Glossary, abbreviations
DiSEqC
DiSEqC (Digital Satellite Equipment Control) is a
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.
Eb/No ratio
The Eb/No ratio is a measure for the
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
signal. The
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