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Apparatus for performing radio frequency pulse modulation with automatic modulation control

  • US 4,409,594 A
  • Filed: 10/20/1980
  • Issued: 10/11/1983
  • Est. Priority Date: 09/21/1979
  • Status: Expired due to Term
First Claim
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1. A radio-frequency pulse transmitting system such as DME or Tacan comprising:

  • first means including at least one radio-frequency amplifier responsive on a radio-frequency input to a pulse-modulated carrier signal and to a further-frequency video pulse on a control terminal for producing radio-frequency output pulses having predetermined envelope characteristics;

    second means for discretely sampling said radio-frequency output pulses at a plurality of amplitude levels and for generating discrete modulation control signals each representing the duration of the envelope of said radio-frequency output pulses at a predetermined corresponding amplitude level;

    third means for generating a plurality of separate video pulse trains synchronous with and of pulse duration not exceeding the pulses of said pulse-modulated carrier signal;

    fourth means comprising a separate gain-controllable amplifier responsive to each of said second means modulation control signals and to a corresponding one of said third means video pulses to adjust the amplitude of said corresponding video pulse as a function of the corresponding control signal from said second means;

    and fifth means for combining said video pulses from said third means to provide a train of pulses having peak amplitude substantially equal to the sum of the amplitudes of said video pulses from said third means, said combined pulse train being applied at said radio-frequency amplifier as said further-modulating pulse.

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