What does the Zero Span function on a spectrum analyzer accomplish?

The Zero Span function on a spectrum analyzer is used to stop the sweep and fix the tuner to a specific frequency. This allows the user to observe the signal at that particular frequency over time, providing a real-time view of how the signal behaves, which is critical for analyzing modulation or transient signals. By effectively "freezing" the frequency display, it enables the user to monitor amplitude variations and other characteristics of the signal without the distractions of sweeping across frequencies.

This function is particularly useful in applications where understanding the dynamics of a signal at a specific frequency is essential, such as in troubleshooting communication systems or observing signal modulation. The Zero Span feature transforms the spectrum analyzer into a time-domain display, which can function similarly to an oscilloscope but with an emphasis on the frequency aspect of the signal being analyzed.