HP ESA-E Series Programmer's Manual page 250

Language Reference
SENSe Subsystem
Preselector Center
[:SENSe]:POWer[:RF]:PCENter
Centers the preselector tracking to maximize the amplitude accuracy of
the signal at the specified marker. Maximum signal amplitude occurs
by minimizing the loss through the filter.
This command is available only on HP ESA models E4404B, E4405B,
NOTE
E4407B, and E4408B.
Range:
Remarks:
Front Panel
Access:
5-96
3 GHz to the maximum frequency of the analyzer
A peak search will be done if no marker is on.
AMPLITUDE/Y Scale, Presel Center
Chapter 5