Spectrum-compatible high-definition television

The spectrum-compatible high-definition television (SC-HDTV) System is designed for US terrestrial television broadcasting in the existing TV bands. It is a high-definition system in the accepted sense of doubled horizontal and doubled vertical resolution compared to NTSC, the current US terrestrial television broadcasting system. The aspect ratio is 16:9 and the pixels are square in accordance with the recently proposed Common Image Format (CIF). Compact Disk quality sound accompanies the high-definition video. SC-HDTV is a simulcast system requiring one 6 MHz channel for the high-definition version of the program in addition to the 6 MHz channel for the conventional NTSC version. Each version can be received independent of the other. The extra needed spectrum space is found in the existing TV bands in the so-called `Taboo´ channels. These channels cannot be used for NTSC-format programs for a variety of reasons but mainly because of excess interference. The SC-HDTV transmission signal is designed for significantly reduced mutual interference between NTSC and SC-HDTV