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LOW PHASE NOISE DIGITAL FREQUENCY DIVIDER

  • US 3,737,676 A
  • Filed: 11/18/1971
  • Issued: 06/05/1973
  • Est. Priority Date: 11/18/1971
  • Status: Expired due to Term
First Claim
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1. In a frequency divider the arrangement comprising:

  • a source of an input signal which varies sinusoidally about a reference level at a frequency f, each cycle of said signal having a positive half cycle and a negative half cycle with respect to said reference level;

    a tuned amplifier tuned to a frequency f/n where n is an integer;

    control means for generating a succession of control signals at a frequency f/n, each control signal having a duration between its leading and trailing ends which is greater than 1/2 cycle and less than 3/2 cycles of the input signal, said control means including phase shifting means for controlling the phase between said input signal and said control signal so that a selected portion of every nth cycle of said input signal occurs during the duration of a different control signal other than during the leading and trailing ends thereof; and

    gating means coupled to the input of said tuned amplifier and responsive to said input signal and each control signal for inhibiting the level at the input of said tuned amplifier to vary from a preselected reference level in the absence of a control signal and during the leading and trailing ends of each control signal and for controlling the level at the input of said tuned amplifier to vary in a manner corresponding to the change of level of the input signal during a selected portion of every nth cycle of said input signal which is in time coincidence with a control signal other than during the leading and trailing ends thereof, said selected portion being not more than one half cycle.

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