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Frequency divider circuit

  • US 4,694,475 A
  • Filed: 05/08/1986
  • Issued: 09/15/1987
  • Est. Priority Date: 05/18/1985
  • Status: Expired due to Fees
First Claim
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1. Frequency divider circuit for divisors consisting of an integral part and a fractional part which is designed in the manner of a rate multiplier and comprises:

  • a digital first accumulator including a clocked data register and an m-bit first adder having a first input presented with an m-bit first digital word corresponding to the fractional part of the divisor, and having a second input fed from the output of said data register, the input of said data register being connected to the output of said first adder said first accumulator having a sum output;

    an n-bit second having a first input receiving an n-bit second digital word corresponding to the integral part of said divisor and having a second input connected to the carry output of said first adder;

    an n+1 bit third adder having a first input coupled to the output of said second adder, said third adder having a second input and an output;

    a subtracter having its minuend input coupled to the output of said third adder output, said subtracter having a subtrahend input and an output;

    a presettable counter having its preset input coupled to the output of said subtracter output, and having a count input receiving a signal to be frequency divided;

    said counter having a counter output at which a pulse occurs after a number of pulses equal to the value applied to said preset input, output pulses at said counter output being the frequency-divided signal;

    said frequency divided signal clocking said data register, and;

    an r-bit second accumulator, wherein 1≦

    r≦

    m, having an input receiving the r most significant output bits of said first accumulator sum output, and having a carry output coupled to a second input of said third adder and coupled to the subtrahend input of said subtracter; and

    a delay means disposed between said second accumulator carry output and said subtracter subtrahend input, said delay means having a delay equal to the period of said frequency divided signal.

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