Patent ID: 7126321

Claim:
An apparatus for measuring the transmission delay time of a signal propagation path between a sending point of a first printed circuit board and a receiving point of a second printed circuit board, comprising: a frequency domain analyzer that measures a frequency-domain response of a transmission medium that forms part of said signal propagation path; a time domain analyzer that measures a first time-domain response of said propagation path at said sending point and a second time-domain response of the propagation path at said receiving point; and a processor that estimates from said first time-domain response and said frequency-domain response a third time-domain response of said propagation path which would be observed at said receiving point if there is no waveform distortion over the surface of each of said printed circuit boards, calculates a time-domain correlation between the second and third time-domain responses, determines a first delay time from said estimated third time-domain response, and determines a second delay time from the calculated time-domain correlation, and provides a sum of the first and second delay times to produce a transmission delay time of said signal propagation path.