参数资料
| 型号： | AC300030 |
| 厂商： | Microchip Technology |
| 文件页数： | 14/64页 |
| 文件大小： | 0K |
| 描述： | KIT ACOUSTIC ACCESSORY |
| 标准包装： | 1 |
| 附件类型： | 配件套件 |
| 适用于相关产品： | 杂讯抑制/回声消除库 |
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dsPIC ? DSC Acoustic Echo Cancellation Library User’s Guide
The AEC library uses a fixed 8 kHz sampling rate and is especially suitable for
applications such as:
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Hands-free cell phones
Speaker phones
Intercoms
Teleconferencing systems
For hands-free phones intended to be used in automotive environment, such as inside
an automobile, this library is compatible with the G.167 standard for AEC and with other
relevant ITU-T standards.
The AEC library is written almost entirely in assembly language, and is highly optimized
to make extensive use of the dsPIC ? DSC device instruction set and advanced
addressing modes. The algorithm avoids data overflow. The AEC library provides an
EC_init function for initializing the various data structures required by the algorithm
and an EC_apply function to remove the echo component from a 10 ms block of
sampled 16-bit speech data. You can easily call both the functions through a
well-documented Application Programmer ’s Interface (API).
The AEC algorithm is primarily a time-domain algorithm. The received far-end speech
samples (typically received across a communication channel, such as a telephone line)
are filtered using an adaptive Finite Impulse Response (FIR) filter and then subtracted
from the near-end input speech signal. The coefficients of this filter are adapted using
the Normalized Least Mean Square (NLMS) algorithm, such that the filter closely
models the acoustic path between the near-end speaker and the near-end microphone
(that is, the path traversed by the echo). A Nonlinear Processor (NLP) algorithm is
available to eliminate the residual echo.
1.2
FEATURES
Key features of the AEC library include:
DS70134F-page 14
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Simple user interface – only one library file and one header file
All functions can be called from a C application program
Compatible with the Microchip C30 Compiler, Assembler and Linker
Highly optimized assembly code that uses DSP instructions and advanced
addressing modes
Acoustic Echo Cancellation for 16 ms, 32 ms, 64 ms or 128 ms echo delays or
“tail lengths” (configurable)
Compatible with G.167 specifications for in-car applications
Audio Bandwidth: 0 kHz to 4 kHz at an 8 kHz sampling rate
Convergence Rate: Up to 47 dB/sec., typically greater than 30 dB/sec
Acoustic Echo Cancellation: Up to 50 dB, typically > 40 dB
Can be used together with the Noise Suppression (NS) library
Demonstration application source code is provided with the library
NLP attenuation level can be adjusted to suit application requirements
AEC adaptation can be force-enabled or disabled by the user application
Run-time control of key algorithm parameters is provided
? 2004-2011 Microchip Technology Inc.
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| AC300031 | 制造商:Microchip Technology Inc 功能描述:ACOUSTIC ACCESSORY KIT SPEECH RECOGNITION - Boxed Product (Development Kits) 制造商:Microchip Technology Inc 功能描述:SPEECH RECOGNIZE KIT ACOUSTIC |
| AC3000-52 | 制造商:GE Energy (formerly Lineage Power) 功能描述:Front-End Power Supply 制造商:Lineage Power 功能描述:Front-End Power Supply |
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| AC3000A-R2-W1 | 制造商:Black Box Corporation 功能描述:1 YEAR WARRANTY FOR AC3000A-R2 |
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