Description of the Software Modules and Parameters
Parameter manual b maXX BM3000
Document no.: 5.12001.07
237
of 820
4
– Biquad filters
n Filter function
n The filter amplitude increases from the cutoff frequency counter onwards.
n The filter amplitude decreases from the cutoff denominator onwards.
n The slope is set via the damping.
– Elliptical filters
n Low-pass filter with steep transition between passband and stopband from the set
cutoff frequency onwards.
n Stopband damping corresponds to the amplitude in the stopband ripple (negative
setting [db])
n Passband ripple corresponds to the amplitude's fluctuation of the passband
The filters are exemplified in the following table. The following settings were selected for
the individual filters:
Pt
1
bilinear Cutoff frequency 100 Hz
Notch filter
Cutoff frequency 200 Hz
Band width 100 Hz
Biquad filter
Cutoff frequency numerator 200 Hz
Cutoff frequency denominator 100 Hz
Damping numerator 0.1
Damping denominator 0.7
Elliptical filter
Order 4
Cutoff frequency 200 Hz
Block damping -40 dB
Passband ripple 3 dB
Fs
s
2
2d
z
z
z
z
++
s
2
2d
x
x
x
2
++
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