Tiernan TDR7, Manual

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Demodulator Status
Demodulator Status
The TDR7 Status function allows you to monitor the receive signal
Eb /No and level, carrier offset, and the lock status of the demodulator,
decoder, and transport stream. If the demodulator, decoder, or
transport stream status is unlocked, follow the troubleshooting
procedures defined below.
Receive Signal
Eb/No Level
The Eb/No value that the TDR7 displays is the estimated Eb/ No level
of the receive signal in units of dB. This value, when used in
conjunction with the DVB minimum performance requirements,
indicates the link margin for the transmission. An Eb/No value at least
3 dB above these limits is reasonable. Eb/No levels that drop near the
DVB limits may cause interrupted or poor quality video service.
If the Eb/No level is above the minimum DVB requirements, the TDR7
should acquire the carrier, demodulate the signal, allow the decoder to
lock to the transport stream, and provide decoded video and audio
output.
The minimum
Eb/No levels required for successful reception of a
signal that will guarantee flawless video performance at each Viterbi
code rate are listed below.
Eb/No vs. Viterbi Code Rate Performance Levels
Viterbi Code Rate Minimum Eb/No (dB)
1/2 4.5
2/3 5.0
3/4 5.5
5/6 6.0
6/7 6.4