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FM HETERODYNE TRANSMITTER

  • US 3,789,302 A
  • Filed: 03/31/1972
  • Issued: 01/29/1974
  • Est. Priority Date: 03/31/1972
  • Status: Expired due to Term
First Claim
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1. In an FM heterodyne transmitter, RF amplifier means comprising input means (to provide an) for a modulated RF signal at a specified carrier frequency, voltage-controlled local oscillator means to provide a signal at a frequency which is a specified fraction of said carrier frequency, first frequencymultiplier means arranged to accept a sample of said local oscillator signal and to provide in response thereto a first output signal having the same frequency as said carrier frequency, phase-comparator means arranged to accept said RF signal and said first output signal and to provide (an) a DC error signal responsive in magnitude to a phase difference between them and an AC signal which substantially repeats the modulation information of said RF signal, error signal feedbackamplifier means arranged to receive said error signal and to provide in response thereto a controlling voltage to said local oscillator whereby to cause said local oscillator to oscillate at a frequency tending to negate said error signal, local oscillator signal amplifier means coupled to said local oscillator to receive local oscillator output signal and amplify same, and second frequency-multiplier means arranged to receive amplified local oscillator signal from said amplifier and to provide in response thereto a second output signal having an output carrier frequency which may be the same frequency as said input carrier frequency, and substantially repeating the frequency deviations of said input modulated RF signal.

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