Audio Note Empress Bedienungsanleitung PDF herunterladen (Seite 9)

Using Video4Linux2 SAA7134 Driver with VFG73xx - 9 -

When audio signal is passed through, it makes its way through the board as follows:

* audio input connector

* enters SAA7133 chip

* analog input crossbar

* analog output crossbar

* exits SAA7133 chip

* audio output connector

Signal taking this path remains analog and cannot be captured via DMA.

When audio signal is not passed through, it makes its way through the board as follows:

* audio input connector

* enters SAA7133 chip

* analog input crossbar

* baseband A/D converter

* digital input crossbar

* DSP

* digital output crossbar

* stereo D/A converter

* analog output crossbar

* exits SAA7133 chip

* audio output connector

Signal taking this path is converted from analog to digital then back to analog and may be captured via DMA.

The analog input crossbar controls which of the two external audio inputs provide the audio signal for the SAA7133

chip. To change the signal allowed through this crossbar, you need to change the audio input source or the

recording source.

The digital input crossbar controls the digital matrix and signal source for each of the four DSP paths (MAIN, Dolby

ProLogic, AUX1, and AUX2). The AUX1, AUX2, and Dolby ProLogic paths are not used. The MAIN path digital

matrix is always set to AB stereo with automatrix off and the signal source depends upon the recording source.

The digital output crossbar controls the source of the DMA, D/A converter, and I2S channels. The MAIN left path

always feeds DMA channel 1, the D/A converter left channel, and the I2S 1 & 2 left channels. The MAIN right path

always feeds DMA channel 2, the D/A converter right channel, and the I2S 1 & 2 right channels. DMA channels 3,

4, 5, and 6 are not used.

The analog output crossbar controls which internal audio signal is allowed out of the SAA7133 chip. To change the

signal passed off chip, you need to change the audio input source or change the recording source.

Audio Capture

Audio data can be captured via DMA from each of the two external inputs. To prepare the board for capture, you

need to set the recording source. The SAA7134 driver supports three recording sources: Video, Line1, and Line2.

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Audio Note Empress Bedienungsanleitung Seite 9