BasicB-003-003-008
In an FM receiver, what is the purpose of the discriminator?
A
Answer
Basic radio theory
Type
A
Recover the original modulation from the carrier
B
Provide most of the receiver's selectivity
C
Select narrowband or wideband FM reception
D
Remove amplitude modulation from the received signal
Answer Notes
An FM discriminator is the detector stage of an FM receiver. Just as a product detector is used for SSB and a diode detector for AM, a discriminator is designed specifically to decode Frequency Modulation.
As the frequency of the incoming IF signal shifts slightly up and down due to modulation, the discriminator translates these frequency shifts into changing voltage levels. These voltage changes precisely recreate the original audio waveform that was transmitted.
While the limiter is responsible for removing unwanted amplitude variations before this stage, the discriminator's sole job is to demodulate the signal and recover the original audio information from the carrier.
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