Spectrum Analyzer Measurement Guide : Spectrum Analyzer : Preamplifier Measurement Example
 
Preamplifier Measurement Example
The preamplifier can be turned on and off by pressing the Amplitude main menu key, then selecting the Preamp On/Off submenu key.
Figure: Preamplifier On and Off shows the noise floor with the preamplifier off (green trace) and on (yellow trace). Notice that when the preamplifier is turned on, the noise floor drops significantly.
Preamplifier On and Off