STA326 STMicroelectronics, STA326 Datasheet - Page 45

• Manufacturer Part Number: STA326
• Description: DIG AUDIO SYSTEM, 2-CH, 36POWERSSOP
• Manufacturer: STMicroelectronics

Specifications of STA326

• Svhc: No SVHC (15-Dec-2010)
• No. Of Pins: 36
• Operating Temperature Range: -20°C To +85°C
• Supply Voltage Max: 36V
• Supply Voltage Min: 10V
• Termination T: RoHS Compliant
• Package / Case: PowerSO
• Interface: I2C
• Interface Type: I2C
• Rohs Compliant: Yes

STA326
7.4
Mix/bass management
The STA326 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 18. Mix/bass management block diagram
After a mix is achieved, STA326 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 I
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.
from EQ
Channel #2
from EQ
Channel #1
User-defined Mix Coefficients
Doc ID 11531 Rev 3
2
C register 0x0C. If XO = 000, user specified crossover filters
C1MX1
C1MX2
C2MX1
C2MX2
C3MX1
C3MX2
+
+
+
by XO setting.
User-defined when XO = 000
Crossover Frequency determined
High-Pass
High-Pass
Low-Pass
Filter
Filter
Filter
XO
XO
XO
User programmable processing
Channel#2
to GC/Vol
Channel#3
to GC/Vol
Channel#1
to GC/Vol
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