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Bidirectional digital signal communication system

  • US 4,635,274 A
  • Filed: 04/25/1985
  • Issued: 01/06/1987
  • Est. Priority Date: 04/27/1984
  • Status: Expired due to Fees
First Claim
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1. A bidirectional digital signal communication system including a plurality of terminal units in communication with a center unit, wherein each of said terminal units comprises:

  • signal generating means for generating digital data spread with a pseudo-noise code;

    modulating means for modulating said digital data on a carrier; and

    means for transmitting said modulated digital signal to said center unit;

    and said center unit comprises;

    receiving means for receiving said modulated digital signal;

    a pseudo-noise code generator for generating a pseudo-noise code which corresponds to the pseudo-noise code of one of said terminal units;

    a multiplier responsive to said receiving means and said pseudo-noise code generator to produce a digital signal de-spread from said pseudo-noise code;

    demodulating means connected to said multiplier to reproduce the digital data from said modulated digital signal;

    a detector for detecting a maximum level of the digital signal from said multiplier and producing a corresponding level indication signal; and

    presetting means including a memory containing a preset code for presetting said pseudo-noise code generator with said preset code in response to said level indication signal.

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