Digital cable is a term for a type of cable digital television that delivers more channels than possible with analog cable by using digital video compression. Digital cable also enables two-way communication, enabling services such as the ability to purchase pay-per-view programming without the use of a phone line. Recently, some companies have also added video on demand services. Digital cable signals are often worse than analog signals, due to compression artifacts in both the image and sound. Coaxial cable is often used to transmit cable television into the house Cable television or Community Antenna Television (CATV) (often shortened to cable) is a system of providing television, FM radio programming and other services to consumers via radio frequency signals transmitted directly to people’s televisions through fixed optical... Digital television (DTV) uses digital modulation and compression to broadcast video, audio and data signals to television sets. ... Video compression deals with the compression of digital video data. ... Pay-per-view is the name given to a system by which television viewers can call and order events to be seen on TV and pay for the private telecast of that event to their homes later. ... Video on demand systems are systems which allow users to select and watch video content over a network as part of an interactive television system. ...

The standard for HDTV signal transmission over digital cable television systems in the United States is now fixed as both 64-QAM and 256-QAM (Quadrature Amplitude Modulation), which is specified in SCTE 07, and is part of the DVB standard (but not ATSC). This method carries 38.4 Mbit/s using 256-QAM on a 6 MHz channel, which can carry nearly two full ATSC 19.39 Mbit/s transport streams. Each 6-MHz channel is typically used to carry 7–12 digital SDTV channels (256-QAM, MPEG2 MP/ML streams of 3–5 Mbit/s). High-definition television (HDTV) means broadcast of television signals with a higher resolution than traditional formats (NTSC, SECAM, PAL) allow. ... Quadrature amplitude modulation (QAM) is a modulation scheme which conveys data by changing (modulating) the amplitude of two carrier waves. ... The Society of Cable Telecommunications Engineers (SCTE) is an organization that develops training for cable television installers and engineers; in this role it is analogous to the Society of Broadcast Engineers for broadcast television. ... DVB, short for Digital Video Broadcasting, is a suite of internationally accepted, open standards for digital television maintained by the DVB Project, an industry consortium with more than 300 members, and published by a Joint Technical Committee (JTC) of European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC... The Advanced Television Systems Committee (ATSC) is the group that helped to develop the new digital television standard for the United States, also adopted by Canada, Mexico, and South Korea and being considered by other countries. ... A megahertz (MHz) is one million (106) hertz, a measure of frequency. ...

The ATSC standards include a provision for 16-VSB transmission over cable at 38.4 Mbit/s, but the encoding has not yet gained wide acceptance. Some MATV systems may carry 8-VSB and QAM signals, mostly in apartment buildings and similar facilities that use a combination of terrestrial antennas and cable distribution (e.g., HITS) sources. The Advanced Television Systems Committee (ATSC) is the group that helped to develop the new digital television standard for the United States, also adopted by Canada, Mexico, and South Korea and being considered by other countries. ... 16VSB is an abbreviation for 16-level vestigial sideband modulation, capable of transmitting four bits (24=16) at a time. ...

Digital cable channels typically are allocated above 552 MHz, the upper frequency of cable channel 78. (N.B.: over-the-air channels are at higher frequencies than cable channels.) Between 552 and 750 MHz, there is space for 33 6-MHz channels (231–396 SDTV channels); when going all the way to 864 MHz, there is space for 52 6-MHz channels (364–624 SDTV channels).

In the U.S., digital cable systems with more than 750 MHz activated channel capacity are required to comply with a set of SCTE and CEA standards, and to provide CableCARDs to customers that request them. CableCARD is the trademarked term for the Point of Deployment module (POD) defined by standards including SCTE 28, SCTE 41, CEA-679 and others. ...

External links

• National Cable and Telecommunications Association - Digital Cable
• Digital cable & Digital house