With reference to the figure, a short description of the single processing blocks follows.
- ''' (see the bottom figure for a complete listing).
- a first level of protection is applied to the transmitted data, using a nonbinary Block Code , a Reed-Solomon RS(204, 188) code, allowing the correction of up to a maximum of 8 wrong bytes for each 188-byte packet.
- convolutional interleaving is used to rearrange the transmitted data sequence, such way it becomes more rugged to long sequences of errors.
- data bytes are encoded into bit ''m''-tuples (''m'' = 4, 5, 6, 7, or 8).
- the two most significant bytes in each ''m''-tuple are encoded in order to give some ruggedness to the signal.
- the bit sequence is mapped into a base-band digital sequence of complex symbols. There are 5 allowed , 32-QAM, 64-QAM, 128-QAM, 256-QAM.
- the QAM signal is filtered with a raised-cosine shaped filter, in order to remove mutual signal interference at the receiving side.
and Symbol Rate . All (decimal) values in Mbit/s.]]
The receiving STB adopts techniques which are dual to those ones used in the trasmission.
- ETSI Standard: ETSI EN 300 429 V1.2.1 (1998-04), ''Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for cable systems'', download from ETSI .
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