| 摘要 |
A data compression/expansion method and apparatus are provided. The data compression apparatus (70) includes a repetitive symbol detector (72), a shift register (74), a FIFO (76), a byte counter (78), and a map buffer (80). The symbol detector (72) generates an output signal indicating the presence of repetitive symbols in an input data segment (10). The shift register (74) functions as a map generator, producing a map (16) for locating the repetitive symbols in the input segment (10). The FIFO (76) acts as a gate for removing the repetitive symbols from the input segment to produce a compressed output segment (14). The compressed segment (14) and map (16) can then be transmitted to the expansion apparatus (90). The data expansion apparatus (90) includes a buffer (92), a shift register (94), and a multiplexer (95). The buffer (92) temporarily stores the compressed segment (14). The shift register (74) and multiplexer (95) cooperate to decompress the output segment (14) by re-inserting the repetitive symbols according to the map (16). The compression/expansion apparatuses (70, 90) provide an efficient system for removing frequently occurring symbols from a communications channel.
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