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TYPE
1391-B
PULSE, SWEEP, AND TIME-DELAY GENERATOR
FIGURE
2.6.
A. POS SWP,
10 kc
60psec, lOpsec/cm
B. NEG PULSE
5 0 p s e c
lOpsec/cm
C. START PULSE
D. STOP PULSE
FIGURE
2.7.
MULT PULSING, EXTERNAL METHOD
(2Opsec/cm)
2.3 INITIAL CONTROL SETTINGS. (Cont)
Control
Setting
SWEEP DURATION
6
60-psec sweep
pSEC
VERNIER
0
PULSE START
INTERNAL (NORMAL)
STOP TRIGGERS
2.4 SY NCHRONIZATION PROCEDURE.
a. Connect an audio oscillator (output a t least one volt) to
the P R F DRIVE binding posts, and s e t the oscillator for a fre-
quency of 10 kc.
b. Connect an oscilloscope (prepared to write at about 20
A.
10 kc
CIRECT SYNC PULSE
B. 100-kc PULSES TO POS COJNC DRIVE
C. DELAYED SYNC
D.
6 - p s e c
SWEEP (SWEEP TRIGGER SWITCH
I
IN DELAYED POSITION)
p s e c per division) a s follows:
(1) Cbnnect the oscilIoscope ground to the ground of the
Type 1391-B.
(2) Connect the oscilloscope external synchronizing ortrig-
ger input to the Type 1391-B DIRECT SYNC OUT.
(3) Set the oscilloscope to accept a positive-going e x t e r
nal synchronizing signal.
(4)
Connect the oscilloscope vertical amplifier to the Type
1391-B P R F DRIVE binding posts.
c. Turn all equipment on. After a warm-up time of about a
minute, both neon indicators on the Type 1391-B should glow.
If either indicator does not light, flip the RESET switch to start
the sweep or delay circuit.
d. Adjust oscilloscope to give a stable presentation and ob-
serve the input waveform on the oscilloscope. It should appear
a s shown in Figure 2.1A.
e. Set the TRIGGER SELECTOR switch to NEG GOING AC.
The oscilloscope pattern should change phase by about 180
degrees, and should appear a s shown in Figure 2.lb.
f . Connect the oscilloscope input to the Type 1371-B DI-
RECT SYNC OUT terminals and observe the 75-volt, 1.5-psec
positive synchronizing pulse. It should appear a s shown in Fig-
ure 2.1C or 2.2A.
2.5
DELAY CIRCUIT.
2.5.1 NORMAL USE.
a. Leave the input circuits connected a s in paragraph 2.4,
with the TRIGGER SELECTOR switch s e t for either positive- or
negative-going triggering. Input oscillator frequency should be
s e t a t 10 kc.
b. Move the oscilloscope vertical input to the DELAYED
SYNC OUT terminals. The positive delayed synchronizing pulse
should appear a s shown in Figure 2.2A.
c. Move the TIME DELAY MICROSECONDS dial t o 2.00 and
observe the motion of the delayed synchronizing pulse. It should
appear a s in Figure 2.2B. Change the setting of the TIME DE-
LAY RANGE switch to 1-10 p s e c , and again observe the pulse.
d. Set the TIME DELAY RANGE switch to the 10-100-psec
range, and increase the MICROSECONDS dial setting from 5.00
to 11.00 (fully clockwise). This produces a delay of 110 p s e c .
If the delay indicator lamp goes out, flip the RESET switch to
start the delay.
e. Remember that the period s e t by the timing oscillator was
only 100 psec. The delay circuit i s now "counting downy and
the output period from the delay circuit is 5kc or 200 p s e c .
Figure 2.3 illustrates this principle.
f . Return the DELAY MICROSECONDS dial to 5.00.
2.5.2 TIME SELECTION. There are two methods of using the
delay circuits for time selection. The method described in para-
graph 2.5.2.1 (Figure 1.4d) does not require an external timing
source, but uses the direct sync to produce internal multiple
pulses. The second method, described in paragraph 2.5.2.2, re-
quires the use of a timingpulsegenerator.
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