US Patent 7778319 Jitter measuring apparatus, jitter measuring method and test apparatus

There is provided a jitter measuring apparatus for measuring jitter in a signal-under-measurement having a first pulse generator for detecting edges of the data-signal-under-measurement to output a first pulse signal having a pulse width set in advance corresponding to the edge, a second pulse generator for detecting boundaries of data sections where data values do not change in the data-signal-under-measurement to output a second pulse signal having a pulse width set in advance corresponding to timing of the detected boundaries of the data sections, a filter for removing carrier frequency components of said data-signal-under-measurement from first and second pulse signals and a jitter calculating section for calculating timing jitter in the data-signal-under-measurement based on the first and second pulse signals.