Why is there a "chirping" noise coming out of my ESA Series Spectrum Analyzer?

This noise is the ESA Series automatic alignment feature that realigns a small portion of the IF during each retrace (the time between sweeps). During some of these realignments, the analyzer switches signals in the IF using several relays. It is these relays that cause the chirping or clicking sounds, which is normal.

Since some portions of the realignment process do not require switching signals in the IF, the noise does not occur during every retrace. However, you can turn off the internal alignment by pressing: [System] {Alignments}{Auto Align} {Off}.

If Auto Align Off is selected, the analyzer will meet its specifications only under certain conditions that are explained in the ESA Series Specifications Guide.