WM8770
Production Data
ADC FILTER RESPONSES
0.02
0.015
0.01
0
-20
-40
-60
-80
0.005
0
-0.005
-0.01
-0.015
-0.02
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0
0.5
1
1.5
2
2.5
3
Frequency (Fs)
Frequency (Fs)
Figure 32 ADC Digital Filter Ripple
Figure 31 ADC Digital Filter Frequency Response
ADC HIGH PASS FILTER
The WM8770 has a selectable digital highpass filter to remove DC offsets. The filter response is characterised by the
following polynomial.
1 - z-1
H(z) =
1 - 0.9995z-1
0
-5
-10
-15
0
0.0005
0.001
Frequency (Fs)
0.0015
0.002
Figure 33 ADC Highpass Filter Response
PD Rev 4.1 June 2005
46
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