WM8711_06 Datasheet, PDF (17/47 Pages) Wolfson Microelectronics plc – Internet Audio DAC with Integrated Headphone Amplifier

Production Data
WM8711 / WM8711L
AUDIO SIGNAL PATH
DAC FILTERS
The DAC filters perform true 24 bit signal processing to convert the incoming digital audio data from
the digital audio interface at the specified sample rate to multi-bit oversampled data for processing by
the analogue DAC. Figure 6 illustrates the DAC digital filter path.
FROM DIGITAL
AUDIO
INTERFACE
DIGITAL
DE_EMPHASIS
MUTE
DIGITAL
INTERPOLATION
FILTER
TO LINE
OUTPUTS
DEEMP
DACMU
Figure 6 DAC Filter Schematic
The DAC digital filter can apply digital de-emphasis under software control, as shown in Table 3. The
DAC can also perform a soft mute where the audio data is digitally brought to a mute level. This
removes any abrupt step changes in the audio that might otherwise result in audible clicks in the
audio outputs.
REGISTER
ADDRESS
0000101
Digital Audio
Path Control
BIT
2:1
LABEL
DEEMP[1:0]
DEFAULT
00
3
DACMU
1
Table 3 DAC Software Control
DESCRIPTION
De-emphasis Control
(Digital)
11 = 48kHz
10 = 44.1kHz
01 = 32kHz
00 = Disable
DAC Soft Mute Control
(Digital)
1 = Enable soft mute
0 = Disable soft mute
w
PD Rev 4.3 September 2006
17