Pulse Generator Output.

TM 11-5820-509-35

(4) On the front panel of the test fixture,

c. Pulse Generator Output.

leave switch S1 at O and rotate switch S2 one complete

(1) Connect the vertical input of the

revolution clockwise to a reading of 1.0.

oscilloscope and the frequency counter to 100 kHz

(5) Adjust capacitor C88 (fig. 3-104) for

sinewave input test point (fig. 3-83) and verify that the

minimum 100-kHz modulation on the oscilloscope trace

amplitude of the waveform is 1.8 0.5 volts peak-to-

and observe that the waveform amplitude is not less

peak, and that the pulse width is 0.3 0.1 microsecond.

than 3.4 volts peak-to-peak and the frequency counter

NOTE

indicates 1.7 MHz.

The pulse width is the interval

(6) Repeat step (4) except rotate switch S2

between the points on the wave-form

one complete revolution clockwise to a reading of 2.0.

where 10 % of the peak amplitude

(7) Adjust capacitor C86 (fig. 3-104) for

occurs.

minimum 100-kHz modulation on the oscilloscope trace

(2) Connect the oscilloscope and frequency

and observe that the waveform amplitude is not less

counter to the 500 kHz input test point (fig. 3-83) and

than 4.3 volts peak-to-peak and the frequency counter

verify that a 500-kHz sinewave signal of approximately

indicates 1.6 MHz.

1.5 volts peak-to-peak is present.

(8) Repeat step (4) except rotate switch S2

(3) Connect the vertical input of the

one complete revolution clockwise to a reading of 3.0.

oscilloscope and the frequency counter to the 1 MHz

(9) Adjust capacitor C84 {fig. 3-104) for

pulses test point (fig. 3-83) and verify that the amplitude

minimum 100-kHz modulation on the oscilloscope trace

of the waveform is 6.0 2.5 volts peak-to-peak, and that

and observe that the waveform amplitude is not less

the pulse fall time is 0.1 0.03 microsecond.

than 3.4 volts peak-to-peak and the frequency counter

NOTE

indicates 1.5 MHz.

The pulse fall time is the total

(10) Repeat step (4) except rotate switch S2

interval required for the wave to

one complete revolution clockwise to a reading of 4.0.

return to the base line from its peak

(11) Adjust capacitor C82 (fig. 3-104) for

value.

minimum 100-kHz modulation on the oscilloscope trace

(4) With the oscilloscope connected as in

and observe that the waveform amplitude is not less

step (3), adjust capacitor C15 (fig. 3-102) for minimum

than 2.8 volts peak-to-peak and the frequency counter

500 kHz signal in the 1 MHz pulses. Repeat step (3) if a

indicates 1.4 MHz.

major adjustment is made.

(12) Repeat step (4) except rotate switch S2

d. 1.8- to 0.9-MHz Ringer Circuit Alignment.

one complete revolution clockwise to a reading of 5.0.

NOTE

(13) Adjust capacitor C80 (fig. 3-103) for

Verify that the ringer circuit is

minimum 100-kHz modulation on the oscilloscope trace

operating properly and not merely

and observe that the waveform amplitude is not less

oscillating.

If oscillating, the

than 2.6 volts peak-to-peak and the frequency counter

frequency will change smoothly as

indicates 1.3 MHz.

the setting of the trimmer capacitor

(14) Repeat step (4) except rotate switch S2

is varied. If ringing, the wavetrain

one complete revolution clockwise to a reading of 6.0.

will

ragged

until

proper

(15) Adjust capacitor C78 (fig. 3-103) for

adjustment of the trimmer is

minimum 100-kHz modulation on the oscilloscope trace

obtained, and then the wavetrain will

and observe that the waveform amplitude is not less

stabilize.

than 2.8 volts peak-to-peak and the frequency counter

(1) Verify that switches S1 and S2 on the

indicates 1.2 MHz.

front panel of the test fixture are at O and OO

(16) Repeat step (4) except rotate switch S2

respectively.

one complete revolution clockwise to a reading of 7.0.

(2) Adjust the oscilloscope sweep rate to 10

(17) Adjust capacitor C76 (fig. 3-103) for

microseconds per centimeter and connect the vertical

minimum 100-kHz modulation on the oscilloscope trace

input and the frequency counter to the 1.8 - 0.9 MHz

and observe that the waveform amplitude is not less

input test point (fig. 3-83).

than 3.6 volts peak-to-peak and the frequency counter

(3) Adjust capacitor C90 (fig. 3-104) for

indicates 1.1 MHz.

minimum 100-kHz modulation on the oscilloscope trace

(18) Repeat step (4) except rotate switch S2

and observe that the waveform amplitude is not less

one complete revolution clockwise to a reading of 8.0.

than 2.3 volts peak-to-peak and that the frequency

(19) Adjust capacitor C74 (fig. 3-103) for

counter indicates 1.8 MHz.

minimum 100-kHz modulation on the oscilloscope

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