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S7200 TV Signal Analyzer Operation Manual
receiver. A TV receiver is able to identify and correct certain amounts of error in
the transmission channel. In the TV receiver, error correction takes place in two
distinct stages called Viterbi (or 'outer') and Reed Solomon (or 'inner') correction.
The bit error rate (BER) before Viterbi correction stage is known as CBER. It is also
known as 'pre Viterbi BER', raw BER' or channel BER. CBER indicates errors
present before any correction has taken place in the TV, set-top box or test
instrument. Therefore, CBER is a very important part in digital TV measurements
and it should be better than 2E-2 (2 errors in every 100 bits of data) for good
quality TV reception.
The bit error rate after the Viterbi correction is known as VBER or post Viterbi. It
should be better than 2E-4 (2 errors in every 10000 bits of data).
In average power measurement interface, the screen display DVB-T/H signal
average power, MER, CBER and VBER. The average power use the histogram
display.
Figure 6-47 DVB-T2 Average Power Measurement
Rotated constellations were introduced in DVB-T2 for improving the system
performance in fading scenarios by means of signal-space diversity. When rotated
constellations are used, a rotation is applied to the constellation symbols in such
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