Keysight x-series User Manual

3 Spectrum Analyzer Mode
3.2 Swept SA Measurement
Video BW
Lets you change the instrument post-detection filter (VBW or “video bandwidth”)
from 1Hz to 8MHz in approximately 10% steps. In addition, a wide-open video filter
bandwidth may be chosen by selecting 50MHz. The VBW is annotated at the
bottom of the display, in the center.
NOTE
An asterisk (*) is displayed next to the VBW annotation when certain detector
types (Average, EMI Average, Quasi Peak, and RMS Average) are in use. This
is because the VBW filter is out of the circuit for these detectors and does not
affect any traces that use them. If there is any active trace using one of these
detectors, * is displayed. See "Annotation Examples" on page 250.
Normally, Video BW (Auto) selects automatic coupling of Video BW to Res BW using
the ratio set by "VBW:3dB RBW" on page 251. To decouple the resolution
bandwidth, press the Auto/Man toggle on Video BW, or simply enter a different
value for Video BW.
When Video BW is manually selected, it may be returned to the coupled state by
pressing the Auto/Man toggle on Video BW. This may also be done by pressing
"Auto Couple" on page 2017 or by performing a Preset.
Remote Command
[:SENSe]:BANDwidth|BWIDth:VIDeo <freq>
[:SENSe]:BANDwidth|BWIDth:VIDeo?
Example
:BAND:VID 1 KHZ
:BAND:VID?
Notes For numeric entries, the instrument selects the nearest (arithmetically, on a linear scale, rounding up)
available Video BW to the value entered. The 50MHz VBW is defined to mean “wide open”
The values shown in this table reflect the conditions after Mode Preset
Dependencies Sometimes the displayed Video BW is not actually used to process the trace data:
–
When the Average"Detector" on page 521 is selected and Sweep Type is set to Swept, the video
bandwidth filter cannot be used, because it uses the same hardware as the Average Detector
–
When the Quasi-Peak, EMI Average, or RMS AverageDetector is selected, Video BW is
implemented by the digital IF as part of the detector
When this is the case, Video BW still acts to change "Sweep Time" on page 480, if Sweep Time is in
Auto, and still affects the data on other traces for which this is not the case
In VXT, when in Zero Span, this control does not appear
Couplings Video BW (VBW) is normally coupled to Res BW. If VBW is set to Auto, then Video BW changes as Res
BW changes, to maintain the ratio set by VBW:3dB RBW (usually 10:1 for measurements that do not
have VBW:3dB RBW)
Preset Auto (unless noted in table below)
Spectrum Analyzer Mode User's &Programmer's Reference 249

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)