| 摘要 |
A variable-length encoder using a code table having a symbol/code-word re-association feature, which includes a first storing portion for storing previously generated code table information, a first re-associating portion for generating re-associated code table information and re-association information indicative of the relation between a symbol and a corresponding code word from a previously generated code table information stored in the first storing portion, based on the frequency of occurrence of externally applied symbols during a predetermined time period, a delay for delaying and outputting the same symbols as those input to the first re-associating portion during the predetermined time period, a re-association information storing portion for storing the re-associated code table information and re-association information and sequentially outputting the re-association information, a variable-length encoder for receiving the symbols stored in the delay and generating and sequentially outputting code words according to the re-associated code table information stored in the re-association information storing portion, and a multiplexer which outputs the re-association information from the re-association information storing portion and the code words output from the variable-length encoder, to thereby reduce the code length of code words generated by variable-length encoding even when the frequency of occurrence of symbols used in forming a previously generated code table is different from that of the symbols applied during the predetermined time period.
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