Variables Längen-Kodier- und Dekodiersystem

摘要

A variable-length encoder using the symbol-code word re-association of a code table is disclosed including a first storing portion (14) for storing a previously made code table information, a first re-associating portion (13) for generating re-associated code table information and re-association information indicative of the relation of a symbol and a corresponding code word from the previously made code table information stored in the first storing portion (14), on basis of the occurring frequency of externally applied symbols for a predetermined time period, a delay (10) for delaying and outputting the same symbols as those input to the first re-associating portion (13) for the predetermined time period, a re-association information storing portion (12) for storing the re-associated code table information and re-association information and outputting said re-association information sequentially, variable-length coding means (11) for receiving said symbols stored in the delay (10) and generating and sequentially outputting code words according to the re-associated code table information stored in the re-association information storing portion (12), and means (15) for multiplexing and outputting the re-association information from the re-association information storing portion (12) and the code words output from said variable-length coding means (11), to thereby reduce the code length of code words generated by variable-length coding even when the occurring frequency of symbols used in forming a previously made code table is different from that of symbols for the predetermined time period.