In the transmission circuit propagation delay time measurement system the propagation delay time amendment manner

摘要

PROBLEM TO BE SOLVED: To reduce measurement errors, and to measure the transmission delay time of high precision by taking attenuation in a transmission line into consideration, and executing the linear interpolation of the measured value of the transmission delay time. ;SOLUTION: First of all, in order to determine test starting time, time T₁ at which the waveform 23 of a measuring point becomes voltage V₂ is measured by a timing measurement circuit 12. Besides, in order to determine the time during which a reflected wave is returned by reflection due to an open end 11, the time T₂ at which the waveform 23 of the measuring point becomes V₃ is measured by the timing measurement circuit 12. Next, an arithmetic circuit 7 calculates the propagation delay time T_rf1 of the round trip of the transmission line 10 from the difference T₂-T₁ of the measured time T₁ and the measured time T₂, and calculates the calculated propagation dealy time T_rf1 of the round trip, and divides the calculated propagation delay time T_rf1 of the round trip by '2', and derives the propagation delay time T_pd of the transmission line. Further, the arithmetic circuit 7 refers to the propagation delay time of the round trip obtained by simulation and the data of the measuring error from a data table 13.;COPYRIGHT: (C)1997,JPO