| 摘要 |
PCT No. PCT/GB91/01164 Sec. 371 Date Jan. 7, 1993 Sec. 102(e) Date Jan. 7, 1993 PCT Filed Jul. 12, 1991 PCT Pub. No. WO92/01252 PCT Pub. Date Jan. 23, 1992.Digital data, in the form of blocks delimited by end-of-block words, that is to be coded into variable length codewords, is protected against errors occurring within a block, as well as errors crossing block boundaries, by modulating the respective end-of-block words with a bit, or bits, of a larger reference pattern which bit, or bits, have been conditioned to carry information on the content of VLC codewords coding a corresponding (eg. preceding) data block. The "modulation" may be by means of selecting between different possible end-of-block words dependent upon the value of the conditioned reference pattern bit, or bits, or by means of appending the conditioned bit(s) to the end-of-block word. The reference pattern may be a repeated pseudo-random sequence.
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