This paper addresses the problem of speech enhancement and acoustic noise reduction by blind structures. Recently, the backward blind source separation (BBSS) structure has shown efficiency in cancelling the acoustic ...
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This paper addresses the problem of speech enhancement and acoustic noise reduction by blind structures. Recently, the backward blind source separation (BBSS) structure has shown efficiency in cancelling the acoustic noise and improving corrupted speech signals form very noisy observations without any a priori information of source signals. In this paper, we propose a new algorithm based on the combination between the BBSS structure and the simplified fast transversal filter (SFTF) algorithm. The proposed two-channel simplified fast transversal filter (TCSFTF) algorithm succeeded an important blind improvement of steady state and convergence speed performances in diverse noisy situations when only the noisy signals are known. The performances of the new TCSFTF algorithm are compared with four state-of-the-art algorithms in different noisy conditions. This comparison is evaluated in terms of cepstral distance (CD), system mismatch (SM), segmental signal to noise ratio (SegSNR), and segmental mean square error (SegMSE) criteria. (C) 2018 Elsevier Ltd. All rights reserved.
This study addresses the problem of in-phase and quadratic-phase (IQ) imbalance in digital transmitter and receiver communication systems. Recently, several adaptive and non-adaptive solutions to this problem have bee...
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This study addresses the problem of in-phase and quadratic-phase (IQ) imbalance in digital transmitter and receiver communication systems. Recently, several adaptive and non-adaptive solutions to this problem have been proposed. In this study, an adaptive solution to this problem is given. The authors propose a new robust two-channel adaptive algorithm to compensate the IQ imbalance problem of quadratic receivers. The new algorithm is based on the combination between the backward blind source separation (BBSS) structure and the fast Newton transversal filter (FNTF) technique to form a two-channel algorithm that cancels the noisy IQ signal adaptively. The combination of the Newton recursion of the FNTF algorithm with the BBSS principle shows the efficiency of the new algorithm to enhance the output signal to interference ratio and allows distortion correction at the output. Simulation results show the efficiency of the new algorithm to compensate the IQ imbalance problem in comparison with the conventional two-channel normalised least mean square algorithm.
We present an improved version of GACP (Global Aerosol Climotatology Project) algorithm which uses channel I and 2 radiances of the Advanced Very High Resolution Radiometer (AVHRR) to retrieve aerosol optical thicknes...
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ISBN:
(纸本)081944264X
We present an improved version of GACP (Global Aerosol Climotatology Project) algorithm which uses channel I and 2 radiances of the Advanced Very High Resolution Radiometer (AVHRR) to retrieve aerosol optical thickness and Angstrom exponent over the ocean. We specifically discuss recent changes in the algorithm as well as the results of a sensitivity study analyzing the effect of several sources of retrieval errors not addressed previously. Uncertainties in the AVHRR radiance calibration (particularly in the deep-space count value) may be among the major factors potentially limiting the retrieval accuracy. On the other hand, the performance of two-channel algorithms weakly depends on a specific choice of the aerosol size distribution function. The updated algorithm is applied to a 10-year period of observations (July 1983-Aug 1994), which includes data from NOAA-7, NOAA-9 (February 1985-November 1988), and NOAA-11 satellites. The results are posted on the world wide web at http://***/retrievals. The NOAA-9 record shows no discernable Iong-term trends in the global and hemisphere averages of the optical thickness and Angstrom exponent. On the other hand, there is a discontinuity in the Angstrom exponent values derived from NOAA-9 and NOAA-11 data and a significant temporal trend in the NOAA-11 record. The latter are unlikely to be related to the Pinatubo eruption and may be indicative of a serious calibration problem.
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