Short technical lexicon, DiSEqC components

Short technical lexicon

AC3

Audio Coding MPEG 2/Layer 3 – the coded digital sound signal for Dolby Digital. It transmits 5 sound channels and one reduced sound channel for the subwoofer.

DiSEqC

DiSEqC (Digital Satellite Equipment Control) is a communication system between the Sat receiver (master) and the peripheral Sat components (slaves), such as LNBs, multi-switch, motorised antenna systems.

This is a single master/multi-slave system, i.e. there is always only one master in the Sat system. All activities emanate from the master.

DiSEqC components

When DiSEqC switchover matrices are cascaded, the master receiver must send out the DiSEqC signal several times so that all DiSEqC multi-switches in the cas- cade receive their commands.

Nowadays, DiSEqC components (slaves) must be retrocompatible, i.e. they must also respond to the analogue switching criteria of receivers which are only equipped with the control signals H/V and 22 kHz.

A DiSEqC switchover matrix operates with analogue switching criteria until the DiSEqC command is received from the master. All analogue switching criteria are then ignored.

DVB MPEG-2

DVB is the abbreviation for digital video broadcasting. DVB-S refers to the type of transmission (S=satellite). MPEG is the abbreviation for Moving Picture Experts Group, a working group which draws up internationally valid standards for the digi- tal compression of video together with audio. MPEG-2 has been promoted to the standard for the compression of digital TV signals. MPEG-2 operates at a data rate of up to 100 MBit/s.

Eb/No ratio

The Eb/No ratio is a measure for the signal-to-noise ratio of the digital signal. This value is not identical to the C/N value as known from analogue reception technol- ogy. As a rule, reception is no longer possible at Eb/No levels below 5 dB.

FEC

FEC is the abbreviation for Forward Error Correction. The FEC error rate corre- sponds to the viterbirate.

PID

The PID number (Package Identification) is an identification number for video sig- nals and audio signals in the digital data stream of DVB MPEG-2 signals. The re- ceiver uses the PID number to establish distinct allocation of the video and audio data transmission. PID-PCR is the identification number for the synchronisation signal. PID-PCR is normally identical to PID video. In the case of multi-language channel transmissions, by means of manual entry of the audio PID, it is possible to allocate another language to the TV broadcast. After entering the PID, the digital receiver automatically selects audio data from the data stream identified by the PID number and allocates these data to the video signal.

Programme package

The programme package of a digital transponder mostly contains several TV and radio channels. Each channel package has a fixed allocation with regard to the