WM8985
Pre-Production
Figure 22 Noise Gate Operation
OUTPUT SIGNAL PATH
The WM8985 output signal paths consist of digital application filters, up-sampling filters, stereo Hi-Fi
DACs, analogue mixers, stereo headphone and stereo line/mono/midrail output drivers. The digital
filters and DAC are enabled by register bits DACENL and DACENR. The mixers and output drivers
can be separately enabled by individual control bits (see Analogue Outputs). Thus it is possible to
utilise the analogue mixing and amplification provided by the WM8985, irrespective of whether the
DACs are running or not.
The WM8985 DACs receive digital input data on the DACDAT pin. The digital filter block processes
the data to provide the following functions:
Digital volume control
Graphic equaliser
A digital peak limiter
Sigma-Delta Modulation
High performance sigma-delta audio DAC converts the digital data into an analogue signal.
PP, Rev 3.4, October 2006
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
