US Patent 7276982 High frequency digital oscillator-on-demand with synchronization

A High Frequency Digital Oscillator contains a ring oscillator having an output fn, and having coarse and fine frequency adjustments, wherein the input signal f1 is the input to both the ring oscillator and the High-Frequency Digital Oscillator, which has a multiplicity of output signals including f2, f4, and f8 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=1/4*(f4) causing a coarse frequency adjustment and a signal A=(1/f1−1/fc) making a fine adjustment, and by stopping the new output before the rising edge of f1; and then restarting starting the new output at the rising edge of so that the output and input are synchronized.