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.
Leak-type bias must be used
The circuit is always biased in class C, by virtue of the leak-type bias.
The output must be tuned

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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

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

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Radio Receivers
The local oscillator of a broadcast receiver is tuned to a frequency higher than the incoming frequency

To help the image frequency rejection
Because otherwise an intermediate frequency could not be produced
To allow adequate frequency coverage without switching
To permit easier tracking

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Radio Receivers
In a broadcast superheterodyne receiver, the

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

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Radio Receivers
Indicate the false statement in connection with communications receivers.

Double conversion is used to improve image rejection
The noise limiter cuts off the receiver’s output during a noise pulse.
Variable sensitivity is used to eliminate selective fading
A product demodulator could be used for the reception of Morse code.

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