Kathrein UFD 574/S manual Small Technical Encyclopaedia, DVB MPEG-2

Small Technical Encyclopaedia

DVB MPEG-2

DVB is short for Digital Video Broadcasting. DVB-T points to the transmission method (T = terrestrial). MPEG is short for Moving Picture Experts Group, a task force drawing up internationally valid standards for the digital audio and video compression. MPEG-2 was made the standard in the compression of digital TV signals. MPEG-2 functions in 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 know of the analogue reception technology. In the case of Eb/No values below 5 dB

reception is normally no longer possible.

FEC

FEC is short for Forward Error Correction. The error rate FEC corresponds to the Viterbi rate.

PID

The PID number (Packet Identification) is an identification number for video and audio signals in the digital data stream of the DVB-MPEG-2 signals. With the PID number, the receiver can establish a clear allocation of the video and audio data transmission. The PID-PCR is the identification number for the synchronisation signal. The PID-PCR normally is identical to PID-Video. In multilingual programmes, another language could be assigned to the TV programme via manual audio PID input. After the PID input, the receiver automatically selects the audio data identified by the PID from the data stream and assigns them to the video signal.

Channel Package

For the most part, the channel package contains several TV and radio channels. Each channel package is fixedly assigned to the transmit frequency, the polarisation (horizontal or vertical), the symbol rate and the Viterbi rate or error rate.

Symbol Rate

The symbol rate describes the amount of data transmitted per second. The symbol rate is measured in MSymbole/s and equal to the amount of symbols coming in per second.

Video Bit Rate

The video bit rate describes the amount of data of the digitalised video signal transmitted per second.

Viterbi Rate

The Viterbi rate (Code rate, error rate) characterises the type of error protection utilised by the programme provider. The DVB standard determines the following values: 1/2 - 2/3 - 3/4 - 5/6 - 7/8

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