Patent ID: 7276982

Claim:
A High Frequency Digital Oscillator comprising: (a) a gated ring oscillator comprising an output signal sfn, having a frequency fn, and comprising coarse and fine frequency adjustments; (b) means for inputting an input signal sf 1 , further connected to an input to the ring oscillator; (c) a multiplicity of output signals further comprising signals sf 2 , sf 4 , and sf 8 having the frequency one-half, one-fourth, and one-eighth the frequency of signal sfn, respectively; (d) an input gating signal causing the oscillator to start or stop; (e) means for measuring the period p 1 =1/sf 1 further comprising a counter which measures the largest integral number of unadjusted ring oscillator periods Nu of signal sfn, which fit within the period p 1 ; (f) a counter circuit generating signal sfc, having a frequency equal to one-fourth fn; (g) means for making a coarse adjustment to the ring oscillator as a function of measured results of p 1 , comprising an adder which adds a predefined oscillator delay Δtd, corresponding to the value of Nu, to the coarse delay path, and wherein each different value of Nu has a different corresponding value Δtd; (h) means for measuring time delay Δ=(1/f 1 )−(1/fc) further comprising a counter which counts the number n of individual time delays required, and further comprising a multiplicity of time delay circuits N 1 c disposed in series, each having a precise time delay period td, which are activated during the duration Δ, wherein n*td=Δ; (i) means for making a fine adjustment, and thereby generating a new value of signal sfn, having a frequency of (new fn) as a function of Δ; (j) means for generating signal sf 0 , having a frequency equal to one-fourth times (new fn); (k) means for stopping sf 0 and new sfn before a rising edge of sf 1 ; and (l) means for starting sf 0 and new sfn at the rising edge of sf 1 , so that sf 0 is synchronized with, and has the same frequency as sf 1 , sf 2 has a frequency equal to one half that of (new fn), and sf 4 has a frequency equal to f 0 , which is one-fourth that of (new fn).