c. a frequency doubler stage in the IF system.
d. an additional frequency converter stage.
9. The primary function of a limiter in an FM receiver is to
a. increase the selectivity of the receiver.
b. remove amplitude variations from the IF signal.
c. provide an AVC voltage for the preceding stages.
d. restrict the frequency deviation to keep signal within bandpass limits.
10. The requirements of a limiter stage used in an FM receiver include
a. large input signal, low plate and screen voltage, and sharp cutoff tube.
b. large input signal, sharp cutoff tube, and high plate and screen voltages.
c. sharp cutoff tube, low plate and screen voltage, and high gain.
d. low plate and screen voltage, low gain, and remote cutoff tube.
11. The operating characteristic of a typical discriminator is shown in figure 3-
5. If this discriminator is to produce an output that is free of distortion, the
signal bandwidth should not exceed
a. 40 kHz.
c.
120 kHz.
b. 80 kHz.
d.
200 kHz.
12. Assume that an oscilloscope is being used to determine the nature of the
voltage at point X with respect to ground in the circuit shown in figure 3-6.
Analysis shows that during normal operation the voltage is
a. zero
c.
negative dc.
b. positive dc.
d.
audio-frequency ac.
13. The ratio detector shown in figure 3-6 has a network that serves to eliminate
AM noise impulses from the signal. The components that make up this network are
a. capacitor C3 and capacitor C4.
b. capacitor C5 and resistor R2.
c. tube V1 and tube V2.
d. tube V1 and coil L3.
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