Keysight Technologies Inc. N9927A-215 TDR cable measurements
Option 215 adds time domain reflectometry (TDR) measurements to CAT mode. The measurements include TDR (linear rho) and TDR impedance (ohm).
TDR measurements are useful in not only identifying the location of faults along cables, but also the nature of the fault. Resistive, inductive and capacitive faults will each have a different response. These differences help line-sweep technicians in the trouble-shooting process.
FieldFox's TDR measurements are based on an inverse Fourier transform of the frequency-domain data. The y-axis is either linear (rho) or impedance. The x-axis is distance.