High Definition Television (HDTV) - Compatibility and Distribution

High definition television (HDTV) pictures are, by all accounts, dramatically superior to today's NTSC color television, both in resolution and in realism. Picture quality approaching that of 35 mm color film is obtainable by most systems under investigation in recent years. One of the basic premises of a recent SMPTE study was that "the HDTV signal should be capable of a standards conversion ... to the NTSC ... domestic service." Otherwise, there would be "so many political, social, and economic Impediments that [HDTV] might never succeed ...." However, the same study wound up by concluding that such compatibility was "not feasible by any means known ... or envisaged." Here we suggest a possible solution to the compatibility dilemma. We propose an HDTV signal with a camera line-scan rate exactly twice that of NTSC. From this we construct an intermediate waveform called the semicompatible-high-definition television signal (SCHDTV), which has the virtue of being easily convertible to an NTSC picture. The SC-HDTV signal requires three present-day CATV channels for local distribution and is suitable for transmission via direct broadcast satellite (DBS). Moreover, HDTV could also be sent on most present-day satellite facilities if the SC-HDTV signal were split into two parts and two transponders were used.