Clock generator and a method of generating a clock signal

摘要

The present invention is directed to a clock generator and a method of generating a clock signal. A digital control oscillator (DCO) generates a clock signal. A first frequency calibration unit extracts a periodic signal and determines a frequency error quantity between the extracted periodic signal and a derived clock signal. A second frequency calibration unit generates a coarse tuning signal when an absolute value of the frequency error quantity is greater than a first predetermined threshold, and generates a fine tuning signal when the absolute value of the frequency error quantity is less than a second predetermined threshold.