sta323wqs STMicroelectronics, sta323wqs Datasheet - Page 60

• Manufacturer Part Number: sta323wqs
• Description: 2.1-channel High-efficiency Digital Audio System With Qsound Qhd??
• Manufacturer: STMicroelectronics

User-programmable settings
8.4
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Mix/bass management
The STA323WQS provides one post-EQ mixing block per channel. Each channel has two
mixing coefficients, which are each 24-bit signed fractional multipliers, that correspond to
the two channels of input to the mixing block. These coefficients are accessible via the User
Controlled Coefficient RAM described below. The mix coefficients 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 52. Mix/bass management block diagram
After mixing, STA323WQS also permits the implementation of crossover filters on all
channels corresponding to 2.1 bass management operation. Channels 1 and 2 use a 1st
order, high-pass filter and channel 3 uses a 2nd order low-pass filter corresponding to the
setting of the XO bits of I2C register 0Ch. 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
and Limiter block.
Channel #2
Channel #1
from EQ
from EQ
User defined mix coefficients
C1MX1
C1MX2
C2MX1
C2MX2
C3MX1
C3MX2
.
.
.
Crossover frequency determined
by XO setting.
User defined when XO = 000
High pass
High pass
Low pass
filter
filter
filter
XO
XO
XO
to GC/vol
Channel #1
to GC/vol
to GC/vol
Channel #2
Channel #3
STA323WQS