HBM GEN3i, Руководство пользователя

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Butterworth IIR Filter (Digital Anti
-
Alias)
Passband Stopband
Magnitude [dB]
δp: Passband ripple
δs: Stopband attenuation
ωp:
ωc:
Passband frequency
Corner frequency
Stopband frequency ωs:
ωp ωs
Frequency [kHz]
ωc
1 + δp
1 - δp
-3 dB
δs
Figure A.142: Digital Butterworth IIR Filter
When Butterworth IIR filter is selected, this is always a combination of an analog Butterworth anti
-
alias filter and a digital Butterworth IIR filter.
Analog anti
-
alias filter bandwidth 450 kHz
±
25 kHz (
-
3 dB)
Analog anti
-
alias filter characteristic 7
-
pole Butterworth, extended passband response
Butterworth IIR filter characteristic 8
-
pole Butterworth style IIR
Butterworth IIR filter user selection Auto tracking for sample rate divided by: 4, 10, 20, 40
The user selects a division factor from the current sample rate; software then adjusts the
filter when the sample rate is changed.
Butterworth IIR filter bandwidth (ωc) User selectable from 1 Hz to 50 kHz
Butterworth IIR 0.1 dB passband (ωp)
(1) DC to 0.7 * ωc
Butterworth IIR filter stopband attenuation (δs) 75 dB
Butterworth IIR filter roll
-
off 48 dB/octave
Frequency [kHz]
Magnitude
[dB]
Frequency [kHz]
Magnitude [dB]
Frequency [kHz]
Magnitude
[dB
]
Frequency [kHz]
Magnitude
[dB
]
20 V: Butterworth 50 kHz Passband flatness 20 V: Butterworth 50 kHz overview
4 V: Butterworth 50 kHz overview 4 V: Butterworth 50 kHz
Passband flatness
100 10 1 0.1
100 10 1 0.1
-130
-150
-110
-90
-70
-50
-30
-10
10
-130
-150
-110
-90
-70
-50
-30
-10
10
0.1 1 10 100 1000 10000
0.1 1 10 100 1000 10000
0.2
0.1
0
0.05
0.15
-0.1
-0.15
-0.05
-0.2
Magnitude
[%]
0
2.33
1.74
1.15
0.57
-0.57
-1.14
-1.71
-2.28
0.2
0.1
0
0.05
0.15
-0.1
-0.15
-0.05
-0.2
Magnitude
[%]
0
2.33
1.74
1.15
0.57
-0.57
-1.14
-1.71
-2.28
Figure A.143: Representative Butterworth IIR examples
(1) Measured using a Fluke 5700A calibrator, DC normalized
GEN3i
I3763-3.1 en HBM: public 555