The Keysight N9928A-010 Option 010 time domain computes the inverse Fourier transform of the frequency-domain data to display reflection or transmission coefficients versus time. Time domain gating can be used to remove unwanted responses such as connector mismatch or cable discontinuities, and the results can be displayed in either time or frequency domain.
The transform used by the analyzer resembles time domain reflectometry (TDR) measurements. TDR measurements however are made by launching an impulse or step into the test device and observing the response in time with a receiver similar to an oscilloscope. In contrast, FieldFox makes swept frequency response measurements, and mathematically transforms the data into a time domain reflectometer-like display.
If Option 010 is added to N9925/6/7/8A FieldFox vector network analyzers, users can measure S11 and S21 in time domain. To obtain time domain data for all four S-parameters and full 2-port error correction, Option 211 (VNA full 2-port S-parameters) should be ordered.