NARDA IDA, Руководство по эксплуатации, Страница: 104 / 292

6 Common Functions
96
IDA - 3106 Narda
6.5 Setting the video bandwidth (VBW)
Direction Finding
Spectrum
Level Meter
Time Domain (Scope)
I⁄Q Analyzer
The video filter can smooth signals and reduce flutuations. It results in RMS
averaging with an integration time that is affected by the VBW. The selection
of the video filter bandwidth (VBW) is relative to the RBW / CBW setting:
• Spectrum mode: VBW = RBW/10 … RBW/1000 or
Off
• Other operating modes: VBW = CBW/1 … CBW/10000 or
Off
To set the video bandwidth:
1.
Press the
BW
softkey, followed by the
VBW
softkey.

The
Select Video Bandwidth (VBW)
entry box opens.
2.
Use the rotary control knob to select the desired setting and
press the
OK
key.

The selected value is applied. The selected
VBW
is shown in the
lower status bar.
NOTE:
The smaller the VBW, the longer the measurement time (Sweep Time) in
Spectrum mode. The measurement time in other operating modes is
unaffected.
The effective integration time for forming the RMS value can be defined as
follows:
Setting the integration time T-RMS directly
You can set the desired integration time directly on the device in Spectrum
mode. The integration time T-RMS is selected and set instead of the VBW.
The trace label on the measurement screen changes from Actual (Act) to
RMS when you do this.
To set the integration time T-RMS directly:
1.
Press the
BW
softkey, followed by the
Set T-RMS
softkey.

The VBW softkey label changes to T-RMS.
2.
Press the
T-RMS
softkey.

The
Select RMS Integration Time (T-RMS)
entry box opens.
T = 1 / (

× VBW) or T

0.32 / VBW