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Digital single-sideband modulator

  • US 3,868,601 A
  • Filed: 06/18/1973
  • Issued: 02/25/1975
  • Est. Priority Date: 06/18/1973
  • Status: Expired due to Term
First Claim
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1. Modulator apparAtus comprising:

  • input means for receiving digital data;

    generator means connected to said input means and being responsive to said digital data to produce trigger pulses at a selectively predetermined rate;

    in-phase read-only memory means connected to the output of said generator means and being responsive to said trigger pulses to store the binary representation thereof on a selectively predetermined waveform and wherein each binary word stored represents a distinct amplitude of said waveform;

    first digital-to-analog converter means connected to the output of said in-phase read-only memory means;

    quadrature read-only memory means connected to the output of said generator means and being responsive to said trigger pulses in the same manner as said in-phase read-only memory means, second digital-to-analog converter means connected to the output of said quadrature read-only memory means;

    first and second mixer means connected to the outputs of said first and second digital-to-analog converter means, respectively;

    oscillator means connected at the output to said first mixer means to provide at the output thereof an in-phase carrier signal, and being further connected through a 90* phase shifter to said second mixer to provide a quadrature carrier signal; and

    , summation network means connected at the input to the outputs of said first and second mixer means and being responsive to said in-phase and quadrature carrier signals to provide a singlesideband, suppressed carrier signal.

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