Radio Receivers
In a broadcast superheterodyne receiver, the

Local oscillator operates below the signal frequency
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

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

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

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

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

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

The output must be tuned
Leak-type bias must be used
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.

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