8
1-65. What is the purpose of the squelch circuit
in a receiver?
1. To attenuate very strong signals in
order to prevent their overdriving the
remaining stages in the receiver
2. To suppress receiver noise output
when no input signal is being
received
3. To suppress the electronic "whine" of
the rf amplification stage
4. To reject signals of other than the
desired frequency should the receiver
drift off frequency
1-66. How does a receiver accomplish the
squelch function?
1. By proportional blocking of the rf
amplifier stage output
2. By blocking the detector or audio
amplifier when there is no signal
3. By switching an inductive/capacitive
filter into the output of the last rf
amplifier
4. By switching in a matched-frequency
stage which passes matching
frequencies and rejects all others
1-67. A quartz crystal filter is used in a
communications receiver to improve
which of the following characteristics?
1. Fidelity
2. Sensitivity
3. Selectivity
4. Reproduction
Figure 1B.
IN ANSWERING QUESTION 1-68, REFER
TO FIGURE 1B.
1-68. When the wiper of R1 is placed in the
full treble position, which of the
following actions occur?
1. Bass response is improved
2. High frequency shunting is reduced
3. Higher frequencies are shunted to
ground
4. The capacitor and resistor are placed
in parallel
1-69. Automatic frequency control circuits are
used in a receiver for which of the
following purposes?
1. To adjust IF amplifier gain
2. To correct for oscillator frequency
drift
3. To extend the frequency range of the
receiver
4. To automatically tune the receiver to
the desired frequency
