GENERAL RADIO COMPANY 1398-A User manual

OPERATING INSTRUCTIONS
Type 1396-A
PULSE GENERATOR
Form 1398-0100A
ID- 1032
March, 1966
Copyright 1966 by General Radio Company
West Concord, Massachusetts,
USA
GENERAL RADIO COMPANY
WEST CONCORD, MASSACHUSETTS, USA

TABLE OF CONTENTS
..............................................
Section 1 INTRODUCTION 1
.................................................
1.1 Purpose 1
....................................... 1.2 General Description 1
1.3 Controls and Connectors ................................... 1
.....................................
1.4 AccessoriesSupplied 1
.................................... 1.5 Accessories Available 1
Section 2 INSTALLATION .............................................. 5
2.1 Cooling ................................................. 5
2.2 Power Supply
............................................ 5
2.3 Rack Mounting
........................................... 5
.....................................
Section 3 OPERATING PROCEDURE 6
.......................................
3.1 Definition of Terms 6
..................................
3.2 Normal Internal Operation 7
3.3 Normal External Operation
................................. 7
...................................
3.4 PRF vs Pulse Duration 9
..............
3.5 Precautions for Very Long or Very Short Pulses 9
......................................
3.6 Rise and Fall Times 10
..............................
3.7 External Load Considerations 10
.....................
3.8 Output Dc Component - Dc Translation 11
.........................
3.9 Locking on High Frequency Signals 12
.....................................
3.10 Count-Down Operation 12
....................................
3.1 1 Single-Pulse Operation 12
..................................
3.12 Use as a Delay Generator 12
................................
3.13 Use for Complex Waveforms 13
.................................
Section 4 PRINCIPLES OF OPERATION 14
.................................................
4.1 General 14
........
4.2 Input and PRF Oscillator Circuit - External Operation 14
........
4.3 Input and PRF Oscillator Circuit - Internal Operation 15
...........................
4.4 Output Pulse and Timing Circuits 16
............................................
4.5 Power Supply 19
................................
Section 5 SERVICE AND MAINTENANCE 20
.................................................
5.1 Warranty 20
...................................................
5.2 Service 20
.........................................
5.3 Removal of Cover 20
......................................
5.4 Routine Maintenance 20
....................................
5.5 Trouble-Shooting Notes 21
...............................................
5.6 Waveforms 23
.................................
5.7 Voltages .and Resistances 22
.....................................
5.8 Calibration Procedure 23
...............................................
Parts Lists and Schematics 28

SPECIFICATIONS
PULSE REPETITION FREQUENCY
Internally Generated:
2.5 c/s to 1.2 Mc/s, with calibrated points
in a 1-3 sequencefrom 10c/s to 300 kc/s, and 1.2Mc/s, all
+ 5%.
Continuous coverage with an uncalibrated control.
Externally Controlled: Aperiodic, dc to 2.4 Mc/s with 1-V, rms,
input (0.5V at 1 Mc/s and lower); input impedance at 0.5 V,
rms, approximately 100kD shunted by 50 pF. Output pulse is
started by negative-going input transition.
OUTPUT-PULSE CHARACTERISTICS
Duralion:
100ns to 1s in 7 decade ranges, +5y0 of reading or
+2y0of full scaleor + 35 ns, whichever isgreater.
\\ Rise and Fall Times: Less than 5 ns into 50 or 100 0; typically
60 ns
+ 2 ns/pF external load capacitance into 1 kD (60V).
Voltage: Positive and negative 60-mA current pulses available
simultaneously. Dc coupled, dc component negative with respect
to ground. 60 V, peak, into 1-kD internal load impedance for
both negative and positive pulses. Output controlhas 10steps
plus continuous adjustment.
Overshoot: Overshoot and noise in pulse, less than 10yoof ampli-
tude with correct termination.
Ramp-off: Less than 1 %.
Synchronizing Pulses:
Prepulse: Positive and negative 8-V, approx, pulses of 150-ns
duration.
If positive sync terminals are shorted. negative pulse
can be increased to approximately 50
V.
Sync-pulsesource impedance:
positive - approx 300 D;
negative - approx 1kD.
Delay-Sync Pulse: Consists of a negative-going transition of
approximately 5 V and 100-ns duration, coincident with the late
edge of the main pulse. Duration control reads time between
prepulse and delayed syncpulse. Thisnegative transition is imme-
diately followed by a positive transition of approximately 5 V
and 150ns to reset theinputcircuits of afollowingpulse generator.
(See oscillogram.)
Stability: With external-drive terminals short-circuited, prf jitter
and pulse-duration jitter are each 0.04~0.(Jitter figuresmay vary
somewhat with range switch settings, magnetic fields, etc.)
Power Required: 105 to 125, 195 to 235, or 210 to 250 V, 50 to
60 c/s, 90 W.
Accessories Available: TYPE 1217-P2 Single-Pulse Trigger, rack-
adaptor panel.
MECHANICAL DATA Convertible-Bench Cabinet.
Net
Weight
lb kg
14Yz 1 7.0
Depth
in
mm
8% 1 210
Width
in
mm
12 1 305
Shipping
Weight
lb kg
18 1 8.5
Height
in
mm
5% 1 135

INTRODUCTION
INTRODUCTION
1.1 PURPOSE.
The Type 1398-A Pulse Generator is a gen-
eral-purpose pulse source intended primarily for labora-
tory use. The repetition rates of the pulses may be
either internally controlled, at frequencies from 2.5 c/s
to 1.2 Mc/s, or externally controlled at frequencies up
to 2.4 Mc/s.
In addition to the main positive and negative out-
put pulses, the instrument also supplies synchronizing
pulses that correspond to the beginning and end of the
main pulse. The early sync pulse ( prepulse )is intended
chiefly for synchronizing an oscil~oscopewhile the late
pulse (delay pulse
) is intended to make the instrument
an accurate time-delay generator.
1.2 GENERAL DESCRIPTION.
The Type 1398-A comprises three main circuit
groups:
(1) A combination input circuit and oscillator that
establishes the repetition rate of the main pulse.
(2) A combination pulse-timing and output circuit
that establishes the duration and amplitude of the
main pulse.
(3) A power supply that provides regulated voltage
for the other two circuit groups.
The repetition frequency, duration, and amplitude
of the main output pulse are adjustable by front-panel
controls. Theinstrument, which
is housed in a convert-
ible-bench cabinet, may be used as supplied as a
bench instrument or may be quickly and easily adapted
for use in a relay-rack. (Refer to paragraph 2.3.)
1.3 CONTROLS AND CONNECTORS.
See Figure 1-1 and Table 1-1 for the location and
the description of the controls and connectors used on
the Type 1398-A.
1.4 ACCESSORIES SUPPLIED.
One instruction book,form number 1398-0100.
One power cord, part number 4200-9622.
1.5 ACCESSORIES AVAILABLE.
Type 1217-P2 Single-PulseTrigger, catalognumber
1217-9602. Used to generate single pulses. See Figure
1-2 and paragraph 3.11.4 for further details.
Type 480-P312 Relay-Rack Adaptor Set, catalog
number 0480-9632. Used to rack-mount theType 1398-A.
Refer to paragraph 2.3 for further details.

,TYPEl398-A PULSE GENERATOR
[ABLE 1-1
S AND CONN
Function
Sets PRF range. In EXT
DRIVE, it changes prf
oscillator to an aperiodic
input circuit.
Continuous Adjusts prf continuously
rotary control between calibrated switch
positions. When set fully
clockwise, PRF switch is
calibrated. When PRF
switch is set to EXT DRIVE,
flF control sets triggering
level of pulse generating
circuits.
PULSE DURATION Continuous Sets pulse duration.
rotary dial
(no stop)
Sets pulse duration range
rotary switch in decade steps.
POWER OFF Toggle switch Turns instrument on and off.
OUTPUT PULSE
-
For negative main output
OUTPUT PULSE
+ Jack-top binding For positive main output
AMPLITUDE
Inner Control Continuous Adjusts amplitude
rotary control continuously between
switch positions.
Outer Switch 10-position Sets pulse amplitude
rotary switch in ten steps from zero
to maximum.
EXT OFFSET Jack-top binding For connection to an
post pair external power supply
10 SYNC DELAYED Jack-top binding For delayed sync pulse.
post pair Amount of delay
is
controlled by PULSE
DURATION controls.
11 SYNC - Jack-top binding For negative prepulse.
post pair
12 SYNC
+ Jack-top binding For positive prepulse.
post pair
13 EXT DRIVE Jack-top binding For external drive signal.
post pair
12-terminal For use with forthcoming
female connector Type 1398-P1 DC Component
Control Unit.

- --
INTRODUCTION
Figure 1-1. Type 1398-A Pulse Generator.
Figure 1-2. Type 1217-P2
Single-Pulse Trigger.

@
TYPE 1398-A PULSE GENERATOR
RUBBER FOOT
WlNG SCREW
LOCKWASHER
WlNG
Figure 2-1. Rack Mounting: Preparation
of instrument for attachment of wings.
Figure 2-2. Rack Mounting: Wing assembly.

SECTION 2
2.1 COOLING.
It is important that the interior of the instrument
be adequately ventilated; therefore make sure the air
holes in the cover, especially those on the right side,
are not blocked.
2.2 POWER SUPPLY.
Connect the pulse generator to a source of power
as indicated by the legend at the input socket at
the rear of the instrument, using the power cord pro-
vided. While normally connected for 115-volt operation,
the transformer input circuit
is so arranged that one
can make the conversion from 115-volt to 215-volt
operation simply by throwing a switch located directly
below the input socket. To do this, unscrew the two
clamp fastners on the back of the instrument and slide
off the dust cover. Flip the switch over so that the
white indicator
is on the 195- 235-volt side. The circuit
can also be adapted to accommodate a 230-volt line.
To do this, set the line voltage switch to the 195- to
233-volt position, and remove the two wires from ter-
minal 2L, which
is on the same panel as the line volt-
age switch, and connect them to terminal 2. For instru-
ments changed to 215-volt or 230-volt operation, name-
plates (Type LAP166E5 for 215-volt operation, Type
LAP166E2 for 230-volt operation) may be ordered from
General Radio.
2.3 RACK MOUNTING.
The pulse generator can be rack-mounted by
means of a Type 480-P312 Relay-Rack Adaptor Panel
Set (catalog number 0480-9632). The adaptor panels
are finished in charcoal gray crackle paint to match the
front panel of the instrument and come complete with
the necessary hardware to mount the instrument in the
rack. To make the installation, proceed as follows:
(a.) Remove the rubber feet. Retain the screws.
(b.) Remove and retain the screws that secure the
front panel to the aluminum end frames (see Figure
2-1).
(c.) Remove the spacers between the front panel and
the end frames.
(d.) Install two clips on each wing using lock wash-
ers and nuts provided (seeFigure 2-2).
(e.) Attach the wings to the instrument with the front
panel screws removed in step b
( see Figure 2-3 ).
(f.) The assembly is now ready co be rack-mounted
in
a standard 19-inch relay rack.

@
TYPE 1398-A PULSE GENERATOR
SECTION 3
OPERATING PROCEDURJE
3.1 DEFINITION OF TERMS.
main pulse.. ................... .The principal output of the instrument; available at the OUT-
PUT PULSE binding posts.
prepulse..
..................... .The positive or negative sync pulse supplied just before the
start of the main pulse; available at the SYNC +and SYNC
-
binding posts.
delayed pulse
................... The pulse coincidentwith the end of the mainpulse; available
at the DELAYED SYNC binding posts.
internal operation..
............. The mode where pulse repetition frequency is determined by
the pulse generator itself and controlled by the
PRF controls
on the front panel.
external operation
............... The mode where pulse repetition frequency is determined by
an external signal source; the pulse generator generates
pulses only when triggered by signals applied to the EXT
DRIVE binding posts.
duty ratio..
.................... .The ratio of pulse aonn time to the total time of the period
established by the prf setting; duty ratio, in percent
= prf x
duration x 100.