UHF TELEVISION: requirements for long-term and short-period carrier drive frequency stability

摘要

The frequency stability required for the carrier drives of a group of co-channel television transmitters is examined theoretically. An upper limit is suggested for the permissible levels of long-term frequency drift and of frequency modulation uncorrelated with the video waveform. This takes into account both protection against co-channel interference and impairment of the received picture in the absence of interference. Also considered are the requirements of the inter-carrier sound signals where the sound and vision carrier drives are separate.