wm8987 Wolfson Microelectronics plc, wm8987 Datasheet - Page 52

• Manufacturer Part Number: wm8987
• Description: Stereo Codec For Portable Audio Applications
• Manufacturer: Wolfson Microelectronics plc

WM8987L
Figure 40 De-emphasis Frequency Response (44.1kHz)
Figure 42 De-emphasis Frequency Response (48kHz)
w
HIGHPASS FILTER
The WM8987L has a selectable digital highpass filter in the ADC filter path to remove DC offsets. The filter response is
characterised by the following polynomial:
Figure 44 ADC Highpass Filter Response
-10
-10
-2
-4
-6
-8
-2
-4
-6
-8
-10
-15
0
0
-5
0
0
0
0
5000
5000
0.0005
Frequency (Fs)
Frequency (Fs)
Frequency (Fs)
10000
10000
0.001
H(z) =
0.0015
15000
15000
1 - 0.9995z
1 - z
20000
20000
0.002
-1
Figure 41 De-emphasis Error (44.1kHz)
Figure 43 De-emphasis Error (48kHz)
-1
-0.1
-0.2
-0.3
-0.4
-0.1
-0.2
-0.3
-0.4
0.4
0.3
0.2
0.1
0.4
0.3
0.2
0.1
0
0
0
0
5000
5000
Frequency (Fs)
Frequency (Fs)
10000
10000
PD Rev 4.0 August 2008
15000
15000
Production Data
20000
20000
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