Radio Receivers
In a broadcast superheterodyne receiver, the

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

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Radio Receivers
In a ratio detector

the output is twice that obtainable from a similar phase discriminator
the linearity is worse than in phase discriminator
the circuit is the same as in a discriminator, except that the diodes are reversed
stabilization against signal strength variations is provided

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

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

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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.
A product demodulator could be used for the reception of Morse code.
Variable sensitivity is used to eliminate selective fading

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