Scrambler

Energy dispersal is a term used in telecommunications.

In the energy dispersal (English energy dispersal scrambling ), the transmission power is distributed to the available bandwidth of the transmission frequency, thus reducing adjacent channel interference, particularly in telecommunications satellites. The energy dispersal is particularly necessary when there is little information to be transmitted.

If the analog information black screen or digitally transmitted all zeros, the total transmit energy focusing on the modulation signal. In a digital signal can be lost in addition to sync.

Analog television programs are therefore frequency-modulated with a triangular signal. A modulation frequency of 25 Hz can be the signal within the bandwidth to 1 MHz oscillating. Digital signals are encoded by a scrambler that it resembles a noise signal with the highest possible uniform distribution of the level values ​​and maintains a high level of entropy.

Source

• Alexander Brown, Markus Hofbauer: Semester work on digital satellite TV. Zurich 1997 ( term paper on ICT ETH Zurich, HTML).

• Satellite technology
• Satellite broadcasting