Proper Preselector Operation - Keysight x-series User Reference Manual

Status Bits/OPC
dependencies
Initial S/W Revision
Modified at S/W Revision

Proper Preselector Operation

A number of considerations should be observed to ensure proper operation:
1. If the selected marker is off, the analyzer will turn on a marker, perform a peak search, and adjust the
preselector using the selected marker's frequency. It uses the "highest peak" peak search method
unqualified by threshold or excursion, so that there is no chance of a 'no peak found' error. It continues
with that peak, even if it is the peak of just noise. Therefore, for this operation to work properly, there
should be a signal on screen in a preselected range for the peak search to find.
2. If the selected marker is already on, the analyzer will attempt the centering at that marker's frequency.
There is no preselector for signals below about 3.6 GHz, therefore if the marker is on a signal below 3.6
GHz, no centering will be attempted and an advisory message generated
3. In some models, the preselector can be bypassed. If it is bypassed, no centering will be attempted in
that range and a message will be generated.
Preselector Adjust
Allows you to manually adjust the preselector filter frequency to optimize its response to the signal of
interest. This function is only available when
For general purpose signal analysis, using Presel Center is recommended. Centering the filter minimizes
the impact of long-term preselector drift. Presel Adjust can be used instead to manually optimize the
preselector. One application of manual optimization would be to peak the preselector response, which
both optimizes the signal-to-noise ratio and minimizes amplitude variations due to small (short-term)
preselector drifting.
Key Path
Scope
Remote Command
Example
EMI Receiver Mode Reference
If the analyzer s in a measurement such as averaging when centering is initiated, the act of centering
the preselector will restart averaging but the first average trace will not be taken until the centering
is completed.
When centering the preselector, *OPC will not return true until the process is complete and a
subsequent measurement has completed, nor will results be returned to a READ or MEASure
command.
The Measuring bit should remain set while this command is operating and should not go false until
the subsequent sweep/measurement has completed.
Prior to A.02.00
A.03.00
"Presel Center" on page 897
AMPTD Y Scale
Meas Global
[:SENSe]:POWer[:RF]:PADJust <freq>
[:SENSe]:POWer[:RF]:PADJust?
POW:PADJ 100KHz
POW:PADJ?
9 Strip Chart Measurement
AMPTD Y Scale
is available.
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