User Manual

84 Chapter 2
Instrument Functions: A - L
BW/Avg
Instrument Functions: A - L
Factory Preset: Auto (3 MHz)
Range: 1 Hz to 8 MHz
Remote Command:
[:SENSe]:BANDwidth|BWIDth[:RESolution] <freq>
[:SENSe]:BANDwidth|BWIDth[:RESolution]?
[:SENSe]:BANDwidth|BWIDth[:RESolution]:AUTO OFF|ON|0|1
[:SENSe]:BANDwidth|BWIDth[:RESolution]:AUTO?
Example: BAND 1 kHz
BAND?
BWID:AUTO On
BWID:AUTO?
2.2.2 Video BW
Enables you to change the analyzer post-detection filter from 1 Hz to 8 MHz in
approximately 10% steps. In addition, a wide-open video filter bandwidth (VBW) may be
chosen by selecting 50 MHz.
Video BW (Auto) selects automatic coupling of the Video BW
filter to the resolution bandwidth filter using the VBW/RBW ratio set by the VBW/RBW key.
NOTE Sweep Time is coupled to Video Bandwidth (VBW). As the VBW is changed,
the sweep time (when set to Auto) is changed to maintain amplitude
calibration. This occurs because of common hardware between the two
circuits, even though the Video BW filter is not actually “in-circuit” when the
detector is set to Average. Because the purpose of the average detector and
the VBW filter are the same, either can be used to reduce the variance of the
result.
Although the VBW filter is not “in-circuit” when using the average detector,
the Video BW key can have an effect on (
Auto) sweep time, and is not disabled.
In this case, reducing the VBW setting increases the sweep time, which
increases the averaging time, producing a lower-variance trace.
When using the average detector with either
Sweep Time set to Man,orinzero
span, the VBW setting has no effect and is disabled (greyed out).
A“#” mark appears next to VBW on the bottom of the analyzer display when it is not
coupled. To couple the video bandwidth, press
Video BW (Auto) (or press Auto All).
Key Path:
BW/Avg
Saved State: Saved in Instrument State