ST STA380BW, Manual

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STA380BW Device overview
4.3.1 STC block diagram
Figure 10. STCompressor
TM
block diagram
The STC takes as input 2 channels and every channel is processed independently (i.e. an
independent DRC for each band of each channel) following the steps listed below
(
Figure 10 ):
1. Splits the input signal into 2 bands (band splitter)
2. Measures the level of the signal (level meter)
3. Computes the attenuation (mapper)
4. Applies the attenuation and offset (attenuator)
The band splitter settings are common to both the processing channels while the settings of
the remaining blocks can be independently set for each band of each processing channel.
Caution: All the settings explained hereafter apply only to the behavior of the STCompressor
TM
. For
the settings concerning other device operating configurations (see Chapter 4.1: Processing
data path ) please refer to the appropriate paragraphs and registers.
4.3.2 Band splitter
The band splitter block is used to divide the signal into 2 sub-bands (typically low- and high-
frequency bands). This is done through two 2
nd
order biquads (IIR filters) for each band,
thus allowing to have up to a 4
th
order filter per band. This feature guarantees a totally flat
band recombination (see Figure 11 ). Using different filtering orders, indeed, causes a non-
negligible gain around the filter’s cutoff frequency, endangering the overall audio fidelity and,
eventually, also the safety of the speaker. The sub-band recombination can be enabled or
disabled.
Level
Meter
Map p er Atten uato r
O ffs et
X
Level
Meter
Map p er
Atten uato r X
O ffs et
+
Ban d
Sp litter
Ban d 0
(Lo w freq s)
Ban d 1
(Hig h freq s)
In p ut
Ch 0
O utp ut
Ch 0
DRC 0
DRC 1
Lev el
Meter
Map p er Atten uato r
O ffset
X
Lev el
Meter
Map p er
Atten uato r X
O ffset
+
Ban d
Sp litter
Ban d 0
(Lo w freq s )
Ban d 1
(Hig h freq s)
In p ut
Ch 1
O utp ut
Ch 1
DRC 2
DRC 3
Obsolete Product(s) - Obsolete Product(s)