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App-14

IM 701210-06E

Appendix 5 User-Defined Computation

Digital Filter

Type

Type Bandwidth

Gaussian LowPass

Sharp LowPass/HighPass/BandPass

IIR (Butterworth) LowPass/HighPass/BandPass

Filter Order

See the following table for the filter orders

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 Attenuation Slope Attenuation at the Phase

Ripple Stop-band

Gauss 0dB

– Linear phase

Sharp ±0.3 dB –40 dB at 1 oct (Lowpass), –40 dB Linear phase

–40 dB at –1oct (Highpass)

IIR 0 dB –5 dB at 1/6 oct (Lowpass), Not linear phase

–20 dB at –1 oct (Highpass) –

1. For Gaussian filter : –3.0× (f/fc) 2 dB (f : frequency, fc : cutoff frequency)

Frequency Characteristics of Filters

f: Sampling frequency (Hz)

Gauss(Cutoff: 10%) Sharp(Low Pass, Cutoff: 10%) IIR(Low Pass, Cutoff: 10%)

Note

The higher the filter order the longer it takes for computation.

YOKOGAWA DL750 User Manual

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