Standards
Analog television distributed via satellite is usually sent scrambled or unscrambled in NTSC, PAL, or SECAM television broadcast standards. The analog signal is frequency modulated and is converted from an FM signal to what is referred to as baseband. This baseband comprises the video signal and the audio subcarrier(s). The audio subcarrier is further demodulated to provide a raw audio signal.
If the signal is a digitized television signal or multiplex of signals, it is typically QPSK.
In general, digital television, including that transmitted via satellites, are generally based on open standards such as MPEG and DVB-S or ISDB-S.
The conditional access encryption/scrambling methods include NDS, BISS, Conax, Digicipher, Irdeto, Cryptoworks, DG Crypt, Beta digital, SECA Mediaguard, Logiways, Nagravision, PowerVu, Viaccess, Videocipher, and VideoGuard. Many conditional access systems have been compromised.
Read more about this topic: Satellite Television
Famous quotes containing the word standards:
“That’s the great danger of sectarian opinions, they always accept the formulas of past events as useful for the measurement of future events and they never are, if you have high standards of accuracy.”
—John Dos Passos (1896–1970)
“To arrive at a just estimate of a renowned man’s character one must judge it by the standards of his time, not ours.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)
“Chief among our gains must be reckoned this possibility of choice, the recognition of many possible ways of life, where other civilizations have recognized only one. Where other civilizations give a satisfactory outlet to only one temperamental type, be he mystic or soldier, business man or artist, a civilization in which there are many standards offers a possibility of satisfactory adjustment to individuals of many different temperamental types, of diverse gifts and varying interests.”
—Margaret Mead (1901–1978)