Appendix 4 User-Defined Computation - YOKOGAWA DL7440 User Manual

Appendix 4 User-Defined Computation

Digital Filter
Gauss (Cutoff 10%)
App-18
Type
Type Bandwidth
Gauss Low-pass
Sharp Low-pass, high-pass, and band-pass
IIR (Butterworth) Low-pass, high-pass, and band-pass
Filter Order
See the following table for the filter orders
Gauss Low-pass
Sharp Low-pass
High-pass
IIR Low-pass
High-pass
* The cutoff percentage is with respect to the sample rate.
Filter Characteristics
Filter Pass-band
Ripple
Gauss 0 dB
Sharp ±0.3 dB
IIR 0 dB
* For Gaussian filter : –3.0 × (f/fc)
Frequency Characteristics of Filters
f: Frequency (Hz)
Sharp (Low Pass, Cutoff 10%)
Note
The higher the filter order the longer it takes for computation.
2% 5% 10% 20%
49 21 9 5
88 36 18 9
159 65 33 17
4 4 4 3
4 4 4 4
Attenuation Slope
*
–40 dB per octave (low-pass),
–40 dB per octave (high-pass)
–5 dB per 1/6 octave (low-pass),
–20 dB per octave (high-pass)
2
dB (f : frequency, fc : cutoff frequency)
30% (Cutoff*)
5
8
13
2
3
Attenuation at Phase
the Stop-band
– Linear phase
–40 dB Linear phase
Not linear
– phase
IIR (Low Pass, Cutoff 10%)
IM 701450-01E