Apparatus and method for generating clock signal

摘要

A clock generating apparatus is provided for producing an output clock signal responsive to a source clock signal with a source frequency and a reference clock signal with a reference frequency. The clock generating apparatus includes a counting sequence generator, a measuring value generator and a ratio counter. The counting sequence generator is used for outputting a series of counting values in response to a triggering signal with a specified period determined by the source frequency of the source clock signal and a predetermined counting value. The measuring value generator generates a measuring value by operating the series of counting values according to a predetermined formula. The ratio counter produces the output clock signal with a frequency determined by the source frequency of the source clock signal and the measuring value.