Analyzer Calibration
The purpose of analyzer calibration (sometimes called "alignment") is to improve measurement accuracy. Calibration completely characterizes the current measurement hardware; it is not necessary to recalibrate if the or parameters such as range, coupling, channel, span, or frequency band are changed. When the Calibrate Button in the Calibration Dialog () is clicked, the VSA instructs the connected measurement hardware (specified in the Current Analyzer Configuration) to perform a calibration.
Calibrate is only available for hardware configuration that support calibrations. The button is greyed out for those configurations that do not support calibrations.
The software monitors instrument state and indicates current calibration state on the right side of the status line at the bottom of the display. Additionally, the display shows "CAL?" in the Trace Indicator whenever full accuracy is not available (because of incomplete or invalid calibration data, or because corrections are turned off).
Calibration during instrument warm-up is a good idea, even though full accuracy is not guaranteed until the hardware has warmed up. During warm-up, calibration provides an estimate of the instrument's frequency response that allows some of the measurement algorithms to work more successfully. This is especially true when demodulating some digital formats. Without even a rough calibration, demodulation may fail.
If a calibration is done when a measurement is paused, the VSA will restart the measurement (rather than continue it) when or the 
button is clicked. Any accumulated average data is discarded. This prevents a measurement from using two different sets of calibration data.
See Also
