Digital cable signals can carry more data than analog signals within the same bandwidth, allowing for more channels, on-demand content, and internet connectivity. The first digital cable systems were implemented in the 1980s, and most carriers offered digital service by 2000. A 6 MHz digital cable signal can carry two Full HD channels or 10 SD channels.
Digital cable signals are used to transmit data over terrestrial cable systems. The primary advantage of a digital cable signal over an analog signal is the ability to transmit more data within the same bandwidth. Traditional cable systems use channels that each occupy 6 MHz, but a digital cable signal that occupies the same bandwidth can carry two channels of high definition (HD) or 10 channels of standard definition (SD). Digital cable signals can also carry music stations, carry on-demand content, and provide Internet connectivity. The first digital cable systems were implemented in the 1980s, and most carriers were offering some type of digital service by 2000.
Early cable systems were designed to carry over the air (OTA) broadcasts to remote and inaccessible communities. To this end, they essentially rebroadcast the analog signals OTA over physical wires. Since each OTA channel took up 4.8 MHz of bandwidth and cable systems required a small amount of extra bandwidth for modulation, each channel was allocated 6 MHz of bandwidth. Over the years, 6 MHz has remained the standard bandwidth allocation for cable television channels. Because terrestrial cable systems have a limited amount of bandwidth, they can only carry a finite number of 6 MHz signals.
In the late 1980s, the first digital cable system was designed and tested. Due to data compression, it has been shown that a 6 MHz digital cable signal could carry more data than a traditional analog signal. Adoption of this new technology took several years, although increased demand for more channels, on-demand content, and other types of data helped spur the deployment of digital cable systems. This is because modern digital cable systems can carry more channels than older analog systems. Digital broadcasting also makes it possible to carry additional music channels, on-demand content and Internet data over the existing cable infrastructure.
Digital cable is not synonymous with high definition television, although a digital cable signal can carry HD programming. Approximately 38 Mbit/s of data can be transmitted on each 6 MHz channel block, which can be split in a variety of different ways. A 6 MHz block can carry two Full HD channels, and digital cable signals are capable of transmitting in 720p or 1080i. Standard definition programming can also be carried over a digital cable signal, and each 6 MHz block has room for about 10 SD channels, including video programming that complies with the 480p standard for enhanced definition television (EDTV).
Protect your devices with Threat Protection by NordVPN
