Wm8776 Application; Block Diagram; Audio Sample Rate - Vizio VX32L Service Manual

WM8776 Application

The WM8776 is a high performance, stereo audio codec with five channel input selector. The
WM8776 is ideal for surround sound processing applications for home hi-fi, DVD-RW and other
audiovisual equipment. Etch ADC channel has programmable gain control with automatic level
control. Digital audio output word lengths from 16-32 bits and sampling rates from 32kHZ to 96KHZ
are supported. The DAC has an input mixer allowing an external analogue signal to be mixed with
the DAC signal. There are also Headphone and line outputs, with control for the headphone
The WM8776 supports fully independent sample rates for the ADC and DAC. The audio data
interface supports I2S, left justified, right justified and DSP formats.

BLOCK DIAGRAM

1. Audio sample rate

The master clock forWM8776 supports DAC and ADC audio sampling rates 256fs to 768fs, where
fs is the audio sample frequency (DACLRC or ADCLRC) typically 32KHZ, 44.1KHZ, 48KHZ or
96KHZ (the DAC also supports operation at 128fs and 192fs and 192KHZ sample rate). The
master clock is used to operate the digital filters and the noise shaping circuits.
In slave mode the WM8776 has a master detection circuit that automatically determines the
relationship between the master clock frequency and the sampling rate (to within +/- 32 system
clocks) If there is a greater than 32 clocks error the interface is disabled and ADCLRC/DACLRC
for optical performance, although the WM8776 is tolerant of phase variations or jitter on this clock.
Table shows the typical master clock frequency inputs for the WM8776
CONFIDENTIAL DO NOT COPY
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File No. SG-0204