STA32813TR View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
STA32813TR Datasheet PDF : 57 Pages
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User programmable processing
STA328
7.4
Mix/bass management
The STA328 provides a post-EQ mixing block per channel. Each channel has 2 mixing
coefficients, which are each 24-bit signed fractional multipliers, that correspond to the 2
channels of input to the mixing block. These coefficients are accessible via the user
controlled coefficient RAM described below. The mix coefficients are expressed as 24-bit
signed; fractional numbers in the range +1.0 (8388607) to -1.0 (-8388608) are used to
provide three channels of output from two channels of filtered input.
Figure 19. Mix/bass management block diagram
Channel #1
from EQ
Channel #2
from EQ
C1MX1
+
C1MX2
High-Pass
XO
Filter
Channel#1
to GC/Vol
C2MX1
+
C2MX2
High-Pass
XO
Filter
Channel#2
to GC/Vol
C3MX1
+
C3MX2
Low -Pas s
XO
Filter
Channel#3
to GC/Vol
User-defined Mix Coefficients Crossover Frequency determined
by XO setting.
User-defined when XO = 000
After a mix is achieved, STA328 also provides the capability to implement crossover filters
on all channels corresponding to 2.1 bass management solution. Channels 1 and 2 use a
first-order high-pass filter and channel 3 uses a second-order low-pass filter corresponding
to the setting of the XO bits of I2C register 0x0C. If XO = 000, user specified crossover filters
are used.
By default these coefficients correspond to pass-through. However, the user can write these
coefficients in a similar way as the EQ biquads. When user-defined setting is selected, the
user can only write 2nd order crossover filters. This output is then passed on to the
volume/limiter block.
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