US Patent 7545858 Method of measuring jitter frequency response

A method of measuring jitter frequency response includes recovering a clock signal from a data input stream to provide a recovered clock signal and counting the recovered clock signal over a selected time period to provide a recovered clock count. A reference signal is counted over the selected time period to provide a reference signal count. The recovered clock count is compared to the reference signal count and a frequency of the recovered clock signal for the selected time period is calculated.