Chapter 6  Control Mode of Operation  ASDA-A2 
6-44     Revision February, 2017 
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.