Radio Receivers
In a broadcast superheterodyne receiver, the

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

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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 ratio detector

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

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