FM Stereo Vs FM Mono

Daktologist

In this thread I'll show you the technical differences between FM Mono and Stereo broadcasts

Below are spectrograms of both mono and stereo signals


Mono

Stereo

As you can see with the stereo signal there is a tone at 19 KHz which is the stereo pilot tone. What this does is tells the receiver to switch on the stereo light and also that there is stereophonic information at 38 kHz which is the second harmonic of 19 KHz, the receiver doubles the frequency so it can be used as a phase reference when decoding the stereo signal. The receiver cuts the audio frequency's off at 15 KHz so interference wont occur with the stereo pilot tone which would prevent it from working correctly. As you can see this doesn't happen with a mono signal as there is no pilot tone to worry about

Katzenklavier

Stereo FTW. FM radios don't exactly have very high fidelity anyway, and the 15khz cutoff isn't easily noticed.

Daktologist

I hardly listen to the radio these days except shortwave. FM is that badly censored its a waste of time listening to.

Katzenklavier

I usually listen to AM radio, mostly because I have so many old radios. The talk shows here can say anything, so long as it's not racist or profane.