Oscillator Control C-4311JPRC-47 (A8A8)

TM 11-5820-509-35

Transistors Q5 and Q6 are arranged in a Schmitt trigger

association with Inductor L3. These capacitors form a

circu it that uses inductor L2 for a common emitter load.

voltage divider network that not only provides a

The inductor maintains a constant dc emitter current

convenient means for obtaining a positive feedback

(common mode current) that flows in each transistor as

voltage for the emitter circuit, but also permits selection

they are alternately switched at a l-MHz rate. The

of the proper output voltage for subsequent stages. The

resulting pulse train is amplified by Q7 before being

output of 500. kHz amplifier Q5 is divided with part of

routed to signal data translator A3.

the signal being routed to the l-MHz pulse generator

circuit of oscillator control A7 and the remainder passing

b. The 100-kHz signal from amplifier A6Q9 is

through 500-kHz amplifier Q6 before being applied to

applied to the 100-kHz pulse generator circuits

the balanced modulator and product detector circuits of

consisting of pulse generator Ql-Q2 and pulse amplifier

amplifier-modulator A2.

Both Q5 and Q6 are

Q3. Transistors Q1 and Q2 form a Schmitt trigger

conventional amplifier circuits that have tip jacks

circuit that provides a squarewave output at the 100-kHz

provided in each output path to facilitate measurement

switching rate. The coupling network that interconnects

of output levels and waveforms.

Q2 with the base of pulse amplifier Q3 differentiates this

c. The 500-kHz signal from locked oscillator Q4 is

squarewave signal and produces troth positive-going

and negative-going pulses at the base of Q3. Limiter

also routed to the 100-kHz circuits. Follower Q7

CR1 conducts during the negative-going transitions and

provides isolation before applying this signal to Q8. A

shorts these pulses to ground, but during the positive-

frequency division of five occurs in locked oscillator Q8

going transitions, the pulses ring the parallel-resonant

with the natural period of this stage being determined by

tank circuit contained on the 1.8- to 0.9-MHz tuned-

the network consisting of capacitors C28 through C31 in

circuit board. Switch S3 in the 1.8- to 0.9-MHz tuned-

association with inductor L7. The capacity voltage-

circuit assembly is controlled by the 100-kHz shaft

divider in the output of this stage also provides taps for

associated with the middle frequency-control knob on

conveniently obtaining positive feedback voltage for the

the front of the receiver-transmitter. The selection

emitter circuit, and provides proper output voltage for

made by this knob resonates the parallel circuit to

following stages. The 100-kHz signal from Q8 remains

enhance the pulse amplitude applied to the amplifier-

in synchronism with the input signal and hence the

limiter circuits. Transistors Q7 through Q19 clip and

3.000-MHz crystal oscillator output. 100-kHz amplifier

amplify the sinousoidal output of pulse amplifier Q3 to

Q9 is a conventional circuit that routes the output of Q8

assure that a constant level is maintained across the

to the 100-kHz pulse generator circuit of oscillator

entire frequency range from 1.8to 0.9-kHz. Spurious

control A7 and effectively isolates these circuits.

frequencies introduced by limiting are attenuated by the

bandpass filter consisting of capacitors C66 through C70

2-14. Oscillator Control C-4311JPRC-47 (A8A8)

and inductors L16 through L18 that are connected

(fig. 2-15 and 7-14)

across the output of transistor Q19.

c. Crystal oscillators Q20 and Q21 are

a. Oscillator control A7 contains pulse generator

conventional common-emitter circuits that have a

circuits, tuned amplifier/limiter circuits, crystal

bandswitching turret in each base.

The crystals

oscillator/mixer

circuits,

and

two-channel

associated with switch S1 are selected by the position of

discriminator. The 500-kHz standard signal from A6Q5

the shaft associated with the 1-kHz frequency-control

is applied to the 1-MHz pulse generator circuit consisting

knob on the front panel of the receiver-transmitter. The

of transistors Q4 through Q6 and their associated

crystals associated with switch S2 are selected by the

components.

Following amplification by Q7, the

position of the 10-kHz shaft associated with the middle

resulting 1-MHz pulse train is applied to the 5- to 14-

frequency.

control knob on the front of the RT-

MHz amplifier circuits of signal data translator A3. The

671/PRC-47. The output signals from oscillators Q20

1-M Hz pulse generator circuit consists of frequency

and Q21 are combine in mixer Q22 to provide one-

doubler Q4, pulse generator Q5-Q6, and amplifier Q7.

hundred 1-kHz channels between 601- and 700-kHz.

Doubler Q4 is operated in the nonlinear portion of its

The circuit duality of these oscillators and a similarity of

characteristic to produce an output rich in harmonics of

temperature coefficient for 811 crystals associated with

the 500-kHz input signal. The tuned circuits consisting

these oscillators provides an

of capacitors C14 and C15 in association with inductor

L1 is resonant at the second harmonic of the input signal

and provides an output of 1-M Hz.

2-29