Echo cancellation: the generalized likelihood ratio test for double-talk versus channel change

  • Authors:
  • Jean-Yves Toumeret;Neil J. Bershad;José Carlos M. Bennudez

  • Affiliations:
  • IRIT-ENSEEIHT-TéSA, University of Toulouse, Toulouse cedex 7, France;Department of Electrical Engineering and Computer Science, University of California at Irvine, Newport Beach, CA;Department of Electrical Engineering, Federal University of Santa Catarina, Florianópolis, SC, Brazil

  • Venue:
  • IEEE Transactions on Signal Processing
  • Year:
  • 2009

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Abstract

Echo cancellers (EC) are required in both electrical (impedance mismatch) and acoustic (speaker-microphone coupling) applications. One of the main design problems is the control logic for adaptation. Basically, the algorithm weights should be frozen in the presence of double-talk and adapt quickly in the absence of double-talk. The optimum likelihood ratio test (LRT) for this problem was studied in a recent paper. The LRT requires a priori knowledge of the background noise and double-talk power levels. Instead, this paper derives a generalized log likelihood ratio test (GLRT) that does not require this knowledge. The probability density function of a sufficient statistic under each hypothesis is obtained and the performance of the test is evaluated as a function of the system parameters. The receiver operating characteristics (ROCs) indicate that it is difficult to correctly decide between double-talk and a channel change, based upon a single look. However, detection based on about 200 successive samples yields a detection probability close to unity (0.99) with a small false alarm probability (0.01) for the theoretical GLRT model. Application of a GLRT-based EC to real voice data shows comparable performance to that of the LRT-based EC given in a recent paper.