Which spectrum analyzer mode converts the analyzer to a time domain display?

Zero span mode on a spectrum analyzer allows for the display of a signal in the time domain by effectively "freezing" the frequency display at a specific frequency. In this mode, the analyzer sweeps at a single frequency rather than across a range of frequencies. This means that as time progresses, the amplitude of the signal at that particular frequency can be observed, allowing for a clear view of its temporal behavior.

This mode is particularly useful for analyzing changes over time, such as pulse signals or transients, because it shows how the signal varies as a function of time rather than frequency. Other modes, while they may provide information about the signal’s characteristics in a frequency context, do not facilitate the same time-domain analysis that zero span does.