I'm having great trubs posting this message, so here's a second resend - don't know what happened to my first send s last week ! Kit
******* Bob, What you're looking for is "'FM Improvement factor". This is a ratio of the unmodulated C/N to the detector i/p to the SNR of the demodulated signal. The formula for (satellite) TV signals which used to be FM-modulated is: 20log (deltaFv/2Bv) + 10log(IF BW / video BW) +k (usually ~7) and for SCPC type services is simply 10log(df^2/fm^2) where f = rms channel deviation and m = highest modulating (baseband) frequency. So a C/N of 10dB transforms to a baseband SNR of ~16dB. Rgds, Kit VK2LL snip>> I had always wondered what the 12 dB SINAD level equated to in dB of signal above the noise floor. Thanks for posting this info. BTW, I'm curious about the theory behind the SINAD-C/N relationship. If you have any links to references on this subject please post. Thanks. Bob NO6B >>
