HBM Genesis GEN5i User Manual page 407

FIR (Fc @ -3 dB) filter
When FIR (Fc @ -3 dB) filter is selected, this is always a combination of an analog Butterworth anti alias filter and a digital FIR (Fc @ -3 dB)
filter. Adapted FIR filter with ωp reduced by a factor of ≈1.4 compared to the FIR (Fc @ -0.1 dB) filter. Supported by Perception V6.40 and
higher.
Analog anti aliasing filter bandwidth
Analog anti aliasing filter characteristic
FIR (Fc @ -3 dB) filter characteristic
FIR (Fc @ -3 dB) filter user selection
FIR (Fc @ -3 dB) filter bandwidth (ωc)
FIR (Fc @ -3 dB) filter passband flatness (ωp)
FIR (Fc @ -3 dB) filter stopband attenuation (δs)
FIR (Fc @ -3 dB) filter roll-off
(1) Measured using Fluke 5700 calibrator, DC normalized
I2679-4.0 en
Figure A.58: Digital FIR (Fc @ -3 dB) filter
370 kHz ± 20 kHz (-3 dB)
7-pole Butterworth, extended passband response
12-pole FIR; FIR is a pure digital characteristic. Closest analog resemblance to elliptic filters,
however FIR has both overshoot on step response and pre-shoot to step response. This
means ringing on the signal starts before the step input starts and the ringing continues
after the step input ends.
Auto tracking to sample rate divided by: 4, 10, 20, 40
Auto tracking the sample rate with the selected FIR (Fc @ -3 dB) filter user selection from
0.031 Hz to 50 kHz
0.1 dB; DC to ≈ωc/1.4 (Adapted FIR filter behavior)
(1)
-60 dB
-72 dB/Octave
Figure A.59: Typical FIR (Fc @ -3 dB) ωc = 50 kHz, Overview and passband flatness
GEN5i
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