WM8940
Pre-Production
HIGHPASS FILTER
The WM8940 has a selectable digital high pass filter in the ADC filter path. This filter has two
modes, audio and applications. In audio mode the filter is a 1st order IIR with a cut-off of around
3.7Hz. In applications mode the filter is a 2nd order high pass filter with a selectable cut-off
frequency.
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Figure 42 ADC High pass Filter Response, HPFAPP=0
Figure 43 ADC High pass Filter Responses (48kHz),
HPFAPP=1, all cut-off settings shown.
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Figure 44 ADC High pass Filter Responses (24kHz),
HPFAPP=1, all cut-off settings shown.
Figure 45 ADC Highpass Filter Responses (12kHz),
HPFAPP=1, all cutoff settings shown.
Pre-Production, Rev 3.0, February 2007
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