The clock generation method contains the following steps. In a pulse recognition step, an input pulse signal is first filtered to remove a shorter signal. Then, a width digitization calculation is conducted on the remaining pulse signal. Based on the width digitization calculation, a signal is recorded and a period of the recorded signal is determined. The value of the period is delivered to a gain module. In a step for verifying the input value to D/A converter, two values are input to a D/A converter from the gain module, and the output from the D/A converter is delivered to an oscillator. The gain module determines a desired input value from the gain module to the D/A converter. In a pulse generation step, the gain module inputs the desired input value to the D/A converter which in turn delivers to the oscillator for the generation of a corresponding clock.