Signal Processing
Once a television signal is received, it must be processed. For digital satellite TV signals, a dedicated commercial satellite receiver such as a GI DSR4400X or a Scientific Atlanta/PowerVu satellite receiver is needed for each channel that is to be distributed by the cable system; these are usually rack-mountable receivers that are designed to take up less space than consumer receivers. They output video and stereo audio signals as well as a digital signal for digital plants.
Analog terrestrial TV signals require a processor which is a RF receiver that outputs video and audio. In some cases the processor will include a built-in modulator.
Digital terrestrial TV signals require a special digital processor.
Digital channels are usually received on an L band QAM stream from a satellite, which uses multiplexing. Using special receivers such as the Motorola MPS, the signal can be demultiplexed or "Demuxed" to extract specific channels from the multiplexed signal. At this point, local insertion may be performed to add content specifically targeted to the local geographic area.
Read more about this topic: Cable Television Headend
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