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QUIZ - FM SECTION
INSTRUCTIONS: Complete the following examination, check your answers carefully.
1. The FM broadcast band is . . .
A) 550 - 1,600kHz.
B) 10.7MHz.
C) 88 - 108MHz.
D) 98.7 - 118.7MHz.
2. The maximum audio frequency used for FM is ...
A) 7.5kHz.
B) 15kHz.
C) 20kHz.
D) 10.7MHz.
3. The frequency of the modulating signal
determines the . . .
A) number of times the frequency of the
carrier changes per second.
B) maximum deviation of the FM carrier.
C) maximum frequency swing of the FM
carrier.
D) amount of amplitude change of the FM
carrier.
4. The AFC circuit is used to ...
A) automatically hold the local oscillator on
frequency.
B) maintain constant gain in the receiver to
prevent such things as fading.
C) prevent amplitude variations of the FM
carrier.
D) automatically
frequencies in the receiver.
5. The ratio detector transformer is tuned to ...
A) 10.7MHz.
B) 88MHz.
C) 455kHz.
D) 10.9MHz.
control
the
audio
B
10.
D,
9.
A,
8.
C,
7.
B,
6.
6. The ratio detector is used because ...
A) it is sensitive to noise.
B) it is insensitive to noise.
C) it provides amplification.
D) it doesn't need a filter.
7. The device most often used for changing the
local oscillator frequency with the AFC voltage is
a ...
A) feedthrough capacitor.
B) variable inductor.
C) varactor.
D) trimmer capacitor.
8. The capacitance of a varactor is determined by ...
A) the voltage level.
B) the amount of current in the circuit.
C) the signal strength of the RF carrier.
D) the amount of resistance in the circuit.
9. Limiting in FM receivers is the process of ...
A) removing interfering FM stations.
B) providing greater station selectivity.
C) separating the FM stations from the AM
stations.
D) removing noise from the FM carrier.
10. A detector circuit that does not require a limiter is
a ...
A) slope detector.
B) ratio detector.
C) Travis detector.
D) Foster-Seeley detector.
A,
5.
A,
4.
A,
3.
B,
2.
C,
1.
-52-
Answers:
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