wm8775 Wolfson Microelectronics plc, wm8775 Datasheet - Page 35

• Manufacturer Part Number: wm8775
• Description: 24-bit, 96khz Adc With 4 Channel I/p Multiplexer
• Manufacturer: Wolfson Microelectronics plc

Production Data
DIGITAL FILTER CHARACTERISTICS
Table 14 Digital Filter Characteristics
ADC FILTER RESPONSES
Figure 25 ADC Digital Filter Frequency Response
ADC HIGH PASS FILTER
The WM8775 has a selectable digital highpass filter to remove DC offsets. The filter response is characterised by the
following polynomial.
Figure 27 ADC Highpass Filter Response
w
PARAMETER
Passband
Passband ripple
Stopband
Stopband Attenuation
Group Delay
ADC Filter
H(z) =
-10
-15
-5
-20
-40
-60
-80
0
0
0
0
1 - 0.9995z
0.5
1 - z
0.0005
-1
-1
1
Frequency (Fs)
Frequency (Fs)
0.001
1.5
TEST CONDITIONS
2
f > 0.5465fs
0.0015
±0.01 dB
-6dB
2.5
0.002
3
0.5465fs
Figure 26 ADC Digital Filter Ripple
MIN
-65
0
-0.005
-0.015
0.015
0.005
-0.01
-0.02
0.02
0.01
0
0
0.05
0.4892fs
TYP
22
0.1
0.15
0.4535fs
0.2
±0.01
Frequency (Fs)
MAX
0.25
0.3
PD, Rev 4.4, October 2008
0.35
UNIT
dB
dB
fs
0.4
0.45
WM8775
0.5
35