 for an example of how data
values are converted to volts in processed data records.
8-bit
16-bit
Variable verticalgain, in units of 0.005 of unity.
0 = gain of 0.4,
120 = gain of 1.000.
See Section 7.10.1 for an example of how data values are
converted to volts in processeddata records.
Unused
16-bit
Vertical offset in units of 0.04 of the vertical
deflectionfactor, i.e. 0.04 V/div.
0 = - 8 div
25 = - 7 div
50 = 6
div
.....
200 =
0 div
225 = i div
2
div
.....
250 =
400 =
8 div
See Section 7.10.1 for an example of how data values are
convertedto volts in processed data records.
8-bit
Input channel coupling at acquisition.
1 = Ground
0 = DC, 50 ~
3 = Ground
2 = DC, 1M~
4 = AC,
1M~
8-bit
Attenuation of external probe (must have been set up
manuallyor by remote control)
0 = *I
I = *i0
2 = *I00
3 = *i000
This value is already absorbed into the fixed vertical
gain (position 0), it serves only as a reminderhere.
8-bit
Bandwidth limit at acquisition.
0 = off
i = on
8-bit
Time base at acquisition,coded as an integer.
4 = 2 nsec/div
5=
5 nsecldiv
6 = I0 nsec/div
7 = 20 nsec/div
.....
34 = 20 sec/div
35 = 50 sec/div
36 = I00 sec/div
Remote Operations
7-44
Heaning
Pos
Size
10
8-bit
Sampling interval at acquisition, coded as an integer.
In interleaved sampling,
12 =
.4 nsec
ii = .2 nsec
13 = .8 nsec
In non-interleaved sampling,
17 = 20 nsec
16 = lO nsec
19 = 80 nsec
18 = 40 nsec
21 = 400 nsec
20 = 200 nsec
....
34 = 8 msec
36 = 40 msec
35 = 20 msec
In addition to the intervals of the non-interleaved
sampling, SEQNCE mode also uses
41 = 1 ~sec
40 = i00 nsec
42 = 10 psec
43 = i00 psec
45 = 10 msec
44 = I msec
11
8-bit
Record type
0 = non-interleaved
3 = interleaved with 25 sweeps at .8 nsec interval
4 = interleaved with 50 sweeps at .4 nsec interval
5 = interleaved with i00 sweeps at .2 nsec interval
8 segments
-3 = SEQNCE with
-4 = SEQNCE with 15 segments
-5 = SEQNCE with 31 segments
-6 = SEQNCE with 62 segments
-7 = SEQNCE with 125 segments
-8 = SEQNCE with 250 segments
12
8-bit
Trigger coupling at acquisition
1 = HF REJ
0 = DC
3 = AC
2 = LF REJ
13
8-bit
Trigger mode at acquisition
1 = NORM
0 = SINGLE
3
= SEQNCE
2 = AUTO
14
8-bit
Trigger source at acquisition
I = EXT
0 = EXT/10
3 = CHAN 2
2 = LINE
4 = CHAN I
15
8-bit
Trigger slope at acquisition
I = positive
0 = negative
2 = window
16
16-bit
Trigger level at acquisition
The coding depends on the
trigger source.
trigger slope and on
Remote Operations
7-45
the
Pos Size
Meaning
Positive or negative trigger slope
Parameter
0
25
50
I00
125
150
200
250
CHAN
5.00
4.00
3.00
1.00
0
+ 1.00
+ 3.00
+ 5.00
-
1,2
dlv
dlv
dlv
div
dlv
div
div
div
EXT
-
2.00
1.60
1.20
.40
0
+ .40
+ 1.20
+ 2.00
V
V
V
V
V
V
V
V
In EXT/IO, the trigger voltages are multiplied by I0.
Window trigger
Parameter
<25
25
50
i00
125
150
200
250
±
+
+
±
±
±
±
±
CHAN 1 2
.50 dlv
.50 dlv
1.00 dlv
2.00 div
2.50 dlv
3.00 dlv
4.00 dlv
5.00 div
EXT
±
±
±
±
i
±
±
±
.20
.20
.40
.80
1.00
1.20
1.60
2.00
V
V
V
V
V
V
V
V
In EXT/10, the trigger voltages are multiplied by I0.
Note that the window size is limited to ±.5 div (or
.20 V), due to the nature of the trigger hardware.
Trigger delay at acquisition,
in units of .02 of
TIME/DIV, relative to the left hand side of the screen.
500 = + I0 div, i.e. I00 % pre-trigger
0 % pre-trigger
0 =
0 div, i.e.
div,
i.e.
post-trigger
of 1TIME/DIV
-50 =
- 1
-500000 = -I0000 div, i.e. maximum post-trigger of I0000
divisions
18
32-bit
22
16-bit
Number of measured data points per division, at the time
of acquisition. This number is independent of whether
the user reads all or a fraction of the data values, by
specifying <intval> larger than 1 (See READ command).
24
16-bit
Address of first measured data point, relative
left-hand edge of the screen.
to the
26
16-bit
Address of last measured data point,
left-hand edge of the screen.
to the
28
16-bit
Internal use.
relative
Remote Operations
7-46
Pos
Size
Heaning
30
16-bit
Internal use.
32
16-bit
Internal use.
34
8-bit
Data
99 =
0 =
2 =
4 =
35
8-bit
36 - 149
7.8
processing of this record
no processing, raw data
averaging
i = extrema
3 = functions
arithmetic
smoothing
Unused
Additional parameters, reserved for the
the waveform processing (if any).
Format of Trigger
description of
Time(s)
The trigger time is the time interval between the occurrence of the
trigger and the measurement of the next data sample. This time is
always expressed in units of 2,*(-14) of the nominal sampling interval,
and spans integer values from 0 to 2"*(14)-1 = 16383. The transmission
format is a 16-bit integer, with the most significant byte sent before
the least significant byte.
In single-shot acquisition
value.
(INTERLEAVED
OFF), there is a single time
In SEQNCE acquisition, there are as many trigger times as there are
sweeps. The trigger times are transmitted in the order i to N, where N
is the number of sweeps.
In INTERLEAVED acquisition, there are as many trigger times as there
are interleaved sweeps making up the acquired trace:
- At 2 ~sec/div, there are 25 sweeps at a nominal interval of 800 psec.
- At I ~sec/div, there are 50 sweeps at a nominal interval of 400 psec.
- At 500 nsec/div and below, there are i00 sweeps at a nominal interval
of 200 psec.
The times are transmitted in the order 0 to N-I, where N is the number
of sweeps. Note that time i (0 <= i < N) corresponds to the data points
at address i, N + i, 2N + i, 3N + i, etc., i.e. to all data points of a
single sweep.
Remote Operations
7-47
In many data analyses, the trigger times may be ignored, especially if
relative time measurements
are made. In INTERLEAVED acquisition,
however, ignoring the trigger times results in the interleaved sweeps
being put on an equidistant
timing grid, although they are not
necessarily
equidistant
at acquisition.
This is equivalent
to
introducing
an acquisition
jitter of up to 0.~ nominal sampling
interval, i.e. degrading the (apparent) dynamic behavior of the ADC.
7.9
Data Addressing Conventions
Data values are always addressed in a screen-oriented manner. Address 0
always corresponds to the data value at the left hand edge of the
display screen. Although the 9400A always digitizes 32000 points
(except in interleaved sampling or in SEQNCE mode), it is not possible
to display all of them on the screen, because of the ratio TIME/DIV to
sampling interval. Points which are inaccessible on the screen are
always positioned to the LEFT of the display screen, and can be read by
remote control (using negative address values).
Examples:
(a)
At 0.5 msec/div, a sampling interval of 200 nsec is used, which
covers a total time of 32000 * 200 nsec = 6.4 msec. However, only
10 * 0.5 msec = 5 msec can be shown on the screen. Thus, only
25000 out of 32000 acquired points are shown. The other 7000
points cannot be displayed on the screen, but are accessible by
remote control with the READ command (using negative addresses).
.5 ms/div
left edge
of screen
I
-7000
I
I
0
250OO
displayed record, 2500Opts, 5ms
digitized
(b)
record, 3200Opts, 6.4 ms
At 5 ~sec/div, a sampling interval of i0 nsec is used, covering a
total time of 32000 * 10 nsec = 320 usec. However,
only
10 * 5 usec = 50 usec can be shown on the screen at this time-base
setting. Only 5000 out of 32000 acquired points are shown. The
other 27000 values are not displayed, but are accessible by remote
control.
Remote Operations
7-48
left edge
of screen
P
I
0
-27000
SO00
displayed record
500Opts, 50 .us
digitized
record,
32000pts, 320)JS
It is important to realize that at the fastest sampling rate of I0 nsec
per point, a record always covers a time interval of 320 ~sec,
regardless of the time base (which can range from 50 nsec/div to
20 psec/div). However, the trigger point is always interpreted relative
to the left hand edge of the screen, i.e. relative to the address point
0 of the record.
Example:
Compare a time base of 20 usec/div to a time base of I ~sec/div,
both with a pre-trigger of i0 percent, i.e. 1 division to the
right of the left edge of the screen.
20 p s/div
-12000
trigger point
left edge
of screen
2000C
displayed record, 20000pts, 200 .us
digitized
record, 32000pts, 320 ~s
311ps
JO~trigger
1000
-31000
left
edge
of screen
digitized
~/pomt
displayed record,
1000 pts, I0 ps
record, 32000 pts,320 /Js
Remote Operations
7-49
In RIS, the 9400A digitizes 24000 data points (except: 24800 at I ~sec/div and 25000 at 2 Bsec/div; see Section 5.1.2). In this mode and in
SEQNCE mode, it may happen that the memory is slightly too small to
cover the entire screen. In this case, the waveform does not extend all
the way to the left hand side of the display screen, and the address of
the first valid data point of the record is a positive number. The
principle is still maintained, that address 0 corresponds to the data
point at the left edge of the screen, even if it refers to a virtual
data point. This case occurs in interleaved sampling at 0.5 usec/div:
. 5~$/di~
left edge
of screen
0
interleaved
~000
25O00
digltizeda
displayed record, 24000pts, 4.8ps
m
~ssing dqta on displo
As the data-record
limits
depend on the time base and on the acquisition mode, the 9400A allows
the user to read these address limits
with
the command "INSPECT xx. LIHIT".
The response
is a data block
of 2
16-bit
words, corresponding
to the lowest
and the highest
address o£
the data record in question.
If the user specifies
larger
limits
than
valid,
the 9400A automatically
replaces
them with the legal
ones (and
sets the VALUE ADAPTED bit in the Main Status Byte STB 1).
7.10
Interpretation
of Waveform Data Values
The conversion of the integer waveform data into volts requires the use
of three scale and offset parameters found in the descriptor (see
Section 7.7):
- Fixed gain, transmitted as an 8-bit BYTE at address 0 relative
to the beginning of the descriptor. This coded value can be
transformed into a number of VOLTS/DIV with a user-defined
table. This transformed value is called ’gain’ in the formula.
- Variable gain, transmitted
as an 8-bit BYTE at address 1
relative to the beginning of the descriptor. This value is
called ’vgain’ in the formula below.
- Offset, transmitted as a 16-bit (signed) WORD at address
relative to the beginning of the descriptor. This value is
called ’offset’ in the formula below.
7.10.1
Waveform Data in 8-bit Format
This is the default format of all data records (if the Waveform
Processing option is installed, it is possible to modify it to 16 bits
with the command COMM FORMAT). The unsigned 8-bit "data" values in the
numerical range 0 .... 255 are transformed to volts as follows:
Remote Operations
7-50
V = gain
20°
Idata-128
°fret
2°oil
1
32
vgain + 80
25
- The first expression "(data - 128)/32" transforms the unsigned data
value to a signed value, in units of vertical divisions.
- The second expression "(offset - 200)/25" translates the internal
coding of the offset into a signed offset, units: vertical divisions.
+ 80)" takes into account the
- The third expression "200/(vgain
variable gain. It reduces, to the value 1 when "vgain" assumes the
"calibrated" value of 120.
Examples:
gain = I00 mV byt e 0 of descriptor
offset = 200
no offset
vgain = 120
calibrated gain
= 26
The formula reduces to
V = I00 mV (data - 128)/32
data
0
128
129
160
240
255
volts
-400
0
3.12
+I00
+350
+396.88
gain = 500 mV byte 0 of descriptor
offset = 250
offset
vgain = 20
variable gain
mV
mV
mV
mV
mV
mV
= 28
= + 2 div
= .500 (equivalent to
MULTIPLYING the
vertical scale by 2)
The formula reduces to
V = 500 mV ((data - 128)/32 - 2) *
data
volts
0
64
128
192
193
200
240
255
-6.0 V
-4.0 V
-2.0 V
0 V
31.25 mV
.25 V
I. 5 V
i. 969 V
Remote Operations
7-51
7.10.2
Waveform
Data
in
16-bit
Format
This format is only possible if the Waveform Processing option is
installed. The 9400A must be set to this format with the command
COMM FORMAT. In this format, raw data, i.e. 8-bit ADC output, are
represented in the most significant byte. The least significant byte
consists of 8 bits of zeros. The unsigned 16-bit data values in the
range 0 - 65535 are transformed into volts as follows:
V = gain * ((data - 32768)/8192 - (offset - 200)/25) * 200/(vgain
The terms are identical to those of Section 7.10.1, except that the
factors of the first expression are multiplied by 256.
7.11
Use of the
Service
Request
(SRQ) Interrupts
A Service Request (SRQ) is generated whenever the RQS bit of the Main
Status Byte (STB i) becomes 1. The user must demask the condition bits
of interest in order to allow the generation of SRQ, e.g., to make the
9400A generate an interrupt upon the occurrence of an overload in
either channel I or 2:
7.11.1
MASK 4,6
Sets the mask of the INTERNAL STATE byte (STB 4) to the
binary value 00000110, i.e. it demasks the 2 overload bits.
If an overload occurs, the mask now allows the propagation of
the bit to the INTERNAL STATE CHANGE bit of the Main Status
Byte (STB I).
MASK 1,8
Sets the mask of the Main Status Byte (STB
value 00001000, i.e. it demasks the bit
CHANGE. This now allows the propagation of
RQS bit of STB i. Note that the R0S bit need
it always generates an SRQ when set.
Service
Request
in
I) to the binary
INTERNAL STATE
this bit to the
not be demasked;
GPIB
The Service Request (SRQ) is a dedicated interrupt line on the GPIB
bus. The handling of this interrupt is the responsibility of the user’s
GPIB driver on the host computer. The driver may allow the linking of a
user-written service routine to the interrupt. The GPIB protocol allows
an alternative way of reading the Main Status Byte (STB I) through the
Serial Poll. The execution of the serial poll is again a GPIB driver
routine on the host computer. Normally, the value of STBI is identical,
whether it is read by Serial Poll or with the explicit read command
"STB i,?". A difference occurs, however, when more than one condition
occurs that may set the RqS-bit:
Remote Operations
7-52
"STB i,?", keeps
- The Main Status Byte (STB i), as read with
accumulating further bits as they get set.
Serial Poll, only
- The Main Status Byte (STB I), as read with the
shows the bits that were set at the time the RQS was set. Any bits
that should get set due to subsequent events are not taken into
account (but are remembered), until a Serial Poll reads STB 1 and
clears it; at this point in time, any remembered bit is set in STB 1
and may again generate an SRQ. The principle in Serial Poll is that
SRQ may be generated by one event at a time.
Example:
MASK 1,48
Sets the mask of the Main Status Byte (STB i) to the
binary value 00110000, allowing the ERROR bit or the
OPERATION COMPLETE bit to generate an RQS bit, i.e. to
generate a Service Request.
MASK 5,4
Sets the mask of the OPERATION COMPLETE byte (STB 5)
the binary value 00000100, allowing the propagation of the
"calibration done" bit to the OPERATION COMPLETE bit of
STB i.
MASK 6,1
Sets the mask of the ERROR byte (STB 6) to a non-zero
value, allowing the propagation of errors to the ERROR bit
of STB i.
CAL
Instructs
the 9400A
to calibrate
itself.
After
approximately 500 msec, the 9400A sets the "calibration
done" bit in the OPERATION COMPLETE byte (STB 5). Since
this bit is demasked, it is propagated to the OPERATION
COMPLETE bit of STB I. And because this bit is also
demasked, it sets the RQS bit and generates a Service
Request interrupt on the GPIB bus.
TRIG LEVEL
Instead of responding to the Service Request, the host
computer sends this illegal command. It generates
a
semantic error and sets the ERROR byte (STB 6) to the
value 40. Since this byte is demasked, the ERROR bit in
STB 1 is also set, and because this bit is also demasked,
it may set the RQS bit. However, the RQS bit is already
set.
At this point, the host computer may choose to respond to the Service
Request in either of the following ways:
Remote Operations
7-53
If it responds with a Serial Poll, it will read the binary value
01010000, i.e. the R0S bit and the OPERATION COMPLETE bit. Upon
execution of the Serial Poll, these two bits are reset in STB I.
However, the 9400A remembers that another bit, capable of setting ROS,
was set, in this case the ERROR bit. Thus, it generates a second
Service Request. When the host computer executes a second Serial Poll,
it will read the binary value 01100000, i.e. the ROS bit and the ERROR
bit. Upon execution of the second Serial Poll, STB 1 will be cleared
completely. Thus, 2 different bits of STB I (when demasked) always
generate two different Service Requests, provided that STB 1 is read by
Serial Poll. This follows the principle that SRQ should be generated by
one event (at the level of STB I) at a time.
the status byte(s) with "STB
If the host computer responds by reading
1,?" or "STB ?", it will read the binary value 01110000 in STB I. The
Main Status Byte (STB I) is cleared, and no more Service Requests are
generated. Thus, STB I, when read explicitly, keeps accumulating other
status bits, and there might be fewer Service Requests than events (at
the level of STB I).
Another Example:
MASK 1932
Sets the mask of the Main Status Byte (STB i) to the
binary value 00100000, allowing the ERROR bit to generate
an R0S bit, i.e. to generate a service request.
MASK 6,1
Sets the mask of the ERROR byte (STB 6) to a non-zero
value, allowing the propagation of errors to the ERROR bit
of STB I.
TIME/DIV?
This legal command generates a response message which can
(and should) be read by the host computer. In addition,
the MESSAGE READY bit is set in STB i. Because this bit is
not demasked it does not generate an SRQ. However, if STB
1 is now read explicitly or by Serial Poll, the binary
value I0000000 (= 80 in hexadecimal) would be read.
AAA?
This illegal command generates a syntax error and sets the
ERROR byte (STB 6) to the value II. Simultaneously, the
ERROR bit of STB I is set. Since this bit is demasked in
STB I, it sets the R0S bit and generates a service request
SR0.
CALL HOST
This command is illegal, since the required parameter is
missing. It generates a semantic error and sets the ERROR
byte (STB 6) to the value 40. This error should again
propagated
to the ERROR bit of STB l, but it cannot
generate a service request, since it is still pending.
Remote Operations
7-54
If the host computer executes a Serial Poll at this moment, the binary
value Iii00000 (= E0 in hexadecimal) is read, i.e. the MESSAGE READY
bit from the previous command "TIME/DIV?" and the ERROR bit + RQS bit
from the command "AAA?" are set. Upon the execution of the Serial Poll,
these bits are reset. Since no DIFFERENT bit, capable of setting RQS,
was generated in the intervening time, no more Service Requests are
generated. If the host computer reads the ERROR byte (STB 6) with the
command "STB 6,?", it will receive the value 40, corresponding to the
second error. Thus, if several errors occur before the host computer
responds, only the last error is retained by the 9400A.
7.11.2 Service Request in RS-232-C
The Service Request must be simulated on a RS-232-C connection, since
it is not predefined. On the 9400A, the RS-232-C Service Request
consists of i to 3 characters, followed by the RS-232-C version of
<END> (as defined by the command RS CONF in Section 7.6.10, default is
CR), sent by the 9400A to the host -computer. It is the responsibility
of the programs on the host computer to recognize them. By default,
they consist of 1 bell character (binary value 7).
Since transfers over RS-232-C can only be in ASCII, the bell character
is rather easily recognized as a special message. Also, the user may
redefine the SRQ characters to some other sequence with the command
"RS SRQ". The Serial Poll does not exist on an RS-232-C connection
either. The only way to get more information about the status of the
9400A, or the reasons for an "interrupt", is to read the value of STB i
or the other status bytes.
Of course, the user always has the choice of working without any
Service Requests by "polling" the Main Status Byte (STB I) with the
command "STB I,?" (See Section 7.6.8).
Example:
Byte (STB I) to the
the ERROR bit or the
an RQS bit, i.e. to
MASK 1,40
Sets the mask of the Main Status
binary value 00101000, allowing
INTERNAL STATE CHANGE to generate
generate a service request.
MASK 4,6
Sets the mask of the INTERNAL STATE byte (STB 4) to the
binary value 00000110, i.e. it demasks the 2 overload
bits. If an overload occurs, the mask now allows the
propagation of the bit to the INTERNAL STATE CHANGE bit of
STB i.
MASK 6,1
Sets the ERROR byte (STB 6) to a non-zero value, allowing
the propagation of errors to the ERROR bit of STB i.
Remote Operations
7-55
TIME/DIV ?
This legal command generates a response message which
should be read by the host computer. In addition, the
MESSAGE READY bit is set in STB i. Because this bit is not
demasked, it does not generate a Service Request. However,
if STB I were now read with "STB I,?", the binary value
I0000000 (= 80 in hexadecimal or = 128 in decimal) would
be read, and this bit would be cleared.
Overload I
This event, internal to the 9400A (but due to too large
signal at input 1 with 50 Q coupling), sets the OVERLOAD1
bit of STB 4. Since this bit is demasked, the INTERNAL
STATE CHANGE bit of STB 1 is also set. And because this
bit is also demasked, the RQS bit is set and the Service
Request is generated. If set to the default string, it
consists of sending 1 bell character (decimal 7), followed
by the carriage return character (default value of <END>),
via RS-232-C to the host computer.
AAA?
This illegal command generates a syntax error, and sets
the ERROR byte (STB 6) to the value ii. Since this byte
demasked, the ERROR bit in STB I is also set. And because
this bit is also demasked, it should also set the RQS bit
and generate a Service Request. However, it cannot since
it is already pending.
If the host computer reads the Main Status byte with the command "STB
i,?" at this moment, it will read the binary value llll0000, coded as
the decimal value 240 = 128+64+32+16. The Main Status Byte (STB i) acts
as an accumulator of all condition bits. Thus several bits are set.
After reading STB i, all bits will be cleared and no more Service
Requests are generated until some new event occurs.
Remote Operations
7-56
SECTION 8
BASIC 9400A WAVEFORM MEASUREMENTS AND
OPERATING PROCEDURES
The purpose
of this
section
is to provide
the user
with
a concise
overview
of the wide range of measurement
capabilities
offered
by the
LeCroy
9400A.
While
you may already
be familiar
with
traditional
oscilloscope
operation,
this
brief
outline
will
help to acquaint
you
with the many powerful
features
of the 9400A.
********
*NOTE*
********
In the following
section we have chosen to set all acquisition
parameters from the Panel Status menu; however, it is not necessary to
be in this menu to make front panel setting changes. In the majority of
cases, viewing the Abridged Panel Status Field (IV) will provide all
necessary indications.
8.1
Repetitive
Signal
Applying
I.
1)
2)
3)
4)
5)
6)
7)
8)
9)
i0)
ii)
12)
13)
14)
15)
16)
17)
18)
19)
Probe
Acquisition
Calibration
Signal
Connect
the P9010 probe connector
to CHAN 1 input
(21).
Connect
the probe’s
grounding
clip
to lug (20) and touch the tip
to lug (19).
In the Main Menu, press the Recall PANEL push button (5).
Recall the Default panel setup (9).
Return to the Main Menu by pressing the Return push button (i0).
Call the Panel Status menu (2).
Set CHAN 1 Fixed VOLTS/DIV to I0 mV (27).
Adjust CHAN 1VAR vernier (28) for a Total V/div of 13.0 mV.
Set CHAN 1 OFFSET to -50 mV (32).
Set CHAN 1 COUPLING to DC 1 M9
Adjust TRIGGER DELAY control (34) to 20.0~ Pre.
Adjust TRIGGER LEVEL control (33) to .00 division.
Set TRIGGER COUPLING to AC (30).
Set TRIGGER SOURCE to CHAN i (23).
Set TRIGGER SLOPE to POS (25).
Set TRIGGER MODE to AUTO (29).
Set TIME/DIV control (36) to .5 msec.
Note that at this TIME/DIV setting, INTERLEAVED SAMPLING (RIS)
OFF.
Set BANDWIDTH LIMIT to OFF (50).
Basic 9400A Waveform Measurements
and Operating Procedures
8-1
20)
21)
22)
Return to the Main Menu by pressing
the
Set CMAN1 to ON and CHAN 2 OFF (49).
Set DUAL GRID mode to OFF (14).
Return
push
button
(10).
Resulting Display:
Ponml
STATUS
PANEL
’III
......................................
....
’ .......
¯ ...................
Cl~nnel 1
¯ 5 .m~tO
mV
Figure 8.1
The PD010 probe
has a xl0 attenuation
factor.
Thus,
the 1 V, 976 Hz
output
calibration
signal
is displayed
with
a total
amplitude
of
approximately
7.7 divisions
at a Total V/div setting
of 130 mV. In case
of over- or under-shoot,
adjust
the probe compensation
trimmer,
located
on the barrel
of the PDOIO, for a clean square
wave contour.
II.
i)
2)
3)
4)
5)
6)
7)
8)
9)
I0)
ii)
12)
Acquisition of a 10-20 nsec Repetitive Signal
Connect a fast pulse generator providing an output signal having a
10 to 20 nsec period to CBAN 2 input (21).
In the Main Menu, press the Recall PANEL push button (5).
Recall the Default panel setup (9).
Return to the Main Menu by pressing the Return push button (I0).
Call the Panel Status menu (2).
Set CHAN 2 Fixed VOLTS/DIV as appropriate (27).
Set CHAN 2 OFFSET to .0 mV.
Set CHAN 2 COUPLING to DC 50
Adjust CHAN 2 VAR vernier (28) as appropriate.
Adjust TRIGGER DELAY control (34) to 40.0Z Pre.
Adjust TRIGGER LEVEL control (33) to .00 division.
Set TRIGGER COUPLING to AC (30).
Basic 9400A Waveform Measurements
and Operating Procedures
8-2
a
13)
14)
15)
16)
17)
18)
19)
20)
21)
Set TRIGGER SOURCE to CHAN 2 (23).
Set TRIGGER SLOPE to POS (25).
Set TRIGGER MODE to NORM (29).
Set TIME/DIV control (36) to 5 nsec/div (36).
At this point INTERLEAVED SAMPLING (RIS) is ON.
Set BANDWIDTH LIMIT to OFF (50).
Return to the Main Menu by pressing the Return push button (I0).
Set CHAN 2 to ON and CMAN 1 to OFF (49).
Set DUAL GRID mode to OFF (14).
Resulting Display:
A :
I%
Parwl
STATUS
~
It
A
II
r:
....
......
Store
PANEL
Reo=tl
Trio
.00 dlv+CItANZ ffi
Figure 8.2
A waveform is displayed in the center of your screen.
Signal acquisition is performed in the Random Interleaved
mode.
8.2
Single
Shot
Acquisition
Sampling
Acquisition
of
a single
100 nsec
wide
pulse.
In this case the pulse generator is not free-running. It must be in
external or manual trigger, and set to provide a I00 nsec wide pulse
with an amplitude of your choice.
l)
2)
Connect signal source to CHAN 1 input (21).
In the Main Menu, press the Recall PANEL push button (5).
Basic 9400A Waveform Measurements
and Operating Procedures
8-3
3) Recall the Default panel setup (9).
4) Return to the Main Menu by pressing the Return push button (I0).
5) Call the Panel Status menu (2).
Set CHAN 1 Fixed VOLTS/DIV as appropriate
(27)
6)
match the
generator.
7) Adjust CHAN 1 VAR vernier (28) as appropriate
match the
generator.
8)
Set CHAN 1 OFFSET as appropriate.
9)
Set CHAN 1 COUPLING to DC 50 Q
I0) Adjust TRIGGRR DELAY control (34) to 20.0~ Pre.
11) Adjust TRIGGER LRVEL control (33) to .00 division.
12) Set TRIGGER COUPLING to AC (30).
13) Set TRIGGER SOURCE to CHAN i (23).
14) Set TRIGGER SLOPE to POS (25).
15) Arm the trigger by setting the TRIGGER MODE (29) to single.
16) Set TIMEIDIV control (36) to 50 nsec/div (36).
17) Set INTERLEAVED SAMPLING to OFF (37).
18) Set BANDW-IDTff LIMIT to OFF (50).
19) Return to the Main Menu by pressing the Return push button (10).
20) Set CHAN 1 to ON and CHAN 2 to OFF (49).
21) Set DUAL GRID mode to OFF (14).
22) Now trigger the signal source.
Resulting Display:
......
¯
,......o
...o ...., ¯
,,,,,.,,i.,,.,,,..i,..,i.,..i
f,,.
!ll
l,,,,i,,,.lq,,,,
...... Cl’mr~l’J,
50 rm~.1 V
Figure 8.3
Basic 9400A Naveform Measurements
and Operating Procedures
8-4
8.3
Trace
Expansion
- Expand AIB
Using the same i00 nsec signal and front panel settings described in
Section 8.2, but with your pulse generator free-running this time,
perform the following procedure:
I)
2)
Set push button (14) to DUAL GRID mode.
Press EXPAND A (46) in order to expand CHAN 1 trace.
If the source for signal expansion shown in the Displayed Trace field
(V) is not X-Chan I, you must perform the following procedure
redefine the expansion signal source to CHAN i.
a)
b)
Press
Source
Press
source
the REDEFINE push button (45) to display the Redefine
menu in the Menu Field (I).
push button (I) in order to redefine CHAN I as the new
for the expanded (X-Chan i) display.
At this point the new source for the expanded (X-than i) line in the
Displayed Trace Field (V) is updated to X-Chan I and all or a portion
of CHAN 1 trace is intensified.
3)
4)
5)
6)
Turn the TIME MAGNIFIER control (43) to adjust the magnification
factor (length of the intensified
section) as desired (e.g.
5 nsec).
Displace
the intensified
section
by adjusting
Horizontal
POSITION
control
(39) and position
it on the risetime
of your pulse.
Position
the expanded
trace
in lower grid by adjusting
the Vertical
POSITION control
(40).
Adjust
VERT GAIN control
(42) if required.
At this
7)
point
the
digitized
points
are
clearly
seen
every
10 nsec.
Set INTERLEAVED SAMPLING to ON.
The equivalent
risetime
of the
sampling
pulse is
frequency
very clearly
is
now 5 gigasamples/sec
defined.
and
the
Note: The procedure to follow for Expand B is identical to the above,
except that in Step 2 the EXPAND B push button (46) is pressed rather
than the EXPAND A push button.
Basic 9400A gaveform Measurements
and Operating Procedures
8-5
Parml
STATUS
5n~.t
1
V
PANEL
,/
f
ChaTml 1
EO n~.l V
RS2~
SETUP
Plol~ter
/
(:h t>.1 V~
T/d;I.vSOrw Ch2 EOmV
Tr;I.o .00d:l.v +CHAN
1 ,,
H~u OPP
Figure
8.4
Sequential
I.
Recording
31 Segment
8.4
of Single
Events
in Segmented
Memory Partitioning
Using the same 100 nsec signal
and front
panel
Section
8.2,
and with
your
pulse
generator
trigger,
perform the following
procedure:
1)
2)
3)
4)
5)
6)
7)
8)
Memory
settings
described
in
in external
or manual
Call the Panel Status
menu by pressing
push button
(2).
Press
Modify # Segments
push button
(4) as often
as necessary
display
the value 31 in the # Segments
for SEONCE line.
Set RANDOMINTERLEAVED SAMPLING to OFF.
Set the Time Base to .1 psec/division.
Select
SEQNCE trigger
mode (29).
Press the Return push button
(10) to return
to the main menu.
Set DUAL GRID (14) to ON.
Actuate
your generator
external
trigger
a total
of 31 times
order to generate
31 signals
to be recorded.
in
At this
point
a compacted
trace
of 31 segments
is displayed
in the
upper
grid.
Trace
expansions
EXPAND A and EXPAND B must be used to
display
details
of one or two selected
segments.
9)
Press
EXPAND A (46)
in
order
to
expand
CHAN
Basic 9400A Waveform Measurements
and Operating
Procedures
8-6
If the source for signal expansion shown in the Displayed Trace field
(V) is not X-Chart I, you must redefine the expansion signal source
CHAN I (see Section 8.3).
10)
II)
12)
13)
14)
15)
Press
EXPAND B (46) in order
to expand a second
portion
(segment)
of CHAN I.
Select EXPAND B for display control by pressing the SELECT push
button (44). Redefine EXPAND B to be an expansion of channel 1
necessary.
Choose the segment of interest by adjusting Horizontal POSITION
control (39). The number of the selected segment is displayed
the upper right corner of the Displayed Trace field.
Position the expanded trace in lower grid by adjusting the vertical
POSITION control (40).
Select EXPAND A for display control.
Choose another segment of interest (39).
II. 125 Segment
Memory Partitioning
To make a sequential recording of 125 single events, you need only
modify the value displayed in the # Segments for SEONCE line of the
Panel Status menu by pressing Modify # Segments push button (4) until
the value 125 appears in the # Segments for SEQNCE line.
Keeping all other settings as above, generate 125 triggers. The
resulting display shows the same waveform but the number of digitized
points per segment has changed from 1024 to 256.
Resulting display with 31 segments:
kJJiJJ|lJiJmdJJdJJJhJlhlJkJJiJm
I II II II I III III IIIII IIII III III I II II ~.I~e>.1V8
I
I
Panol
STATUS
X-Cho~1 24.
.]~Ji~.5
Y
PANELI- ~--n---r
RS2S2
SETUP
Plc*.~."
-r-
-r-
r----T-
1----1--
Chant 91x
.~.~ V
L
Ch4.>.’J. V~
T/dlv .t.ue Ch2 50mV
TN.O.00 d:Lv + CHANt,,
OFP
Figure 8.5
Basic 9400A Waveform Measurements
and Operating Procedures
8-7
With 125 segments:
Panel
STATUS
MemoPy
8~oPe
PANEL
Re(x~11
t
Ch 1>.1 V~
T/dJ.v .1.uo Ch2 F~mV
Tr’J.g .00 dlv + CH/kN1 =
Menu OPP
Figure 8.6
8.5
Slow Signal
Recording
Acquisition
of a 1 Hz sine
I)
2)
3)
4)
5)
6)
7)
8)
9)
I0)
II)
12)
13)
14)
rave
signal.
Connect a 1Hz signal source to CHAN 2 input connector (21).
Call the Panel Status menu by pressing push button (2).
Set CHAN 2 sensitivity to 1V/div (27).
Adjust CHAN 2 OFFSET to .00 V (32).
Set CHAN 2 COUPLING (22) to DC 1Mg
Set the Time Base to 1 sec/div (36).
Set the TRIGGER SLOPE to POS (25).
Set the TRIGGER LEVEL to 1.00 dlv (33).
Set the TRIGGER DELAY to 50~ Pre (34).
Set the TRIGGER MODE to NORM (29).
Set the TRIGGER SOURCE to CHAN 2 (23).
Press Return push button (i0) to return to the Main Menu.
Set CHAN 1 to OFF and CHAN 2 to ON by pressing push button (49).
Set DUAL GRID mode to OFF (14).
Resulting Display:
A sine wave signal will be displayed, rolling from right to left across
the screen. The display can be halted by pressing the SINGLE push
button (29) when in NORMAL trigger mode. When in AUTO trigger mode, the
display is halted upon receipt of an external trigger signal.
Basic 9400A Waveform Measurements
and Operating Procedures
8-8
8.6
Vindov Triggering
Window triggering allows the user to capture signals exceeding the
positive or negative limits set around the base line (in internal
trigger) or ground (in external trigger) with the TRIGGER LEVEL control
(33).
Using the same basic acquisition parameters and signal used in Section
8.5, it is possible to halt the rolling signal by increasing its
amplitude until it crosses the positive or negative "window" which
defines the trigger conditions.
Procedure:
I)
2)
3)
4)
Set the TRIGGER SLOPE push button (25) to POS/NEG. (Both the
and NBG LEDs will light up when push button (25) has been pressed
the correct number of times).
Set the COUPLING MODE push button (30) to the AUTO Trigger Mode.
Adjust the CHAN 2 OFFSET control (32) in order to center the sine
wave display at mid-screen.
Select a trigger "window" just beyond the positive or negative half
cycle of the currently displayed sine wave by adjusting the TRIGGER
LEVEL control (33) to approximately± 3.0 divisions.
Note that when Window Triggering has been selected via push button
(25), a correspondingmessage is displayed below the bottom graticule
line on the right-hand portion of the screen in the abridged Panel
Status field. This field enables you to adjust the positive/negative
trigger window desired without having to call the Panel Status menu.
5) Gradually increase the amplitude of the output signal from your
signal generator until the positive and negative half-cycle of the
displayed sine wave exceeds 3.0 divisions with reference to the
zero base line.
ResultingDisplay:
Rolling will cease when the rolling waveform reaches ± 3 divisions in
amplitude.
8.7
Storing
and Recalling
Front
Storing
repetitivesignals.
Panel Setups
i)
Follow the same procedure as in Section 8.1 applying the probe
calibratorsignal.
2)
Press the STORE PANEL (4) push button.
Basic 9400A Waveform Measurements
and Operating Procedures
8-9
At this point the listing of 7 possible front panel storage locations
appears in the MENU FIELD.
3)
Press the push button adjacent
selected (e.g. 2).
to the storage location
you have
All the front panel settings are now stored.
4)
Set CHAN 1 Fixed VOLTS/DIV to 20 mV (28) and TIME/DIV (36)
to .2 msec.
Your display is now half the amplitude and the sweep speed 2.5 times
faster.
5)
6)
7)
8)
Press
Press
Press
Press
the STORE PANEL push button (4).
push button 3 to store the new panel settings.
the RECALL PANEL (5) push button.
push button 2.
At this point the first
corresponding display.
setting
stored
is recalled
with
the
Pressing push button (3) will recall the second setup.
8.8
Signal Storage in Memories C, D
I.
Storage of CHAN 1 gaveform into Memory C
Apply the same signal as in Section 8.1-I, and recall the front panel
setup by pressing push buttons (5) and (2) in that order.
Procedure:
i) Stop acquisition by setting the TRIGGER MODE (29) to single.
2) Press STORE push button (1) to call the Store Trace menu.
Store CHAN i into Memory C (2).
3)
Set CHAN 1 to OFF by pressing push button (49).
4)
5)
Set MEMORY C to ON by pressing push button (47).
II. Storage of CHAN 2 Waveform into Memory D
Apply a second signal, as in Section 8.3, from your pulse generator to
CHAN 2 BNC connector (21).
Procedure:
I)
2)
Press STORE push button (I) to call the Store Trace menu.
Store CHAN 2 into Memory D (5).
Basic 9400A Waveform Measurements
and Operating Procedures
8-10
3)
4)
5)
6)
7)
Set CHAN 2 to OFF (49).
Set MEMORY D to ON (47).
Set DUAL GRID to ON by pressing push button (14).
Select Memory D by pressing SELECT push button (44).
Adjust VERT CAIN control (42) and Vertical POSITION control (40)
center the trace.
The above procedure
enables
two independent
waveforms
to be
simultaneously stored and displayed. Calling the Memory Status menu (3)
enables the user to review all the acquisition parameters.
Note that instead of storing the currently acquired CHAN 1 waveform
into Memory C and CHAN 2 waveform into Memory D, the Store Trace menu
also allows the user to inverse this configuration, and to store the
CHAN 1 waveform into Memory D and the CHAN 2 waveform into Memory C.
8.9
Redefinition
Function
- Expand Memories
C, D
As mentioned in Section (5.2.4), the default signal sources for Expand
A and B are CHAN 1 and 2, respectively. It is possible, however, to
expand a waveform stored in reference Memories C and/or D by redefining
these memories to be the new signal expansion source.
I.
Expansion
of MEMORY
C with
EXPAND A
Just as Expand A and B enabled the user to expand the signals contained
in CHAN I and 2 (Section 8.3), the signals in reference Memories
and/or D can be expanded as described below.
Procedure:
1)
2)
3)
4)
5)
6)
7)
Store the signal into Memory C as described in Section 8.8.
Press EXPAND A push button (46).
Use the Vertical POSITION knob to separate the traces on the
screen.
Set CHAN 1 to ON.
Press SELECT push button (44) to frame the X-Chan i message.
Press REDEFINE push button (45).
Press push button (4) to define Memory C as the new signal source
for Expand A.
From this step on, the procedure to follow is identical to that
described in Section 8.3 for CHAN i, 2 expansion (steps 3 through 6).
II. Expansion of Memory D with Expand B
The procedure used here is identical to that detailed above, except
that Expand B is substituted for Expand A in Step i, and Memory D is
redefined as the new source for expansion (Step 4).
Basic 9400A Waveform Measurements
and Operating Procedures
8-11
It is possible
while studying
these reference
waveforms
to
simultaneously acquire signals via the CHAN 1 and CHAN 2 acquisition
memories in real time. Note that you cannot display more than 4 traces
on the 9400A’s screen at any time.
8.10
Auto-store
in Memory C, D
As mentioned
in Section
5.2.5,
pressing
the Special
Modes push button
(7) permits
the user to automatically
store
the current
CHAN 1 and/or
CHAN 2 display
into
the unit’s
two 32K reference
memories
following
acquisition
of each waveform.
The Auto-store mode is particularly useful
acquire single events in the Normal trigger
> 2 sec. (As explained in Section 5.2.5, in
trigger circuit automatically
re-arms
currently stored waveform to be erased from
whenever the user wishes to
mode appearing at intervals
the Normal trigger mode the
after 2 see, causing the
memory).
pressing the Modify Auto-store push button (2) once causes the waveform
currently contained in the 9400A’s CHAN 1 acquisition memory to be
stored automatically
into Memory C. Continue pressing the Modify
Auto-store push button (2) to see all the possibilities:
CHAN
CHAN
CHAN
CHAN
CHAN
i
1
2
2
1
into
into
into
into
into
Memory
Memory
Memory
Memory
Memory
C
D
C
D
C and CHAN 2 into Memory D.
Auto-store in Memory C
Procedure:
I)
Using the same signal as in measurement example 8.2, set TRIGGER
MODE push button (29) to NORM rather than SINGLE (HOLD).
2)
With the Main Menu displayed
push button (7).
3)
Press Modify Auto-store push button (2) once in order to cause the
signal input to CHAN 1 to be automatically stored into Memory C
with each new trigger cycle.
4)
Return to the Main Menu by pressing Return push button (i0).
5)
Call Memory C by pressing MEMORY C push button (47).
6)
Trigger the signal source.
on the CRT, press the Special Modes
Basic 9400A Waveform Measurements
and Operating Procedures
8-12
Note that Memory C contains an exact copy of the most recent waveform
stored in CHAN I. The display of CHAN 1 waveform disappears about
2 seconds after a valid trigger is detected.
8.11
Common Expand Mode
Sections 8.3 and 8.8 describe the expansion of displayed traces
independently, in order to provide a magnified version of a portion of
the waveform currently in CHAN 1, CHAN 2 or those stored in reference
Memories C or D. However, in certain applications it is convenient to
be able to move the intensified region along two traces simultaneously.
Procedure:
Using the same front panel setup and the i00 nsec signal described
in Section 8.2, connect one of the outputs of your pulse generator
to the CHAN I input connector (21).
2)
Connect a second output
input connector (21).
3)
With the Main Menu displayed on the left-hand side of the CRT,
press push button (7) to call the Special Modes menu.
4)
Press Modify Common Expand push button (4) to set the oscilloscope
to the Common Expand mode.
5)
Return to the Main Menu
6)
Press DUAL GRID (14).
7)
Press EXPAND A and EXPAND B (46).
8)
Press RESET (41), to synchronize
the CHAN 1 and 2 trace.
of your pulse generator
to the CHAN 2
by pressing Return (I0).
the intensified
sections along
of overlapping traces will be
Note that at this point two sets
displayed on the screen. Separate CHAN 1 and CHAN 2 by adjusting the
CHAN 1 or 2 OFFSET controls (32).
Separate expanded traces A and B by first selecting the X-CHAN i,
push button (44), and then adjusting Vertical POSITION control (40).
ensure easy display readability
repeat this step, if necessary,
selecting X-CHAN 2 instead of X-CHAN i, with the SELECT push button
(44).
Basic 9400A Waveform Measurements
and Operating Procedures
8-13
In the Common Expand mode, only the Horizontal
POSITION control
(39)
and the TIME MAGNIFIER control (43) act simultaneously on both the
Expand A and B signal source, while the VERT GAIN control (42) and the
Vertical POSITION control (40) act independently on each expanded
waveform.
When input signals to the 9400A are to be observed at different points
in time, it is possible to independently adjust the time difference
between the two intensified regions prior to calling the Common Expand
mode.
When the Common Expand mode is subsequently called by pressing push
buttons (7) and (4) in that order, the intensified regions for the
expansion sources may then be magnified by means of the TIME MAGNIFIER
control (43) and moved horizontally at a fixed time interval by means
of the Horizontal POSITION control (39).
The time cursors may be called by pressing push button (17) for highprecision measurement of the time interval between the two displayed
regions.
Note that at any time the user may eliminate
the time interval
separating the intensified regions by pressing RESET push button (41).
8.12
Remote
Control
Via the
RS-232-C
Port
The 9400A has been designed to permit control of all of the scope’s
functions by means of a computer/terminal. For a complete listing of
the various commands used to program the 9400A see Section 7.6.
The following examples are given to present the 9400A’s remote control
from a computer. To disable the character echoing from the 9400A issue
the following command:
<ESC>
[
Preliminary Hardware Setup:
1)
2)
3)
4)
Set the thumbwheel switch (54) on the rear panel of the 9400A to
value greater than 31.
Power up the 9400A.
Connect a computer through an RS-232-C cable to the Remote port
connector (56) on the rear panel of the 9400A.
Call the RS-232-C menu by pressing push button (8). Then match the
data transfer speed and character formats of the computer and
oscilloscope (See Section 5.2.6).
Basic 9400A Waveform Measurements
and Operating Procedures
8-14
I.
Remote
Operation
in the
Interrogation
Mode
Programming Example: Terminal Display of Current Time Base Setting.
Programming Procedure:
I) Using any combination of upper or lower case charactersp enter the
letters TD on your keyboard, followed by a space, comma or by the
equal sign, followed by a question mark, followed by <CR> as
follows:
TD ? <CR>
Resulting Display:
Immediately upon execution of the above sequence you will see the
9400A’s current time base setting displayed on your terminal, e.g.:
TIME/DIV I00 S
II.
Remote Operation
in the
Control
Mode
To modify the currently selected oscilloscope parameters, the user must
first set the 9400A to remote use. This is done by entering <ESC>R
(i.e. the character <ESC> followed by upper case "R").
Programming Example: Set the Time Base to 2 msec.
Programming
Procedure:
i) Enter TD 2MS <CR> (upper or lower case characters). Other possible
character formats are:
TIME/DIV 2 MS <CR>
TD 2E-3 <CR>
TD .002 <CR>
(upper or lower case characters)
(upper or lower case characters)
(upper or lower case characters)
Resulting Display:
Observe the Abridged Panel Status field in the lower right-hand portion
of the screen while the above character sequence is entered via the
terminal keyboard. When (<CR> is pressed, you will see the currently
displayed time base setting change to 2 msec.
In order to return the 9400A to Local use, type <ESC>L (i.e. the
character <ESC> followed by upper case "L"), at which point you will be
returned to the 9400A’s initial menu (i.e. the menu which appears at
unit power up).
Basic 9400A Waveform Measurements
and Operating Procedures
8-15
III.
Example
of a Typical
Program
A short
BASICA interactive
program
showing
communication
between a 9400A and an IBM PC-AT is
I00
105
II0
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
205
210
215
220
225
230
235
240
245
250
255
260
265
270
275
280
285
290
295
300
305
310
315
320
325
330
how
given
to initialize
below:
’SAMPLE PROGRAM FOR LINKING THE LECROY 9400A DSO TO AN IBM PC-AT’
’VIA THE RS232C ASYNCHRONOUS COMMUNICATIONS INTERFACE’
’
’AUTHOR : M. SCHUMACHER
’
CLS: ON ERROR GOTO 575
TRUE = I: FALSE = 0: LOOP = TRUE: EXIT = FALSE: ECHO = TRUE: STORE =FALSE
CPRM$="Z"
’
OPEN "COMI:9600,N,8,1" AS #i
OPEN "SCRN:" FOR OUTPUT AS #2
PRINT #2,"SAMPLE INTERACTIVE PROGRAM FOR LINKING THE LECROY 9400A DSO TO AN"
PRINT #2,"IBM PC-AT VIA THE RS232C ASYNCHRONOUS COMMUNICATIONS INTERFACE"
PRINT #2, "":PRINT #2, "Settings : 9600 Bd, no parity, 8 bits, 1 stop bit"
PRINT #2, "": PRINT #2, "Commands :" : X$=STRING$(15,32)
PRINT #2, X$"REM
: Remote,
LOC
: Local"
PRINT #2, X$"STORE : Store to disk, RECALL : Retrieve from disk"
PRINT #2, X$"Any valid command described in the User’s Manual"
PRINT #i, CHR$(27);"["
PRINT #i, "CHLP PPO"
PRINT #i, "CTRL OFF"
PRINT #i, "CFMT,L,BYTE,UNSIGNED_SHORT"
PRINT #i, "CBLS 70"
PRINT #I, "MASK 6,1" ’Enable STB 1
PRINT #I, "RS CONF 6,13,0,0,0" ’<ACK>,<CR>
PRINT #I, "CPRM "+CHR$(34)+CPRM$+CHR$(34)
’
WHILE LOOP
PRINT #2,""
LINE INPUT "Enter command (EX --> exit) : ",
IF LEN(C$) < 2 THEN 245
IF C$ = "EX" THEN LOOP=FALSE: GOTO 285
IF C$ = "REM" THEN C$ = CHR$(27)+"R"
IF C$ = "LOC" THEN C$ = CHR$(27)+"L"
IF C$ = "STORE" THEN GOSUB 380: GOTO 285
IF C$ = "RECALL" THEN GOSUB 460: GOTO 285
IF C$<>"" THEN PRINT #I,C$: GOSUB 300
VEND
CLOSE
SYSTEM
’
’SUBROUTINE GET STRING FROM DS0
’
ON TIMER(2) GOSUB 595: TIMER
CYCLE=TRUE
WHILE CYCLE
PRINT #1,CHR$(6);
Basic 9400A Waveform Measurements
and Operating Procedures
8-16
335
340
345
350
355
360
365
370
375
380
385
390
395
400
405
410
415
420
425
IF EOF(1) THEN 335
TIMER STOP
AS = INPUT$(LOC(1),#1) : C$=MID$(A$,I,LEN(A$))
L=INSTR(C$,CPRM$): IF L>0 THEN L=L-I: C$=MID$(A$,I,L): CYCLE=FALSE
IF ECHO THEN PRINT #2,C$;
IF STORE THEN FOR I=l TO LEN(C$): PRINT #3, MID$(C$,I,I); : NEXT
WEND
TIMER OFF
RETURN
’
’SUBROUTINE OPEN DISK FILE
’
CLOSE #3
LINE INPUT "Specify dir and disk file name : ",AS
OPEN AS FOR OUTPUT AS #3
STORE=TRUE
LINE INPUT "Enter READ command (A --> abort) : "P
IF C$="A" THEN 450
IF INSTR(C$,"R")<>I THEN PRINT #2,"Wrong syntax" : GOTO 450 ELSE PRINT #3,C$:
PRINT #i,C$
430 L=INSTR(C$,"."): IF L=0 THEN PRINT #3,"" ELSE PRINT #3,MID$(C$,L)
435 LINE INPUT "Echo data to screen (Y/N) : ",AS
440 IF A$="N" THEN ECHO=FALSE: PRINT #2,"Uploading ..." ELSE ECHO=TRUE
445 GOSUB 300
450 STORE=FALSE: ECHO=TRUE: CLOSE #3
455 RETURN
460 ’
465 ’SUBROUTINE READ DISK FILE
470 ’
475 CLOSE #3
480 LINE INPUT "Specify dir. and disk file name : ",AS
485 OPEN AS FOR INPUT AS #3
490 A$=CHR$(27)+"R": PRINT #1,AS
495 LINE INPUT "Specify target memory (C/D) : ",B$’. IF B$<>"D" THEN B$="C"
500 LINE INPUT #3,C$: PRINT #2,"Read command was :";C$
505 LINE INPUT #3,C$
510 A$="WT M"+B$+C$+CHR$(13): PRINT #1,AS;
515 LINE INPUT "Echo data to screen (Y/N) : ",AS
520 IF A$="N" THEN ECHO=FALSE: PRINT #2,"Downloading ..." ELSE ECHO=TRUE
525 WHILE NOT EOF(3)
530
AS=INPUTS(I,#3)
535
IF ECHO THEN PRINT #2,A$;
540
PRINT #1,AS;
545 WEND
550 CLOSE #3
555 GOSUB 300
560 A$=CHR$(27)+"L": PRINT #1,AS: GOSUB 300
565 ECHO=TRUE
570 RETURN
575 ’
580 ’DOS ERROR AND TIMEOUT HANDLER
585 ’
590 PRINT #2, "Error no. "; ERR: GOTO 235
595 PRINT #2, "Timeout": TIMER OFF: GOTO 235
Basic 9400A Waveform Measurements
and Operating Procedures
8-17
8.13
Remote
Control Via
GPIB (Option
OP02 only)
If the 9400A has been equipped with option OP02, it is also possible to
control the various functions of the 9400A via the General Purpose
Interface Bus (GPIB).
Example:
Set
the
Time Base
to 1 msec.
This example is given to present the different steps necessary to use a
GPIB bus. Note that most languages offer high-level routines that
perform these steps automatically.
In this example an IBM PC, or compatible computer equipped with a
National Instruments
GPIB PC2 or PC2A GPIB adapter and National
Instruments IBIC program (default settings are selected), is used.
Preliminary Hardware Setup:
i) Before powering up the 9400A, select GPIB operation by setting the
thumbwheel address switch (54) to
2) Connect a GPIB cable to the 9400A’s rear panel GPIB connector (55)
and to the GPIB connector of the PC.
Note that upon system initialization, the PC must be at address O.
3) In the Handler default configuration
displayed on your PC’s CRT, enter:
IBIC <CR>
and
with
the
prompt
A>
(upper or lower case letters)
The following message will be displayed on your CRT:
National Instruments
Interface Bus Interactive Control Program (IBIC Rev C.0)
Copyright (C) 1984 National Instruments, Inc.
All rights reserved
In the following description the commands which must be sent are in
upper case letters. Answers or comments are in lower case. Each
command must be followed by <CR>.
Basic 9400A Waveform Measurements
and Operating Procedures
8-18
4) Enter IBFIND [email protected] (in upper or lower
following program will be executed:
case),
at
which
point
the
Meaning:
IBSIC
Status Message Returned
PC acts as controller
IBTMO 12
Status Message Returned
3 sec
IBEOT 1
Status Message Returned
PC automatically enables <EOI> line
on final character of message
IBSRE i
Status Message Returned
Enable Remote 9400A operation
IBCMD "? @$"
Status Message Returned
PC Talker; 9400A Listener
9400A enters REMOTE
IBWRT "TD IMS;TD ?"
Status Message Returned
TIME/DIV set to 1 msec; read
current value
IBCMD "? D"
Status Message Returned
PC Listener; 9400A Talker
IBRD 120
Status Message Returned
PC to read < 120 characters and
stop when it encounters <EOI>
time-out
At this point the following message will be displayed
(with corresponding Hexadecimal ASCII codes to the left):
54 44 20 31 2E 30 30 45
2D 30 33 20 53 0D OA
8.14
T D I . 0 0 E
- 0 3 S
IBONL
Status Message Returned
Disconnect PC from GPIB; set
9400A to Local operation
E
Exit IBIC program
Making a Plot
when the Computer,
the 9400A,
and
Connected
Together
on a GPIB Bus (Option
OP02 only)
the Plotter are all
In this configuration,
the computer controls the GPIB bus and the
devices that are on the bus, such as the 9400A and the plotter. The
9400A cannot directly send plot data to the plotter even when it is in
LOCAL. It is the task of the computer to organize the data transfer.
The following sequence should be followed.
Basic 9400A Waveform Measurements
and Operating Procedures
8-19
I) The computer sets the 9400A into REMOTE.
2) The computer sets itself to Talker and
sends the command:
"SCREEN DUMP"
the 9400A to
Listener and
3) The computer organizes the transfer between the 9400A and the
plotter in one of the ways described below. The choice depends on
the computer GPIB controller software.
The computer tells the 9400A to talk and the plotter to listen. It
puts itself in Standby Mode while waiting for E0I that will be set
by the 9400A when the plot is finished.
or
The computer tells the 9400A to talk and the plotter to listen. It
puts itself in Listener mode while reading but NOT while storing the
plot data.
or
The computer tells the 9400A to talk and sets itself to Listener. It
reads AND stores the plot data. Afterwards it sets itself to Talker
and tells the plotter to Listen and sends the stored data to the
plotter.
Notice that a larger amount of data has to be stored: up to
50 kilobytes if all the traces are on.
4) The computer terminates the transfer by sending UNT (UNTalk) and UNL
(UNListen) and setting the 9400A into LOCAL.
8.15
Configuring
the
Parallel
Polling
(Option
OP02 only)
Send the following sequence of GPIB commands to the 9400A:
- listen address of the 9400A.
- PPC (Parallel Poll Configure).
- PPE (Parallel Poll Enable).
in binary : 0 11 0 S P3 P2 P1
Where P3 to P1 represents DIO line number - 1
S = 1 if 1 must be sent while Service Request is active.
= 0 otherwise.
- UNT (UNTalk) and UNL (UNLlisten) non obligatory.
Basic 9400A Waveform Measurements
and Operating Procedures
8-20
To "unconfigure" the parallel polling, send
GPIB commands to the 9400A:
-
-
the following sequence of
Listen address of the 9400A.
PPD (Parallel Poll Disable).
in binary : 0 1 11 S P3 P2 P1
as mentioned above.
PPU (Parallel Poll Unconfigure).
UNT or UNL non obligatory.
Other sequences of commands are also possible.
Basic 9400A Waveform Measurements
and Operating Procedures
8-21
SECTION 9
GETTING THE MOST OUT OF YOUR 9400A
The 9400A is a highly accurate digital
optimum precision when handled properly.
oscilloscope
which achieves
The purpose of this section is to familiarize the user with operations
and functional hints that will ensure the best possible operation of
the instrument.
9.1
Front Panel Controls
All front panel controls are fully remotely controllable
and are
therefore constantly monitored by the 9400A’s internal processor.
Any action performed on the front panel is detected by the processor
and the requested changes are implemented very rapidly.
During data acquisition (measurement of input signals), the internal
processor is also busy with the data-taking controls, calculations and
display generation. Under certain conditions, (e.g. RIS mode or slow
time base), the response time of the front panel controls increases.
When for example, the user tries to move a trace up or down on the
screen, it tends to move with a jumping motion.
Whenever slow response to the control knobs is noticed, set the trigger
mode to SINGLE. Acquisition is stopped, the display of the waveform is
frozen and the response time of control knobs returns to normal. Once
waveform manipulations are done, return to NORMAL or AUTO trigger.
9.2
Accurate Amplitude
Measurements
The 9400A digitizers
measure the amplitude
levels.
are 8-bit analog-to-digital
converters that
of input signals by subdividing them into 256
You can ensure maximum measurement accuracy by using the full dynamic
range of the converters, i.e. using input signals close to full scale.
Half-scale signals are in 128 levels only, reducing measurement
accuracy by a factor of two.
To facilitate the adjustment of a full-scale ADC signal, the 9400A
display has been designed to represent the zero level of the ADC as the
bottom line of the grid. Full scale, level 256, is represented by the
top line of the grid.
Getting the Most Out of Your 9400A
9-1
r~
/~
-j -\-.:--.-~! .... .~
/ \::
!...........
/ ...........
!..............
"’"
.....
~"" I ........
’1.............
~\
.....I.........
...... (:l~x~l
~..i..t. -~..~
2p~.2 V
k/
display
grid
500
points
resolution
’J
Cht>.2 V *
T/dlv ZJm Ch2 t V Trig- ~.48dlv + CHAN
tFigure 9.1
To make the best use of the ADC’s dynamic range,
and therefore
accurate
amplitude
measurements,
the displayed
signal
should
fill
the display
grid.
the most
completely
The fully calibrated and continuously adjustable input-signal
conditioning
permitsyou to meet this requirementeasily withoutloss
of calibration.
As an overlapping display of two full scale waveforms could become
quite confusing, the 9400A provides a dual grid option to be used in
applications where both channels are used simultaneously.
HrIJ
\
\
\
\,,j/
J"k
/
/
/
/
/
I
I
\
/
I
I
I
I
\
I
\
A
\ /I
~J mmm,~ o
I
FIGURE9.2
display
dual
grid
2 x 250
points
resolution
Ch t>.2 V *
T/d~v 2~ Ch2 t V =
Trl0-1.4E dlv+CHN~1-
Getting the Most Out of Your 9400A
9-2
9.3
Accurate Time Measurements
Two deep acquisition memories, each storing 32000 points, provide the
unprecedented time resolution of the 9400A.
In order to match the time base settings, a maximum of 25000 digitized
points are displayed on the screen with a resolution of 500 display
points. A compacting algorithm showing all minimum and maximum values
ensures that no information is lost in the display of a trace.
Time cursors can be positioned accurately on any one of the 500 display
points of a compacted trace. The corresponding measurement accuracy is
1/500 or 0.2%.
digitized
waveform
max
:"
:¯
,:
:¯
¯
¯ ,
: :
: ¯
¯
digitized
points
......
" :
<)............
O..........
""":..
...........
O..........
: f........
..
: .
.;
¯ ~ displayed
¯ $
points
compacted
display
with
min max
algorithm
To improve measurement accuracy, two expansion functions, EXPAND A and
EXPAND B are provided to display every digitized point trace.
When the expansion factor is such that 500 measured points are to be
displayed, every display point corresponds to a digitized point.
When the time base requires that less then 500 digitized points fill
the screen, the 9400A interpolates using straight line segments between
the actual points¯
In the example below, the compacted trace of a 25000 point waveform is
expanded by a factor of I00 with EXPAND A and B to provide maximum time
measurement accuracy.
Under these conditions, each expanded trace displays 250 digitized
points.
Every other display point is interpolated and the time measurement
accuracy is 1/50000 = 0.002%.
Getting the Most Out of Your 9400A
9-3
---
r’~
!
’
¯
!
rt
:
i
:
A.
:
"
:
I X.-Q"D’s
I
i
_"
i
i
n
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, [I
’L
1
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--
P’ U44.12.
klk
(=1t1~.2 !
T/d.l.v t Jal ChZ~lV |
’l’V"d, li .3KPdA.v-CI4AN
1,,
Figure 9.3
9.4
Auto-callbratlon
As described in Section 2.5, the 9400A calibrates its time interpolator
relative to the internal 100 MSz crystal-controlled clock generator
every time the time base is modified by front panel operation or by
remote control.
The vertical gain and offset of an input channel are calibrated by
means of a very stable internal 12-blt digital-to-analog
converter
every time the fixed gain control of this channel is modified.
Calibration of both channels also takes place whenever the bandwidth
limit is changed.
These calibrations are necessary largely because of drifts caused by
temperature changes which could arise if the 9400A is left in the same
state for a very long time. To avoid measurement
errors due to
potential drifts, an internal timer of the 9400A forces a complete
auto-calibration
every minute during the first I0 minutes after
power-up and every 20 minutes thereafter. This operation is transparent
to the user, but is audible due to relay switching.
Note that
auto-calibration does not occur in SINGLE or SEQNCE trigger mode.
In remote control, all auto-calibration can be turned off. It may be
the
CALIBRATE
command
in
requested
(see
executed
whenever
7.6.6)
Section
Getting the Most Out of Your 9400A
9-4
SECTION I0
WP01 VAVEFORM PROCESSING OPTION
10.1
Processing
Capabilities
The WP01 Waveform
Processing
Option
includes
an additional
0.5 megabytes
random access
memory for accumulation,
computation
waveform
buffers.
This allows
accumulation
of averaged
waveforms
32000 data points
in 32-blt
form.
and
of
All waveform processing
occurs
through
the waveforms
E and F which may
be displayed
on the screen
by pressing
the corresponding
FUNCTION E, F
(48) push button.
Whenever the FUNCTION E or F trace
or an expansion
one or both
of these
traces
(in
EXPAND A or B) is turned
ON, the
corresponding
waveform processing
is executed.
Whenever the trace
(and
its expansion)
is turned
OFF, the processing
is suspended.
This is true
even for
remote
control.
The display
can be turned
off
by remote
control
in order
to gain speed
(command
SCREEN OFF, Section
7.6.3);
however,
even in this
case the corresponding
function
trace
must be
turned
ON although
nothing
is displayed
on the screen.
FUNCTIONS E and F are waveforms that exist independently of (i.e. in
addition to) the acquisition memories of CHANNELS 1 and 2 and of the
reference memories C and D. On the display, they are treated similarly
to memories C and D, i.e. the vertical display gain and the vertical
position can be modified, but not the horizontal position and the time
magnifier. Of course, they can be expanded by redefining the source
waveform of the traces EXPAND A or B.
Two different processing functions can be executed simultaneously.
FUNCTIONs E and F may be read by remote control just like the other
traces, with the additional option of reading 16-bit data values, and,
as with Channels 1 or 2, they may be stored in reference memories C or
D by pressing the STORE push button (I). Waveform processing functions
operate on one or two source waveforms which may be CHANNEL i or 2,
Memory C or D. FUNCTION F may also operate on FUNCTION E. Since the
results of the processing functions can be stored in the reference
memories, and since FUNCTIONS E and F may operate on these reference
memories (and F may operate on E), chaining of operations is possible.
Waveform processing
can take an appreciable
execution time when
operating on many data points. The user has the option of reducing the
execution time by limiting the number of data points which are used in
the computation.
WP01 Waveform Processing Option
i0-i
The 9400A then executes the waveform processing function og. the entire
waveform (as displayed on the screen) by taking every ~n point, N
depending on the time base. The first point of such a reduced record is
always the data value at address 0 (i.e. the point on the left hand
edge of the screen). For readout and display, the data record is
re-expanded
to the original
number
of data points by linear
interpolation. By remote control the user can read either the entire
expanded record or the reduced record. In the second case, the user
must know the "skip factor", i.e. the value of <intval> in the read
command (see section 7.6.5). This factor can be inspected on the memory
status display screen, or by the inspect command.
10.2
Setting
Up a Waveform Processing
Function
Manually
It is generally good practice to stop data acquisition while preparing
new conditions for waveform processing (by setting the trigger mode to
SINGLE) because the response time might otherwise be slow, depending on
the current function setup. In order to prepare FUNCTION E or F for new
conditions, or to inspect the current setup, the trace FUNCTION E or F
(48) must be turned ON. Select this trace for display control with the
SELECT (44) push button and press REDEFINE (45). A full page setup
for this function appears on the screen. Return to the normal waveform
display by either pressing the "Return" soft key (I0) or the REDEFINE
(45) push button.
The currently selected processing function and its parameters may be
modified with the soft keys. First select the field to be modified. The
rectangular frame around parameter values indicates the currently
selected field. Pressing the Previous FIELD push button (2) will cause
the frame to move towards the top of the list, whereas pressing the
Next FIELD push button (3) will cause the frame to move downwards.
Following field selection, the current value of the field may be
modified by pressing either the Previous or Next VALUE push button (6
or 7). Since the identity of the lower fields may depend on the
function chosen, modify the parameters from top to bottom.
The following waveform processing functions are available:
-
Average: summed and continuous averaging
Extrema: "Roof" for maxima, "Floor" for minima
Arithmetic: Sum, Difference, Product and Ratio
Functions: Negation, Integral, Differentiation,
Root
Smoothing:
1-, 3-, 5-, 7- and 9-point
smoothing
Square and Square
WP01Waveform Processing Option
10-2
10.2.1
Summed
Average
Summed averaging consists of the repeated addition, with equal weight,
of recurrences of the source waveform. Whenever the maximum number of
waveforms is reached, the averaging process stops. The averaging
process may be interrupted by switching the trigger mode from NORM to
SINGLE (29) or by turning the function trace OFF (48). Averaging
continue when these actions are reversed.
The currently accumulated average may be reset either by changing an
acquisition parameter, such as input gain, offset or coupling, trigger
condition or time base, or by pressing the RESET push button (41) twice
in quick succession (remember that FUNCTION E or F must be selected).
The number of currently
averaged waveforms
is displayed
in the
Displayed Trace Field (V in Figure 4.1) of the corresponding function
or of its expansion.
Whenever the maximum number of sweeps is reached, a larger number of
sweeps may be accumulated by simply changing the maximum number of
sweeps in the setup menu. In this case care must be taken to leave the
other parameters unchanged, otherwise a new averaging calculation is
started.
Summed averaging may be performed over CHANNEL I or 2. FUNCTION F may
also average over FUNCTION E, therefore allowing averaging over
functions.
Whenever a waveform containing overflow or under-flow values is to be
added to an average, unknown values will be added. The user may choose
the action to be taken:
- If "Artifact Rejection" is OFF, any overflows are set to the maximum
(256) possible value of the ADC and any under-flows to the minimum
(0). The waveform is then added to the average. Of course, the
average will be incorrect at the overflow positions.
- If "Artifact Rejection" is ON, waveforms containing at least one
overflow or under-flow are rejected from the average, i.e. not added
at all. If waveforms consistently contain overflows or under-flows,
averaging cannot proceed and the number of accumulated sweeps may
stay at zero indefinitely.
In order to improve the signal to noise ratio even further, the 9400A
offers the possibility of performing "offset dithering". When turned on
(i.e. when set to > 0 least significant bits of the ADC), the 9400A
adds a small "hardware" offset to each acquired waveform. This offset
is different for different waveforms, and the values are chosen such
that their average is negligibly small. The function setup menu allows
a choice of the maximum excursion of this offset.
WP01Waveform Processing Option
10-3
When set to the largest possible value of 6 LSB, the waveforms are
offset by up to ±.2 vertical divisions (remember that a vertical
division corresponds to 32 least significant bits of the ADC). In this
case, care must be taken that the waveform to be averaged is contained
within 1/5 of a vertical division from the top and the bottom of the
display grid; otherwise overflows or under-flows might occur. Whenever
dithering is ON, the displays of CHANNELS 1 or 2 vary vertically with
the dithering offset. Their waveform descriptors take the additional
offset into account so that waveforms, as read out by remote control,
and cursor measurements are always correct.
Offset dithering is of interest when the waveform to be averaged is
already relatively "clean", i.e. contains noise variations of the order
of 1/5 of a division or less. In this case, dithering makes the
sequentially acquired waveforms use slightly different portions of the
ADC. Thus the differential non-llnearities (that any flash ADC has) are
averaged out. It can be expected that the differential non-linearities
are reduced by up to a factor of 4 when using 6 LSB dithering.
Waveforms which have high levels of noise (>1/5 of a vertical division)
do their own "dithering",
making artificial offset variations
unnecessary.
10.2.2
Continuous
Average
Continuous averaging (sometimes
of the repeated addition, with
source waveform.
Each newly
accumulated average according to
(N-I)
S(i,new)ffi
N
S(i,old)
called exponential averaging) consists
UNEQUAL weight, of recurrences of the
acquired
waveform
is added to the
the formula:
+ --
[ ] [ ]
N
Where
i
W(i)
S(i,old)
S(i,new)
N
Index over all data points of the waveforms
Newly acquired waveform
"old" accumulated average
"new" accumulated average
May be 2, 4, 8, 16, 32, 64 or 128
The coefficients
(N-I)/N and I/N are the weighting factors which
determine the speed at which the continuous
average follows any
modification of the source waveform. Note that they add up to the value
of i, so that the continuous
average
of noisy, but otherwise
unmodified, waveforms resembles the summed average of such waveforms.
gPOl Waveform Processing
10-4
Option
However,
the statistical
significance
of a continuous
average
is less
good,
since
the last
acquired
waveform
has more weight
than
all
previously
acquired
ones.
Thus the continuous
average
is dominated
by
the statistical
fluctuations
of the most recently
acquired
waveforms.
The continuous
average
never stops
at a maximum number of sweeps.
The
weight
of "old"
waveforms
gradually
tends
to zero,
but they
are
theoretically
never completely
forgotten.
The averaging
process
may be
interrupted
by switching
the trigger
mode from NORM to SINGLE (29)
by turning
the function
trace
OFF (48).
Averaging
will
continue
when
these
actions
are reversed.
The currently
accumulated
average
may be
reset
by either
changing
an acquisition
parameter,
such as input
gain,
offset
or coupling,
trigger
condition
or the time base,
or by pressing
the RESET push button
(41) twice
in quick
succession
(remember
that
FUNCTION E or F must be selected).
Continuous averaging may be performed over CHANNEL 1 or 2. FUNCTION F
may also average over FUNCTION E, therefore allowing averaging over
functions.
10.2.3
Bxtrema
The computation
of extrema
consists
of a repeated
comparison
of
recurrences
of the source
waveform with the already
accumulated
extrema
waveform.
Whenever
a given
data
point
of the new waveform
exceeds
(either
positively
or negatively)
the corresponding
data point
of the
accumulated
extrema
waveform,
it replaces
the former
value
in the
extrema
waveform.
Thus a maximum (called
"roof")
or a minimum (called
"floor")
envelope
of all waveforms
is accumulated.
Whenever the maximum number of waveforms is reached, the accumulation
process stops. The accumulation process may be interrupted by switching
the trigger mode from NORM to SINGLE (29) or by turning the function
trace OFF (48). Accumulation will continue when these actions are
reversed. The currently accumulated extrema waveform may be reset by
either changing an acquisition parameter, such as input gain, offset or
coupling, trigger condition or the time base, or by pressing the RESET
push button (41) twice in quick succession (remember that FUNCTION E
F must be selected). The number of currently accumulated waveforms is
displayed in the Displayed Trace Field (V in Figure 4.1) of the
corresponding function or of its expansion.
Whenever the maximum number of sweeps is reached, a larger number
sweeps may be accumulated by simply changing the maximum number
sweeps in the setup menu. In this case, care must be taken to leave
other parameters unchanged, otherwise the extrema calculation
started again.
of
of
the
is
WPOI Waveform Processing Option
10-5
Extrema may be performed over CHANNEL 1 or 2. FUNCTION F may also
generate extrema over FUNCTION E, therefore allowing extrema over
functions.
10.2.4 Arithmetic
The arithmetic waveform processing options consist of the basic
arithmetic functions performed on two source waveforms on a data point
per data point basis. Different vertical gains and offsets of the two
sources are automatically taken into account. However, both source
waveforms must have the same time base, and both must have either
INTERLEAVED OFF or INTERLEAVED ON. The trigger point may be different
in the two source waveforms, although such a case would usually give
results that are difficultto interpret.
The first source waveform may be multiplied by a constant factor in the
range .01 to 9.99 and be offset by an additional constant in the range
of ± 9.99 times the volts/division setting (of the first source
waveform).
10.2.5 Functions
This option consists of the following mathematical functions on single
waveform sources: negation, square, square root, integral and
differentiation. The first source waveform may be multiplied by a
constant factor in the range .01 to 9.99 and be offset by an additional
constant in the range of ± 9.99 times the volts/division setting (of
the first source waveform).
IO. 2.6 Smoothing
Five options are available:I-,3-,5-,7-and 9-point smoothing.
l-point smoothing consists of adding adjacent data points to each other
with equal weight. The data points of the source waveform are
considered as members of adjacent bins, each containing NI/N2 data
points. N1 is the number of data points in the source waveform whereas
N2 is the number of data points specified by the third line of the
setup menu. The data points within each bin are averaged, resulting in
a waveform consisting of N2 data points. For readout and display this
reduced record is then re-expanded to the original number of data
points by linear expansion.
WPOI Waveform ProcessingOption
10-6
3-point
waveform
smoothing
according
consists
of computing
to the formula:
W(i-1)
W(i)
Y(i)
each
data
point
of
the
source
W(i+l)
+
+
4
2
4
where W(i) is the th point of the source waveform and Y(i) is the ith
point of the computed waveform. If the maximum number of data points,
specified in the third llne of the setup menu, is smaller than the
original number of points, the smoothing is applied to the reduced data
record.
5-point
smoothing
twice
in sequence.
computed by applying
consfsts
of the application
of 3-point
smoothing
Similarly,
7-point
and 9-point
smoothing
are
3-point
smoothing
3 and 4 times.
The resulting averaging formula for 5-point smoothing is:
W(i-2)
Y(i) =
W(i-l)
+
W(i)*6
W(i+l)
+
16
+
4
16
Whereas, for 7-point smoothing, it
W(i-3)
W(i-2)’6
Y(i) =
+-
W(i)*20
W(i+l)*15
+
64
W(i+2
is:
W(i-l)*15
+
64
16
4
64
64
64
)*6 W(i+3)
+
+
64
64
And for 9-point smoothing:
W(i-4)
Y(i)
W(i-3).8
+
W(i-2).28
+
256
256
W(i+i)’56
+
256
W(i+2)’28
+
256
V(i-I).56
+
256
256
W(i+3)’8
+
256
+
256
256
WPOI Waveform Processing Option
I0-7
10.3
Remote Control of Naveform Processing Functions
Remote control of the waveform processing is essentially achieved with
extensions
of existing
commands.
No processing
occurs if the
corresponding TRACE FUNCTION E (TRFE) or TRACE FUNCTION F (TRFF) is
(see Section 7.6.3). This -is also true even if the -SCREEN has been
turned OFF. Averaging can be stopped and continued by switching from
TRIG MODE NORM to TRIG MODE SINGLE and vice versa. Of course, it can
also- be stopped by turning its corresponding trace OFF. An average or
an accumulation
of extrema
can be reset
by a new command,
AVERAGE RESET. A new function or new processing parameters are defined
with extensions to the command REDEFINE. In addition, the command
INSPECT allows some characteristics of the waveform to be known before
it is read out.
i) AVERAGE RESET (ARST)
The accumulated average or extrema of the SELECTed trace is reset.
This command can only be applied to FUNCTION E or to FUNCTION_F.
The 9400A sets the ENVIRONMENT ERROR:
- if the SELECTed trace if OFF.
- if the SELECTed trace is neither FUNCTION E nor FUNCTION F.
The INSPECT commands of Section 7.6.5 have been extended to cover the
inspection of FUNCTIONS E and F by including the following mnemonics:
2) INSPECT (INS)
< FUNCTION E.LIMIT (FE.LI)
< FUNCTION F.LIMIT (FF.LI)
instructs the 9400A to return a character string containing
lower and upper address limits of the current waveform,
the
or
INSPECT (INS) , < FUNCTION E.NSWEEPS (FE.NS)
< FUNCTION-F.NSWEEPS (FF.NS)
instructs
the 9400A to return
a character
string
number of acquired
sweeps (in averaging
and extrema),
containing
the
or
INSPECT (INS) , < FUNCTION E.INTVAL (FE.IV) >
< FUNCTION-F.INTVAL (FF.IV)
WP01Waveform Processing Option
10-8
instructs
the
interval
between
This value
may
such waveforms
points
and none
9400A to return
a character
string
containing
the
data points
used by a waveform processing
function.
be used as the <intval>
parameter
in the readout
of
if the user
wishes
to read only
the computed
data
of the re-interpolated
points.
3) REDEFINE (RDF) ,
?
Instructs the 9400A
SELECTed trace,
to report
the
current
configuration
of the
or
REDEFINE (RDF) , AVERAGE (AVG) , SUMMED , <maxpts>
<source> , <maxswps> , <reject> , <dither>
configures the SELECTed trace for a summed average,
or
REDEFINE (RDF) , AVERAGE(AVG) , CONTINUOUS(CONT) , <maxpts>
<source> , <weight>
configures the SELECTed trace for a continuous average,
or
REDEFINE (RDF) , EXTREMA (EXTR) <e-type> , <maxpts> ,
<source> , <maxswps>
configures the SELECTed trace for an extrema accumulation,
or
REDEFINE (RDF) , ARITHMETIC (ARI) <a-type> , <maxpts> ,
<sourcel> , <source2> , <m-fact> , <a-const>
configures
sources,
the SELECTed
trace
for waveform
arithmetic
*
on two
or
WP01Waveform Processing
10-9
Option
REDEFINE (RDF) , FUNCTIONS (FNC) <f-type> , <maxpts> ,
<sourcel> , <m-fact> , <a-const>
configures
on a single
the SELECTed trace
source,
for
a mathematical
waveform
function
or
REDEFINE (RDF) SMOOTHING (SMO) , <s-type> , <maxpts> ,
<sourcel>
configures the SELECTed trace for a smoothing operation.
The parameters have the following options:
<maxpts>
<
<
<
<
<
<
<
<
<
<
Maximum number of data
points
to be used in the
computation
50 >
125 >
250 >
625 >
1250 >
2500 >
6250 >
12500 >
25000 >
32000 >
Default: 1250
Any other number generates a semantic error.
<source>
=
<sourcel> =
<source2>
< CHANNEL 1
< CHANNEL-2
< FUNCTION E
(el)
(C2)
(FE)
Source waveform
<
<
<
<
<
(Cl)
(C2)
(MC)
(MD)
(FE) >
Source
CHANNEL 1
CHANNEL-2
MEMORY C
MEMORY-D
FUNCTION E
Default: CHANNEL 1
waveform(s)
Default: CHANNEL 1
NOTE: a distinction is made between <source> and <sourcel> to
indicate the fact that averaging and extrema cannot be executed on
MEMORY C
or MEMORY D, whereas all the other functions
can.
FUNCTION E can only be a source for waveform FUNCTION_F.
WPO1 Waveform Processing
I0-i0
Option
<maxswps> =
<
<
<
<
Maximum number of sweeps
i0 >
20 >
50 >
I00
>
Default: i000
< 500000 >
< I000000 >
Any number outside the 1-2-5 progression generates a semantic error¯
<reject>
=
< ON >
< OFF >
Overflow rejection
Default: OFF
Dithering range; 0 = no dithering
Default: 0
<dither> = [ 0 to 6 ]
Any other number generates a semantic error¯
<weight>
= <
<
<
<
<
<
<
Continuous averaging weight
1 >
3>
7>
15 >
31 >
63 >
127 >
Default: 7
Any other number generates a semantic error¯
Extrema type
Default: ROOF
<e-type>
= < ROOF >
< FLOOR >
<a-type>
= <
<
<
<
SUM
> Arithmetic type
DIFFERENCE (DIF) >
PRODUCT
(PRD) > Default: SUM
RATIO
(RIO)
<f-type>
= <
<
<
<
<
DIFFERENTIATE
INTEGRAL
NEGATION
SQUAREROOT
SQUARE
(DIFF)
(INTEG)
(NEGAT)
(SQRT)
(SQR)
Function type
Default: NEGATION
WPOI Vaveform Processing Option
i0-II
<s-type>
Smoothing
=<I>
<3>
<5>
<7>
<9>
Default:
type
3-pt
smoothing
Any other number generates a semantic error.
Multiplication factor
Default: 1.00
<m-fact> = [ 0.01 to 9.99 ]
Any value
smaller
than
nearest
legal
value.
0.01
or
greater
0.01
9.99
is
adapted
to
the
is
adapted
to
the
Additive constant
Default: 0.00
<a-const> = [ -9.99 to 9.99 ]
Any value
smaller
than
nearest
legal
value.
than
or
greater
than
9.99
NOTE: <a-const> is interpreted as the number of vertical divisions
of <sourcel>
Whenever a parameter
substituted.
is not
specified,
the
default
value
is
Examples:
RDF,AVG,SUMMED,,C2
Configures the SELECTed trace (which must be
FUNCTION E or FUNCTION F) for the summed
averaging of CHANNEL 2 with a maximum of 1250
data points over IO00 sweeps. By default,
overflow rejection and dithering are off.
RDF,ARI,PRD,2500,CI,MD,2.00,1.00
Configures the SELECTed trace to compute the
waveform 2.00*(CHANNEL 1 + 1 div)*Memory_D.
maximum of 2500 of data points (equidistantly
distributed over the screen) are to be used.
REDEFINE,FNC,INTEG,25000,FE
Configures the SELECTed trace (which must be
FUNCTION F, since FUNCTION E is specified as
source waveform) to compute the integral over
the waveform in FUNCTION_E, using a maximum of
25000 data points. Note that the use of 25000
data points implies that all data points on
the screen are to be used, regardless of the
time-base setting.
WPOI Waveform Processing Option
10-12
4) The READ commands
FUNCTIONS E and F:
READ (RD)
of Section
7.6.5
have
been
extended
to read
< FUNCTION E.DESC (FE.DE)
< FUNCTION-F.DESC (FF.DE)
READ (RD) , < FUNCTION E.DATA (FE.DA) > , <Parameter list>
< FUNCTION-F.DATA (FF.DA)
READ (RD) , FUNCTION E.TIME (FE.TI) >
< FUNCTION-F.TIME (FF.TI)
READ (RD) , < FUNCTION E.*
< FUNCTION-F.*
(FE.*)
(FF.*)
> , <Parameter list>
>
<Parameter list> = <intval> , <# values> , <addr> , <sweep #>
See Section 7.6.5 for more detailed explanations.
10.4
Additional
Values
in the
Descriptors
of
Processed
Waveforms
The waveform
descriptor
contains
all
the information
needed to
correctly interpret the waveform data. The parameters which describe
the raw data records are explained in Section 7.7; they are still valid
for processed waveforms. However, some additional parameters describe
the processing which was applied to obtain the current waveform.
IMPORTANT: The parameters in the following list have NO meaning if the
"Data Processing" byte (number 34 of the descriptor record)
is set to 99 (raw data).
In the following list, each parameter is identified by its (decimal)
address relative to the beginning of the descriptor, and by the number
of bits. Data values shown are always in decimal.
Pos. Size
Meaning
36 16-bit
256*Power of volts (see explanation in Section 10.5).
38 16-bit
256*Power of seconds (see explanation in Section 10.5).
40 - 63
Reserved
64 8-bit
Identity of function waveform; 4 = E, 5 = F.
WPOI Waveform Processing Option
10-13
65 B-bit
Functiontype.
0 = Average
2 = Arithmetic
4 = Smoothing
1 = Extrema
3 = Functions
66 B-bit
Sub-functiontype, depending on function type. Takes on
values between 0 and (n-l), where n is the number
sub-functions possible. The order is the same as in the
sub-functionlists of Section 10.3.
67 8-bit
Primary source of this waveform.
0 = CHANNEL 1 1 = CHANNEL 2
2 = Memory C
3 = Memory D
4 = FUNCTION E
68 B-bit
Secondary source of this waveform (arithmeticonly), with
the same interpretationas the previous byte (67).
69 8-bit
Continuousaveragingweight.
1=1:3
0=I : 1
3 = 1 : 15
2 = 1 : 7
5 = 1 : 63
4 = 1 : 31
6 = 1 : 127
70 32-bit
Maximum number of sweeps (summed averaging and extrema).
74 16-blt
Multiplicationfactor * I00
76 16-bit
Additive constant * I00
78 16-blt
Maximum number of data points = <maxpts> in the REDEFINE
command.
80 8-bit
Reject (summed averagingonly).
0 = Reject off 1 = Reject on
81 8-bit
Dithering
(summed averaging only).
0 = No dithering
Otherwise
= approximate
number of
bits,
corresponding
to
excursion.
82 - 97
Reserved
98 32-bit
Actually
extrema).
acquired
ADC least significant
the maximum dithering
number of sweeps (summed averaging
and
102 32-bit Number of acquired waveforms with overflows (summed
averaging).
WPOI Waveform ProcessingOption
10-14
106 32-bit
Number of acquired waveforms with under-flows (summed
averaging).
110 32-bit
Number of rejected waveforms (summed averaging with Reject
ON).
114 16-bit
Number (+ 1) of data points
used in the
data record
(may be less
than <maxpts>).
computation
of this
116 16-bit
Ratio of the number of data points in the source waveform
over the number of data points used.
118 - 149 Reserved
10.5
Vertical
Scaling
Units
With the introduction
of waveform processing
functions,
such as
multiplication, division, square-root, integration and differentiation,
which alter the vertical scaling units, a more general system for the
vertical scales must be introduced. Three variables are now involved:
now interpreted slightly
"fgain" (byte 0) = "fixed vertical gain"
the notion of volts
differently,
by dropping
(Compare with Section 7.7).
22 = 5 mU/div
24 = 20 mU/div
.....
23
25
31
= I0 mU/div
= 50 mU/div
= 5 U/div
Where U now stands for a general unit, which may be a
product of a power of volts and of a power of seconds.
"P V" (bytes 36 + 37) = 256*power of volts
"P-s" (bytes 38 + 39) = 256*power of seconds
Thus, U = Volts**(P_V/256) * Seconds**(P_s/256).
NOTE: Whenever the WP01 waveform processing option is installed, "P V"
and "P s" are always valid, even in raw data records (see the following
example). However, in software versions without waveform processing,
they cannot be relied upon. (Of course, in these cases the vertical
scales are always in volts).
WP01Waveform Processing Option
10-15
Examples:
"fgain" = 22
"P V"
= 256
"P-S" =
0
corresponding
corresponding
corresponding
to 5 mU/div
to power of 1
to power of 0
The resulting vertical scale is thus 5 mV/div. Such
a scale might occur in raw data records, in
averaging,extrema or sums of raw data records.
"fgain" = 17
"P V"
= 512
"P-s" =
0
correspondingto I00 ~U/div
correspondingto power of 2
correspondingto power of 0
The resulting vertical scale is thus i00 ~V2/div.
Such a scale would result from the multiplication
of two raw data records.
"fgain" = 26
"P V"
= 64
"P-s" = 0
correspondingto i00 mU/div
correspondingto power of 1/4
correspondingto power of 0
The
resulting
vertical
scale
is
thus
I00 mV**(I/4)/div (i.e. one-tenth of the fourth
root of volts per division). Such a scale might
result from the double application of the
square-rootoperation on a raw data record.
"fgain" = -2
"P V"
= 256
"P-s" = 256
corresponding
corresponding
corresponding
to 50 pU/div
to power of 1
to power of 1
The resulting vertical scale is thus 50 pVsecldlv.
This scale might result from an integration over a
raw data record.
The following cases can also occur:
-
Both powers may be zero, corresponding to a dimensionless record,
e.g. resultingfrom a division of raw data records.
Powers may be negative, e.g. due to a division of raw data records,
followed by another division. Differentiation also gives negative
powers of the time unit.
WP01Waveform Processing Option
10-16
Index of Topics
10.6
Paragraph
Topic
10.2.4
10.3
10.2.2
10.2.1
10.2.3
I0.i
10.3
10.2.5
10.3
10.3
10.2
10.2.6
10.5
10.4
i0.I
Arithmetic
options
AVERAGE RESET (ARST)
Averaging,continuous
Averaging,summed
Extrema
Function E
INSPECT (INS)
Mathematicalfunctions
REDEFINE (RDF)
Remote control of waveform processing functions
Setting up a waveform processingfunction manually
Smoothing,N-point
Vertical scaling units
Waveform descriptorsyntax
WPOI waveform processingcapabilities
i)
2)
3)
WP01Waveform Processing Option
10-17
0
SECTION Ii
FAST FOURIER WAVEFORM PROCESSING OPTION
(WP02, V 2.06FT)
11.1
Processing
Capabilities
The FFT option (WP02) adds a spectrum analysis capability to a 9400A
already equipped with the waveform processing option WP01.
The 9400A’s Functions E and F can be defined as the fast Fourier
transform of one of the source waveforms - Channel 1, Channel 2, Memory
C, Memory D, and Function E (for Function F only). A glossary of the
terms used in this chapter is given in Section 11.6.
Values of the following FFT processing parameters can be selected in
the FFT redefine menu or with remote control commands.
Function Type:
Fourier Transform
Display Type:
Power Spectrum (dBm)
Power Density (dBm)
Magnitude
Phase
Real Part
Imaginary Part
Transform size:
50 to 25000
Source Trace:
Channel 1
Channel 2
Memory C
Memory D
Function E (for Function F only)
Window Type:
Rectangular
von Hann (Hanning)
Hamming
Flat Top
Blackman-Harris
Multiplication Factor:
0.01 to 9.99
Additive Constant:
-9.99 to +9.99
Zero Suppression:
OFF or ON.
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-1
The 9400A’s Function F can also be defined as the Power Average of the
FFT computed by Function E.
Values of the following FFT processing parameters can be selected in
the FFT Power Average redefine menu or with remote control commands:
Function Type:
FFT Power Average
Display Type:
Power Spectrum (dBm)
Power Density (dBm)
Magnitude
Transform Size:
same as Function E
Source Trace:
Function E
Max number of sweeps:
i0 to 200
functions (Averaging, Extrema, Arithmetic, Functions and
All WPOI
Smoothing) can be applied to waveforms either before or after the FFT
processing.
Menus and front panel controls related to FFT are similar
corresponding WPOI controls (see Section i0.i).
to the
Remote control commands related to FFT provide for the definition of
processing and the readout of waveform data and status, as well as the
loading of reference waveforms into the 9400A’s memories (C, D).
The commands are similar to the corresponding
WP01 commands (see
Sections 7, 10.3 and 11.3).
Spectra are computed over the full length of the source time domain
waveform.
Sub-sampling of the source waveform is available (with the Transform
Size option in the FFT menu), so that the the computation speed can be
traded against the frequency range.
Spectra are displayed with frequency axes running from zero to Nyquist
frequency, over 5 or 6.25 divisions, with the frequency scale factor in
a I-2-5 sequence.
The Time Magnifier operates on the FFT output traces as a Frequency
Magnifier (up to 100 times).
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-2
The Display
and vertical
Control knobs provide
position
control.
vertical expansion (up
to 10 times)
To read the amplitude and frequency of the data point, the Marker can
be moved over into the frequency domain by going beyond the right hand
edge of the time domain waveform.
The Time Cursors can be moved beyond the right hand edge of the time
domain waveform
and thus become Frequency
Cursors,
providing
simultaneous
readout
of frequency
difference
and of amplitude
difference between two points on each frequency domain trace.
Table
Display
11.1
Display
Types
type
Unit
Power Spectrum
Power Density
spectrum
Magnitude
Phase
Real Part
Imaginary Part
Vertical
position
of zero
dBm
dBm
V
degree
V
V
-3
0
0
0
(mark)
(mark)
div
div
div
div
Note: Vertical position of 0 dBm varies with the
gain. A mark at the left hand edge of the screen
level of a trace. Generally, a sinusoidal source
peak-peak will give a spectrum point of about +3 div
source waveform’s
indicates the dBm
waveform of 8 div
at any gain.
Since the computation of FFT may take up to 1 minute (for a Transform
Size of 25000 points), it is possible to interrupt an undesired FFT
either by turning off the corresponding trace(s) or by pushing the
Redefine button, if the FFT trace is the selected trace.
11.2
Modification
to WPO1 Functions
With the option
as follows:
WP02 (FFT)
installed,
the
WP01 functions
are
modified
When any WP01 function operates on a frequency domain waveform (a
result of FFT processing), the Max # of Points value selected in the
menu of the function is ignored. Instead, the number of points of the
frequency domain waveform is used for further processing.
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-3
11.3
FFT Processing Examples
Example: spectrum of the 9400A Probe Calibrator waveform.
I)
Connect the 9400A calibration signal (976.6 Hz, 1.0 V pp square
wave) to the channel 1 input.
2)
If you use a xlO probe, select Panel STATUS and adjust the Set Chl
Attenuator to )d0.
Set Channel i volts/div to 20 mV/div (for)dO probe), AC, 1
Set the Channel 1 offset to a value near 0.
3)
Select a time base of 1 msec/div.
4)
Adjust the triggering conditions
normal; trigger level about 0 div.
as follows: Chl, AC coupling,
You should obtain a repetitive display of almost I0 periods of a
square wave, 5 divisions peak-to-peak.
5)
Turn on and Select Function E
6)
Redefine Function E as follows:
Function Class:
Display Type:
Transform Size:
Source Trace:
Window Type:
Multiplication Factor:
Additive Constant:
Zero Suppression:
Fourier Transform
Magnitude
1250
Chan 1
Rectangular
1.00
+0.00 div
ON
Notice that at the bottom of the menu page the effective number of
points, N = 1250, and the Nyquist frequency = 62.5 kHz are
displayed.
Fast Fourier Waveform Processing
Option (VP02, V 2.06FT)
11-4
7)
Start
computing
the
FFT (press
either
Return
or Redefine
button)
Note the message COMPUTING in the lower left corner of the screen.
After 2 seconds, the computed Magnitude spectrum is displayed.
If you are using the Normal or Auto trigger mode, you will get a
new spectrum about every 1.7 seconds.
Note the frequency scale factor of i0 kHz/div and the frequency
range of 6.25 divisions, from zero to 62.5 kHz, the Nyquist
frequency. The zero frequency is always displayed at the left hand
edge of the screen.
The frequency interval, 6f, between two computed points equals
I/T, where T is the duration of the time domain record (i0 msec).
In this case,
Af = I00 Hz.
Observe that the signal spectrum has a prominent peak - the
fundamental harmonic - at about 1 kHz, followed by the peaks of
the odd harmonics, of decreasing amplitude.
8)
Freeze
the
spectrum
by selecting
the
Single
Trigger
mode
You can use the Marker to check the exact frequency and amplitude
of the 1 kHz peak. You may use trace expansion (A or B) to view
details of the peaks and to adjust the Marker.
Note that the step size with which you can advance the Marker is
not related to the interval between the computed points. The step
becomes finer when you increase the expansion factor.
With the Rectangular Window, the amplitude of the 1 kHz peak may
be inexact ("picket fence effect"). In the example above, with
0.50 V peak square wave, you would expect 0.50 V * 4/K = 0.636 V
for the first harmonic but you will find about 0.43 V.
9)
Redefine the Window Type to the Flat Top, press the Return button.
The amplitude of the 1 kHz peak should now be very close to the
expected 0.636 V, but at the cost of a broader peak and a reduced
frequency resolution.
1o)
Increase the time record duration
Switch to the slower time base of 2 msec/div.
To repeat the acquisition of input and the spectrum computation,
push the Single Trigger button.
Fast Fourier Waveform Processing
Option (WF02, V 2.06FT)
11-5
The frequency
resolution
is now increased
(the harmonic
further
apart),
but the frequency range is reduced.
You can use the Marker to check the Nyquist frequency
at the right
hand edge of the spectrum
trace,
which
the value displayed
in the FFT menu.
11)
Switch
further
to 10 msec/div
and push the Single
increase
the time record duration.
peaks
are
of 25.0 kHz
agrees with
Trigger
button
to
The Nyquist frequency is now 6.25 kHz, so that only the harmonics
1, 3 and 5, a~. approximately1, 3 and 5 kHz fit into the frequency
range. The 7"n harmonic, at about 7 kHz, has been aliased (folded
back) into the peak visible at 2 * 6.25 - 7 = 5.5 kMz. Further
aliased harmonics of decreasingamplitude are also visible between
the originalpeaks.
12)
Redefine the Display Type to Power Spectrum, and the Window Type
back to Rectangular.
You now see the harmonics on the logarithmicscale, at 10 dB/dlv.
Look at the broad skirts exhibited by the peaks: this is the
leakage of the signal energy of each peak into the neighboring
frequencybins.
13) Redefine the Window Type to von Hann (also called Hanning)
The skirts are reduced considerably;the leakage is diminished.
14) Redefine the Transform size to 2500
You will obtain N = 2500 and the Nyquist frequency of 125 kHz,
while the interval between the points (bins) will remain unchanged
at 1/0.01 sec = 100 Hz.
15) Define Function F as the FFT Power Average of Function E
Using the Normal or Auto trigger mode, you can average up to 200
spectra and see the intermediate or final average on a linear
scale (Magnitude)or dBm scale (Power Spectrum or Power Density).
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-6
16)
Experiment
Try other tlme-base settings, display modes, numbers of points,
window types and signals, to become familiar with the system. Try
combinations of FFT and the WPOI processing functions.
You can define both Functions E and F as FFT of the same source
waveform, but with different parameters, and compare the resulting
traces.
11.4
Remote Control of FFT Processing
Consult Sections 7 and 10.3 - 10.4 for general information on remote
control using either the GPIB or the RS-232-C interface. The additional
forms of commands specific to the FFT option and the related fields of
the Waveform Descriptor are described below.
11.4.1
Remote Commands
The ’Redefine’
related to FFT:
command
REDEFINE (RDF), FFT,
has
been
extended
to
accept
the
<disptype>,
<maxpts>,
<source>,
<m_fact>, <a_const>, <z_suppr>
parameters
<window>,
The parameters have the following options:
<disp_type> = <
<
<
<
<
<
<maxpts> =
<
<
<
<
<
<
<
<
<
POWER SPECTRUM
POWER-DENSITY
MAGNITUDE
PHASE
REAL PART
IMAGINARY PART
5O >
125 >
250 >
625 >
1250 >
2500 >
6250 >
12500 >
25000 >
(PWS)
(PWD)
(MAG)
(PHASE)
(REAL)
(IMAG)
> (default)
>
>
>
>
>
(default)
Any other number generates a semantic error.
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-7
<source> = <
<
<
<
<
(Cl)
CHANNEL 1
CHANNEL-2
(C2)
MEMORY C
(MC)
MEMORY-D
(MD)
FUNCTION E (FE)
(default)
NOTE: FUNCTION E can be a source only for FUNCTION_F.
<window> = <
<
<
<
<
RECTANGULAR
V0N HANN
HAMMING
FLAT TOP
BLACKMAN HARRIS
<m fact> = 0.01 to 9.99
(default)
(RECT)
(HANN)
(HAHN)
(FLT)
(BH)
(default = 1.0)
Multiplication factor applied to
waveform before FFT computation.
the source
<a const> = -9.99 to 9.99 (default = 0.0)
Additive constant (divisions) applied to the
source waveform before multiplication.
<z_suppr> = <OFF>
<ON>
(default)
If ON, the DC component
waveform is forced to O.
The ’redefine’
related
to the
REDEFINE (RDF),
The parameters
command has also been
FFT Power Average:
extended
accept
the
the
source
parameters
FFT AVG (FFTA), <dlsp_type>, <nsweeps>
have the
following options:
<disp_type> = < POWER SPECTRUM (PWS)
< POWER-DENSITY
(PWD)
< MAGNITUDE
(MAG)
<nsweeps> =
to
of
< I0
< 20
< 50
< I00
< 200
>
>
>
>
>
(default)
(default)
Any other number generates a semantic error.
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-8
NOTE: This definition can be applied only to Function F. It will be
executed only if Function E is defined as FFT (any display mode). The
number of points will be that of the output of the FFT (i.e. N/2).
Examples:
RDF,FFT,MAG,1250,CI
Redefines the SELECTed trace (E or F) for the
FFT of Channel 1 with maximum 1250 points,
displayingthe Magnitude on a linear scale.
Default settings
are applied to the
remaining
parameters (Rectangular window,
m fact = 1.0, a const = 0.0, zero suppression
ON).
RDF,FFT,PNS,625,C2,BH,2.0,,OFF
Redefines the SELECTed trace (E or F) for the
FFT of Channel 2 with maximum 625 points,
displaying
the Power Spectrum on a
logarithmic (dBm) scale. Window Type
Blackman-Harris,m fact = 2.0, a_const = 0.0,
zero suppressionis OFF.
RDF,FFTA,PWD,20
Redefines the SELECTed trace (must be F) for
the FFT Power Average of the FFT computed
simultaneously by Function E. Number of
sweeps is 20.
11.4.2
Additional
Values
in
the
Descriptors
of FFT Processed
Waveforms
The oscilloscope waveform and descriptors can be read into a host
computer(see Section 7.6.5).
With the WP02 option, the Waveform Descriptor length is unchanged
(150 bytes). However, in addition to the Descriptorfield values defined
in Section 7.7 and 10.4, the following fields have new or additional
values pertainingto the results of FFT processing:
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-9
Pos
9
Size
8-bit
Meaning
Time base (sec/div):
4 .. 36: see Section 7.7
Frequency
59
60
61
62
base (Hz/div):
=
=
=
=
5
I0
30
50
mHz
mHz
mHz
mHz
.e.
86 =
87 =
88 =
5 MHz
I0 MHz
20 MHz
eee
91 = 0.2 GHz
92 = 0.5 GHz
Displayed Record Length
59 .. 86 = 12500 points
87 = i0000 points
88 .. 92 = 12500 points
i0
8-bit
Sampling interval(sec/point):
II .. 45: see Section 7.7
Frequencyinterval (Hz/point):
59
60
61
62
=
=
=
=
2.0 ~Hz
5.0 ~Hz
10.0 wHz
20.0 ~Hz
e,e
91 = 0.I MHz
92 = 0.2 MHz
34
8-bit
Data processingof this record
5 = FFT
6 = FFT AVERAGE
36
16-bit
Units: code for power of volts
code = 256 * power
38
16 bit
Units: code for power of seconds
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
II-i0
code = 256 * power
40
16 bit
Units: code for power of arbitrary unit
code = 256 * power
42
8 bit
Units: identity of arbitrary unit
0 = undefined
1 = dB
4 = degrees
56
8 bit
Display Type:
0
1
2
3
4
5
82
dBm Power Spectrum
dBm Power Density
Magnitude
Phase
Real Part
Imaginary Part
Window Type:
8 bit
0
I
2
3
4
8 bit
89
=
=
=
=
=
=
= rectangular
=von Hann
= Hamming
= Flat Top
= Blackman-Harris
Zero Suppression:
0 = OFF
1 = ON
118-119
11.5
16 bit
FFT Application
11.5.1 Some practical
Ratio of the number of data points of the
expanded waveform over the number of data
points computed.
Hints
suggestions:
(I) To increase the frequency resolution, increase the length of the
time domain waveform record (i.e. use a slower time base).
(2) To increase the frequency range, increase the effective sampling
frequency (i.e. increasethe Transform Size).
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
ii-II
(3) With transient signals use the Rectangularwindow. You should adjust
the time base and the triggeringconditionsso that the transient is
completelycontainedin the time domain window (i.e. on the screen).
(4) For the best amplitude accuracy of isolated spectrum peaks, use the
Flat Top window.
(5) For the best reduction of leakage and good detection of small peaks
several bins away from a large peak, use the Blackman-Harriswindow.
(6) For moderate improvement of amplitude accuracy and of leakage
rejection,use the von Hann or Hamming window.
(7) If your time domain signal is repetitive but noisy, preventing you
from having a stable trigger, you can define Function E as the FFT
of the signal channel and Function F as the FFT Power Average of
Function E to obtain a stable spectrumof the input signal.
(8) You can display the FFT Power Average either on a linear scale
(Magnitude)or on a dBm scale (Power Spectrum or Power Density).
11.5.2 Relationshipsof 9400A FFT output vaveforms to the FFT computationsteps
For comparisonof the 9400A’s FFT results with those obtained from other
FFT instrumentsthe following informationmay be useful:
(I) In the 9400A’s FFT computation, the first step is the sub-sampling
of the source waveform. Data points for the FFT calculation are
measured at regular intervals over the full length of the waveform
displayedon the screen.
You can select
the maximum transform
size in the FFT menu or via
remote control.
The actual
transform
size,
N, is selected
to be
equal
to or smaller
than
the Displayed
Record
Length
(see
Table 5.1).
Exception:
you may get a 125 point transform
when you
have specified
50 points.
The sub-sampling interval and the actual transform size selected
provide the frequency scale factor in a 1-2-5 sequence.
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-12
the addition of the selected constant to the
(2) The second step is
waveform, followed by multiplication
by the
sub-sampled source
selected factor.
(3) The third step is the multiplication
selected window function.
of the source waveform by the
step is the computation
of FFT, using
(4) The fourth
implementation of the DFT (Discrete Fourier Transform)
a fast
k=N-i
I
X =
n
N
n*k
x*W
k
~
k=0
where
x
k
is a complex array whose real part is the modified source
time domain waveform, and whose imaginary part is 0
X
is the resulting complex frequency domain waveform
n
(-j * 2 * rJN)
is the number of points in xk and
X
n
N
The generalized FFT algorithm, implemented in the 9400A, works on N
which need not be a power of 2.
(5) The fifth step is the division of the resulting complex vector X
by the coherent gain of the window function, to compensate for th~
loss of the signal energy due to windowing. This compensation
provides accurate amplitude values for isolated spectrum peaks.
The real part of Xn is symmetric
is:
about the Nyquist frequency, that
Rn =
n RN_
while the imaginary part is anti-symmetric, that is
In =
n _ IN_
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-13
It can be considered that the energy of the signal at some frequency
n is distributed 50/50 between the first half and the second half of
the spectrum; the energy at frequency 0 is completely contained in
the 0 term.
the redundant part of the
(6) The sixth step is the elimination of
results. Only the first half of the
spectrum (Re, Im), 0 to the
Nyquist frequency is kept:
R’ = 2 * ~n
I ’n = 2 *
n
n
0 < n < N/2
0 <- n < N/2
(7) The seventh and last step is the computation of the waveform to be
displayed.
If you select the Real Part or Imaginary Part Display Type, no
further computation is done: the displayed waveform is R’ or I’ as
defined above.
If you select Magnitude mode, the magnitude is computed as:
!
M = | R’2 ’2
+ I
n~
n
In practice,
result:
n
the
steps
described
above
lead
to the
following
An AC sine wave of amplitude 1.0 V and an integral number
of periods in the time window, transformed
with the
rectangular window, results in a fundamental peak of 1.0 V
magnitude in the spectrum.
However, a DC component of 1.0 V, transformed with the
rectangular window, results in a fundamental peak of 2.0 V
magnitude in the spectrum.
The displayed waveforms for the other available modes are computed
as follows:
Phase: angle = arctan (In/Rn)
n
angle = 0
~n > M .
< Mm~
n - mln
where M
is the minimal magnitude, fixed at about 10-3 of the full
scale ~e. 64 units on the scale of 65536, 16 bits), at any gain
setting.
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-14
dBm Power
Spectrum:
2M
M
n
n
= 20 * log
I0
Log PS = 10 * log
10
n
M
ref
ref
where M r = 0.316 V (that is, 0 dBm is defined as the sine wave of
0.316 V ~k or 0.224 V RMS, giving 1.0 mW into 50 9).
Note that the "dBm Power Spectrum" could also be called the "dBm
Magnitude" as suggested by the formula above.
dBm Power Density:
Log PD = log PS - I0 * log (ENBW
n
n
I0
where
* Af)
ENBW
is the equivalent noise bandwidth
corresponding to the selected window
Af
is
the
current
frequency
resolution
of the filter
(bin
width)
The FFT Power Average (Function F only) takes the complex frequency
domain data R’ n, I’ , generated by Function E in step 6 above,
computes the square o~ the magnitude
M2=R,
n
2+i , 2
n
n
and collects the result in a buffer.
the final step is the
(8) In the case of an FFT Power Average
computation of the selected Display Type format (Magnitude, Power
Spectrum, Power Density).
11.5.3
Computation
speed
of FFT
In the 9400A the Fourier transform computation takes about 1.7 sec for a
1250 point FFT and just under one minute for a 25000 point FFT. These
times depend somewhat on the Window Type and the Display Type selected.
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-15
You can speed up the computation by selecting a Transform Size smaller
than 25000. The 9400A will select for you the effective Transform Size,
N, equal to or smaller than your selected value, depending on the actual
number of points in the time domain record.
11.6
FFT/9400A
Glossary
Aliasing
If the input signal to a sampling acquisition system contains components
whose frequency is greater than the Nyquist frequency (half the sampling
frequency) which results in less than two samples per signal period,
these components will be aliased. That is, their contribution to the
sampled waveform will be indistinguishable from that of the components
below the Nyquist frequency.
In the 9400A, the FFT definition menu displays the effective Nyquist
frequency. You should select the time base and Transform Size resulting
in a Nyquist frequency higher than the highest significant component in
the time domain record.
To help you choose suitable settings for FFT analysis,
Nyquist frequencies is given in Section 11.8.
Coherent
a table
of
Gain
The coherent gain of a filter corresponding to each window function is
1.0 (0 dB) for the Rectangular window and less for other windows.
defines the loss of signal energy due to the multiplication by the
window function. In the 9400A this loss is compensated. Table 11.3 lists
the values for the windows implemented.
ENBV (Equivalent
Noise
Bandwidth)
For a filter associated with each frequency bin, ENBW is the bandwidth
of an equivalent rectangular filter (having the same gain at the center
frequency) which would collect the same power from a white noise signal
as the filter considered. In Table 11.3, ENBW is listed for each window
function implemented and is given in bins.
Filters
Computing an N-point FFT is equivalent to passing the time domain input
signal through N/2 filters and plotting the outputs of the filters along
the frequency axis. The spacing of filters is Af = I/T and the bandwidth
depends on the window function used (see Frequency bins).
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-16
Frequency
bins
The FFT algorithm takes a discrete source waveform, defined over N
points, and computes
N complex Fourier coefficients,
which are
interpreted as harmonic components of the input signal.
For a real source waveform (imaginary part equals 0), there are only N/2
independent harmonic components.
The FFT corresponds to analyzing the input signal with a bank of N/2
filters, all having the same shape and width, and centered at N/2
discrete frequencies. Each filter collects the signal energy falling
into the immediate neighborhood of its center frequency, and thus it can
be said that there are N/2 "frequency bins".
The distance,
always
in Hz, between
the center
frequencies
of the bins is
af = I/T
where
T is
the
duration
of the
time
domain
record
in
seconds.
The width of a bin is equal to Af.
The width of the main lobe of the filter centered at each bin depends on
the window function used. With the Rectangular window, the width at
-3.92 dB is 1.0 bins. Other windows have wider main lobes (consult
Table 11.3).
Frequency
Range
The range of frequencies computed and displayed in the 9400A is from 0
Hz at the left hand edge of the screen to the Nyquist frequency at 5 or
6.25 divisions.
Frequency
Resolution
In a narrow sense, the frequency resolution is equal to the bin width,
af. That is, if the input signal changes its frequency by af, the
corresponding spectrum peak will be displaced by ~f. For smaller changes
of frequency, only the shape of the peak will change.
However, the effective frequency resolution
(i.e. the ability to
actually resolve two signals having close frequencies)
is further
limited by the use of window functions. The ENBW value of all windows
other than the rectangular is greater than ~f, i.e. greater than the bin
width. Table 11.3 lists the ENBW value for the windows implemented.
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-17
Leakage
Observe the Power Spectrum of a sinusoidal waveform having an integral
number of periods in the time window (i.e. the source frequency equals
one of the bin frequencies), using the Rectangular window. The spectrum
contains a sharp component whose value reflects accurately the source
waveform’s
amplitude.
For other input frequencies
this spectral
component is lower and broader.
The broadening of the base of the peak, stretching
out into many
neighboring bins is termed the leakage. It is due to the relatively high
side lobes of the filter associated with each frequency bin.
The filter side lobes and the resulting leakage are reduced when one of
the available window functions is applied. The best reduction is
provided by the Blackman-Harris and the Flat Top windows. However, this
reduction is offset by a broadening of the main lobe of the filter.
Numbers
of Points
In the 9400A, FFT is computed over the number of points (Transform Size)
selected in the Redefine Menu. The effective number of points, N, is
displayed at the bottom of the FFT Redefine Menu screen. It is always a
sub-multiple of the number of points actually displayed in the time
domain.
FFT generates N/2 spectrum points as output. These points are expanded
by linear interpolation to 12500 points (I0000 points in the case of
10 MHz/div).
Nyquist Frequency
Equal to one half of the total sampling frequency.
Also, f Nyquist = Af * N/2.
In the 9400A, the value of Nyquist frequency is displayed at the bottom
of the FFT Redefine Menu screen.
Picket Fence Effect
Observe again the Power Spectrum of a sinusoidal waveform having an
integral number of periods in the time window (i.e. the source frequency
equals one of the bin frequencies), using the Rectangular window. The
spectrum is a sharp peak whose value reflects accurately the source
waveform’s amplitude. For other input frequencies the spectrum peak is
lower and broader.
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-18
Its highest point can be lower by 3.92 dB (1.57 times) when the source
frequency is half way between two bin frequencies. This variation of the
spectrum magnitude is called the Picket Fence Effect (the loss is called
the Scallop Loss).
All window functions compensate this loss to some extent but the Flat
Top window provides the best correction (see Table 11.3).
Power Spectrum
The Power
Spectrum
(V 2) is
the
square
of the
The 9400A displays the Powe~ Spectrum
corresponding to (0.316 Vpeak)
Pover
Density
Magnitude
spectrum.
on the dBm scale,
with 0 dBm
spectrum
The Power Density
Spectrum
product
of the
equivalent
frequency bin width in Hz.
(V2/Mz)
noise
is
the Power Spectrum
divided
by the
bandwidth
of the filter
and the
The 9400A displays the Power Density spectrum on the dBm scale, with
0 dBm corresponding to (0.316 Vpeak)-/Hz.
Sampling
Frequency
In the 9400A the time domain records
are acquired
at sampling
frequencies which depend on the selected time base (consult Table 5.1).
Before FFT, the time domain record may be sub-sampled. If the selected
number of points is lower than the displayed record length (Table 5.1),
the total sampling frequency will be reduced.
The total sampling frequency
equals
(displayed in the FFT Redefine Menu).
Scallop
twice
the Nyquist
frequency
Loss
Loss associated with the picket fence effect
windows implemented).
(listed in Table 11.3 for
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-19
Window Functions
All window functions
implemented
in the WP02 package
belong
of cosines
family
with one to three
non-zero
cosine
terms:
to
the
sum
m=M-I
w =
k
a * cos
m
0 _< k < N
N
!
m=O
where
H=3
is the maximum number of terms
am
are the coefficients of the terms
N
is the number
waveform
k
is
the
time
of
points of the
source
index
Table 11.2 lists the am coefficients.
The window functions,
seen
point
k = N/2,
(mid-screen
amplitude
of 1.0.
in the time domain are symmetric
about the
on the 9400A)
where they
all
have a peak
Table
window
11.2
Coefficients
of
functions
Window type
a0
a
I
a
2
Rectangular
1.0
0.0
0.0
yon Hann
0.5
-0.5
0.0
Hamming
0.54
-0.46
0.0
Flat-Top
0.281
-0.521
0.198
Blackman-Harris
0.423
-0.497
0.079
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-20
Table
11.3
Window frequency
Highest
side-lobe
(dB)
Window type
11.7
domain
Scallop
loss
(dB)
parameters
ENBV
Coherent
gain
(dB)
(bins)
Rectangular
- 13
3.92
1.0
yon Hann
- 32
1.42
1.5
- 6.02
Hamming
- 43
1.78
1.37
- 5.35
Flat-Top
- 44
0.01
2.96
-11.05
Blackman-Harris
- 67
1.13
1.71
- 7.53
Errors
0.0
and Warnings
and processing
The appropriate
Certain combinations of source waveform properties
functions may result in an error or raise a warning.
message is displayed at the top of the 9400A screen.
On Error,
On Warning,
processing
is
processing
abandoned.
is
performed,
but
the
results
are
corrupted.
ERROR: FFT src wfm is in sequence mode.
FFT of sequence
abandoned.
mode waveform
has not
ERROR: FFT src wfm is in frequency
been
implemented.
Processing
domain.
FFT of a frequency domain waveform has not been implemented. Processing
abandoned.
ERROR: FFT AVG src wfm not
in freq domain.
FFT Power Average mode (Function F only) is active only if Function E
defined as FFT. Processing abandoned.
You should define Function E as FFT.
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-21
WARNING:FFT src wfm (ils
mode) extended.
In the Interleaved Sampling Mode, there are two time-base settings
(I ~sec/div and 0.5 ~sec/div) in which the record of 25000 points shown
on the screen is incomplete. Starting at the left hand edge of the
screen, 0.08 and 0.4 div respectively are blank. Before computing the
FFT, the leftmost valid point of such records is copied leftward,
through to the left edge of the screen. This will generate harmonic
componentsnot present in the original record.
If possible, you should use the Single-shot mode before FFT at these
time-basesettings.
WARNING:FFT src wfm (roll
mode) incomplete.
In the Roll Mode (time/div < 0.5 sec), you can stop the acquisitionof
trace before it fills the entire width of the screen. The remaining
portion of the record is blank on the display, but the memory contents
remain undefined.FFT is computed on this partiallyundefined record.
You should avoid stopping the acquisition in this manner if you wish to
obtain meaningfulFFT results.
VARNING:FFT src vfm overlunderflov.
The source waveform has been clipped in amplitude, either in the
acquisition (too high gain or inappropriate offset) or in the previous
processing. The resulting FFT contains harmonic components which were
not present in the unclipped waveform.
You should repeat the acquisition or previous processing of the source
waveform,with changed settings.
11.8
Table of Nyquist
Number of
Points
FNyquist
25.000 mHz
62.500 mHz
0.125
0.125
0.125
Frequencies
Hz
Hz
Hz
SS/RIS
Time/div
50
125
SS
SS
I00
I00
sec
sec
50
125
250
SS
SS
SS
20
50
i00
sec
sec
sec
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-22
Number of
Points
FNyquist
0.250
0.250
0.250
0.250
Hz
0.625
0.625
0.625
0.625
Hz
1.250
1.250
1.250
1.250
1.250
1.250
Hz
2.500
2.500
2.500
2.500
2.500
2.500
2.500
Hz
6.250
6.250
6.250
6.250
6.250
6.250
6.250
Hz
12.500
12.500
12.500
12.500
12.500
12.500
12.500
12.500
12.500
I.]z
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
3S/RIS
Time/div
50
i00
250
500
SS
SS
SS
SS
I0
20
50
I00
sec
sec
sec
sec
125
250
625
1250
SS
SS
SS
SS
i0
20
50
I00
sec
sec
sec
sec
50
125
250
500
1250
2500
SS
SS
SS
SS
SS
SS
2
5
i0
20
50
I00
sec
sec
sec
sec
sec
sec
5O
i00
250
5OO
i000
2500
5000
SS
SS
SS
SS
SS
SS
SS
I
2
5
I0
20
50
i00
sec
sec
sec
sec
sec
sec
sec
125
25O
625
1250
2500
6250
12500
SS
SS
SS
SS
SS
SS
SS
1
2
5
10
20
50
i00
sec
sec
sec
sec
sec
sec
sec
5O
125
250
50O
1250
2500
5000
12500
25000
SS
SS
SS
SS
SS
SS
SS
SS
SS
200 msec
0.5 sec
1
sec
2
sec
5
sec
I0
sec
20
sec
50
sec
i00
sec
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-23
FNyquist
Time/div
Number of
Points
SS/RIS
50
I00
250
500
I000
2500
5000
25000
SS
SS
SS
SS
SS
SS
SS
SS
i00 msec
200 msec
0.5 sec
1
sec
2
sec
5
sec
I0
sec
50
see
SS
SS
SS
SS
SS
SS
SS
SS
I00 msec
200 msec
0.5 sec
1
sec
2
sec
5
sec
I0
sec
20
sec
25.000
25.000
25.000
25.000
25.000
25.000
25.000
25.000
Hz
62.500
62.500
62.500
62.500
62.500
62.500
62.500
62.500
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
125
250
625
1250
2500
6250
12500
25000
0.125
0.125
0.125
0.125
0.125
0.125
0.125
0.125
0.125
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
50
125
250
500
1250
2500
5000
12500
25000
SS
SS
SS
SS
SS
SS
SS
SS
SS
20
50
I00
200
0.5
1
2
5
I0
msec
msec
msec
msec
sec
sec
sec
sec
sec
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
50
i00
250
500
I000
2500
5000
25000
SS
SS
SS
SS
SS
SS
SS
SS
i0
20
50
I00
200
0.5
1
5
msec
msec
msec
msec
msec
sec
sec
sec
0.625
0.625
0.625
0.625
0.625
0.625
0.625
0.625
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
125
250
625
1250
2500
6250
12500
25000
SS
SS
SS
SS
SS
SS
SS
SS
I0
20
50
I00
200
0.5
I
2
msec
msec
msec
msec
msec
sec
sec
sec
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-24
Number of
Points
FNyquis t
RIS/SS
Time/div
1.250
1.250
1.250
1.250
1.250
1.250
1.250
1.250
1.250
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
5O
125
250
5OO
1250
2500
5000
12500
25000
SS
SS
SS
SS
SS
SS
SS
SS
SS
2
5
i0
20
50
I00
200
0.5
1
msec
msec
msec
msec
msec
msec
msec
sec
sec
2.500
2.500
2.500
2.500
2.500
2.500
2.500
2.500
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
50
I00
250
500
I000
2500
5000
25000
SS
SS
SS
SS
SS
SS
SS
SS
1
2
5
I0
20
50
i00
0.5
msec
msec
msec
msec
msec
msec
msec
sec
6.250
6.250
6.250
6.250
6.250
6.250
6.250
6.250
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
125
250
625
1250
2500
6250
12500
25000
SS
SS
SS
SS
SS
SS
SS
SS
I
2
5
10
20
50
100
200
msec
msec
msec
msec
msec
msec
msec
msec
12.500
12.500
12.500
12.500
12.500
12.500
12.500
12.500
12.500
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
5O
125
250
5O0
1250
2500
5000
12500
25000
SS
SS
SS
SS
SS
SS
SS
SS
SS
0.2
0.5
i
2
5
I0
20
50
i00
msec
msec
msec
msec
msec
msec
msec
msec
msec
25.000
25.000
25.000
25.000
25.000
25.000
25.000
25.000
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
50
100
250
500
I000
2500
5000
25000
SS
SS
SS
SS
SS
SS
SS
SS
0.I
0.2
0.5
i
2
5
i0
50
msec
msec
msec
msec
msec
msec
msec
msec
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-25
Number of
Points
FNyquist
SS/RIS
Time/div
62.500 kHz
62.500 kHz
62.500 kHz
62.500 kHz
62.500 kHz
62.500 kHz
62.500 kHz
62.500 kHz
125
25O
625
1250
2500
6250
12500
25000
SS
SS
SS
SS
SS
SS
SS
SS
0.I
0.2
0.5
1
2
5
I0
20
msec
msec
msec
msec
msec
msec
msec
msec
125.000
125.000
125.000
125.000
125.000
125.000
125.000
125.000
125.000
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
50
125
250
500
1250
2500
5000
12500
25000
SS
SS
SS
SS
SS
SS
SS
SS
SS
20 gsec
50 gsec
0.I msec
0.2 msec
0.5 msec
i
msec
2
msec
5
msec
I0
msec
250.000
250.000
250.000
250.000
250.000
250.000
250.000
250.000
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
50
i00
250
500
I000
2500
5000
25000
SS
SS
SS
SS
SS
SS
SS
SS
I0
~sec
20
Bsec
50
Bsec
0.i msec
0.2 msec
0.5 msec
1 msec
5 msec
625.000
625.000
625.000
625.000
625.000
625.000
625.000
625.000
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
125
250
625
1250
2500
6250
12500
25000
SS
SS
SS
SS
SS
SS
SS
SS
I0
usec
20
~sec
50
~sec
0.i msec
0.2 msec
0.5 msec
i msec
2 msec
1.250
1.250
1.250
1.250
1.250
1.250
1.250
1.250
1.250
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
50
125
250
500
1250
2500
5000
12500
25000
SS/RIS
SS
SS
SS
SS
SS
SS
SS
SS
2
5
I0
20
50
0.I
0.2
0.5
I
~sec
psec
usec
~sec
psec
msec
msec
msec
msec
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-26
Number of
Points
FNyquist
SS/RIS
Time/div
2.500
2.500
2.500
2.500
2.500
2.500
2.500
2.500
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
5O
i00
250
50O
1000
2500
5000
25000
SS/RIS
SS/RIS
SS
SS
SS
SS
SS
SS
i
2
5
I0
20
50
0.I
0.5
~sec
~see
Bsec
~sec
~sec
~sec
msec
msec
6.250
6.250
6.250
6.250
6.250
6.250
6.250
6.250
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
125
250
625
1250
2500
6250
12500
25000
SS/RIS
SS/RIS
SS
SS
SS
SS
SS
SS
1
2
5
I0
20
50
0.i
0.2
~sec
~sec
~sec
~sec
~sec
usec
msec
msec
12.500
12.500
12.500
12.500
12.500
12.500
12.500
12.500
12.500
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
5O
125
250
5OO
1250
2500
5000
12500
25000
SS/RIS
SS/RIS
SS/RIS
SS/RIS
SS
SS
SS
SS
SS
0.2 ~sec
0.5 msec
1
~sec
2
~sec
5
~sec
I0
~sec
20
~sec
50
~sec
0.I msec
25.000
25.000
25.000
25.000
25.000
25.000
25.000
25.000
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
5O
i00
25O
5OO
i000
2500
5OOO
25000
SS/RIS
SS/RIS
SS/RIS
SS/RIS
SS/RIS
SS
SS
SS
0.I
0.2
0.5
1
2
5
I0
50
50.000
50.000
50.000
50.000
50.000
50.000
50.000
50.000
50.000
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
5O
I00
200
5OO
i000
2000
5000
i0000
20000
SS/RIS
SS/RIS
SS/RIS
SS/RIS
SS/RIS
SS
SS
SS
SS
50 nsec
0.I usec
0.2 ~sec
0.5 ~sec
1
~sec
2
~sec
5
~sec
I0
~sec
20
~sec
~sec
~sec
~sec
~sec
~sec
usec
usec
psec
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-27
Number of
Points
FNyqui s t
SS/RIS
Time/div
125.000
125.000
125.000
125.000
125.000
125.000
125.000
HHz
MHz
MHz
HHz
HHz
HHz
HHz
5O
125
25O
5OO
1250
2500
5000
RIS
RIS
RIS
RIS
RIS
RIS
RIS
20 nsec
50 nsec
0.1 gsec
0.2 psec
0.5 ~sec
1 gsec
2 gsec
250.000
250.000
250.000
250.000
250.000
250.000
250.000
MHz
HHz
HHz
MHz
MHz
MHz
MHz
50
I00
250
500
i000
2500
5000
RIS
RIS
RIS
RIS
RIS
RIS
RIS
10
nsec
20
nsec
50
nsec
0.1 gsec
0.2 gsec
0.5 gsec
1 ~sec
625.000
625.000
625.000
625.000
625.000
625.000
625.000
625.000
MHz
HHz
HHz
MHz
MHz
HHz
MHz
HHz
125
250
625
1250
2500
6250
12500
25000
RIS
RIS
RIS
RIS
RIS
RIS
RIS
RIS
10
nsec
20
nsec
50
nsec
0.1 psec
0.2 Bsec
0.5 psec
1 ~sec
2 ~sec
1250.000
1250.000
1250.000
1250.000
1250.000
1250.O00
1250.000
1250.000
1250.000
MHz
MHz
MHz
MHz
HHz
MHz
HHz
MHz
MHz
5O
125
250
5OO
1250
2500
5000
12500
25000
RIS
RIS
RIS
RIS
RIS
RIS
RIS
RIS
RIS
2
5
I0
20
50
0.i
0.2
0.5
1
nsec
nsec
nsec
nsec
nsec
~sec
~sec
psec
~sec
2500.000 MHz
2500.000 MHz
2500.000 MHz
2500.000 MHz
2500.000 HHz
2500.000 MHz
2500.000 MHz
i00
250
5OO
1000
2500
5000
25000
RIS
RIS
RIS
RIS
RIS
RIS
RIS
2
5
10
20
50
0.I
0.5
nsec
nsec
nsec
nsec
nsec
~sec
~sec
Fast Fourier Waveform Processing
Option (WPO2, V 2.06FT)
11-28
11.9
References
Bergland, G. D., "A Guided Tour of the Fast Fourier Transform",
Spectrum, July 1969, pp. 41 - 52.
IEEE
A general introduction to FFT theory and applications.
Harris, F. J., "On the Use of Windows for Harmonic Analysis with the
Discrete Fourier Transform", Proceedings of the IEEE, vol 66, No I,
January 1978, pp. 51 - 83.
Classical paper on window functions
many examples of windows.
Brigham, E.O., "The Fast Fourier
Englewood Cliffs, N. J., 1974.
and their figures of merit, with
Transform",
Prentice
Hall, Inc.,
Theory, applications and implementation of FFT. Includes discussion of
FFT algorithms for N not a power of 2.
Ramirez, R, W., "The FFT Fundamentals
Inc., Englewood Cliffs, N. J., 1985.
and Concepts",
Prentice Hall,
Practice oriented, many examples of applications.
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-29
11.10
Index
of Topics
Paragraph
Topic
11.6
11.6
11.6
11.5.2
11.5.2
11.5.2
11.5.3
11.4.2
11.4.1
11.6
11.7
11.5
11.4.1
11.3
11.5.1
11.5.2
11.6
11.6
11.6
11.6
11.6
11.6
11.2
11.6
11.6
11.8
11.6
11.6
11.6
ii.i
11.9
11.6
11.6
11.6
11.6
Aliasing
Coefficients of window functions in tabular form
Coherent gain
Computation of dBm power spectrum
Computation of magnitude
Computation of real/imaginary parts
Computation speed of FFT
Description of additional values of FFT descriptors
Description of remote FFT commands
Equivalent Noise Bandwidth (ENBW)
Error and warning messages
FFT processing, application hints
FFT processing, description of remote control commands
FFT processing, examples
FFT processing, practical rules for using FFT processing
FFT processing, steps involved in calculating the FFT
FFT/940OA Glossary
Filters
Frequency bins
Frequency range
Frequency resolution
Leakage
Modification to WPOI functions
Number of points used for computing the FFT
Nyquist frequency
Nyquist frequency table
Picket fence effect
Power spectrum
Power density spectrum
Processing capabilities of FFT option
References
Sampling frequency
Scallop loss
Window frequency domain parameters in tabular form
Window functions
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
11-30
APPENDIX
Index of remote commands (GPIB and RS-232-C)
This index groups all remote commands described in sections 7, I0 and
II of this manual. All commands listed in this index are common to both
the GPIB and the RS-232-C interfaces.
For convenience, the commands as well as their abridged forms have been
arranged in alphabetical order. The number on the right hand side
refers to the paragraph section where the command is defined.
AUTO_STORE(AS)
7.6.6
3)
AVERAGE RESET (ARST)
10.3
i)
BANDWIDTH (BW)
7.6.2
14)
CALIBRATE (CAL)
7.6.6
1)
CALL HOST (CH)
7.6.6
4)
CHANNEL 1 ATTENUATION (CIAT)
CHANNEL 2 ATTENUATION (C2AT)
7.6.2
7.6.2
Ii)
Ii)
CHANNEL 1 COUPLING (CICP)
CHANNEL 2 COUPLING (C2CP)
7.6.2
7.6.2
13)
13)
CHANNEL I OFFSET (CIOF)
CHANNEL 2 OFFSET (C20F)
7.6.2
7.6.2
12)
12)
CHANNEL 1 VOLT/DIV (CIVD)
CHANNEL 2 VOLT/DIV (C2VD)
7.6.2
7.6.2
I0)
I0)
COMM BLOCKSIZE (CBLS)
7.6.7
5)
COMM FORMAT (CFMT)
7.6.7
4)
COMM HEADER (CHDR)
7.6.7
I)
COMM HELP (CHLP)
7.6.7
3)
COMM PROMPT (CPRM)
7.6.7
7)
COMM STRDELIM (CSDE)
7.6.7
6)
COMM TRAILER (CTRL)
7.6.7
2)
A-1
DUAL GRID (DG)
7.6.3
1)
HOR POSITION (HP)
7.6.3
7)
IDENTIFY (ID)
7.6.6
5)
7.6.5
7.6.5
10.3
10.3
7.6.5
7.6.5
6)
6)
2)
2)
6)
6)
INTERLEAVED (IL)
7.6.2
2)
KEY
7.6.3
I0)
MASK
7.6.8
MESSAGE (MSG)
7.6.3
9)
PLOTTER (PT)
7.6.4
1)
PLOT SIZE (PS)
7.6.4
PROBE CAL (PC)
7.6.6
2)
READ, CHANNEL 1 (RD Cl)
CHANNEL-2 (RD C2)
FUNCTION E (RD FE)
FUNCTION-F (RD FF)
MEMORY C(RD MC)
MEMORY-D
(RD MD)
7.6.5
7.6.5
10.3
10.3
7.6.5
7.6.5
4)
4)
4)
4)
4)
4)
RECALL (REC)
7.6.5
2)
REDEFINE, ARITHMETIC (RDF ARI)
AVERAGE (RDF AVG)
CHANNEL 1 (RDF CI)
CHANNEL 2 (RDF C2)
EXTREMA
(RDF EXTR)
FFT
(RDF FFT)
FUNCTIONS (RDF FNC)
MEMORY C (RDF MC)
MEMORY-D (ROE MD)
SMOOTHING (ROE SMO)
10.3
10.3
7.6.3
7.6.3
10.3
11.4.1
10.3
7.6.3
7.6.3
10.3
3)
3)
8)
8)
3)
SCREEN DUMP (SD)
7.6.4
3)
INSPECT, CHANNEL 1 (INS
CHANNEL--2 (INS
FUNCTION E (INS
FUNCTION-F (INS
MEMORY C- (INS
MEMORY-D (INS
Cl)
C2)
FE)
FF)
MC)
MD)
A-2
3)
8)
8)
3)
SEGMENTS (SEG)
7.6.2
9)
SELECT (SEL)
7.6.3
3)
SETUP (SU)
7.6.5
3)
STB
7.6.8
I)
STOP
7.6.2
15)
STORE (STO)
7.6.5
1)
TIME/DIV (TD)
7.6.2
i)
TIME MAGNIFIER (TM)
7.6.3
6)
TRACE CHANNEL1
TRACE-CHANNEL-2
TRACE-EXPAND
TRACE-EXPAND-B
TRACE-MEMORY-C
TRACE-MEMORY-D
TRACE-FUNCTION E
TRACE-FUNCTION-F
7.6.3
7.6.3
7.6.3
7.6.3
7.6.3
7.6.3
7.6.3
7.6.3
2)
2)
2)
2)
2)
2)
2)
2)
TRANSMIT (TX)
7.6.4
4)
TRIG COUPLING (TRC)
7.6.2
5)
TRIG DELAY (TRD)
7.6.2
3)
TRIG LEVEL (TRL)
7.6.2
4)
TRIG MODE (TRM)
7.6.2
6)
TRIG SLOPE (TRP)
7.6.2
8)
TRIG SOURCE (TRS)
7.6.2
7)
TSTB
7.6.8
3)
VERT GAIN (VG)
7.6.3
4)
VERT POSITION (VP)
7.6.3
5)
WAIT
7.6.6
6)
7.6.5
7.6.5
5)
5)
WRITE, MEMORY C
MEMORY-D
(TRCI)
(TRC2)
(TREA)
(TREB)
(TRMC)
(TRMD)
(TRFE)
(TRFF)
(WT,MC)
(WT,MD)
A-3
Additional
RS-232-C
only
remote
commands
This subsection contains only those remote commands which are specific
to RS-232-C communication.
<ESC> <
7.6.10
7)
<ESC> L
7.6.10
I0)
<ESC> (
7.6.10 3)
<ESC> )
7.6.10
4)
<ESC> C
7.6.10
II)
<ESC> R
7.6.10 9)
<ESC> T
7.6.10
<ESC> [
7.6.10 5)
<ESC> ]
7.6.10 6)
RS CONF
7.6.10
I)
RS n SRQ
7.6.10
2)
A-4
12)
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