Driving point reference plane time domain reflectometry method for measuring characteristic impedance

摘要

Method for determining the characteristic impedance of a transmission line on a printed wiring board using time domain reflectometry. The method involves selecting a driving point in time, selecting an undisturbed interval, measuring voltage at predetermined time intervals across the undisturbed interval, determining from the measured voltages a curve representative of such voltages, and determining the voltage on the representative curve at the driving point. The characteristic impedance of the transmission line under test, denoted by Z.sub.0, is obtained by using the "driving point" of the transmission line as the reference plane for the impedance measurements.