Wavetek 801 Service manual

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

9045Balboa Ave.,
P. 0.Box 651, SanDiego, California 92112
Tel 7

14/279-2200

San Diego,

Calif.

92123

TWX 9 1 o-335-2007

REV C .

8/77

SECTION

1

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
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.

+20

The output is
provides
levels are fully adjustable through

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.

1.2 SPECIFICATIONS

1.2.1
Five Simultaneous Pulse Outputs

Fixed level ECL,

with variable amplitude
available over a 5 Hz to
to 20 ns periods).

+lO

Versatility

volts with

volts into a

m,

5Oa

source impedance which

5Oa

load. Upper and lower pulse

+20

volts.

TTL and sync pulses and a pulse

and variable rise/fall times. Pulses
50 MHz frequency range (200 ms

ECL

are of

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

Trigger Burst:

time) for pulse burst (1 to 100 pulse range) as shown.

External trigger starts internal gate (delay

TRIGGER LEVEL

TRIGGER

+

I

‘DELAY TIME’ GATE

PULSE

1.2.2

Pulse Outputs

BURST OUTPUT

-I

hlnn

I

Operational Modes

Continuous: Generator
frequency.

Triggered: Generator quiescent until triggered by external

signal or front control, then generates one pulse.

Gated: As triggered mode, except generator oscillates for
the duration of the external signal.

Double

except

Pulse: Continuous, trigger and gate, as above,

two pulses for

oscillates continuously at selected

each period. Space between pulses of

Variable Amplitude Pulse

Upper and lower pulse levels are independently adjustable.

*2OV

Pulse dynamic range

5052 source. The pulse is 20V p-p maximum, 1V p-p mini-

mum. Into a
maximum pulse 1OV p-p, minimum pulse

Overshoot and ringing is less than
+100

mV) into 5Oa load.

Preshoot is less than

5Oa load.

into

is

5Os1

termination, dynamic range is

into an open circuit from the

0.5V

*(5%

of amplitude setting

+(5%

of amplitude setting

p-p.

+100

+lOV,

mV)

l-l

Fixed (ECL, ECL, TTL) Pulses

Pulse levels for

ECL

Em

ECL, ECL Transition Time: < 6 ns.

TTL

TTL Transition Time: < 10 ns.

5On

loading as shown:

-1 8” A

.

-,

.8V

--7-r--

<o

4Vn

.

Sync Pulse

Sync pulse is 0 to at least

+1V

from a

-0.9V

-“”

>2s4V

5Oa

source.

Delay

Pulse occurrence can be delayed from less than 10 ns to

100 ms with respect to the sync pulse. Maximum duty
cycle is 70% for periods to 200 ns, decreasing to 30% for
20 ns periods.

Delay jitter is less than 0.1% plus 50 picoseconds.

Fixed delay is as shown:

TRIGGER LEVEL

TRIGGER INPUT

FIXED

DELAY4 b -4Ons

Normal/Complement Control

Normal pulse or its complement is selected. The normally
quiescent and active levels are reversed in complement
format. This control affects all outputs except sync pulse.

1.2.3

Period range is from less than 20 ns to greater than 200 ms
in 7 overlapping ranges.

Period jitter is less than 0.1% plus 50 picoseconds.

Time Domain

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

‘L

duty cycle is 50 -+4% to 2

50 +15% at 20 ns period.

Width jitter is less than 0.1% plus 50 picoseconds.

( % ).

pus

period changing to

1.2.4

SYNC PULSE

FIXED DELAY

VARIABLE
AMPLITUDE

PULSE

Input Characteristics

t

1

--+( k ~20

__n-

ns

External Trigger

The external signal required to trigger the generator has a
minimum amplitude of
to

k600 mV

mum amplitude of

Input impedance is approximately 1 ka

22 pF

Triggering is selected to occur at either rising or falling edge
of trigger signal; triggering level is adjustable to be between

+4V.

external and manual trigger occurrence accepted.

1.2.5

p-p to 50 MHz (from

An LED lights for approximately 100 ms for each

General

+200 mV

+lOV

with a minimum width of 10 ns.

p-p to 5 MHz increasing

5Oa

source) and a maxi-

in parallel with

Sync pulse duty cycle is 50
period, changing to 50 +I 5% at 20 ns period except in
trigger and external width modes, in which case it is deter­mined by the trigger signal.

24% of pulse period to 2

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
ranges except 5 ns, which gives 25: 1.

Linearity:
10 to 90% points on pulse.

l-2

For transition greater than 10 ns

50:1

adjustment on all

+5% between

pus

Environmental

Specifications apply at 25°C

Instrument will operate from 0°C to 50°C.

*5”C

after 1 hour warm-up.

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

to1 10V,108 to

50to400 Hz;

132V,

60 watts nominal.

to220Vor216

180

to250V;

OPERATION

3.1

CONTROLS

The generator controls and connections are shown in
figure 3-1 and keyed to the following descriptions.

1

MODE Switch

0

modes.

CONT - Continuous pulses at all output connectors.

TRIG

ger appears (see
pulses occur,depending on mode and control settings.

GATE

trigger edge appears (see

occur until the trigger signal transverses the generator

trigger level again.

AND CONNECTORS

Selects one of the following eight

-

DC level at all outputs until a suitable trig-

-

@

, @

);

then one or more

DC level at all outputs until a suitable

-

@

, @

);

then pulses

EXT WIDTH
suitable trigger appears (see
pulse occurs which has the duration of the trigger
signal.

TRIG BURST
suitable trigger appears (see
gate time
as determined by

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 @

@

.

DC level at all outputs until a

-

@

, @

);

then a

DC level at all outputs until a

-

@

, @

)

to trigger a

;

then a fixed number of pulses occur

@

and

@

.

Figure 3-l . Controls and Connections

3-I

50% DUTY TIME

WHEN TRIGGERING

--

IS INTERNAL

--

SYNC PULSE

NORMAL

AT

5Oi2

COMPLEMENT

PULSE AT

PULSE

OUT

50i2OUT

-

DELAY

LEADING EDGE

TRANSITION TIME

I

I

UPPER

-

--1

-LEVEL

TRAILING EDGE

TRANSITION TIME

LOWER

LEVEL

N

LOWER

-LEVEL

J

UPPER LEVE&

--

NORMAL

DOUBLE PULSE

AT

5Oi2

OUT

NO

TE:

Underline indicates a front panel con trolled parameter.

I

I

b

WIDTH

B

F

Figure 3-2. Pulse Parameters

3-2

WIDTH

e

GATE DBL - As for GATE except two pulses occur

for each pulse period. Time to second pulse is set by

5

.

0

0

2

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

Q9

ECL Connector-An output

9

0

logic level pulse whose occurence and duration are
controllable. Levels are
active.

OUTPUT Switch- Selects a normal pulse or its

30

0

complement which swaps the active and quiescent
levels. Affects all outputs, except SYNC,

with an

-1.8V

emitter-coupled-

quiescent,

-0.9V

___ 0 4

--

0

5

0

0

LEVEL Control- Inner knob sets acceptance thresh-

old for trigger signal at

MAN TRIG Switch

3

tion that equals the time the switch is held down.

Output depends on the mode selected (see

TRIG Indicator

mately 100 ms for each trigger signal accepted.

PERIOD/RATE Switch- Selects one of seven ranges

of pulse period. Calibrated in seconds and hertz.

VARIABLE Control - Varies the pulse period within

the range selected by the outer knob. Clockwise in­creases the pulse period and decreases frequency.

DELAY Switch

pulse delay, time to second pulse of double pulses
or length of burst, depending on mode setting. OFF
position ensures minimum delay.

VARIABLE Control

the range selected by the outer knob. Clockwise in­creases the delay.

WIDTH

6

width or an approximate 50% duty cycle.

VARIABLE Control

the range selected by the outer knob except

Switch -

-

-

An LED which lights approxi-

-

Selects one of seven ranges of

Selects one of seven ranges of pulse

@

.

Supplies a trigger with a dura-

-

Varies the delay time within

-

Varies the pulse width within

@

ins.

11

ECL Connector- An output like the ECL out-

0

put
reversed.

32

TTL Connector

).

0

sistor-logic level pulse whose occurence and duration

are controllable. Level is <

active into a 5Ost termination.

13

TRAILING EDGE Control - Varies the duration of

0

the

5Oa

set by 1
time. Full cw exceed upper value of the selected
range. Trailing edge time is not part of WIDTH time.

4 SYNC

0

to

> 0.5V

when the generator is in a continuous mode (see

1 ). In other modes, width is determined by the

0

time between initial transition of the trigger signal
through the trigger level to the trailing transition.

15

LEADING EDGE Control - Same as013 but

0

varies the duration of the leading edge of the

OUT pulse. Leading edge time is part of WIDTH time.

TRIG INPUT Connector - Accepts an external

16

0

signal to trigger the generator. Triggers on rising or

falling edge of input as determined by
paragraph 1.2.3 for input specifications.

except active and quiescent levels are

@

-

An output with a transistor-tran-

0.4V

quiescent, >

OUT pulse trailing edge. Duration range is

Clockwise rotation increases edge

.

0

Connector- An output with a pulse of OV

into

5Oa

termination and a square wave

@

2.4V

SOS2

. See

LOWER LEVEL Control - Outer knob sets the

0

7

--

lower level of the
varied from-20 to
or -10 to
mum pulse height is 20 volts open circuit.

UPPER LEVEL Control

level of the

identical to that stated for the lower level.

5OQ

0

8

erator. Pulses from this output may be controlled in

level and transition time as well as frequency and
width.

OUT

+10

Connector

5Os2

OUT pulse, which may be

+20

volts into an open circuit

volts into a 5052 termination. Maxi-

-

Inner knob sets the upper

5052 OUT pulse. Upper level range is

-

The main output of the gen-

TRANSITION TIME Switch - Selects one of seven

17

0

ranges for
Actual durations within a range are set by
and

POWER Switch -Pulse generator on/off switch.

‘I8

0

NOTES ON OPERATION

3.2

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

5Oa

OUT pulse rise and fall durations.

@

@

.

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.

3.2.1

White Marks

3.2.4

Only
to the circuit under test. A

Output Terminations

5OQ RG58U

cable should be used to connect the 801

5OQ

2W load should be used at

the circuit end of the cable for maximum pulse fidelity.

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.

The 50% duty time width setting

( ‘L )

is meant to be used

in continuous mode. Other modes result in the following
default conditions.

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.

)

MIXED OUTPUT

Mode Selected

TRIG

I-I

DBLX

CONT
TRIG

DBL\

GATE

DBL’L

3.2.3

ECL

Figure 3-3 shows a

output

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

Termination

5.2/0volt 5052

ECL termination. Similar

5Oa terminations can be made for ECL circuits with other

voltage arrangements.

801

ECL

3 FT RG58U COAX

-

-5.2V

ECL CIRCUIT

j

OR EQUIVALENT

Figure 3-3. ECL Termination

3-4

20.5a 20.5a

FROM

FIRST 801

OUTPUT

FROM

SECOND 801

OUTPUT

Maximum output from either generator is limited to 6 volts.

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 to EXT WIDTH, TRIGGER to

mode is useful for this purpose.

fl

and TRIGGER

Set the

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.

Control

MODE CONT

Operation

3.2.9

When measuring rise time in a linear device under test, the
error induced by the rise time of the testing system must be
considered.
on an oscill

Of

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:

3.3

In the following descriptions of operation, observe the
pulse on an oscilloscope. When the

desired, disregard leading and trailing edge adjustments.

(See figure 3-2 for pulse parameters.)

3.3.1

Set the controls as follows for continuous pulse output.

Control

MODE

Rise Time Measurements

For exam

oscope,

t2

observed= 801

OPERATION

Continuous Pulses

pie, when
1 rise time

80

t2

observed

‘801 =

t2+

Operation

CONT

=

t2

t2

observed

rving the 801 rise time

obse

is

+ t2

scope

t2

scope

801

-’

t2

scope

+ t2

c.u.t.

5Oa OUT pulse is not

OUTPUT

PERIOD/RATE Set as desired.
and Level Con­trols

WIDTH Set to desired lower level time (see

SYNC

COMPLEMENT

;;;;;+

Figure

Control

Edge Controls Set as desired.

and DELAY

3.3.3

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

MODE

TRIGGER Set as desired. (Observe TRIG indicator

Triggered Pulses

COMP

figure 3-4). The > 70% pulse will start

WIDTH time after SYNC leading edge

with DELAY OFF.

rl

n

T

>70%

DUTY CYCLE

3-4.

Greater Than 70% Duty Cycle Pulse

Operation

Operation

TRIG

to ensure triggering occurs.)

PULSE

OUTPUT

All Other
Controls

3.3.2

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.

Continuous Wide Duty Cycle Pulses

NORM (or COMP if inverted pulse is

desired)

Set as desired. DELAY is constrained to
be less than PERIOD-(WIDTH

ING EDGE). If a large pulse WIDTH is
desired but cannot be obtained, refer to
paragraph 3.3.2.

+TRAIL-

3.3.4

Set up as in paragraph 3.3.1. If gating with an external

nal, 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

TRIGGER Set as desired. (Observe TRIG indicator

Gated Pulses

sig-

GATE

to ensure triggering occurs.)

3-5

3.3.5

Pulses With Width Controlled Externally

Control

Operation

Connect the trigger source to TRIG INPUT and set the con­trols as follows.

Control

MODE

TRIGGER

Operation

EXT WIDTH

Set as desired. (Observe TRIG indicator

to ensure triggering occurs.)

Edge Controls

Set as desired.
and Output
Controls

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

Control

MODE

Operation

TRIG BURST

follows.

MODE

OUTPUT

CONT DBL

NORM

(or

COMP if inverted

pulse

is

desired)

WIDTH

DELAY

Set as desired.

Set for desired width between double
pulses.

PERIOD/RATE

Set for sum of WIDTH +

DELAY +

time

desired between successive double pulses.

Edge Controls

Set as desired.
and Level
Controls

3.3.8

Set up as in paragraph 3.3.7. If trigqering with an external

Triggered Double Pulses

c

signal, connect the trigger source to TRIG INPUT. Reset
the controls as follows.

Control

Operation

TRIGGER

Set as desired. (Observe TRIG indicator
to ensure triggering occurs.)

PERIOD,

Set as desired.

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.

NOTE

Trigger Period > Delay Time > Pulse Period

3.3.7

Continuous Double Pulses

For continuous double pulses, set the controls as follows.

MODE

Control

TRIGGER

TRIG DBL

Operation

Set as desired. (Observe TRIG

indicator

to ensure triggering occurs.)

3.3.9

Setup as in paragraph

Gated Double Pulses

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.

Control

MODE

TRIGGER

Operation

GATE DBL

Set as desired. (Observe TRIG indicator
to ensure triggering occurs.)

3-6