Radio Receivers
The frequency generated by each decade in a direct frequency synthesizer is much higher than the frequency shown; this is done to

Reduce the number of crystals required
Reduce the spurious frequency problem
Reduce the number of decades
Increase the frequency stability of the synthesizer

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

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

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Radio Receivers
Indicate the false statement. Noting that no carrier is transmitter with J3E, we see that

Adjacent-channel rejection is more difficult
The transmission is not compatible with A3E
The receiver cannot use a phase comparator for AFC
Production of AGC is a rather complicated process

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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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