Figure 27. speaker amplifier signal proc – Rainbow Electronics MAX98089 User Manual
Page 103
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MAX98089
Low-Power, Stereo Audio Codec
with FlexSound Technology
Figure 27. Speaker Amplifier Signal Processing Block Diagram
The transfer function for the user-programmable biquad is:
-1
-2
0
1
2
-1
-2
1
2
b
b z
b z
H(z)
1 a z
a z
+
+
=
+
+
The coefficients b
0
, b
1
, b
2
, a
1
, and a
2
are sample
rate dependent and stored in registers 0xB4 through
0xC7. Store b
0
, b
1
, and b
2
as positive numbers. Store
a
1
and a
2
as negated two’s complement numbers.
Separate filters can be stored for the DAI1 and DAI2
playback paths.
The MAX98089 EV kit software includes a graphic interface
for generating the user-programmable biquad coefficients.
Note: Only change the excursion limiter settings when
the signal path is disabled to prevent undesired artifacts.
EQ1EN
EQ2EN
DVEQ1:
0dB TO -15dB
DV1G:
0/6/12/18dB
DV2:
0dB TO -15dB
DCB2
5-BAND
PARAMETRIC
EQ
5-BAND
PARAMETRIC
EQ
DVEQ2:
0dB TO -15dB
MULTI BAND ALC
EXCURSION LIMITER
DV1:
0dB TO -15dB
MODE1
DVFLT
DALEN
MIXDAR
DACL
DAREN
DACR
+
AUDIO/
FILTERS
AUDIO/
VOICE
FILTERS
MIX
MIXDAL
MIX
MIXSPR
MIX
MIXSPL
MIX
SPKLP
SPKLN
SPVOLL:
+8dB TO -62dB
SPKLVDD
SPKLGND
SPKRVDD
SPKRP
SPKRN
SPLEN
SPREN
POWER/
DISTORTION LIMITER
SPVOLR:
+8dB TO -62dB
SPKRGND
+6dB
+6dB