ABSTRACT
Satellite and cable broadcast services have had a long history of providing pay-TV services. Pay TV is provided through encryption of signal at the “headend” (cable or satellite) and use of a decoder with decryption at the receiving end. A number of encryption systems are in use in broadcast systems worldwide. These include, among others, Viaccess, Nagra, Conax, Videoguard, Cryptoworks, Irdeto, and NDS. The encryption systems are proprietary but are applied as per the DVB standards that are widely used in the broadcast TV industry. The following are the common standards for transmission:
● DVB-S-DVB standard for satellite broadcast using QPSK or 8PSK modulation,
● DVB-C-DVB standard for digital cable using 16QAM or 64QAM modulation, and
● DVB-T-DVB standard for terrestrial broadcast using COFDM modulation.
