TAS3103ADBT datasheet(71/154 Pages) TI2

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3−8

3.3

3D Effects Block

The 3D effects block, shown in Figure 3−10, performs the first suite of processing tasks conducted on the incoming

serial audio data streams. The TAS3103A has three monaural channels—CH1, CH2, and CH3. CH1 and CH2 share

the same effects block, as well as the same dynamic range compression block. CH3 has its own effects block and

its own dynamic range compression block. In typical two-TAS3103A-chip configurations for processing 5.1 audio,

monaural channels CH1 and CH2 are used to process left/right front and left/right surround audio components, and

CH3 is used to process the subwoofer and center audio components. To support such a processing structure, the

effects block for CH1/CH2 offers more options for inserting audio effects into the audio data stream than does the

effects block for CH3.

3.3.1

CH1/CH2 Effects Block

This block consists of five signal flow paths, starting at processing nodes a, b, c, g, and h. All five paths contain four

programmable biquad filters, and paths a and b contain reverb delay lines as well. Nodes a, b, and c can be sourced

by any of the input nodes A, B, C, D, E, and F (SDIN1, SDIN2, SDIN3). Nodes g and h can be sourced by input nodes

G and H, respectively (SDIN4) and/or by weighted replicas of the data on nodes A and B, respectively. Nodes g and

h can also be sourced by the same weighted replica of the data on node f. Node c can also be sourced by weighted

replicas of the data on both node a and node b.

3D effects processing typically consists of installing sound direction effects. Sound direction effects are typically

created by the use of three major components.

•

Time differentiation

•

Loudness differentiation

•

Spectral differentiation

Time differentiation is achieved by using the paths containing the reverb delay elements. Loudness differentiation

is achieved both by the mixers feeding the five paths and the two mixers located at the output of each of the five paths.

Spectral differentiation is achieved using the four biquad filters located in each path.

3.3.2

CH3 Effects Block

This block, starting at node f, typically processes center and subwoofer audio components. Time and spectral

differentiation with respect of CH1 and CH2 can be realized via the reverb delay line and the four biquad filters.

Loudness differentiation can be achieved by adjusting the volume level of CH3. Weighted replicas of the effects block

output for CH1 and CH2 can also be summed into the output of the CH3 effects block. This capability is typically used

when processing the center channel audio component.

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