VTI Instruments Corp.
316
EX1629 Filtering
D
IGITAL
F
ILTERS
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
T
ABLE
B-1:
D
IGITAL
F
ILTER
D
ATA