Patent ID: 7254511

Claim:
A method for calibrating a frequency domain reflectometer connected to a transmission line under test and having an RF frequency source, the reflectometer taking selected outputs from a multi-port junction, measuring the power thereat with power measuring circuits, and generating a complex reflection coefficient as a function of frequency from the measured power based on a gain coefficient and an offset coefficient, the complex reflection coefficient coupled to an Inverse Fourier Transform for detecting distances to a fault, comprising the steps of: presenting the multi-port junction with a number of calibration circuits; measuring the effect of the calibration circuits on the reflectometer; comparing the results from the measuring step with modeled characteristics of the reflectometer, including modeled characteristics of the calibration circuits; generating a fresh set of gain and offset coefficients to calibrate the complex reflection coefficient using the fresh set of gain and offset coefficients to provide a compensated complex reflection coefficient; coupling the compensated complex reflection coefficient to an Inverse Fourier Transform for detecting distances to a fault; and, displaying the output of the Inverse Fourier Transform to indicate distance to a fault.