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Data transmission

  • US 4,286,333 A
  • Filed: 08/28/1978
  • Issued: 08/25/1981
  • Est. Priority Date: 08/27/1977
  • Status: Expired due to Term
First Claim
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1. A spread spectrum system for transmitting and receiving binary data, wherein a spread spectrum transmitter includes:

  • means for deriving according to a first predetermined recurrence relationship a pseudo-random binary pulse train having a greater bit rate than the data signal at least in part from the data signal;

    means for modulating the pseudo-random pulse train with the data signal to produce an increased bandwidth signal; and

    means to phase shift key modulate a coherent RF carrier with the increased bandwidth signal to produce a spread spectrum signal;

    and wherein a spread spectrum receiver includes;

    an input for receiving the spread spectrum signal;

    delay line sections coupled to the input and at least one balanced modulator for combining signals subject to different delays in the delay line sections according to a second predetermined recurrence relationship, the said first second predetermined relationships being such that the delay line sections and at least one balanced modulator derive the said pseudo-random binary pulse train only from the spread spectrum signal, anda further balanced modulator having a first input coupled to the said input for receiving the spread spectrum signal and a second input coupled to receive the said pseudo-random binary pulse train derived from the spread spectrum signal to cross-correlate that pulse train with the signal received at the first input to produce a signal comprising the data demodulated from the pseudo-random binary pulse train.

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