FM modulation concepts

[antoine magdi]

In FM modulation:

1) What's the effect of carrier frequency on the SNR at the output

2) Is there a general formula to find the SNR regardless the genre of the receiver?!!

Thnx in advance

 

[RCinFLA]

In FM modulation:

1) What's the effect of carrier frequency on the SNR at the output

2) Is there a general formula to find the SNR regardless the genre of the receiver?!!

Thnx in advance

1) none
2) never heard receiver having a sex. SNR ratio is based on modulation index, received power, and noise figure of receiver. FM has a threshold where noise causes sudden phase flips, known as clicks. This is usually around 10 db C/N ratio at demodulator. Above threshold, the greater the modulation index the better the S/N ratio on output of demodulator.

Roughly, above threshold, S/N output = 3*(Modulation index)^2 * C/N

A good book on topic is "Information Transmission, Modulation, and Noise" by Mischa Schwartz.