STA333BWQS Datasheet, PDF (20/71 Pages) STMicroelectronics – 2.1-channel high-efficiency digital audio system with QSound QHD

Processing data paths
4
Processing data paths
STA333BWQS
Here are some diagrams that represent the data processing paths inside STA333BWQS.
The first 2-times oversampling FIR filter allows 2x fs audio processing. Then a selectable
high-pass filter removes the DC level. Four biquad filters allow a full equalization system. A
final crossover filter is present that can alternatively be used as a fifth biquad stage, see the
I²C registers for this specific usage. A pre scaler and a final post scaler provide full control
over the signal dynamics before and after the filtering stages, respectively. A mixer function
is also available.
Figure 6. Processing data flow
Sampling
frequency=Fs
Sampling
frequency=2xFs
From
I2S input
interface
x2
FIR
over
sampling
PreScale
Hi-Pass
Filter
If HPB=0
If DEMP=0
Biquad
#1
Biquad
#2
Biquad
#3
Biquad
#4
De-
Emphasis
Bass
Treble
L
User-Defined Filters
If DSPB=0 and C1EQBP=0
If C1TCB=0
BTC: Bass Boost/Cut
TTC: Treble Boost/Cut
x2
FIR
over
sampling
PreScale
Hi-Pass
Filter
If HPB=0
If DEMP=0
Biquad
#1
Biquad
#2
Biquad
#3
Biquad
#4
De-
Emphasis
Bass
Treble
R
User-Defined Filters
If DSPB=0 and C2EQBP=0
If C2TCB=0
BTC: Bass Boost/Cut
TTC: Treble Boost/Cut
L
C1Mx1
Hi-Pass XO
Vol
+
Filter
And
Post scale
Limiter
R
C1Mx2
C2Mx1
+
C2Mx2
Hi-Pass XO
Filter
Vol
And
Limiter
Post scale
C3Mx1
+
C3Mx2
Lo-Pass XO
Filter
Vol
And
Limiter
Post scale
User-Defined Mix Coefficients
Crossover Frequency determined by XO Setting
User Defined If XO=0000
20/71