Kathrein UFD 510 DiSEqC components, Eb/No ratio, Programme package, Symbol rate, Transponder

Glossary, abbreviations

DiSEqC

DiSEqC (Digital Satellite Equipment Control) is a EUTELSAT-specified communications system between sat. receiver (master) and the peripheral sat. components (slaves) such as, for example, LNBs, multiswitches, rotatable antenna systems. DiSEqC is a single master / multi slave system, i.e. there is always only one master in the sat. system. All activities are always initiated by the master.

DiSEqC components

If DiSEqC switching matrices are connected in cascade, the master receiver must send out the DiSEqC signal repeatedly, in order that all DiSEqC multiswitches in the cascade receive their commands.

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

A DiSEqC switching matrix keeps working with analogue switching criteria until the DiSEqC command arrives from the master. After this all analogue switching criteria are ignored.

DVB MPEG-2

DVB is the abbreviation for Digital Video Broadcasting. DVB-S indicates the type of transmission. (S=Satellite). MPEG is an abbreviation for Moving Picture Experts Group, a working group that sets out internationally applicable standards for digital compression of video, along with audio. MPEG-2 has been elevated to the standard for compression of digital TV signals. MPEG-2 works up to a data rate of 100 Mbit/s.

Eb/No ratio

The Eb/No ratio is a measure for the signal-to- noise ratio of digital signals. This value is not identical to the S/N value known from analogue receiving technology. With Eb/No values below 5dB reception is generally no longer possible.

FEC

FEC is an abbreviation for Forward Error

Correction. The FEC error rate corresponds to the Viterbi rate.

PID

The PID number (Packed IDentification) is an identification number for video signals and audio signals in the digital data stream of DVB MPEG-2- signals. With the PID number, the receiver establishes a unique assignment of the video- and audio data transmission. The PID-PCR is the identification number for the synchronisation

signal. The PID-PCR is generally identical to the PID video. With programmes broadcast in several languages, the audio PID of another language of the TV broadcast can be assigned through manual entry. After entry of the PID, the digital receiver automatically fetches from the data stream the audio data identified through the PID number and assigns this to the video signal.

Programme package

A digital transponder‘s programme package mostly contains several TV and radio programmes. Every programme package has a fixed relationship to the transponder transmission frequency, polarisation (horizontal or vertical), to the symbol rate and to the Viterbi rate or error rate.

Symbol rate

The symbol rate describes the amount of data that is transmitted per second. It is measured in Msymbols/s and is equal to the number of symbols that arrive per second.

Transponder

A transponder is a transmitter in the satellite that transmits TV and radio signals on a high transmission frequency to the sat. receiving antennas. A satellite has a number of transponders.

Transponder, analogue

An analogue broadcasting transponder always transmits only one TV programme and possibly a number of radio programs on its transmission frequency..

Transponder, digital

A digital broadcasting transponder is able to transmit several TV and several radio programs simultaneously on its transmission frequency. When a program provider beams down several TV programs via a digital transponder, one then also talks of the program provider’s “program package” The terms “Digital transponder” and “Program package” have the same meaning.

Video bit rate

The video bit rate describes the amount of digitalized video signal data that is transmitted per second.

Viterbi rate

The Viterbi rate (code rate, error rate) characterises the error protection used by the program provider. The DVB standard has earmarked the following values: 1/2 - 2/3 – 3/4 - 4/5 – 5/6 – 6/7 – 7/8..

48