VTI Instruments EX1629 - Digital Filters

VTI Instruments Corp.
316 EX1629 Filtering
DIGITAL FILTERS
The following table provides detailed information concerning the digital filters used by the ADC
of the EX1629. For more information on digital filtering, Discrete-Time Signal Processing (2nd
Edition) by Alan Oppenheim could be used as a reference.
f
s
f
c
max
CIC
dec
FIR
dec
60 Hz
rejection
(dB)
GD for IIR
N=4 (samples)
GD for IIR
N=6 (samples)
GD for IIR
N=8 (samples)
GD for IIR
N=10 (samples)
Delay up to
IIR
(samples)
50000
22650
1
1
39.00000
25000
11500
1
2
51.00000
12500
5255
1
4
25.62000
10000
4005
1
5
20.50000
6250
2130
1
8
12.81200
5000
1505
1
10
10.25000
3125
937.50
2
8
9.71875
2500
970.00
4
5
15.02500
2000
776.00
5
5
14.66000
1250
485.00
8
5
14.11250
1000
388.00
10
5
0.949274
1.403572
1.862067
2.322195
13.93000
833.33
323.33
12
5
0.479686
0.709252
0.940938
1.173450
13.80833
625
242.50
16
5
0.479686
0.709252
0.940938
1.173450
13.65625
500
194.00
20
5
0.479686
0.709252
0.940938
1.173450
13.56500
400
155.20
25
5
0.479686
0.709252
0.940938
1.173450
13.49200
250
97.00
40
5
0.479686
0.709252
0.940938
1.173450
13.38250
200
77.60
50
5
0.479686
0.709252
0.940938
1.173450
13.34600
166.67
64.67
60
5
0.479686
0.709252
0.940938
1.173450
13.32167
125
48.50
80
5
0.479686
0.709252
0.940938
1.173450
13.29125
100
38.80
100
5
0.479686
0.709252
0.940938
1.173450
13.27300
80
31.04
125
5
0.479686
0.709252
0.940938
1.173450
13.25840
50
19.40
200
5
0.479686
0.709252
0.940938
1.173450
13.23650
40
15.52
250
5
0.479686
0.709252
0.940938
1.173450
13.22920
33.33
12.93
300
5
0.479686
0.709252
0.940938
1.173450
13.22433
25
9.70
400
5
0.479686
0.709252
0.940938
1.173450
13.21825
20
7.76
500
5
>100 dB
0.479686
0.709252
0.940938
1.173450
13.21460
16
6.21
625
5
>100 dB
0.479686
0.709252
0.940938
1.173450
13.21168
10
3.88
1000
5
>100 dB
0.479686
0.709252
0.940938
1.173450
13.20730
8
3.10
1250
5
>100 dB
0.479686
0.709252
0.940938
1.173450
13.20584
5
1.94
2000
5
>100 dB
0.479686
0.709252
0.940938
1.173450
13.20365
4
1.55
2500
5
Infinite
0.479686
0.709252
0.940938
1.173450
13.20292
2
0.78
5000
5
Infinite
0.479686
0.709252
0.940938
1.173450
13.20146
1
0.39
10000
5
Infinite
0.479686
0.709252
0.940938
1.173450
13.20073
TABLE B-1: DIGITAL FILTER DATA