A test instrument connectable to a cable television (CATV) network to provide a high resolution time domain reflectometry (TDR) in a fault location measurement is disclosed. The test instrument may have a port connectable to a test point in the CATV network. The test instrument may also have a processing circuit to perform a calibration measurement and a fault location measurement by transmitting frequency-chirped probe pulses into a closed calibration circuit within the test instrument, and receiving return signals at an analog-digital converter in the test instrument. The processing circuit may resample the calibration measurement and the fault location measurement at a high sampling rate, cross-correlate the fault location with the calibration measurement to generate a cross-correlation TDR waveform, and generate a new TDR waveform using a refinement processing technique to remove echoes from the cross-correlation TDR waveform.