Tektronix 442 Operators Instruction Manual

Tektronix 442 Operators Instruction Manual
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BEFORE READING-
THIS MANUAL REPRINTED JULY 1980
PLEASE CHECK FOR CHANGE INFORMA TION
A T THE REAR OF THIS MANUAL.
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TEKTRONIX®
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Tektronix, Inc.
P.O. Box 500
Beaverton, Oregon 97077
070-2373-00
INSTRUCTION
Serial Number
MANUAL
First Printing AUG 1977
WARRANTY
Tektronix warrants that this product is free from defects in materials and workmanship. The
warranty period is one (1) year from the date of shipment. Tektronix will, at its option, repair or
replace the product if Tektronix determines it is defective within the warranty period and if it is
returned, freight prepaid, to a service center designated by Tektronix.
Tektronix is not obligated to furnish service under this warranty:
a.
to
repair
damage
resulting
from
attempts
by
personnel other than Tektronix
representatives to install, repair, or service the product;
b.
to repair damage resulting from improper use or from connecting the product to
c.
if personnel other than Tektronix representatives modify the hardware or software.
incompatible equipment;
There is no Implied warranty of fitness for a particular purpose. Tektronix is not liable for
consequential damages.
Copyright © 1977 Tektronix, Inc. All rights reserved. Contents of this publication
may not be reproduced in any form without the written permission of Tektronix, Inc.
Products of Tektronix, Inc. and its subsidiaries are covered by U.S. and foreign
patents and/or pending patents.
TEKTRONIX, TEK, SCOPE-MOBILE, and
�
are registered trademarks of
Tektronix, Inc. TELEQUIPMENT is a registered trademark of Tektronix U.K.
Limited.
Printed in U.S.A. Specification and price change privileges are reserved.
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TABLE OF CONTENTS
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LIST O F I L LUSTRATIONS
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LIST O F TABLES
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BE FORE OPERATION
Introduction
LOCATION AND OPERATION O F EXTERNA L
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Operating Voltage
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fuse Information
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Vertical
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Triggering
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1
1
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Preliminary
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Signal Ground
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CONTROLS, CONNECTORS, AND INDICATORS
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15
Probe Compensation
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Vertical Gain Check
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Basic Timing Check
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4
Applications
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Peak-to-Peak Voltage Measurements
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Instantaneous Voltage Measurements-Dc
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Crt Display and Power
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External Blanking
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442 Operators
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14
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Power Selectors and Dc Balance
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Normal Sweep Operation
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11
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Input Coupling Capacitor Precharging
LOCATION AND OPERATION O F EXTERNAL
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10
BASIC OSCILLOSCOPE OPERATION
Operators Adjustments and Checks
Introduction
7
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Horizontal
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Safety Information
Power Operation
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CONTROLS, CONNECTORS, AND INDICATORS (cont)
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Page
Page
16
17
17
19
TABLE OF CONTENTS (Cont.)
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BASIC OSCILLOSCOPE OPERAT ION
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Comparison Measurements
Time Duration Measurements
Frequency Measurement
Rise Time Measurements
Time Difference Measurements
Multi-Trace Phase Difference Measurements
x-v Phase Measurement
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23
24
25
27
28
30
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442 Operators
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LIST OF ILLUSTRATIONS
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Page
Fig. No.
1
2
3
4
442 Oscilloscope . . . . . . . . . . . . . . . . .. . . . . . iv
Power switches on bottom . . . . . . . . . . . . . . . . . 2
. . . . . . . . . . .3
Line fuse location on Rear Panel
CRT DISPLAY and POWER front panel
controls and indicators . . . . . . . . . . . . . . . . . 4
External Z-AXIS input on Rear Panel . . . . . . . . . 6
Controls through bottom of cabinet . . . . . . . . . . . 7
Vertical system controls . . . . . . . . . . . . . . . . . . .9
Horizontal system controls . . . . . . . . . . . . . . . . 1 0
Triggering system controls. . . . . . . . . . . . . . 1 1
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9
Probe compensation. . . . . . . . . . . . . . . . . . . . . 15
Display of 0.5 PROBE ADJ output signal. . . . . . . 1 7
Measuring peak-to-peak voltage of a waveform . . . 1 8
Measuring instantaneous dc voltage with respect
to a reference voltage . . . . . . . . . . . . . . . . . . . 1 9
Measuring the time duration between points
on a waveform . . . . . . . . . . . . . . . . . . . . . . . 24
Measuring rise time . . . . . . . . . . . . . . . . . 26
Measuring time difference between two pulses . . . 28
Measuring phase difference . . . . . . . . . . . . . . . 29
Phase difference measurement from an
X-Y display . . . . . . . . . . . . . . . . . . . . . . . . 30
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LIST OF TABLES
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Page
Fig. No.
Page
Table No.
1
2
3
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Ac Regulating R anges. . . . . . . . . . . . . . . . . . . . . 2
Ac Fusing . . . . . . . . . . . . . . . . . . . . . . . . . 3
R ise Time Measurements. . . . . . . . . . . . . . 25
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442 Operators
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2
Fig. 1. 442 Oscilloscope
iv
442 Operators
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BEFORE OPERATING
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INT RODUCT ION
The Tektronix 442 Oscilloscope is a 35 MHz maximum
bandwidth instrument with dual trace capability. A dual
trace dc to 35 megahertz vertical system provides calibrated
deflection factors from 2 millivolts/division to 10 volts/
division. Trigger circuits provide stable triggering over the
full vertical bandwidth. A horizontal deflection system pro­
vides calibrated sweep rates from 0.5 second/division to
0.1 microsecond/division. An X10 magnifier circuit (push­
button switch) extends maximum sweep to 10 nanoseconds/
division. In X-V mode of operation, vertical and horizontal
deflection factors are the same as vertical amplifiers.
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of a 117-234 V single-phase three-wire system) is not re­
commended because only the Line Conductor has over­
current (fuse) protection within the instrument.
Each instrument is provided with a three-wire power
cord with a three-terminal, polarized plug for connection
to power source. The grounding terminal of the recep­
tacle is directly connected to the instrument chassis and
cabinet as recommended by national and international
safety codes. Color coding of cord conductors follows the
I.E.C. which specifies: Line, brown ; Neutral, blue; Safety
Earth or Ground, green with a yellow stripe (or solid
green).
OPE RAT ING VOLTAGE
SA FETY IN FO R MA T ION
The 442 Oscilloscope is designed to be operated from a
single phase power source which has one of its current car­
rying conductors at ground potential (earth ground).
Operation from other power sources where both current
carrying conductors are live with respect to ground (such
as phase-to-phase, a multi-phase system, or across the legs
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Power Operat ion
The 442 operates from either 120 V or 240 V ac input at 48 to 62 Hz. Selection of input function is made with
screwdriver adjusted switches accessible through bottom
of cabinet (see Fig. 2) . Adjustment for high or low power
input can be made with same tool at same cabinet position.
442 Operaton
1
WARNING
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Do not plug instrument into power source until
the fol/owing settings are made or checked.
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Set the Line Voltage Selector switch to the nominal line
voltage available (see Fig. 2).
Set the Regulating Range Selector Switch (see Fig. 2)
so expected line-voltage fluctuations remain within the
Regulating Range selected (see Table 1 ).
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POWER
SWITCHES
Table 1
Ac Regulating Ranges
Regulating
Range Selector
Switch Position
HI
LO
2
Regulating Range
1 20 V
240 V
Nominal
Nominal
2373·2
1 08 to 1 32 V RMS 21 6 to 250 V RMS
90 to 1 1 0 V RMS 1 98 to 242 V RMS
442 Operators
Fig. 2. Power switches at bottom.
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Fuse Information
WARNING
The 442 contains a power fuse located in a fuseholder
on the Rear Panel (see Table 2 and Fig. 3).
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Dangerous potentials exist at several points
throughout this instrument. Qualified person­
nel, only, are authorized to remove cabinet.
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Table 2
Ac Fusing
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LINE FUSE
HOLDER
2373·3
Fused Line
F700
1 20 V ac
0. 75 A Fast Blow
240 V ac
0.30 A Slow Blow
Fig. 3. Line fuse location on Rear Panel.
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442 Operators
3
LOCATION AND OPERATION OF EXTERNAL
CONTROLS, CONNECTORS AND INDICATORS
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Q) INTENSITY
INT RODUCT ION
Turn control clockwise to increase display brightness.
Set for lowest visible display to prolong crt life.
The following information will familiarize an operator
with location and operation of external controls, con­
nectors and indicators. These controls, connectors, and
indicators are accessible from outside the instrument with
its cabinet in place. All other controls are internal and
should not be adjusted except during instrument cali­
bration and service. Procedures and suggestions for cali­
bration and maintenance are presented in the 442 Service
Manual.
C RT D IS PLAY AND POWE R
( Front Panel. See Fig. 4)
CD ASTIGmatism
2373-4
Recessed screwdriver control adjusts crt writing beam
for optimum definition.
4
Fig. 4. CRT DISPLAY and POWER front panel controls and
indicators.
442 Operators
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Q) FOCUS
After releasing BEAM FINDER, adjust VOLTS/DIV
switch, horizontal, and vertical POSITION controls
for a readable, stable display.
Provides optimum display definition.
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CD TRACE ROTation
Recessed screwdriver adjustment aligns crt trace with
horizontal graticule line.
CD BEAM FINDER
Spring-loaded push-button switch to locate offscreen displays. When engaged crt display is electrically
compressed to within graticule area independently
of position controls or applied signals. To locate an
off-screen display:
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a. Set vertical POSITION and INTENSITY controls
to midrange and rotate horizontal POSITION control
clockwise.
b. If a display or dot still is not visible, press BEAM
FINDER and hold in. A compressed display or dot
should appear. If not, increase INTENSITY until a
display appears.
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If a dot or vertical line appears, the sweep is not trig­
gered. Set trigger MODE switch to AUTO and obtain
a display. Center the display with vertical and hori­
zontal POSITION controls. Release BEAM FINDER
push button and adjust trigger LEVEL control for a
stable display.
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(DON Indicator (LED)
Lights when the power is on.
(DON-OFF Push Button Switch
Turns instrument on (in) and off (out).
(D lnternal Graticule
Eliminates parallax. Risetime, amplitude and
measurement points are indicated at the left of
graticule.
(!)PROBE ADJust
442 Operators
Pin connector supplies internally generated square
wave of approximately 0.5 volts at approximately
1 kHz for use in checking attenuation factors and
compensation of probes.
5
EXTERNAL BLANKING
( Rear Panel. See Fig. 5)
POWE R SELECTO RS AND DC BALANCE
(Bottom of Cabinet. See Fig. 6)
BNC connector accepts signals from external sources
for modulating intensity of crt display. Signals must
be time·related to the display for stability. Positive
signals decrease intensity. Input specification at con­
nector is 30 V peak with 1 0,000 ohms impedence.
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® External Z-AXIS INPUT
,
Make sure instrument is unplugged from power
source and appropriate fuse is installed in fuse
holder at rear of instrument-considering ac
power input (see Table 2).
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® Line Voltage Selector
Two-position, screwdriver actuated, slide switch which
can be set to allow operation from an ac source of
either 120 V or 240 V. Position left for 120 V ac and
position right for 240 V ac.
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@ Regulating Range Selector
2373-5
Fig. 5. External Z-AXIS INPUT on Rear Panel.
6
442 Operators
Two-position, screwdriver actuated, slide switch
which can be set to allow operation from one of two
ac ranges (see Table 1). Position left for HI and posi­
tion right for LO.
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® Channel 1 DC Balance
Screwdriver adjustment (through cabinet). When pro­
perly adjusted, prevents trace shift when switching
between adjacent positions of channel 1 VOLTS/
DIV switch.
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® Channel 2 DC Balance
Screwdriver adjustment (through cabinet). When
properly adjusted, prevents trace shift when switching
between adjacent positions of channel 2 VOLTS/
DIV switch.
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VE RT ICAL
( Front Panel. See F ig.
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7)
@ Channel 1 (X) Input
L-__________________-=2.:.3 ;..,;
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73:...
Fig. 6. Controls through bottom of cabinet.
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BNC connector for the application of external signal
to channel 1 vertical deflection system. In X-V oper­
ation, channel 1 or X is horizontal input. Display mode
is selected by VERT MODE switches.
NOTE
brated deflection factors. Extends maximum deflection
factor to 25 V/div in 10 V position. (Notice that VAR
decreases size of display.)
Channel 1 (X) is horizontal input and Channel
2 (Y) is vertical input when instrument is used
in SOURCE X-Y.'
® Input Coupling AC-GND-DC (Both Channels)
@ Channel 2 (V) Input
BNC connector for the application of external signal
to channel 2 vertical deflection system. In X-V oper­
ation, channel 2 or V is vertical input. Display mode
is selected by VERT MODE switches.
® VO LTS/DIV (Both Channels)
AC: Signals are coupled capacitively. Any dc
signal component is blocked. Low frequencies are
attentuated (3 dB down at about 1 Hz using a 10X
probe). Ac coupling causes tilting of square waves
below 1 kHz.
®VARiable (Both Channels)
GND: Disconnects input of vertical amplifier
from the input signal and connects amplifier input
to ground to provide a ground reference display.
Connects input signal to ground through input
coupling capacitor and a 1 Mil resistor to allow in­
put coupling capacitor to be precharged by input
signal.
Controls which select the vertical deflection factors
in 1-2-5 sequence. (VAR control must be in detent
position to obtain the indicated deflection factors.)
R ead the correct deflection factor for a 1X probe
from the 1X (left) position; and for a 10X probe
from the 10X position (right).
Controls-out of detent left-which provide contin­
uously variable (uncalibrated) deflection factors be­
tween calibrated positions of the VOLTS/DIV switches.
Rotate controls clockwise to detent position for cali-
8
Three-position slide switch which selects the circuit
method of coupling input signals to vertical input
amplifier.
442 Operators
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DC: All frequency components of input signal
are passed to vertical amplifier.
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t POSITION (Both Channels)
Controls which position the related channel signal
displays in a vertical position.
@ VERT MODE (Vertical Display Mode)
® External Ground Connector
Banana plug connected directly to chassis and cabinet
provides instrument ground.
Series of five in line push-button switches to select
vertical channel display and operating mode. (Trig­
gering signals are derived from channel 1 input ex­
cept when CH 2and one of DIF F, ALT, or CHOP
switches are engaged simultaneously.)
CH 1: Displays only signals applied to Channel
1 input connector.
DIFF: Provides a display of the algebraic dif­
ference between Channel 1 and Channel 2 input
signals. Trigger signal is derived from Channel 1 un­
less CH 2 and DI F F push-buttons are depressed
si muItaneously.
A LT: Provides a display of Channel 1 and
Channel 2 alternately. Display is switched between
channels at the end of each sweep. Trigger signal is
automatically derived from Channel 1 input signal
unless CH 2 and ALT push buttons are depressed
simultaneously.
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CHOP: Provides a display of signals from both
channels switched from Channel 1 to Channel 2 at
a frequency of approximately 250 kHZ. Trigger
signal is automatically derived from Channel 1 input
signal unless CH 2 and CHOP push buttons are de­
pressed simultaneously.
Fig. 7. Vertical system controls.
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442 Operators
9
CH 2 : Displays only signals applied to the Channel
2 input connector. CH 2 push-button must be en­
gaged for X-V operation.
HO R IZONTAL
( Front Panel. See Fig.
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POSITION
Control to horizontally position the crt display.
8)
@ SEC/DIV
Control selects calibrated sweep rates from 0.5
seconds/division to 0.1 microseconds/division in a
1 -2-5 sequence.
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MODE SOUACE
@ VAR
MAl
Control, inside SEC/DIV control, provides contin­
uously variable uncalibrated sweep rates to at least
2.5 times the calibrated setting (extends the slowest
sweep rate to at least 1.25 sec/div).
@ MAGNIFIER X 10-X1
Push-button switch (in, Xl 0) increases each sweep
rate by a factor of 1 0. Extends the fastest sweep rate
to 1 0 nanoseconds/division.
10
442 Operators
flER
D;:�'
0;:;
n is 0'""
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'4\.Iirl."IliI.,
-=-��--c=----
----
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�T· ,,-� �
�...:.f 0
VOLTS/DIY
if
SLOPt
ItO
VOLTS/DIV
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2373-8
Fig. 8. Horizontal system controls.
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T R IGGE R ING
( Front Panel. See Fig.
LINE: In this position the trigger signal is a sample
of the line voltage applied to instrument.
9)
@ SOURCE
EXT (External Triggering): This position permits
triggering on signals applied to the external triggering
input connector (item 28).
The source of the signal supplied to trigger input
amplifier is determined by six-position SOURCE
switch and associated circuitry.
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EXT/10: External trigger signals are attenuated by
a factor of
10.
COMP (Composite Triggering): In this position
the trigger signal is obtained from signal(s) displayed
on crt. Does not show the time relationship of Chan­
nel 1 and Channel 2 in ALTernate vertical mode. Do
not use composite triggering in CHOP vertical mode
because display will trigger on switching transients,
not on desired signal.
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CH 1/CH 2 (Internal Triggering): In this posi­
tion the trigger signal is a sample of channel signal
displayed on crt-Channel 1 or Channel 2 in single­
trace. In CHOP, ALT, or DI F F vertical mode, the
trigger signal is a sample of Channel 1 input unless
CH 2 is depressed simultaneously with CHOP, ALT,
or DIF F.
@
442 Operators
2373-9
Fig. 9. Triggering system controls.
1 1
X-V: This position permits X-V displays. X input
is through Channel l input.
NOTE
X- Y deflection factors are the same as Channel 1
and Channel 2 attenuator position when MAGNIFIER
is in X 1. When using X 10, X (Channel 1) deflection is
changed by approximately X 1O.
®
@
TV: This position allows triggering on television
signals. Instrument triggers on TV field when SECt
DIV switch is set at .1 ms or slower. Triggers on TV
line when SEC/DIV is set at 50 p.s or faster. Set
SLOPE switch to +OUT for sync-positive input
signals and to -IN for sync-negative signals.
EXT
BNC connector for use while triggering from an ex­
ternal source.
MODE
Three·position switch to select triggering mode.
AUTO: Allows normal triggering-with proper
LEVEL control setting. A sweep will be initiated by
input signals that have repetition rates above 20 Hz
and are within the frequency range set by Coupling
Switch. In the absence of an adequate trigger signal,
or when trigger controls are misadjusted, the sweep
free-runs to provide a reference display.
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NORM: With proper LEVEL control setting,
this position insures that a sweep is initiated by input
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signals that are within the frequency range selected
by CPLG Switch. In the absence of an adequate
trigger signal, or when trigger controls are mis­
adjusted, the sweep does not run and there is no
sweep display.
442 Operators
SLOPE
Push-button switch to select either the positive-going
or negative-going slope of the trigger waveform.
+OUT: Allows triggering from the positive-going
portion of a trigger signal.
-IN: Allows triggering from the negative-going
portion of a trigger signal.
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® LEVEL
DC: Push-button switch (in) provides direct
coupling so frequency components from dc to
above 35 MHz of triggering signal are seen at trigger
input circuit.
Control which selects the amplitude point on trigger
signal at which sweep is triggered. Usually adjusted
for desired display after trigger SOURCE and SLOPE
have been selected.
® CPLG (Coupling)
Push-button switch allows choice of capacitive or
direct coupling to trigger input circuits.
® HOLDOFF
AC: Push-button switch (out) provides circuitry
to block dc component of the triggering signal and
allows triggering only on ac portion. Signals below
approximately 60 Hz are attenuated.
A control which allows control of holdoff time be­
tween sweeps. Provides stable triggering on low re­
petition pulses or aperiodic signals. To obtain the
best display, use all other trigger controls before ad­
justing HOLDO F F control. HOLDO F F increases
clockwise to MAXimum.
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442 Operators
13
BASIC OSCILLOSCOPE OPERATION
The following procedures will familiarize the operator
with basic 442 Oscilloscope operation.
P REL I M INA RY
Signal Ground
The most reliable signal measurements are made when
the 442 and unit under test are connected together by a
common reference (ground) lead in addition to signal
lead or probe. A ground strap on probe provides the best
ground. Also, you can connect a ground lead to chassis
ground connector on 442 front panel (item 21 ).
Setting the AC-GND-DC switch to GND disconnects the
input signal from vertical preamplifier circuit and connects
it to ground through input coupling capacitor and a 1 Mil
resistor. This allows the input coupling capacitor to pre­
charge to average dc level of signal applied to probe. Use
the following procedure to prevent accidently generated
voltage transients from reaching preamplifier circuit and
also reduce the amount of charging current drawn from
circuit under test.
1 . Before connecting probe tip to a signal source, set AC­
GND-DC switch to GND in order to establish reference.
2. Touch probe tip to 442 instrument ground. Wait
several seconds for input coupling capacitor to discharge.
Input Coupling Capacitor Precharging
In AC positions of the AC-GND-DC switches, voltage
transients exceeding 400 V maximum input voltage can be
generated if you take successive measurements on 2 signals
with different dc levels-even though both dc levels are
within the maximum input voltage specification. For in­
stance, after measuring ripple on a +300 V dc supply, if
you connect the probe to a -250 V dc supply the re­
sulting transient amplitude is 550 V.
14
3. Connect probe tip to test signal source.
)
4. Wait several seconds for coupling capacitor to charge.
5. Set AC-GND-DC switch to AC. The display will re­
main on screen so ac component of signal can be measured
in normal manner.
442 Operators
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OPE RATO R'S ADJUSTMENTS AND C HECKS
To verify basic accuracy of the 442, make the following
checks and adjustments.
Any signal of known amplitude may be used to check
vertical gain. Check displayed amplitude to be the same
as known signal within 3%.
Basic Timing C heck
Be sure VAR of SEC/DIV is in calibrated (cw) posi­
tion. Obtain a normal sweep display of any signal of any
known frequency.
Probe Compensation
Improper probe compensation is the most common
source of operator error. Recheck probe compensation
when moving a probe from one scope to another or from
one channel to another.
To compensate probe, obtain a normal sweep display
using the 0.5 V PROBE ADJ signal. Set VOLTS/DIV switch
to .1. Set SEC/D IV to .1 ms. Adjust probe compensation
for a flat-top waveform (see Fig. 10). See the respective
probe Data S heet for specific probe compensation
instructions.
}
IMPROPERLY
COMPENSATED
WAVEFORMS
Vertical Gain C heck
Obtain a normal sweep display using the 0.5 V PROBE
ADJ output. Set the VOLTS/DI V switch to .1 . Be sure
VAR of VOL TS/DIV is in calibrated (fully cw) position.
Check the display for a vertical deflection of about 5
divisions.
@
442 Operators
PROPERLY
COMPENSATED
WAVEFORM
2373-10 (1942-5)
Fig. 10. Probe compensation.
15
WARNING
I
VERT MODE
VOLTS/DIV (both)
VAR (all)
POSITION (all)
SEC/DiV
POWER
INTENSITY
FOCUS
HOLDO FF
SLOPE
LEVEL
SOURCE
CPLG
MODE
To prevent possible cross grounding when using
line voltage, do not use , ground clip on probe.
The 442 instrument ground provides an adequate
ground reference.
Set SEC/DIV control to display one cycle over several
horizontal divisions. Check displayed duration of one cycle
to be the same as the duration of one cycle of known signal
within 3% (duration 1 /frequency). If a 60 Hz line volt·
age is being used, check duration of one cycle to be 8.35
divisions with SEC/DIV at 2 m: or with SEC/DiV in 1 0 m,
exactly 6 cycles should display in graticule area.
=
f
CH 1
.1
Calibrated (cw)
Midrange
1 m
ON
As desired
As desired
ccw
+OUT
ccw
CH 1 /CH 2
AC (out)
AUTO
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2. Connect a signal, -0.5 V PROBE ADJ output will
suffice, via probe supplied with 442 to Channel 1 or X
input connector.
NO R MAL SWEEP OPE RAT ION
1. Preset the 442 controls as follows:
NOTE
See Location and Operation of External Controls,
Connectors, and Indicators for detailed instructions
concerning control operation.
16
3. Set Channel 1 AC·GND·DC switch to select desired
method of coupling input signal to preamplifier circuit.
With PROBE ADJ output signal use DC. AC coupling will
cause tilting (integration) of square waves below about
1 kHz (1 00 Hz with a 1 0X probe).
442 Operators
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4. Adjust Channel 1 VOLTS/DIV switch to obtain desired
display amplitude while adjusting Channel 1 POSITION
control to locate display within crt viewing area.
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APPL ICAT IONS
6. Adjust SEC/DIV switch to obtain desired display.
Using 0.5V PROBE ADJ output signal. display should look
as illustrated in Fig. 1 1 (using a 1 0X probe with a VOLTS/
DIV switch setting of 1 0 m and a SEC/DIV switch setting
of .5 m).
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Peak-to-Peak Voltage Measurements
To make a peak-to-peak voltage measurement. use the
following procedure.
1. Connect test signal to either Channel
input connector.
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1 or Channel 2
--
2. Set VERT MODE to display channel selected.
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Verify correct probe compensation (see beginning
of Operator's Adjustments and Checks).
5. Adjust LEVEL control for a stable display.
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NOTE
--
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--
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3. Set VOL TS/DIV switch to display about five divi­
sions of waveform.
-
2373-11 (1942-6)
Fig. 11. Display of .5V PROBE ADJ output signal.
REV A. APR 1979
4 . Set Triggering controls to obtain a stable display.
Set SEC/DIV switch to a position that displays several
cycles of waveform.
442 Operators
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5. Turn vertical POSITION control so lower portion of
waveform coincides with one of the graticule lines below
center horizontal line, and top of the waveform is in the
viewing area. Move display with horizontal POSITION
control, so one of the upper peaks aligns with center vertical
graticule line (see Fig. 1 2).
6. Measure divisions of vertical deflection from peak-to­
peak. Make sure VAR control of VOLTS/DIV control is
in calibrated (cw) position.
POSITION TO
CENTER LINE
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-- --
V .\
VERTICA L
DEFLECTIO N
_L
/
\L
i\
\
\
-
7-�
,
-
-
,
.
7. Multiply distance measured in step 6 by VOLTS/
DIV switch reading.
I'\.
1\ J
\j
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2373-12
Fig. 12. Measuring peak-to-peak voltage of a waveform.
18
>
This procedure may be used to measure between
two points on the waveform a/so rather than
peak to peak
EXAMPLE: Assume a peak-to-peak vertical deflection
of 4.6 divisions (see Fig. 1 2) and a VOL TS/DIV switch
setting of 5. Using th� formula (assuming use of 1 X probe
or cable):
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NOTE
Volts
Peak-to-Peak
vertical
deflection X
(divisions)
VOLTS/DIV
setting
X
=
4.6 X 5 V X1 (probe)
The peak-to-peak voltage is 23 volts.
442 Operators
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probe
attenuator
factor
Substituting the given values:
Volts Peak-to-Peak
r:
REV A, APR 1979
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3. Set VOLTS/DIV switch to display about five divi­
sions of waveform.
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--
-
- -- �--
4. Set Input Coupling switch to GND.
;1
!!
.1.
5. Set sweep MODE switch to AUTO trigger.
.......
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VERTICAL
DISTANCE
J
NOTE
__
� REFERENCE LINE
2373-13
Fig. 13. Measuring instantaneous dc voltage with respect to a
reference voltage.
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Instantaneous Voltage Measurements
-
DC
To measure dc level at a given point on a waveform,
use the following procedure:
1 . Connect test signal to either Channel 1 or Channel
2 input connector.
2. Set VERT MODE to display channel selected.
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6. Position trace to bottom line of graticule or other
reference line. If voltage to be measured is negative with
respect to ground, position trace to the top line of
graticule. Do not move vertical POSITION control after
this reference line has been established.
To measure a voltage level with respect to a
voltage other than ground, make the fol/owing
changes in step 6: Set Input Coupling switch
to DC and apply reference voltage to selected
channel input connector. Then position trace
to reference line.
7. Set Input Coupling switch to DC. The ground ref­
erence line can be checked at any time by switching to
GN 0 position.
8. Set Triggering controls to obtain a stable display.
Set SEC/DIV switch to a setting that displays several
cycles of signal.
442 Operators
19
9. Measure distance in divisions between reference line
and point on waveform at which de level is to be measured.
For example, in Fig. 1 3 measurement is made between
reference line and point A.
Substituting the given values:
Instantaneous
Voltage
=
4.6 X +1 X
2 V Xl
(probe)
f
The instantaneous voltage is 9.2 volts.
1 0. Establish polarity of signal. If waveform is above
reference line, voltage is positive; below line, negative.
1 1 . Multiply distance measured in step 9 by VOLTS/
DIV switch reading of step 3.
EXAMPLE: Assume that vertical distance measured is
4.6 divisions (see Fig. 1 3), waveform is above reference
line, and VOLTS/DIV switch reads 2.
Using the formula (assuming use of 1 X probe or cable):
Instantaneous
Voltage
vertical
probe
VOLTS/DIV
distance X polarity X
X attenuator
setting
(divisions)
factor
20
Comparison Measurements
In some applications it may be desirable to establish
arbitrary units of measurement other than those indicated
by VOLTS/DIV switch or SEe/DIV switch. This is partic­
ularly useful when comparing unknown signals to a reference
amplitude or repetition rate. One use for the comparison­
measurement technique is to facilitate calibration of equip­
ment (e.g., on an assembly-line test) where desired ampli­
tude or repetition rate does not produce an exact number
of divisions of deflection. The adjustment will be easier and
more accurate if arbitrary units of measurement are estab­
lished so that correct adjustment is indicated by an exact
number of divisions of deflection. Arbitrary sweep rates can
be useful for comparing harmonic signals to a fundamental
frequency, or for comparing the repetition rate of input
and output pulses in a digital count-down circuit. The fol­
lowing procedure describes how to establish arbitrary units
of measure for comparison measurements. Although the
procedure for establishing vertical and horizontal arbitrary
units of measurement is much the same, both processes are
described in detail.
442 Operators
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Vertical Deflection Factor. To establish an arbitrary ver·
tical deflection factor based upon a specific reference am·
plitude, proceed as follows:
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1. Connect reference signal to Channel 1 or Channel 2
input connector. Set SEC/DIV switch to display several
cycles of signal.
2. Set VOLTS/DIV switch and VAR control (selected
channel) to produce a display of an exact number of
graticule divisions in amplitude. Do not change VAR con·
trol after obtaining desired deflection. This display can be
used as a reference for amplitude comparison measure­
ments.
Vertical
Conversion
Factor
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4. Divide amplitude of reference signal (volts) by the
product of vertical deflection established in step 2 (div­
isions) and setting of VOL TS/DIV switch. This is the
vertical conversion factor.
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vertical
deflection
(divisions)
x
VOLTS/DIV
switch
setting
5. To measure amplitude of an unknown signal, discon­
nect reference signal and connect unknown signal to sel­
ected channel input connector. Set VOLTS/DIV switch to
a setting that provides sufficient vertical deflection to make
an accurate measurement. Do not readjust VAR control.
6. Measure vertical deflection in divisions and calculate
amplitude of unknown signal using the following formula:
Signal
Amplitude
3. To establish an arbitrary vertical deflection factor so
the unknown amplitude of a signal can be measured ac­
curately at any setting of VOLTS/DIV �witch, amplitude of
reference signal must be known. If it is not known, it can
be measured before VAR control is set in step 2.
reference signal
amplitude (volts)
VOL TS/DIV
vertical
vertical
switch
X conversion X deflection
setting
factor
(divisions)
EXAMPLE: Assume a reference signal amplitude of 30
volts, a VOLTS/DIV switch of 5, and VAR control is ad­
justed to provide a vertical deflection of four divisions.
Substituting these values in the vertical conversion fac­
tor formula (step 4):
442 Operators
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Vertical
Conversion
Factor
30 V
4X5V
3. To establish an arbitrary sweep rate so the unknown
period of a signal can be measured accurately at any setting
of the SEC/DIV switch, the period of reference signal must
be known. If it is not known, it can be measured before
V AR control is set in step 2.
1. 5
Then with a VOLTS/DIV switch setting of 1 , peak-to­
peak amplitude of an unknown signal which produces a
vertical deflection of 5 divisions can be determined by
using the signal amplitude formula (step 6):
Signal
Amplitude
1 V X 1.5 X 5
7.5 volts
Sweep Rates. To establish an arbitrary horizontal sweep
rate based upon a specific reference frequency, proceed as
follows:
1. Connect reference signal to selected Channel 1 or
Channel 2 input connector. Set VOL TS/DIV switch for
four or five divisions of vertical deflection.
2 . Set SEC/DiV switch and VAR control so one cycle
of signal covers an exact number of horizontal divisions. Do
not change VAR control after obtaining desired deflection.
This display can be used as a reference for frequency com­
parison measurements.
22
4. Divide period of reference signal (seconds) by product
of horizontal deflection established in step 2 (divisions) and
setting of SEC/DIV switch. This is the horizontal conver­
sion factor:
Horizontal
Conversion
Factor
reference signal period (seconds)
horizontal deflection (divisions) X
SEC/DIV switch setting
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5. To measure the unknown period of a signal, discon­
nect the reference signal and connect the questioned signal
to the selected channel input connector. Set the SEC/DIV
switch to a setting that provides sufficient horizontal de­
flection to make an accurate measurement. Do not re­
adjust the VAR control.
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6. Measure the horizontal deflection in divisions and
calculate the period of the unknown signal using the fol­
lowing formula:
442 Operators
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TIME/DIV
horizontal
X conversion
switch
factor
setting
Period
horizontal
X deflection
(divisions)
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EXAMPLE: Assume a reference signal frequency of
455 Hz (period 2.1 9 milliseconds). and a SEC/DIV switch
setting of .2 ms, with the VAR control adjusted to provide
a horizontal deflection of eight divisions. Substituting these
values in the horizontal conversion factor formula (step 4):
Horizontal
Conversion
Factor
2.1 9 milliseconds
.2 X 8
=
Time-Duration Measurements
To measure time between two points on a waveform, use
the following procedure:
1. Connect signal to either Channel 1 or Channel 2 input
connector.
2. Set VERT MODE to display selected channel.
3. Set VOLTS/DIV switch to display about five divisions
of waveform.
1. 37
4. Set Triggering controls to obtain a stable display.
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Then, with a SEC/DIV switch setting of 50 J.1s the un­
known period of a signal, which completes one cycle in
seven horizontal divisions, can be determined by using
period formula (step 6):
Period
=
50 J.1S X 1 .37 X 7
=
480 J.1S
This answer can be converted to frequency (repetition
rate) by taking the reciprocal of the period.
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5. For best accuracy use SEC/DIV setting that gives the
greatest number of divisions between time measurement
points (see fig. 1 4). Sweep MAGNIFIER (to obtain more
displayed divisions) should be used when measuring por­
tions of more complex waveforms.
6. Adjust vertical POSITION control to move points be­
tween which time measurement is made to center horizon­
tal line.
442 Operators
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7. Adjust horizontal POSITION control to center display
within center eight divisions of graticule.
8. Measure horizontal distance between time measure­
ment points. Be sure VAR control is set in detent (cali­
brated, cw).
9. Multiply distance measured in step 8 by setting of
SEC/DIV switch.
EXAMPLE: Assume that distance between time measure­
ment points is five divisions (see Fig. 1 4) and SEC/DIV
switch is set at .1 ms.
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Using the formula:
Time Duration
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Time Duration
DISTANCE
=
5 X 0.1 ms
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Frequency Measurement
2373-14
Fig. 14. Measuring the time duration between points on a waveform.
24
f,
The time duration is 0.5 millisecond.
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horizontal
SEC/DIV
distance
X
setting
(divisions)
Substitute given values:
\
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=
The time measurement technique can also be used to
determine frequency of a signal. The frequency of a periodically recurrent signal is reciprocal of time duration (period)
of one cycle.
Use the following procedure:
442 Operators
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1. Measure time duration of one cycle of waveform as
descr ibed in previous application.
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2. Take reciprocal of time duration to determine
2. Set VERT MODE to display channel selected.
3. Set SEC/DIV switch and VAR control to display an
exact number of divisions in amplitude.
frequency.
4. Center display about center horizontal line.
5. Set SEC/DIV switch to fastest sweep rate that dis­
plays less than eight divisions between 10% and 90% points
on waveform.
EXAMPLE: The frequency of signal shown in Fig. 5
which has a time duration of 0.5 millisecond is:
Frequency
time duration
0.5 ms
Determine 10% and 90% points on rising portion of
waveform. The figures given in Table 3 are for points 10%
up from start of rising portion and 10% down from top of
rising portion (90% point).
2 kHz
Rise Time Measurements
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R ise time measurements employ basically the same
technique as time-duration measurements. The main dif­
ference is points between which measurement is made. The
following procedure gives basic method of measuring rise
time between 10% and 90% points of waveform. Fall time
can b e measured in same manner on trailing edge of wave­
form.
Table 3
Rise Time Measurements
Vertical
display
(divisions)
10% and 90%
points
Divisions vertically
between 10%
and 90% point
4
0.4 division
3.2
5
0.5 division
4.0
6
0.6 division
4.8
1. Connect signal to either Channel 1 or Channel 2
input.
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442 Operators
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Substituting the given values:
NOTE
For a signal amplitude of 5 divisions, 10%
and 90% points are indicated on graticule.
Risetime
4 X 1 /lS
=
The risetime is 4 microseconds.
7. Adjust horizontal POSITION control to move 1 0%
point of waveform to first graticule line. For example,
with a five-division display as shown in Fig. 15, the 1 0%
point is 0.5 division up from the start of the rising portion.
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8. Measure horizontal distance between 1 0% and 90%
points. Be sure VAR control is set to detent (calibrated,cw).
;.....--
9. Multiply distance measured in step 8 by setting of
SEC/DIV switch.
EXAMPLE: Assume that horizontal distance between
1 0% and 90% points is four divisions (see Fig. 1 5) and
SEC/DIV switch is set at 1 /ls. Applying time duration
formula to rise time:
7
V
V "t
POl
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Rise Time
Time Duration
26
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SEC/DIV
setting
r,
90%
POINT
10%
f--
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horizontal
difference X
(divisions)
/
/"
T
HORIZONTAL
DISTANCE
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2373-15
Fig. 15. Measuring rise time.
442 Operators
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Time-Difference Measurements
The calibrated sweep rate and dual-trace features of the
442 allow measurement of time difference between two
separate events. To measure time difference, use the fol­
lowing procedure:
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1. Set Input Coupling switches (AC-GND-DC) to desired
coupling positions.
2. Set VERT MODE to either CHOP or ALT. In general,
CHOP is more suitable for low-frequency signals and AL T
position is more suitable for high-frequency signals.
3. Connect reference signal to Channel 1 input; and com­
parison signal to Channel 2 input. The reference signal
should precede comparison signal in time. Use coaxial
cables or probes which have equal time delay to connect
signals to input connectors.
7. Adjust vertical POSITION controls to center each
waveform (or points on the display between which measure­
ment is made) in relation to center horizontal line.
8. Adjust horizontal POSITION control so Channell
(reference) waveform crosses center horizontal line at a
vertical graticule line.
9. Measure horizontal difference between Channel 1
waveform and Channel 2 waveform (see Fig. 1 6).
1 0. Multiply measured difference by setting of SEC/
DIV switch.
J,l.S, and horizontal difference between waveforms is 4.5
EXAMPLE: Assume that SEC/DIV switch is set to 50
divisions (see Fig. 1 6).
Using the formula:
4. Set VOLTS/DIV switches to produce four or five
divisions of display.
Time Delay
SEC/DIV
X
setting
horizontal
difference
(divisions)
5. Set LEVEL control for a stable display.
f
Substituting the given values:
6. If possible, set SEC/DIV switch for a sweep rate
which shows three or more divisions between two wave­
forms.
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Time Delay
=
50 J,l.S X 4.5
The time delay is 225 microseconds.
442 Operators
27
CHANNEL 1
(REFERENCE)
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50%
AM PLlTUOE
LE EL
�
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/
2. Set VERT MODE to either CHOP or ALT. In gen­
eral, CHOP is more suitable for low-frequency signals; and
ALT position more suitable for high-frequency signals.
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1 . Set Input Coupling switches (AC-GND-DC) to same
position, depending on type of coupling desired.
CHANNEL :2
1
3. Connect reference signal to Channel 1 input con­
nector and comparison signal to Channel 2 input con­
nector. The reference signal should precede comparison
signal in time. Use coaxial cables or probes which have
equal time delay to connect signals through input
connectors.
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HORIZONTAL
2373-16
Fig_ 16_ Measuring time difference between two pulses.
4. Set channel VOLTS/DIV switches and respective
VAR controls so displays are equal and about five divi­
sions in amplitude.
5. Set Triggering controls to obtain a stable display.
Multi-Trace Phase Difference Measurements
Phase comparison between two signals of the same fre­
quency can be made using dual-trace feature of the 442.
This method of phase difference measurement can be used
up to frequency limit of vertical system. To make that
comparison, use the following procedure:
28
6. Set SEC/DIV switch to a sweep rate which displays
about one cycle of waveform.
7. Move waveforms to center of graticule with channel
POSITION controls.
442 Operators
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8. Turn sweep VAR control until one cycle of reference
signal (Channel 1 ) occupies exactly eight divisions between
second and tenth graticule lines (see Fig. 1 7). Each division
°
°
of graticule represents 45 of the cycle (360 .;. 8 divisions
°
45 / division). The sweep rate can be stated in terms of
°
degrees as 45 / division.
=
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Phase Difference
9. Measure horizontal difference between corresponding
points on waveforms.
CHANNEL 1
(REFERENCE)
�
1 0. Multiply measured distance (in divisions) by 45°/
division (sweep rate) to obtain exact amount of phase dif­
ferences.
EXAMPLE: Assume a horizontal difference of 0.6 divi­
°
sion with a sweep rate of 45 /division as shown in Fig. 1 7.
Using the formula:
,�
0.6 X 45°
°
The phase difference is 27 .
,
r
=
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CHANNEL 2
(LAGGING)
V
j�
"
V
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/,
IV
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HORiZONTAL
DIFFERENCE .......
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)
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Phase Difference
NS
II ...·�--- 8 DIVISIO
(360°)
horizontal
sweep rate
difference X
(degrees/div)
(divisions)
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..
____
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2373-17 (1074-27)
Fig. 17. Measuring phase difference.
Substituting the given values:
REV A, APR 1979
V.I
II
442 Operators
29
x-v Phase Measurement
The X-V phase measurement method can be used to
measure phase difference between two signals of same fre­
quency. This method provides an alternate method of
measurement for signal frequencies up to four megahertz.
However, above this frequency the inherent phase difference
between vertical and horizontal system makes accurate
phase measurement difficult. In this mode, one of the
sinewave signals provides horizontal deflection (Xl while
the other signal provides vertical deflection (Yl. The phase
angle between the two signals can be determined from the
lissajous pattern as follows:
4. Center display in relation to center graticule lines.
Measure distance A and B as shown in Fig. 1 8. Distance A
is horizontal measurement between two points where trace
crosses center horizontal line. Distance B is maximum hori­
zontal width of display.
1 _ Connect one of the sinewave signals to Channel 1 or
X connector; and the other signal to Channel 2 or Y input
connector.
V
2. Set Triggering SOURCE to X-V and VERT MODE
to CH 2.
3. Position display to center of crt screen and adjust
Channel 1 and Channel 2 VOLTS/DIV switches to produce
a display less than six divisions vertically (Yl and less than
1 0 divisions horizontally (Xl. The Channel 1 VOLTS/DIV
switch controls horizontal deflection (Xl and Channel 2
VOLTS/DIV switch controls vertical deflection (Yl.
30
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1 0(
V
V
10'"
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".,
v V"
L-"!I
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VI-'"
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B
A
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2373-18 (1331-13)
Fig. 18. Phase difference measurement from an X-V display.
442 Operators
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5. Divide A by B to obtain sine of phase angle (cf»
between two signals. The angle can then be obtained from
- a trigonometric table.
Substituting the given values:
Sine cf>
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6. If display appears as a diagonal straight line, two
signals are either in phase (tilted upper right to lower
left) or 1 800 out of phase (tilted upper left to lower right).
If display is a circle, signals are 900 out of phase.
EXAMPLE: To measure phase of display shown in
Fig. 1 8 where A is 5 divisions and B is 1 0 divisions, use
the formula:
=
�
B
Substituting the given values:
.
S me
,/,.
'I'
=
5
10
-
=
0.5
From trigonometric tables:
If
R E V . A, F E B . 1978
442 Operators
31
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