a high frequency digital oscillator contains a ring oscillator having an output fn , and having coarse and fine frequency adjustments , wherein the input signal f 1 is the input to both the ring oscillator and the high - frequency digital oscillator , which has a multiplicity of output signals including f 2 , f 4 , and f 8 at one - half , one fourth , and one - eighth the frequency of fn respectively , and wherein an input gating signal causes the oscillator to start or stop , a signal fc = ¼ * causing a coarse frequency adjustment and a signal δ = making a fine adjustment , and by stopping the new output before the rising edge of f 1 ; and then restarting starting the new output at the rising edge of so that the output and input are synchronized .