Radio Receivers
The typical squelch circuit cuts off

an audio amplifier when the carrier is absent
RF interference when the signal is weak
An IF amplifier when the AGC is minimum
An IF amplifier when the AGC is maximum

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Radio Receivers
In a broadcast superheterodyne receiver, the

RF amplifier normally works at 455 kHz above the carrier frequency
Mixer input must be tuned to the signal frequency
Local oscillator frequency is normally double the IF
Local oscillator operates below the signal frequency

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Radio Receivers
If a FET is used as the first AF amplifier in a transistor receiver, this will have the effect of

Improving the selectivity of the receiver
Reducing the effect of noise at low modulation depths
Reducing the effect of negative-peak clipping
Improving the effectiveness of the AGC

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Radio Receivers
Show which of the following statements about the amplitude limiter is untrue:

When the input increases past the threshold of the limiting, the gain decreases to keep the output constant.
The circuit is always biased in class C, by virtue of the leak-type bias.
The output must be tuned
Leak-type bias must be used

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