Genesis GEN3t, Руководство пользователя

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FIR (Fc @
-
3 dB) Filter (Digital Anti
-
Alias)
Passband Stopband
δp : Passband ripple
δs : Stopband attenuation
ωp
ωc
ωs
: Passband frequency
: Corner frequency
: Stopband frequency
-3 dB
Frequency [kHz]
Magnitude [dB]
+ δp
- δp
δs
ωp ωs ωc
Figure A.33: Digital 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 filter
Analog anti
-
alias filter
Characteristic
7
-
pole Butterworth, extended pass band response
Bandwidth 140 kHz
±
20 kHz (
-
3 dB) All Ranges < 100 mV
350 kHz
±
20 kHz (
-
3 dB) All Ranges ≥ 100 mV
Digital FIR (Fc @
-
3 dB) filter
Characteristic
12
-
pole FIR; FIR is a purely digital characteristic. Its closest analog resemblance is to an
Elliptic filter. However, FIR has both ringing on the signal before the step input is started
and ringing after the step input is complete.
User selection Auto tracking for sample rate divided by: 4, 10, 20, 40
Bandwidth (ωc) User selectable from 0.031 Hz to 50 kHz
0.1 dB passband flatness (ωp)
(1) DC to ≈ωc/1.4 (adapter FIR filter behavior)
For all Ranges < 100 mV, ωp is limited to 10 kHz due to anti
-
alias filter
Stopband attenuation (δs) 60 dB
Roll
-
off
72 dB/Octave
Frequency [kHz]
1000 100 10 1 0.1
Frequency [kHz]
Magnitude [dB]
-150
-130
-110
-90
-70
-50
-30
-10
10
Magnitude [dB]
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
10000 1000 100 10
1
0.1
±20 mV FIR (Fc @-3 dB) 50 kHz Overview ±20 mV FIR (Fc @-3 dB) 50 kHz Passband flatness
0
Magnitude [%]
Magnitude [dB] Magnitude [dB]
Magnitude [%
]
2.33
1.74
1.15
0.57
-0.57
-1.14
-1.71
-2.28
Frequency [kHz]
1000 100 10 1 0.1
Frequency [kHz]
-150
-130
-110
-90
-70
-50
-30
-10
10
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
10000 1000 100 10
1
0.1
±1 V FIR (Fc @-3 dB) 50 kHz Overview ±1 mV FIR (Fc @-3 dB) 50 kHz Passband flatness
0
2.33
1.74
1.15
0.57
-0.57
-1.14
-1.71
-2.28
Figure A.34: Representative FIR examples
(1) Measured using a Fluke 5700 calibrator, DC normalized
GEN3t
I3995-3.1 en HBM: public 449