Energy dispersal

from Wikipedia, the free encyclopedia

Energy dispersal is a term used in communications technology.

With energy dispersal scrambling , the transmission power is distributed over the available bandwidth of the transmission frequency, thereby reducing reception interference from neighboring transmitters, particularly in the case of telecommunication satellites. The energy dispersal is particularly necessary when only little information is transmitted.

If the analog information black picture or digital all zeros are to be transmitted, the entire transmission energy is concentrated on the modulation signal. In the case of a digital signal, synchronization can also be lost.

Analog television programs are therefore frequency-modulated with a triangular signal . A modulation frequency of 25 Hz causes the signal to oscillate around 1 MHz within the bandwidth. Digital signals are encoded by a scrambler in such a way that it resembles a noise signal with the highest possible uniform distribution of the level values ​​and has a high entropy.

source

  • Alexander Braun, Markus Hofbauer: Term paper on digital satellite television . Zurich 1997 ( HTML - semester paper at the IKT of the ETH Zurich).