Apparatus and method for measuring transmission delay time of a signal propagation path between printed circuit boards

A method of 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 the steps of:

• a) measuring a frequency-domain response of a transmission medium that forms part of said signal propagation path and measuring 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;
• b) estimating, from the measured frequency-domain response and the measured first time-domain response, a third time-domain response which would be observed at said receiving point if there is no waveform distortion over the surface of each of said printed circuit boards;
• c) calculating a time-domain correlation between the measured second time-domain response and said estimated third time-domain response;
• d) determining a first delay time from said estimated third time-domain response and determining a second delay time from the calculated time-domain correlation;
• and
• e) summing the first and second delay times to produce a transmission delay time of said signal propagation path.

A computer-readable storage medium storing a program 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 by measuring a frequency-domain response of a transmission medium that forms part of said signal propagation path and measuring 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, said program comprising the steps of:

• a) estimating, from the measured frequency-domain response and the measured first time-domain response, a third time-domain response which would be observed at said receiving point if there is no waveform distortion over the surface of each of said printed circuit boards;
• b) calculating a time-domain correlation between the measured second time-domain response and said estimated third time-domain response;
• c) determining a first delay time from said estimated third time-domain response and determining a second delay time from the calculated time-domain correlation;
• and
• d) summing the first and second delay times to produce a transmission delay time of said signal propagation path.