wm8952 Wolfson Microelectronics plc, wm8952 Datasheet - Page 66

• Manufacturer Part Number: wm8952
• Description: Mono Adc With Microphone Pre-amplifier
• Manufacturer: Wolfson Microelectronics plc

WM8952
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NOTCH FILTERS AND LOW PASS FILTER
Figure 38 ADC Notch Filter Responses (48kHz); fc=100Hz, 1kHz, 10kHz; fb = 100Hz, 600Hz, 2kHz
Figure 39 ADC Low Pass Filter Responses (48kHz); fc= 1kHz, 5kHz, 10kHz
R
E
S
P
O
N
S
E
(dB)
R
E
S
P
O
N
S
E
(dB)
-10
-15
-20
-25
-30
-35
-40
-45
-50
-55
-60
+0
-5
-10
-15
-20
-25
-30
-35
-40
-45
-50
-55
-60
+0
20
-5
20
50
50
The WM8952 supports four programmable notch filters. The fourth notch filter can be configured as
a low pass filter. The following illustrates three digital notch filters, followed by a single low pass filter
in the ADC filter path. Both the centre frequency and -3dB bandwidth are programmable for the
notch filters. The cut off frequency is programmable for the low pass filter. The following graphs
show the responses of 1) a single notch filter at three chosen centre frequencies, with three
bandwidths for each, 2) the low pass filter at three chosen cut off frequencies and 3) the cascade of
three notch filters followed by the low pass filter, each with a different centre / cut off frequency with
three bandwidths for each.
100
100
200
200
500
500
Frequency (Hz)
Frequency (Hz)
1k
1k
2k
2k
5k
5k
PP, Rev 3.0, December 2008
10k
10k
20k
Pre Production
20k
T T
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