To enable antialiasing
Aliasing can occur when the instrument's sampling rate is less than twice as fast as the
waveform's highest frequency component. When enabled (default) the Antialiasing softkey
switches a 100-kHz, low pass filter into the analog measurement front end before signals are
digitized. This reduces aliasing by reducing the signal's frequency content above the
instrument's sample rate that reaches the analog to digital converter.
Keysight IntegraVision PA2200 Series Power Analyzers Operating and Service Guide 49