Keysight x-series User Manual

3 Spectrum Analyzer Mode
3.13 Phase and Amplitude vs Time Measurement
In N9041B, Software Preselection only applies for frequencies above 50GHz,
therefore it is only used for RF Input 2. Even if turned on, it is not used for other
inputs, and never for frequencies below 50GHz. This is why the label of this control
contains the parenthetical note “(>~50GHz)”.
Note that in N9041B, in Swept SA measurement, Software Preselection works even
if the measurement is using an FFT Sweep Type. In measurements other than Swept
SA, Software Preselection is not used if the measurement is using an FFT sweep
type.
N9042B+V3050A
Software Preselection compensates for the frequency range limit of the microwave
preselector. Since the microwave preselector only goes up to 50GHz, software
preselection must be used to suppress and separate images above 50GHz. The
specific algorithm used for software preselection is specified by the SW Preselection
Type selection – Normal or Advanced.
For N9042B+V3050A, Software Preselection only applies for frequencies above
50GHz, therefore it is only used for External RF. Even if it is turned on, it will not be
used for other inputs and never for frequencies below 50GHz. This is why the label
of this control contains the parenthetical note “(>~50GHz)”.
Note that for N9042B+V3050A, in the Swept SA measurement, Software
Preselection works even if the measurement is using an FFT Sweep Type. In
measurements other than Swept SA, Software Preselection is not used if the
measurement is using an FFT Sweep Type.
VXT models M9410A/11A/15A/16A
Software Preselection is used to provide the preselection function, as there is no
hardware preselector in these models. Two background traces are taken and
compared point by point, and the point with the lowest amplitude from the two
traces is used. This provides a method to reduce spurs that are internally generated
within the VXT, but you should note the following when using Software Preselection:
–
There is some speed cost due to the need to take multiple captures
–
Taking the point with the lowest amplitude in each trace will make the average
noise level lower at all points that do not have a spur. This can reduce the
accuracy of the measurement of noise and noise-like signals
Because of the difficulty in identifying spurs manually, you are recommended to
leave Software Preselection ON at all times in VXT models M9410A/11A. If you turn it
off in order to speed up your measurement or improve noise accuracy, be aware of
unwanted onscreen spurs.
Remote Command
[:SENSe]:POWer[:RF]:SWPResel:STATe 0 | 1 | ON | OFF
Spectrum Analyzer Mode User's &Programmer's Reference 1993

Keysight x-series Specifications

General

Analysis Bandwidth	Up to 1 GHz (depending on model)
Real-Time Bandwidth	Up to 1 GHz (depending on model)
Form Factor	Benchtop
Connectivity	LAN, USB, GPIB
Resolution Bandwidth	1 Hz to 10 MHz (depending on model)