WM8983 Datasheet, PDF (30/88 Pages) Wolfson Microelectronics plc – Mobile Multimedia CODEC with 1W Speaker Driver

WM8983
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SELECTABLE HIGH PASS FILTER
A selectable high pass filter is provided. To disable this filter set HPFEN=0. The filter has two
modes controlled by HPFAPP. In Audio Mode (HPFAPP=0) the filter is first order, with a cut-off
frequency of 3.7Hz. In Application Mode (HPFAPP=1) the filter is second order, with a cut-off
frequency selectable via the HPFCUT register. The cut-off frequencies when HPFAPP=1 are shown
in Table 14.
REGISTER
ADDRESS
R14
ADC Control
BIT
LABEL
8
HPFEN
7
HPFAPP
6:4
HPFCUT
Table 13 ADC Enable Control
DEFAULT
DESCRIPTION
1
High Pass Filter Enable
0 = disabled
1 = enabled
0
Select audio mode or application mode
0 = Audio mode (1^st order, fc = ~3.7Hz)
1 = Application mode (2^nd order, fc =
HPFCUT)
000
Application mode cut-off frequency
See Table 14 for details.
HPFCUT
[2:0]
SR=101/100
8 11.025 12
SR=011/010
fs (kHz)
16 22.05 24
000
82
113 122 82 113 122
001
102 141 153 102 141 153
010
131 180 156 131 180 156
011
163 225 245 163 225 245
100
204 281 306 204 281 306
101
261 360 392 261 360 392
110
327 450 490 327 450 490
111
408 563 612 408 563 612
Table 14 High Pass Filter Cut-off Frequencies (HPFAPP=1)
SR=001/000
32 44.1 48
82 113 122
102 141 153
131 180 156
163 225 245
204 281 306
261 360 392
327 450 490
408 563 612
Note that the High Pass filter values (when HPFAPP=1) are calculated on the assumption that the
SR register bits are set correctly for the actual sample rate as shown in Table 14.
w
PP Rev 1.1 August 2005
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