Television Sound Subcarrier Transmission in Space Communication

In a nonideal transmission enviromnent, the transmission of video sound in the form of an FM subcarrier above the video baseband causes interactions between video and sound subcarrier which result in signal distortion. The degree of distortion depends on the type of channel impairments and the selection of transmission parameters. While the fidelity of the video signal can be preserved by mainly limiting the subcarrier level, the quality of the audio channel can be optimized by choosing the right subcarrier frequency. It can be shown that for a given video-carrier-to-noise ratio, subcarrier power below video signal power, and for given system impairments, there exists an optimum subcarrier location which provides a maxinum audio-signal-to-noise ratio.