THE DIGITAL SPECTRUM-COMPATIBLE HDTV TRANSMISSION-SYSTEM

The Digital Spectrum-Compatible HDTV (DSC-HDTV) System allows noise-free and imperfection-free display of a received signal throughout a television broadcast station's service area. Compared to an NTSC station with the same service area, the DSC-HDTV station radiates less power for two reasons. The DSC-HDTV transmission signal is more efficient and, secondly, a digital receiver operates with a lower carrier-to-noise ratio. As a result, the DSC-HDTV transmitter can operate closer to a cochannel NTSC station than another NTSC station without increasing the interference into receivers tuned to the cochannel NTSC station and yet achieve a HDTV service area comparable to NTSC. The decreased cochannel spacing does not cause unacceptable NTSC interference into DSC-HDTV receivers for three reasons. First, there is a newly devised interference rejection system; secondly, the receiver operates with a lower acceptable carrier-to-interference ratio compared to an NTSC receiver; and, thirdly, a directional antenna is assumed for the new service.