In an FM stereo receiver, why is there a frequency doubler stage in the stereo demodulation section?
A) It doubles the frequency of the L+R audio signals
B) It is part of the FM discriminator stage
C) It doubles the 19 kHz pilot carrier so that the AM detector will work properly
D) It is required in the de-emphasis network

Question

Quizplus · Accepted Answer

The frequency doubler stage in an FM stereo receiver is used to double the 19 kHz pilot carrier to 38 kHz, which is necessary for the stereo decoder to properly demodulate the stereo difference signal (L-R) that is amplitude modulated on a 38 kHz subcarrier. This process is essential for the AM detector in the stereo demodulation section to work correctly, allowing the receiver to reconstruct the left and right audio channels.

In an FM Stereo Receiver, Why Is There a Frequency