App-9
App
IM 701830-01E
Appendix
Appendix 6 About User Defined Computations
Digital Filter
Type
Type
Band
Gaussian
LowPass
Sharp
LowPass/HighPass/BandPass
IIR(Butterworth)
LowPass/HighPass/Bandpass
Filter order
The following figure shows the filter order.
2%
5%
10% 20% 30%(Cutoff)
Gauss
LowPass
49
21
9
5
5
Sharp
LowPass
88
36
18
9
8
HighPass
159
65
33
17
13
IIR
LowPass
4
4
4
3
2
HighPass
4
4
4
4
3
Filter characteristics
Filter
Pass-band ripple
Attenuation slope
Attenuation at stop-band
Phase
Gauss
0dB
*1
-
Linear phase
Sharp
±
0.3dB
-40dB at 1oct(Lowpass),
-40dB
Linear phase
-40dB at -1oct(Highpass)
IIR
0dB
-5dB at 1/6oct(Lowpass),
No linear phase
-20dB at -1oct(Highpass)
-
* Attenuation in the case of Gaussian filter : -3.0x(f/fc)
2
dB (f : frequency, fc : cutoff frequency)
Frequency characteristics of each filter
f : frequency(Hz)
Gauss(Cutoff : 10%)
Sharp(Low Pass, Cutoff10%)
IIR(Low Pass, Cutoff10%)
Note
The higher the order of the filter the more time it takes for the computation.