Wavetek -- 801 - UCSD Department of Physics

INSTRUCTION MANUAL
MODEL 801
50 MHz PULSE
-THIS DOCUMENT CONTAINS INFORMATION PROPRIETARY TO WAVETEK. THE INFORMATION IN
THIS DOCUMENT IS NOTTOBE USED FOR DUPLICATED
IN ANY MANNER WITHOUT THE PRIOR APPROVAL
IN WRITING OF WAVETEK.
-_
SAN DIEGO
9 0 4 5 Balboa Ave., San Diego, Calif. 92123
P. 0. Box 651, San Diego, California 92112
TWX 9 1 o-335-2007
Tel 7 14/279-2200
REV C . 8/77
1
SECTION
GENERAL DESCRIPTION
1.1 THE MODEL 801
The Model 801 is a 50 MHz general purpose laboratory pulse
generator. The instrument gives you full control in primary
pulse triggering and shaping plus simultaneous TTL, ECL,
ECL and sync pulses. The primary pulse output has controllability in offset and independent rise/fall durations, as well
as pulse width, pulse delay and a choice of positive, negative
or complementary outputs. The TTL, ECL and ECL are of
fixed levels and rise times that are standard for use with
compatible devices. The primary pulse has minimum rise
and fall times of 7 ns and a maximum of 250 ms.
double pulse controlled by delay control. Double pulse at
all outputs except sync.
External Width: External signal at trigger input and trigger
level control determine output pulse width and period as
shown.
TRIGGER LEVEL WINDOW
TRIGGER LE
The output is +20 volts with 5Oa source impedance which
provides +lO volts into a 5Oa load. Upper and lower pulse
levels are fully adjustable through +20 volts.
External triggering can be set to any point of the rising or
trailing edge of the trigger signal. Single pulses or pulse pairs
may be triggered; pulse width may be trigger controlled;
continuous pulses may be gated and a precise number of
pulses may be triggered for a ‘burst’ output. Manual and
external triggering is indicated by an LED on the front panel
for rapid visual set of trigger level.
Trigger Burst: External trigger starts internal gate (delay
time) for pulse burst (1 to 100 pulse range) as shown.
TRIGGER LEVEL
TRIGGER
+
I
1.2 SPECIFICATIONS
1.2.1
‘DELAY TIME’ GATE
-I
I
Versatility
Five Simultaneous Pulse Outputs
Fixed level ECL, m, TTL and sync pulses and a pulse
with variable amplitude and variable rise/fall times. Pulses
available over a 5 Hz to 50 MHz frequency range (200 ms
to 20 ns periods).
PULSE BURST OUTPUT
1.2.2
hlnn
Pulse Outputs
Triggered: Generator quiescent until triggered by external
signal or front control, then generates one pulse.
Variable Amplitude Pulse
Upper and lower pulse levels are independently adjustable.
Pulse dynamic range is *2OV into an open circuit from the
5052 source. The pulse is 20V p-p maximum, 1V p-p minimum. Into a 5Os1 termination, dynamic range is +lOV,
maximum pulse 1OV p-p, minimum pulse 0.5V p-p.
Gated: As triggered mode, except generator oscillates for
the duration of the external signal.
Overshoot and ringing is less than *(5% of amplitude setting
+100 mV) into 5Oa load.
Double Pulse: Conti nuous, trigger and gate, as above,
except two pulses for each period. Space between pulses of
Preshoot is less than +(5% of amplitude setting +100 mV)
into 5Oa load.
Operational Modes
Continuous: Generator oscillates continuously at selected
frequency.
l-l
Fixed (ECL, ECL, TTL) Pulses
Delay
Pulse levels for 5On loading as shown:
Pulse occurrence can be delayed from less than 10 ns to
100 ms with respect to the sync pulse. Maximum duty
ECL
-1 .8” A -0.9V
cycle is 70% for periods to 200 ns, decreasing to 30% for
Em
-, .8V --7-r--
-“”
20 ns periods.
Delay jitter is less than 0.1% plus 50 picoseconds.
ECL, ECL Transition Time: < 6 ns.
TTL
<o .
4Vn >2s4V
Fixed delay is as shown:
TRIGGER LEVEL
TTL Transition Time: < 10 ns.
TRIGGER INPUT
Sync Pulse
F I X E D DELAY4 b -4Ons
Sync pulse is 0 to at least +1V from a 5Oa source.
1
SYNC PULSE
t
FIXED DELAY --+( k ~20 ns
Normal/Complement Control
Normal pulse or its complement is selected. The normally
quiescent and active levels are reversed in complement
VARIABLE
AMPLITUDE PULSE
format. This control affects all outputs except sync pulse.
1.2.3
__n-
Time Domain
1.2.4
Input Characteristics
Period range is from less than 20 ns to greater than 200 ms
External Trigger
in 7 overlapping ranges.
The external signal required to trigger the generator has a
Period jitter is less than 0.1% plus 50 picoseconds.
to k600 mV p-p to 50 MHz (from 5Oa source) and a maximum amplitude of +lOV with a minimum width of 10 ns.
minimum amplitude of +200 mV p-p to 5 MHz increasing
Width
Width range is from less than 10 ns to 100 ms in 7 overlapping ranges. Maximum duty cycle is 70% for periods to
200 ns, decreasing to 50% for 20 ns periods. Range switch
also has a square wave detent
( % ).
Input impedance is approximately 1
ka in parallel with
22 pF
Triggering is selected to occur at either rising or falling edge
of trigger signal; triggering level is adjustable to be between
+4V. An LED lights for approximately 100 ms for each
‘
L duty cycle is 50 +4% to 2 pus period changing to
50 +15% at 20 ns period.
external and manual trigger occurrence accepted.
Width jitter is less than 0.1% plus 50 picoseconds.
1.2.5
Sync pulse duty cycle is 50 24% of pulse period to 2 pus
period, changing to 50 +I 5% at 20 ns period except in
trigger and external width modes, in which case it is deter-
General
Environmental
Specifications apply at 25°C *5”C after 1 hour warm-up.
Instrument will operate from 0°C to 50°C.
mined by the trigger signal.
Transition Time
For variable amplitude pulse only. Independently adjustable
leading and trailing edges from less than 7 ns (5 ns typical)
to 250 ms in 7 overlapping decade ranges (measured from
10 to 90% points). Verniers give 50:1 adjustment on all
ranges except 5 ns, which gives 25: 1.
Linearity:
For transition greater than 10 ns +5% between
10 to 90% points on pulse.
l-2
Dimensions
28.8 cm (11.4 in.) wide; 17.3 cm (6.8 in.) high; 29 cm
(11.4 in.) deep.
Weight
5.4 kg (12 lb) net; 7.3 kg (16 lb) shipping.
Power
90 t o 1 10V, 108 to 132V, 180 t o 220V or 216 t o 250V;
50 t o 400 Hz; 60 watts nominal.
OPERATION
3.1
CONTROLS AND CONNECTORS
The generator controls and connections are shown in
figure 3-1 and keyed to the following descriptions.
01
MODE Switch - Selects one of the following eight
modes.
CONT - Continuous pulses at all output connectors.
TRIG - DC level at all outputs until a suitable trigger appears (see @ , @ ); then one or more
pulses occur,depending on mode and control settings.
GATE - DC level at all outputs until a suitable
trigger edge appears (see @ , @ ); then pulses
occur until the trigger signal transverses the generator
trigger level again.
EXT WIDTH - DC level at all outputs until a
suitable trigger appears (see @ , @ ); then a
pulse occurs which has the duration of the trigger
signal.
TRIG BURST - DC level at all outputs until a
suitable trigger appears (see @ , @ ) to trigger a
gate time @ ; then a fixed number of pulses occur
as determined by @ and @ .
CONT DBL - As for CONT except two pulses occur
for each pulse period. Time to second pulse is set by
5
0
TRIG DBL - As for TRIG except two pulses occur
in the one pulse period. Time to second pulse is set”
by @ .
Figure 3-l . Controls and Connections
3-I
50% DUTY TIME
WHEN TRIGGERING
IS INTERNAL
--
--
I
SYNC PULSE
I
N
UPPER LEVEL
NORMAL PULSE
- DELAY -
AT 5Oi2 OUT
TRAILING EDGE
TRANSITION TIME
LEADING EDGE --1
TRANSITION TIME
COMPLEMENT
PULSE AT 50i2OUT
LOWER
- L E V E L
NORMAL
DOUBLE PULSE
AT 5Oi2 OUT
I
I
b WIDTH B
F WIDTH e
NO TE: Underline indicates a front panel con trolled parameter.
Figure 3-2. Pulse Parameters
3-2
LOWER
- L E V E L
-
J UPPER LEVE&
-
GATE DBL - As for GATE except two pulses occur
for each pulse period. Time to second pulse is set by
5 .
02
09
0
TRIGGER Switch - Selects one of three trigger
methods: manual, an external trigger signal’s rising
edge or an external trigger signal’s falling edge. The
external trigger signal is applied at
030
LEVEL Control - Inner knob sets acceptance threshold for trigger signal at @ .
011
MAN TRIG Switch - Supplies a trigger with a duration that equals the time the switch is held down.
Output depends on the mode selected (see @ ).
32
0
Q9
03
TRIG Indicator - An LED which lights approximately 100 ms for each trigger signal accepted.
___
04
PERIOD/RATE Switch - Selects one of seven ranges
of pulse period. Calibrated in seconds and hertz.
013
VARIABLE Control - Varies the pulse period within
the range selected by the outer knob. Clockwise increases the pulse period and decreases frequency.
--
0
5
DELAY Switch - Selects one of seven ranges of
pulse delay, time to second pulse of double pulses
or length of burst, depending on mode setting. OFF
position ensures minimum delay.
VARIABLE Control - Varies the delay time within
the range selected by the outer knob. Clockwise increases the delay.
06
WIDTH Switch - Selects one of seven ranges of pulse
width or an approximate 50% duty cycle.
4
0
--
08
LOWER LEVEL Control - Outer knob sets the
lower level of the 5Os2 OUT pulse, which may be
varied from -20 to +20 volts into an open circuit
or -10 to +10 volts into a 5052 termination. Maximum pulse height is 20 volts open circuit.
OUTPUT Switch - Selects a normal pulse or its
complement which swaps the active and quiescent
levels. Affects all outputs, except SYNC,
ECL Connector - An output like the ECL outexcept active and quiescent levels are
put @
reversed.
TTL Connector - An output with a transistor-transistor-logic level pulse whose occurence and duration
are controllable. Level is < 0.4V quiescent, > 2.4V
active into a 5Ost termination.
TRAILING EDGE Control - Varies the duration of
the 5Oa OUT pulse trailing edge. Duration range is
set by 0
1 . Clockwise rotation increases edge
time. Full cw exceed upper value of the selected
range. Trailing edge time is not part of WIDTH time.
SYNC Connector - An output with a pulse of OV
to > 0.5V into 5Oa termination and a square wave
when the generator is in a continuous mode (see
1 ). In other modes, width is determined by the
time between initial transition of the trigger signal
through the trigger level to the trailing transition.
0
01 5
01 6
VARIABLE Control - Varies the pulse width within
the range selected by the outer knob except ins.
07
ECL Connector-An output with an emitter-coupledlogic level pulse whose occurence and duration are
controllable. Levels are -1.8V quiescent, -0.9V
active.
017
0
LEADING EDGE Control - Same as
13
but
varies the duration of the leading edge of the SOS2
OUT pulse. Leading edge time is part of WIDTH time.
TRIG INPUT Connector - Accepts an external
signal to trigger the generator. Triggers on rising or
falling edge of input as determined by @ . See
paragraph 1.2.3 for input specifications.
TRANSITION TIME Switch - Selects one of seven
ranges for 5Oa OUT pulse rise and fall durations.
Actual durations within a range are set by @
and
@ .
UPPER LEVEL Control - Inner knob sets the upper
level of the 5052 OUT pulse. Upper level range is
identical to that stated for the lower level.
0‘I8
POWER Switch - Pulse generator on/off switch.
3.2
NOTES ON OPERATION
5OQ OUT Connector - The main output of the generator. Pulses from this output may be controlled in
level and transition time as well as frequency and
width.
Operational modes are described in paragraph 3.1 under the
mode switch. The pulse itself may be shaped in width,
leading and trailing edge transition times, upper level, lower
level, frequency of occurrence (period) and delay with
3-3
respect to its sync pulse. These pulse parameters are shown
in figure 3-2. Specific setups for each mode are given in
paragraph 3.3.
White Marks
3.2.1
When first becoming familiar with the 801, the white mark
settings are handy. The white mark settings for the front
panel switches will always give a 5k to 50 kHz sync signal
when power is on. The same settings will give 50% duty
time, TTL, ECL, ECL and 5Os2 OUT pulses; the LOWER
LEVEL/UPPER LEVEL control may need adjusting to observe the 501sz OUT on an oscilloscope. Once the output is
observed, each control can be adjusted and observed until
the desired result is obtained.
3.2.2
Pulse Width, Transition and Delay
Narrow duty cycle pulses require the NORMAL OUTPUT
while greater than 70% duty cycle pulses require the COMP
OUTPUT setting. Pulse width plus trailing edge time plus
delay time settings should not exceed the period time. (See
figure 3-2.) The sum of width, trailing edge and delay actually must be somewhat less than period time by an amount
that depends upon the period time selected. Therefore,
when the sum of the desired width, trailing edge and delay
time exceeds 70% of the period time, the pulse should be
observed to make sure it is as desired.
3.2.4
Output Terminations
Only 5OQ RG58U cable should be used to connect the 801
to the circuit under test. A 5OQ 2W load should be used at
the circuit end of the cable for maximum pulse fidelity.
The 5Oa terminations should always be used on the SYNC
and TTL outputs and 5OQ Thevenin loads should be used
on the ECL outputs.
3.2.5
Nonlinear and Reactive Loads
Both nonlinear and reactive loads will cause pulse distortion.
Reactive loads driven with fast transitions cause voltage
spikes that can damage the 801 output amplifier. If it is
necessary to drive reactive loads directly, the instrument
must be protected against these voltage spikes.
3.2.6
Duty Cycle
Always use the lowest range possible for both delay and
width functions. This will reduce the recovery time of the
one-shots and extend the maximum duty cycle of the 801
to its fullest capability.
3.2.7
Output Mixing
The outputs of two 801’s may be mixed using the following
network.
The 50% duty time width setting ( ‘L ) is meant to be used
in continuous mode. Other modes result in the following
default conditions.
Mode Selected
TRIG I-I
CONT DBLX
TRIG DBL\
GATE DBL’L
output
20.5a
A triggered 10 ns pulse
A continuous output of paired 10 ns pulses
A triggered output of paired 10 ns pulses
A gated output of paired 10 ns pulses
ECL Termination
3.2.3
FROM
FIRST 801
OUTPUT
20.5a
FROM
SECOND 801
OUTPUT
Maximum output from either generator is limited to 6 volts.
Figure 3-3 shows a 5.2/0volt 5052 ECL termination. Similar
5Oa terminations can be made for ECL circuits with other
voltage arrangements.
801
-5.2V
ECL
ECL CIRCUIT
3 FT RG58U COAX
-
j OR EQUIVALENT
Figure 3-3. ECL Termination
3-4
) MIXED OUTPUT
3.2.8
Precise Output Levels
Many times when testing a circuit it is desirable to lock the
output of the generator at either the high or low level. A
precise measurement of this level may then be obtained
using a DVM.
The external width mode is useful for this purpose. Set the
MODE to EXT WIDTH, TRIGGER to fl and TRIGGER
LEVEL maximum cw. The output will now be locked to
the lower level. Switching the trigger to fi will lock it to
the upper level.
The OUTPUT NORM/COMP switch could also be used to
reverse the upper and lower levels as the trigger edge does,
but some error could be introduced by the X-Y multiplier.
3.2.9
Rise Time Measurements
When measuring rise time in a linear device under test, the
error induced by the rise time of the testing system must be
considered. For exam pie, when obse rving the 801 rise time
on an oscill oscope, 80 1 rise time is
t2
observed
= t2
scope
Control
Operation
MODE
CONT
OUTPUT
COMP
PERIOD/RATE Set as desired.
and Level Controls
W IDTH
+ t2
Set to desired lower level time (see
figure 3-4). The > 70% pulse will start
W IDTH time after SYNC leading edge
with DELAY OFF.
801
Of
t2
t2
‘801 =
-’
observed
scope
SYNC
That is, the observed rise time must be corrected for by the
inherent oscilloscope rise time to determine the actual 801
rise time. Extending the method to include a circuit under
test will determine circuit under test rise time:
t2
t2
observed = 801
+ t2
scope
c.u.t.
In the following descriptions of operation, observe the
pulse on an oscilloscope. When the 5Oa OUT pulse is not
desired, disregard leading and trailing edge adjustments.
(See figure 3-2 for pulse parameters.)
Continuous Pulses
Set the controls as follows for continuous pulse output.
Control
Operation
MODE
CONT
OUTPUT
NORM (or COMP if inverted pulse is
desired)
All Other
Controls
3.3.2
n
COMPLEMENT
;;;;;+
T >70% D U T Y
C Y C L E PULSE
Figure 3-4. Greater Than 70% Duty Cycle Pulse
+ t2
3.3 OPERATION
3.3.1
rl
Set as desired. DELAY is constrained to
be less than PERIOD-(WIDTH +TRAILING EDGE). If a large pulse WIDTH is
desired but cannot be obtained, refer to
paragraph 3.3.2.
Control
Operation
Edge Controls
and DELAY
Set as desired.
3.3.3
Triggered Pulses
Set up as in paragraph 3.3.1. If triggering with an external
signal, connect the trigger source to TRIG INPUT. Ensure
that the trigger rate is slower than the pulse rate.
Control
Operation
MODE
TRIG
TRIGGER
Set as desired. (Observe TRIG indicator
to ensure triggering occurs.)
3.3.4
Gated Pulses
Set up as in paragraph 3.3.1. If gating with an external signal, connect the gate source to TRIG INPUT. Set the gate
pulse width to allow the number of pulses desired. Reset
the controls as follows.
Control
Operation
MODE
GATE
TRIGGER
Set as desired. (Observe TRIG indicator
to ensure triggering occurs.)
Continuous Wide Duty Cycle Pulses
Follow this setup for pulses greater than those that can be
obtained in paragraph 3.3.1. The “pulse” that appears to be
positive going is referred to as the > 70% pulse.
3-5
Pulses With Width Controlled Externally
Control
Operation
Connect the trigger source to TRIG INPUT and set the controls as follows.
MODE
CONT DBL
OUTPUT
NORM (or COMP if inverted pulse is
desired)
3.3.5
Control
Operation
MODE
EXT WIDTH
W IDTH
Set as desired.
TRIGGER
Set as desired. (Observe TRIG indicator
to ensure triggering occurs.)
DELAY
Set for desired width between double
pulses.
Edge Controls
and Output
Controls
Set as desired.
PERIOD/RATE
Set for sum of WIDTH + DELAY + time
desired between successive double pulses.
Edge Controls
and Level
Controls
Set as desired.
3.3.6
Triggered Burst of Pulses
In triggered burst mode, the trigger initiates a gate pulse,
controlled by the DELAY control, which gates the output
pulses. Set the controls as follows.
Control
Operation
MODE
TRIG BURST
TRIGGER
Set as desired. (Observe TRIG indicator
to ensure triggering occurs.)
Set as desired.
PERIOD,
WIDTH, Edge
Controls and
Output Controls
DELAY
Set to the total period time of the number
of pulses desired in the burst.
TRIG INPUT
Set input trigger period to greater than
the DELAY time.
3.3.8
Triggered Double Pulses
Set up as in paragraph 3.3.7. If trigqering
with an external
c
signal, connect the trigger source to TRIG INPUT. Reset
the controls as follows.
Control
Operation
MODE
TRIG DBL
Control
Operation
TRIGGER
Set as desired. (Observe TRIG indicator
to ensure triggering occurs.)
3.3.9
Gated Double Pulses
Setup as in paragraph 3.3.7. If gated with an external signal,
connect the gate source to TRIG INPUT. Set the gate pulse
width to allow the number of pulses desired. Reset the
controls as follows.
NOTE
Trigger Period > Delay Time > Pulse Period
3.3.7
Operation
MODE
GATE DBL
TRIGGER
Set as desired. (Observe TRIG indicator
to ensure triggering occurs.)
Continuous Double Pulses
For continuous double pulses, set the controls as follows.
3-6
Control