Journal of the Institute of Electronics Engineers of Korea SD (대한전자공학회논문지SD)

The Institute of Electronics and Information Engineers (대한전자공학회)
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An FPGA Implementation of Acoustic Echo Canceller Using S-LMS Algorithm

S-LMS 알고리즘을 이용한 음향반향제거기의 FPGA구현

  • 이행우 (남서울대학교 전자정보통신공학부)
  • Published : 2004.09.01
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Abstract

This paper describes a new adaptive algorithm which can reduce the required computation quantities in the adaptive filter. The proposed S-LMS algorithm uses only the signs of the normalized input signal rather than the input signals when coefficients of the filter are adapted. By doing so, there is no need for the multiplications and divisions which are mostly responsible for the computation quantities. To analyze the convergence characteristics of the proposed algorithm, the condition and speed of the convergence are derived mathematically. Also, we simulate an echo canceller adopting this algorithm and compare the performances of convergence for this algorithm with the ones for the other algorithm. As the results of simulations, it is proved that the echo canceller adopting this algorithm shows almost the same performances of convergence as the echo canceller adopting the SIA algorithm.

본 논문은 휴대폰의 자동차 핸즈프리를 위한 음향반향제거기의 설계 및 구현에 관한 것이다. 이를 구현하기 위해 효율적인 적응 알고리즘의 개발과 VHDL 회로설계, 그리고 테스트 보드 제작 등을 수행하였다. 적응 알고리즘은 간단하고 안정적이며 수렴속도가 빠른 새로운 S-LMS 알고리즘을 사용하였다 음향반향제거기는 15-bit, 128-tap 회로구조로서 50,000 게이트급 FPGA에 구현하였다. 그리고 회로동작을 검증하기 위하여 보드를 제작하였는데, 2개의 CODEC과 제어입력용 DIP 스위치 및 출력표시용 LED 등이 포함되어 있다. 백색 가우스잡음을 사용하여 시험한 결과, 구현된 회로의 ERLE는 최대 30dB의 반향제거 성능을 나타내는 것으로 확인되었다.

Keywords

References

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