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Regulated suppressed carrier modulation system

  • US 4,243,955 A
  • Filed: 06/28/1978
  • Issued: 01/06/1981
  • Est. Priority Date: 06/28/1978
  • Status: Expired due to Term
First Claim
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1. Regulated suppressed carrier modulator apparatus for modulating a carrier signal with a selected signal and substantially eliminating carrier signal feedthrough, said apparatus comprising:

  • (a) phase shifting means coupled to receive the carrier signal and provide, at two output terminals, first and second versions of the carrier signal with a phase difference of approximately 90°

    ;

    (b) multiplying means having a first input connected to receive the selected signal, a second input coupled to said phase shifting means to receive one of the first and second versions of the carrier, and an output;

    (c) first and second weighting means each having a signal input coupled to a different output terminal of said phase shifting means to receive one of the first and second versions of the carrier, an output, and means for controlling the weighting means for providing signals at the outputs thereof which, when combined, have a value substantially equal to the carrier signal feedthrough; and

    (d) combining means coupled to the outputs of said multiplying means and said first and second weighting means and combining the signals applied thereto in a manner to substantially suppress the carrier signal at an output thereof.

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