Patent ID: 8095102

Claim:
A method of varying an output signal of an oscillator to be within a desired frequency band with respect to a reference signal, the output signal having a plurality of phases, the method comprising: for each phase of the plurality of phases: detecting a falling edge of the output signal; increasing a count for each falling edge detected; detecting a falling edge of the reference signal; summing the count for each phase of the plurality of phases, defining a count summation; and comparing the count summation with a product of a number of phases of the output signal and a factor that the output signal may be divided down by, defining a comparison signal; outputting the comparison signal to a loop filter; generating a control signal by the loop filter based upon the comparison signal; and inputting the control signal to the oscillator, with the control signal altering the output signal such that the output signal is within the desired frequency band with respect to the reference signal.