Datasheet

Equalization and mixing STA309A

60/67 Doc ID 13855 Rev 4

8 Equalization and mixing

Figure 8. Channel mixer

8.1 Postscale

The STA309A provides one additional multiplication after the last interpolation stage and

before the distortion compensation on each channel. This is a 24-bit signed fractional

multiply.

The scale factor for this multiply is loaded into RAM using the same I

C registers as the

biquad coefficients and the bass-management.

This postscale factor can be used in conjunction with an ADC equipped micro-controller to

perform power-supply error correction. All channels can use the channel 1 by setting the

postscale link bit.

Channel 1

Channel 2

Channel 3

Channel 4

Channel 5

Channel 6

Channel 7

Channel 8

CxMIX1

CxMIX2

CxMIX3

CxMIX4

CxMIX5

CxMIX6

CxMIX7

CxMIX8

Channel x

Table 80. RAM block for biquads, mixing, and bass management

Index

(decimal)

Index

(hex)

Description Coefficient Default

0 0x00 Channel 1 - Biquad 1 C1H10 (b1/2) 0x000000

1 0x01 - C1H11 (b2) 0x000000

2 0x02 - C1H12 (a1/2) 0x000000

3 0x03 - C1H13 (a2) 0x000000

4 0x04 - C1H14 (b0/2) 0x400000

5 0x05 Channel 1 - Biquad 2 C1H20 0x000000