An assessment on the accuracy of time-domain reflectometry for measuring the characteristic impedance of transmission lines

An assessment of time-domain reflectometry (TDR) for measuring the characte ristic impedance Z(TL) of transmission lines is performed. The assessment i ncludes the accuracy, of measuring Z(TL) as a function of TDR electrical im pedance Z(O), the ability to measure impedance perturbations as a function Of Z(TL) and Z(O), and the ability to differentiate between transmission li nes of similar Z(TL). The information presented herein will be especially u seful for those using 50 Omega TDR systems to characterize transmission lin es having characteristic impedances less than about 30 Omega.