STA3398 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
STA3398
STMicroelectronics
'STA3398' PDF : 78 Pages View PDF
STA339BW
Register description
7.18 Extended configuration register (addr 0x36)
7.18.1
D7
D6
D5
D4
D3
D2
D1
D0
Mdrc[1]
Mdrc[0]
PS48DB
XAR1
XAR2
BQ5
BQ6
BQ7
0
0
0
0
0
0
0
0
Extended configuration register provides access to B2DRC and biquads 5, 6 and 7.
Dual-band DRC
The STA339BW provides a dual-band DRC (B2DRC) on the left- and right-channel data
path, as depicted in Figure 21. Dual-band DRC is activated by setting MDRC[1:0] = 1x.
Figure 21. B2DRC scheme
Ch1
Volume
DLRiAVmCnoitdl1er
+
PBa2DssRC XO
L
HFi-ipltaesrs
filter
-
Ch3
DLRiAVmCnoitdl2er
Volume
Ch2
Volume
DRC1
+
R
Pass XO
BF2DiltRerC
Hi-pass
filter
-
Ch3
Volume
DLRiAVmCnoitdl2er
The low-frequency information (LFE) is extracted from the left and right channels by
removing the high frequencies with a programmable Biquad filter, so that, using the original
signal, the difference signal can be computed. Limiter 1 (DRC1) is then used to control the
left and right high-frequency component amplitudes while limiter 2 (DRC2) is used to control
the low-frequency components (see Chapter 7.11).
The cutoff frequency of the high-pass filters can be user defined, XO[3:0] = 0, or selected
from the pre-defined values.
DRC1 and DRC2 are then used to independently limit the left- and right-channel high
frequencies and the LFE-channel amplitude (see Chapter 7.11) as well as their volume
control. Note that, in this configuration, the dedicated channel-3 volume control can actually
be used as a bass boost enhancer as well (0.5 dB/step resolution).
The processed LFE channel is then recombined with the L and R channels in order to
reconstruct the 2.0 output signal.
Sub band decomposition
The sub band decomposition for B2DRC can be configured specifying the cutoff frequency.
The cut off frequency can be programmed in two ways, using XO bits in register 0x0C, or
using “user programmable” mode (coefficients stored in RAM adresses 0x28 to 0x31).
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