Audio Signal to Noise

The subcarrier audio S/N ratio is a measure of audio signal power relative to noise power at the output of a satellite receiver. It depends upon factors such as the peak deviation of the subcarrier expressed in kHz, the maximum baseband audio frequency in kHz, the center frequency of the subcarrier in MHz, the de-emphasis improvement factor of the audio broadcast in dB as well as the peak deviation of the main carrier by the subcarrier in MHz, the intermediate frequency (IF) pre-detection or receiver bandwidth in MHz and the downlink C/N ratio. In this calculation, like that of the video S/N ratio, the receiver is assumed to be operating above the non-linear threshold region and that sufficient bandwidth is available to adequately accommodate the audio signal prior to its demodulation by the satellite receiver.