Chapter 6  Control Modes of Operation  ASDA-B2 
6-34     Revision May, 2018 
Here illustrates the effect via low-pass filter (parameter P2-25). The following diagram is 
the system open-loop gain with resonance. 
Gain
Frequency
 
When the value of P2-25 is increased from 0, BW becomes smaller (See as the following 
diagram). Although it solves the problem of resonance frequency, the response bandwidth 
and phase margin is reduced.   
0dB
BW
Gain
Frequency
 
If users know the resonance frequency, notch filter (parameter P2-23 and P2-24) can 
directly eliminate the resonance. The frequency setting range of notch filter is merely from 
50 to 1000 Hz. The suppression strength is from 0 to 32 dB. If the resonance frequency is 
not within the range, it is suggested to use low-pass filter (parameter P2-25). 
Here firstly illustrates the influence brought by notch filter (P2-23 and P2-24) and  
low-pass filter (P2-25). The following diagrams are the system of open-loop gain with 
resonance. 
Resonance suppression with notch filter
 
 
 
0db
 
 
 
Notch Filter
 
Attenuation
Rate P2-24
 
 
 
Resonance
Frequency
 
.
Resonance
Point  
Gain
 
Frequency
 
.
Gain
Frequency
Gain
Frequency
Low-pass
Frequency
Low-pass
Frequency
Resonance
Frequency
P2-23
Resonance
conditions
is suppressed
Resonance
Frequency