WM8904ECSSLASHR datasheet(70/188 Pages) WOLFSON

70 / 188 page

WM8904

Pre-Production

PP, Rev 3.3, September 2012

DAC SLOPING STOPBAND FILTER

Two DAC filter types are available, selected by the register bit DAC_SB_FILT. When operating at

sample rates <= 24kHz (eg. during voice communication) it is recommended that the sloping

stopband filter type is selected (DAC_SB_FILT=1) to reduce out-of-band noise which can be audible

at low DAC sample rates. See “Digital Filter Characteristics” for details of DAC filter characteristics.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R33 (21h)

DAC Digital 1

DAC_SB_FILT

Selects DAC filter characteristics

0 = Normal mode

1 = Sloping stopband mode

(recommended when fs

24kHz

Table 38 DAC Sloping Stopband Filter

DAC OVERSAMPLING RATIO (OSR)

The DAC oversampling rate is programmable to allow power consumption versus audio performance

trade-offs. The default oversampling rate is low for reduced power consumption; using the higher

OSR setting improves the DAC signal-to-noise performance.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R33 (21h)

DAC Digital 1

DAC_OSR128

DAC Oversample Rate Select

0 = Low power (normal OSR)

1 = High performance (double OSR)

Table 39 DAC Oversampling Control

WM8904ECS/R 数据表(PDF) 70 Page - Wolfson Microelectronics plc

WM8904ECS/R 数据表(HTML) 70 Page - Wolfson Microelectronics plc

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