Datasheet

( )
( )
L 0.707 C 0.707 Ls 0.707 Rs
L _ out
3.121
R 0.707 C 0.707 Ls 0.707 Rs
R _ out
3.121
+ ´ - ´ - ´
=
+ ´ - ´ - ´
=
L _ out E3 L E4 C E7 Ls E8 Rs
R _ out E3 R E4 C E5 Ls E6 Rs
= ´ + ´ + ´ + ´
= ´ + ´ + ´ + ´
LEFT
CH
RIGHT
CH
CENTER
CH
RIGHT
OUT
SDIN1
COEF
0XE3
RS
CH
LS
CH
DOLBY
DOWN
MIX
COEF
0XE4
COEF
0XE5
COEF
0XE6
COEF
0XE8
COEF
0XE7
SDIN4
SDIN2
LEFT
OUT
TAS5548
www.ti.com SLES270 –NOVEMBER 2012
– -12 +3 +27(clip) -9
3.10 Downmix Algorithm and I2S Out
Figure 3-17. Dolby Downmix
The TAS5548 has an excellent feature that can mix the input signals to create a downmix to make the I2S
serial output which has an SRC that keeps output sample rate at 48KHz irrespective of input sample rate.
Downmix registers are defined as follows:
0xE3 == Coefficient for L and R channels
0xE4 == Coefficient for Center channel
0xE5 == Coefficient for LS for R_out
0xE6 == Coefficient for Rs for R_out
0xE7 == Coefficient for Ls for L_out
0xE8 == Coefficient for Rs for L_out
L, R, C, Ls, Rs are input cross bar mixer outputs. L, R, C, Ls, Rs are defined as the output of input
mixers. L = Ch1, R = Ch2, C = Ch8, Ls = Ch3, Rs = Ch4, use input mixer to mix any other channels to
I2S Out. (3)
Input Mixers also can be used as other mixers to mix subwoofer channels to I
2
S out.
By default I
2
S out has the following values:
test (4)
Copyright © 2012, Texas Instruments Incorporated TAS5548 DAP Architecture 31
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