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Chapter 5
Test and Measurement Functions
Spectrum Analyzer
Rev. 001
CX300 ComXpert Operation Manual
22130634
5 - 64
February, 2022
VBW Mode
This toggle switch selects whether or not the Video Bandwidth
(VBW) is configured manually by the user or automatically by
the system.
Auto
When
Auto
is selected the system sets VBW the best
appropriate setting based on detected signal characteristics
and the
RBW/VBW
setting.
Manual
When
Manual
is selected, the VBW menu is enabled which
allows the user to define the
VBW
value to a specific setting.
VBW
This setting is enabled when
VBW Mode
is set to
Manual
.
The Spectrum Analyzer includes a low pass filter, called the
video filter, in the signal path following the detector. The video
filter reduces high frequency noise on the detected signal and
allows low level signals to be identified which would otherwise
be buried in the noise. The bandwidth of the video filter is called
the video bandwidth, or VBW.
VBW helps improve resolution of weak signals in the presence
of the noise signal. The narrower the VBW, the less noise there
is in the output signal; however, the narrower the bandwidth,
the longer the sweep time.
NOTE
Values can be set within the range of 1 Hz to 5 MHz.
VBW/RBW
When
VBW Mode
is set to
Auto
; this setting is used by the
system to determine the VBW setting based on the RBW
setting.
Table 5-38 Spectrum Analyzer Bandwidth Controls and Settings (Continued)
Control/Setting
Description