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Digital radio communications system with high noise immunity

  • US 4,314,371 A
  • Filed: 08/17/1979
  • Issued: 02/02/1982
  • Est. Priority Date: 08/17/1979
  • Status: Expired due to Term
First Claim
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1. A radio transmitting system using a noise minimizing code, for selective calling of radio systems, using a selected multibit sequential binary word having a selected number of binary bits, such as 24, for example;

  • and register means for storing said 24 bits;

    comprising(a) means for coding said word of 24 sequential binary bits into a coded transmission of clocked trains of binary signal pulses, where each binary signal pulse of said binary signal comprises a square pulse of selected magnitude, polarity and duration D, followed by a space of equal duration D; and

    wherein(b) for each bit of said 24 binary bits which is a logical one, first means to produce a train of a selected number M of said binary signal pulses; and

    for each bit of said 24 binary bits which is a logical zero, second means to produce a train of a selected number N of binary signal pulses;

    where N is substantially different from M;

    (c) between the end of a first train of said binary pulses and the beginning of the next train, means for providing a clocked time space of zero signal equal in length to the length of P binary signal pulses, where P is less than M or N; and

    (d) means to modulate a radio transmitter with said coded transmission.

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