c. frequency sample needed for comparison in the AFC circuit.
d. degenerative feedback needed to prevent oscillations in V10.
13. The block diagram in figure 82 of TM 11-668 shows the basic appearance of all
AFC circuits. One type of circuit that can be used in the block labeled OSCILLATOR
CORRECTOR is the
a. comparator.
c.
balanced modulator.
b. multiplier.
d.
reactance-tube modulator.
14. Motor-control AFC systems used in FM transmitters require the use of
frequency dividers.
A typical frequency-divider circuit that uses a two-stage
resistance-capacitance-coupled amplifier with the output of the second stage fed
back to the input of the first stage is called a
a. synchronized multivibrator.
c.
regenerative modulator.
b. synchronized oscillator.
d.
trigger circuit.
15. The circuit diagram of an indirect FM transmitter is shown in figure 99 of TM
11-668. The electron tube that is used as a grounded-grid amplifier stage is
a. V3.
c.
V7.
b. V4.
d.
V9.
16. Basically, there are three frequencies present in the circuit shown in figure
4-1--the input, the output, and the resonant frequencies. What is the relationship
between these frequencies?
a. The input frequency is greater than the output frequency but is less than
the resonant frequency.
b. The input frequency is less than the output frequency but is greater than
the resonant frequency.
c. The input frequency
is
greater
than
both
the
resonant
and
output
frequencies.
d. The input frequency is less than both the resonant and output frequencies.
17. One of the purposes for using the resistors in the collector circuits of Q2
and Q3 in the divider circuit shown in figure 4-2 is to
a. multiply the incoming frequency by 3.
b. heterodyne the input and feedback signals.
c. suppress negative resistance oscillations in the transistors.
d. limit the input frequencies to one third of their original values.
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