ASDA-B2  Chapter 6  Control Modes of Operation 
Revision May, 2018     6-35 
Resonance suppression with low-pass filter 
 
Low-pass Filter
 
 
 
Cut-off Frequency
of Low-pass Filter
 
= 10000 / P2-25 Hz
-
 
 
0db
 
 
 
Resonance
conditions
is suppressed
 
 
.
 
 
 
 
.
 
Gain
Frequency
Gain
Frequency
Gain
Frequency
Low-pass
Frequency
Low-pass
Frequency
Resonance
Frequency
Attenuation
Rate -3db
Resonance
Point
Resonance
Frequency
 
When the value of P2-25 is increased from 0, BW becomes smaller. Although it solves the 
problem of resonance frequency, the response bandwidth and phase margin is reduced. 
Also, the system becomes unstable. 
If users know the resonance frequency, notch filter (parameter P2-23 and P2-24) can 
directly eliminate the resonance. In this case, notch filter will be more helpful than low-pass 
filter. However, if the resonance frequency drifts because of time or other factors, notch 
filter will not do.