10. In producing indirect frequency modulation, the equivalent frequency
deviation of the modulated wave is proportional to the modulating frequency. This
undesirable effect is eliminated by using a
a. circuit with an output that is inversely proportional to the frequency.
b. phase-shift modulator with a constant impedance network.
c. circuit that functions as a variable resistance.
d. quartz-crystal oscillator with a stable frequency.
11. Which phase modulator would be used in an FM transmitter to provide the
greatest initial phase deviation?
a. Link-phase modulator
b. Sonar-phase modulator
c. Reactance-tube phase modulator
d. Nonlinear-coil modulator
12. Assume that the carrier shown in A of figure 56 (TM 11-668) is being
modulated by the audio wave shown in B. To obtain a phase-modulated waveform like
that shown in F, the output from a nonlinear-coil modulator must be applied to a
d. rectifier, limiter, and tuned circuit.
13. Assume that a carrier with a peak amplitude of 10 volts is being phase-
modulated by a signal with a peak amplitude of 6 volts.
Figure 58 of TM 11-668
indicates the presence of an amplitude component that must be removed by limiting.
The peak amplitude of this component is
a. less than 2 volts.
b. between 2 volts and 6 volts.
c. between 6 volts and 10 volts.
d. greater than 10 volts.
14. Frequency modulation of the circuit shown in figure 2-2 is accomplished by
reactance modulation. The reactive component that is varied to produce the FM is