TMS320WP010 Datasheet, PDF (1/18 Pages) Texas Instruments – DIGITAL SIGNAL PROCESSOR FOR AEC/LEC/ANS

D Cancels the Acoustic Echo Common in
Hands-Free Use of Cellular Phones in
Automobiles
– Eliminates Echo Created by Speaker
Output Feeding Back Into the
Microphone
D Suppresses Wind, Engine, and Tire Noise
D Line Echo Canceler
D Standard Independent
– IS-54B, IS-136, GSM, AMPS, IS-95
D Continuous, Automatic Adaptation to
Changing Acoustic Environment
– Initial System Training Not Required
D Based on TMS320C5x Platforms
D Support for Industry Standard
Microcontrollers
D Interfaces Easily with TI’s Voice Codec, the
TCM320AC36
TMS320WP010
DIGITAL SIGNAL PROCESSOR
FOR AEC/LEC/ANS
SPRS040–OCTOBER 1995
D Acoustic Echo Canceler Performance
– Length of Echo Path up to 44 ms
– Initial Adaptation Rate > 20 dB/s for
Speech Signals
– Zero Speech Delay
– Echo Return Loss up to 30 dB for
Speech Echo in Automobiles and 41 dB
for Sine Wave Input
D Noise Suppressor Performance
– Up to 10 dB Noise Suppression for
Hands-Free Use of Cellular Phones in
Automobiles Without Distorting Speech
Signals
– 16 ms Processing Delay
– Continuous Adaptation
D Demonstration Platform
– Allows Evaluation of Software Algorithm
Performance in Lab and Automobile
– Ability to Enable/Disable AEC, ANS, and
LEC
description
For the cellular phone cradle market, the TMS320WP010 provides enhanced quality, full-duplex, hands-free
communications. The ’WP010 is a ROM-coded DSP that provides all the adaptive filtering and processing
necessary for acoustic echo cancellation (AEC), line echo cancellation (LEC), and adaptive noise suppression
(ANS).
The ’WP010’s acoustic echo cancellation function is based on a Finite Impulse Response (FIR) filter with an
adaptive coefficient updating algorithm. The adaptive algorithm updates continuously so that it can constantly
track acoustic path changes from the speaker to the microphone. Based upon FIR filter coefficients, the echo
signal can be estimated and subtracted from the observed signal at the microphone. The acoustic echo
cancellation function provides continuous adaptation and needs no initial system training. It is capable of
canceling an echo path of up to 44 milliseconds and provides up to 30 dB cancellation for speech signals. In
addition, the initial convergence rate is faster than 20 dB per second.
The line echo cancellation function cancels the near-end speech that has been reflected at the network switch
and transmitted back to the cellular phone. The principle of the line echo cancellation function is very similar
to that of the acoustic echo cancellation function. The difference is that the line echo cancellation function is
designed to cancel the echo signal caused by network feedback due to impedance mismatch in the network
circuit. The line echo cancellation function is capable of canceling a line echo path of up to 16 milliseconds.
The received signal at the microphone consists of the near-end speech signal, acoustic feedback echo, and
ambient noise from the environment. The purpose of the adaptive noise suppression function is to suppress
ambient noise components without distorting near-end speech. The initial adaptation rate is about 3 dB per
second without initial system training. It tracks the changes of the noise characteristics and suppresses noise
accordingly. The adaptive noise suppression provides up to 10 dB of noise cancellation without degrading
near-end speech.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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Copyright © 1995, Texas Instruments Incorporated
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