Accuracy analysis in the estimation of ToF of TDR signals

In this work, an accuracy analysis of the estimation of the time of flight (ToF) for time domain reflectometry (TDR) signals is carried out. For this purpose, three different criteria (referred to as ‘maximum derivative’, ‘zero derivative’, and ‘tangents crossing’) were comparatively applied for the evaluation of the ToF of a TDR signal propagating along a set of RG-58 coaxial cables (with different known length and with known electric parameters). Successively, as a further experimental test, the same criteria were applied on bi-wire cables with unknown electric parameters. Results show that, among the tested criteria, the ‘zero derivative’ criterion provided the best accuracy in the estimation of the ToF.