A VNA measures the (reflected) impedance over frequency. We can use a Fourier transform to convert this into a series of impedances over time, just as that produced by a TDR instrument.

VNA time-domain results are converted from frequency-domain results into the time domain using the Fourier transform method. Specifically, a variation of the chirp z inverse transform is used.

A time domain reflectometer (TDR) measures reflections along a cable. It is similar in principle to radar. To measure those reflections, the TDR transmits an incident signal into the cable and watches ...