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Wear-toll quality 4.8 kbps speech codec

  • US 5,307,441 A
  • Filed: 11/29/1989
  • Issued: 04/26/1994
  • Est. Priority Date: 11/29/1989
  • Status: Expired due to Term
First Claim
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1. An apparatus for encoding an input speech signal into a plurality of coded signal portions, said apparatus including first means responsive to said input speech signal for generating at least a first coded signal portion of said plurality of coded signal portions and second means responsive to said input speech signal and to at least said first coded signal portion for generating at least a second coded signal portion of said plurality of coded signal portions, said first means comprising iterative optimization means for(1) determining an optimum value for said first coded signal portion assuming no excitation signal, and providing a corresponding first output,(2) determining an optimum value for said second coded signal portion based on said first output and providing a corresponding second output,(3) determining a new optimum value for said first coded signal portion assuming said second output as an excitation signal, and providing a corresponding new first output,(4) determining a new optimum value for said second coded value based on said new first output, and providing a corresponding new second output, and(5) repeating steps (3) and (4) until said first and second coded signal portions are optimized.

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