Datasheet

LB1 LB2

RB1 RB2

TLV320AIC3107

SLOS545D –NOVEMBER 2008 –REVISED DECEMBER 2014

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The N and D coefficients are fully programmable, and the entire filter can be enabled or bypassed. The structure

of the filtering when configured for independent channel processing is shown below in Figure 21, with LB1

corresponding to the first left-channel biquad filter using coefficients N0, N1, N2, D1, and D2. LB2 similarly

corresponds to the second left-channel biquad filter using coefficients N3, N4, N5, D4, and D5. The RB1 and

RB2 filters refer to the first and second right-channel biquad filters, respectively.

Figure 21. Structure of the Digital Effects Processing for Independent Channel Processing

The coefficients for this filter implement a variety of sound effects, with bass-boost or treble boost being the most

commonly used in portable audio applications. The default N and D coefficients in the part are given in Table 4

and implement a shelving filter with 0 dB gain from DC to approximately 150 Hz, at which point it rolls off to a 3

dB attenuation for higher frequency signals, thus giving a 3 dB boost to signals below 150 Hz. The N and D

coefficients are represented by 16-bit two’s complement numbers with values ranging from –32768 to 32767.

Table 4. Default Digital Effects Processing Filter Coefficients,

When in Independent Channel Processing Configuration

Coefficients

N0 = N3 D1 = D4 N1 = N4 D2 = D5 N2 = N5

27619 32131 –27034 –31506 26461

The digital processing also includes capability to implement 3-D processing algorithms by providing means to

process the mono mix of the stereo input, and then combine this with the individual channel signals for stereo

output playback. The architecture of this processing mode, and the programmable filters available for use in the

system, is shown in Figure 22. Note that the programmable attenuation block provides a method of adjusting the

level of 3-D effect introduced into the final stereo output. This combined with the fully programmable biquad filters

in the system enables the user to fully optimize the audio effects for a particular system and provide extensive

differentiation from other systems using the same device.

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