Details for Digital Spectrum Compatible - Zenith and AT&T

Zenith and AT&T have developed an all-digital high-definition television (HDTV) simulcast system that combines powerful video compression technology and a unique simulcast transmission system. The system, called "Digital Spectrum Compatible" (DSC), provides full high-definition resolution -- perceived to be equal to the studio original -- even after compressing the wide bandwidth signal into a 6- MHz channel. The system digitally transmits the compressed signal on currently unusable or ''Taboo'' television channels with only minimal interference to or from NTSC channels.

The DSC-HDTV system's high-performance compression and RF transmission technologies provide transparent picture quality utilizing a maximum video data rate (up to 17 megabits per second, Mb/s) and provide noise-free and ghostfree terrestrial broadcast reception throughout a broad service area. This area will be comparable to or, in many cases, greater than the current NTSC service area, even though transmitter power can be reduced by more than 90% from the power required for NTSC transmissions.

In addition to its unique performance capabilities for terrestrial broadcasting, the DSC-HDTV system is compatible with other media, including cable, satellite, studio video tape recorders, home video cassette recorders, video disc and fiber. Because the complete high-definition television signal (including video, chroma, audio, ancillary signals, decoder address, and encryption information) is encoded into one 6-MHz bandwidth signal, the system can be simply adapted to other media using current electrical and mechanical technologies. (See Section 8.)

The system's 787.5-line progressive scanning format eliminates artifacts of interlaced systems, provides full motion rendition (critical for sports and other fast-action programming) and promotes HDTV compatibility with current and future computer and digital communications technologies. Progressive scanning plus square pixels and unique compression technology make the DSC-HDTV system ideally suited for interconnectivity, extensibility, scalability and other computerrelated considerations. (See Section 9.)