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Transcoder with prevention of tandem coding of speech

  • US 5,991,716 A
  • Filed: 10/14/1997
  • Issued: 11/23/1999
  • Est. Priority Date: 04/13/1995
  • Status: Expired due to Term
First Claim
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1. A transcoder, for a mobile communication system which uses a speech coding method which reduces a transmission rate of speech on a radio path, said transcoder comprising:

  • a speech coder which encodes a speech signal to be transmitted to at least one mobile station into speech parameters, and decodes speech parameters received from at least one mobile station into a speech signal according to said speech coding method; and

    a PCM coder which transmits an uplink speech signal to and receives a downlink speech signal from a PCM interface in the form of PCM speech samples,wherein said transcoder transmits and receives said speech parameters in a subchannel formed by at least one least significant bit of said PCM speech samples simultaneously with said PCM speech samples, in order to prevent tandem coding of speech in a mobile-to-mobile call.

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