Filter
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Channel Power Measurement
BW
Filter Type
Selects the type of bandwidth filter that is used. The choices are Gaussian or Flat top.
Couplings: Video bandwidth (VBW) is coupled to the RBW. As the resolution bandwidth
changes, the video bandwidth (if set to Auto) changes to maintain the ratio set
by VBW/RBW.
Sweep Time is coupled to the 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, or in
zero span, the VBW setting has no effect and is disabled (grayed out).
When the video bandwidth is AUTO coupled, the video bandwidth value is set
to:
Resolution Bandwidth * Video Bandwidth to Resolution Bandwidth Ratio
Preset: WCDMA: 2.4MHz
C2K: 240 kHz
WIMAX OFDMA: Auto
1xEVDO: 300 kHz
LTE: Auto
LTETDD: Auto
WLAN: Auto
ON
State Saved: Saved in instrument state.
Min: 1 Hz
Max: 50 MHz
Initial S/W Revision: Prior to A.02.00
Modified at S/W Revision: A.02.00, A.03.00
Key Path:
BW
Mode: WCDMA, C2K, WIMAX OFDMA, 1xEVDO, LTE, LTETDD, WLAN