Dvb-T/H Measurement - Deviser S7200 User Manual

There are no longer any channels in DVB-C2; instead, there are two channel rasters of either 6 or 8 MHz.
Channels can be bundled together to form a channel with a total width of approx. 450MHz. There are no
gaps (guard bands) between the original channels, enabling more effective frequency spectrum use and
a higher data rate overall. However, interfering signals and other disturbances are common. These can be
notched out in DVB-C2 by simply switching off certain OFDM carriers. This notching process produces gaps
in the frequency spectrum.
6-7

DVB-T/H Measurement

The S7200 supports DVB-T/H signal measurement.
For DVB-T/H signals, the S7200 provides a variety of measurement functions: average power, constellation
diagram, MER/BER, single-carrier or multi-carrier constellation, and single-frequency network echo.
6-7.1 Measurement Settings
In order to demodulate 8VSB signals, the user must first set up the following parameters:
Channel type: the first step is to set the channel type to DVB-T/H in the channel plan editor (see Chapter 3
for details).
Center Frequency: the carrier center frequency
All other parameters will be auto-set according to the pilot and TPS carrier. (Note: DVB-H 4k carrier mode is
not supported.) If the above settings are in place and a clear signal is received, the S7200 can correctly
demodulate 8VSB.
6-7.2 CBER and VBER
CBER and VBER indicate the quality of the signal provided to the receiver. A TV receiver can identify and
correct certain amounts of error in the transmission channel. Error correction takes place in two distinct
stages: Viterbi (or "outer") and Reed Solomon (or "inner") correction.
The bit error rate (BER) prior to Viterbi correction is known as CBER, pre Viterbi BER, raw BER, or channel BER.
CBER indicates errors that are present before any correction has taken place in the TV, set-top box, or test
instrument. Therefore, CBER is a very important factor in digital TV measurements. Ideally, it should be better
than 2E-2 (2 errors in every 100 bits of data) for good-quality TV reception.
The BER after Viterbi correction is known as VBER or post Viterbi BER. Ideally, it should be better than 2E-4 (2
errors in every 10000 bits of data).
6-7.3 Average Power
In the Average Power interface, DVB-T/H signal power is displayed as a histogram. MER, CBER, and VBER
readings are listed in the lower-left.
Part II: Settings and Measurements
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