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Mixed voice and spread spectrum data signaling with multiplexing multiple users with CDMA

  • US 7,796,565 B2
  • Filed: 09/28/2006
  • Issued: 09/14/2010
  • Est. Priority Date: 06/08/2005
  • Status: Expired due to Fees
First Claim
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1. A method of exchanging analog signals and a digital data among at least two transmitters and at least one receiver in a teleconferencing system, the method comprising:

  • by a first transmitter, generating a first CDMA chip sequence;

    combining a first digital bit stream and the first CDMA chip sequence, to form a first spread spectrum sequence;

    modulating the first spread spectrum sequence onto a first analog signal, to form a first modulated signal;

    transmitting the first modulated signal to the receiver via a first communication channel;

    by a second transmitter, generating a second CDMA chip sequence;

    combining a second digital bit stream and the second CDMA chip sequence, to form a second spread spectrum sequence;

    modulating the second spread spectrum sequence onto a second analog signal, to form a second modulated signal; and

    transmitting the second modulated signal to the receiver via a second communication channel;

    wherein the first CDMA chip sequence is different from the second CDMA chip sequence;

    wherein generating the first CDMA chip sequence comprises periodically pseudo-randomly selecting the first CDMA chip sequence from one of a plurality of chip sequence generators, andby the at least one receiver, demodulating a received signal, to produce a demodulated signal;

    generating a third CDMA chip sequence;

    generating a fourth CDMA chip sequence;

    multiplying the demodulated signal by the third CDMA chip sequence, to reconstruct the first digital bit stream; and

    multiplying the demodulated signal by the fourth CDMA chip sequence, to reconstruct the second digital bit stream;

    wherein the third CDMA chip sequence is different from the fourth CDMA chip sequence.

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