Modified statistical coding of digital signals

DC CAFC
  • US 4,813,056 A
  • Filed: 12/08/1987
  • Issued: 03/14/1989
  • Est. Priority Date: 12/08/1987
  • Status: Expired due to Term
First Claim
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1. A statistical encoder for encoding a digitized signal for transmission over a channel, said signal comprising a plurality of different conditions, each condition having a different frequency of occurrence in said signal, said encoder comprising:

  • first means responsive to said signal for generating a first set of codewords, each representing a different signal condition lying in a range of frequencies of occurrences, the codewords having lengths such that the less frequently occurring words generally are longest and the most frequently occurring words generally are shortest;

    second means responsive to said signal for generating a second set of codewords, each word of said second set of words representing a signal condition whose frequency of occurrence is less than the frequency of occurrence of said less frequently occurring words, said second set comprising a number of members whose combined frequency of occurrence is statistically organized in a certain order with said range of frequencies of occurrences, each codeword of said second set including a common codeword portion of a length which is statistically based on said combined frequency of occurrence relative to said range of frequencies of occurrences; and

    third means for causing said codewords of said first and second sets to be generated in accordance to the frequency of occurrence of the corresponding conditions of said signal.

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