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Digital signal encoder

  • US 5,260,980 A
  • Filed: 08/20/1991
  • Issued: 11/09/1993
  • Est. Priority Date: 08/24/1990
  • Status: Expired due to Term
First Claim
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1. An apparatus for encoding an input digital signal, comprising;

  • first frequency analysis means for frequency dividing said input digital signal into frequency components,second frequency analysis means for blocking and frequency analyzing said frequency components to produce blocks of data having analyzed frequency components,first noise level setting means for generating first output signals based on a first allowable noise level set in accordance with an energy of each said analyzed frequency component of said blocks of data output within a predetermined time period from said second frequency analysis means,second noise level setting means for generating second output signals based on a second allowable noise level of each said analyzed frequency component output within said predetermined time period set in accordance with an energy of at least one of said blocks of data which temporally precede and succeed, respectively, said each block, andquantization means for quantizing said blocks of data output from said second frequency analysis means on the basis of a quantization characteristic set in accordance with said first and second output signals from said first and second noise level setting means, respectively.

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