RIGOL DSA875 - Manual (Page 76)

RIGOL Chapter 2 Front Panel Operation
User’s Guide for DSA800 Series 2-24
VBW
Set the desired video bandwidth in order to filter out the noise outside the video
band.
Key Points:
 Reducing the VBW will smooth the spectrum line to differentiate small signals
from noise, but will increase the sweep time (Sweep Time is affected by a
combination of RBW and VBW when it is in Auto mode).
 VBW varies with RBW when it is set to Auto. While in Manual mode, VBW is
not affected by RBW.
 You can modify this parameter using the numeric keys, knob or direction keys.
For more details, please refer to “Parameter Setting”.
Table 2-14 VBW
Parameter Explanation
Default 1 MHz
Range 1 Hz to 3 MHz
Unit GHz, MHz, kHz, Hz
Knob Step in 1, 3, 10 sequence
Direction Key Step in 1, 3, 10 sequence
V/R Ratio
Set the ratio of VBW to RBW.
Key Points:
 This value is different while measuring different kinds of signals:
Sine signal: use 1 to 3 (for faster sweeps)
Pulse signal: use 10 (to reduce the influence on the amplitude of transient
signals)
Noise signal: generally use 0.1 (to obtain the average of noises)
 You can modify this parameter using the numeric keys, knob or direction keys.
For more details, please refer to “Parameter Setting”.