In one implementation an output signal of an oscillator is varied to be within a desired frequency band with respect to a reference signal, the output signal having a plurality of phases. The implementation may include comparing the output signal with the reference signal, counting falling edges about each phase of the number of phases in a predetermined time period and summing to define a count output; comparing the count output with a product of the number of phases of the output signal and the factor to define a comparison, generating a control signal based upon the comparison, and inputting the control signal to the oscillator to alter the output signal thereof.