R261 Datasheet, PDF (13/28 Pages) ON Semiconductor – Advanced Noise Reduction Solution for Voice Capture Devices

BelaSigna R261
Architecture Detailed Information
The architecture of BelaSigna R261 is shown in Figure 5.
Preamps Decimation
A/D
A/D
Two−Microphone
Noise Reduction
(BSE)
DSP−Based
Application Controller
Interpolation
Ch0
Output
Driver0
D/A
Ch1
D/A
SPI
UART
PCM/I2S
Debug
Port
Timers
Interrupt
Controller
Algorithm
Protection
Custom
Mode
Handler
Algorithm
Control
Boot
Selection
Sleep Mode
Control
I²C
Command
Handler
H/W Config
Selection
Mode
Switching
System
Monitoring
BelaSigna R261
DMIC
GPIO
I²C
PLL and
Clock
Detection
Power Mgt
LSAD
Figure 5. BelaSigna R261 Architecture: A Complete Audio Processing System
Two−Microphone Noise Reduction System
Blind Speech Extraction (BSE) from Exaudio AB
BelaSigna R261 contains the BSE algorithm inside its
ROM memory. Exaudio offers a unique solution to the
problem of blindly extracting wave propagating signals
using one or more sensors without having any prior
knowledge about source’s or sensor’s positions. The
solution operates simultaneously in the frequency, temporal
and the spatial domain using one global optimization
criterion, with no constraints on the number of sources vs.
the number of sensors. The solution is Signal−to−Noise
Ratio (SNR) independent, meaning that it operates
optimally in both low SNR as in high SNR environments and
at the same time it performs de−reverberation of the received
signals. The solution is ideal for electronic communication
devices such as mobile phones and portable computers
where it is desired to extract useful speech signals hidden in
various noise fields. The flexibility offered by Exaudio’s
solution allows for flexible microphone positioning and
arbitrary placement of the self adaptive device in the actual
environment.
Algorithm Modes
The noise reduction algorithm built into BelaSigna R261
has two algorithm modes called Algorithm Mode 0 and
Algorithm Mode 1. Algorithm Mode 0 is optimized for
far−talk applications where the end user can be very far from
the microphones (up to 6 meters) such as laptops or
speakerphones (including cell phones in a speakerphone
mode). This algorithm mode is also known as “Conference
Mode”. Algorithm Mode 1 is optimized for close−talk
applications where the end user is close to the microphones
(< 5 cm) such as telephony handset (including cell phones
in a handset mode).
A Custom Algorithm Mode is also available in BelaSigna
R261; it allows supporting special configurations and tuning
by loading new algorithm parameters via an external
EEPROM or the I²C control interface. The algorithm
performance can be optimized for specific applications,
microphones types and positioning as well as other system
parameters via this mechanism.
For additional details on the custom mode handler and
algorithm performance tuning options, please refer to
“BelaSigna R261 Configuration & Communications
Guide.”
http://onsemi.com
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