An empirical study of SD signal delay versus temperature in a plenum grade coaxial cable

A high resolution speedy delivery time domain reflectometer (SD/TDR) has been developed in the Electrical Engineering department at The University of Texas at Austin. The SD/TDR uses a novel non-sinusoidal signal that does not undergo dispersion during transmission in a lossy media. SD/TDR is used to estimate the length and detect the location of faults in the transmission lines. Time of flight (TOF) is one of the critical parameters of SD/TDR and a function of several temperature dependent factors. Given the TOF and length of a transmission line, signal delay can be computed. This research presents an empirical study of the effect of temperature on the TOF in a plenum grade coaxial cable for temperatures ranging from -3 °C to 60 °C. We also study the effect of temperature on characteristic impedance of the coaxial cable. Finally, a SD double exponential waveform is used to estimate TOF for calibrated short and open terminations.