To promote the performance of the traditional multichannel filter bank which leads to speech quality degradation,an efficient design method of the non-uniform cosine modulated filter bank（CMFB） based on the audiogra...To promote the performance of the traditional multichannel filter bank which leads to speech quality degradation,an efficient design method of the non-uniform cosine modulated filter bank（CMFB） based on the audiogram for digital hearing aids is proposed. First, a low-pass prototype filter is designed by the linear iterative algorithm. Secondly,the uniform CMFB is achieved on the basis of the principle formulas. Then, the adjacent channels of a uniform filter bank which have low or gradual slopes are merged according to the trend of audiogram of the hearing impaired person. Finally,the corresponding non-uniform CMFB is obtained. Simulation results show that the signal processed by the proposed filter bank is similar to the original signal in a time-domain waveform and spectrogram without significant distortion or difference. The speech quality results show that the personal evaluation of speech quality（PESQ） of non-uniform CMFB is 35% higher than that of the traditional design, and the hearing-aid speech quality index（HASQI） increases by about 40%.展开更多
With the aid of computation, we consider the variable-coefficient coupled nonlinear Schrodinger equations with the effects of group-velocity dispersion, self-phase modulation and cross-phase modulation, which have pot...With the aid of computation, we consider the variable-coefficient coupled nonlinear Schrodinger equations with the effects of group-velocity dispersion, self-phase modulation and cross-phase modulation, which have potential applications in the long-distance communication of two-pulse propagation in inhomogeneous optical fibers. Based on the obtained nonisospectral linear eigenvalue problems （i.e. Lax pair）, we construct the Darboux transformation for such a model to derive the optical soliton solutions. In addition, through the one- and two-soliton-like solutions, we graphically discuss the features of picosecond solitons in inhomogeneous optical fibers.展开更多
A Korteweg-de Vires-type （KdV-type） equation and a modified Nonlinear Schrodinger equation （NLSE） for the dust lattice wave （DLW） are derived in a weakly inhomogeneous dust plasma crystal. It seems that the ampl...A Korteweg-de Vires-type （KdV-type） equation and a modified Nonlinear Schrodinger equation （NLSE） for the dust lattice wave （DLW） are derived in a weakly inhomogeneous dust plasma crystal. It seems that the amplitude and the velocity of the dust lattice solitary waves decay exponentiaJly with increasing time in a dust lattice. The modulational instability of this dust lattice envelope waves is investigated as well. It is found that the waves are modulational stable under certain conditions. On the other hand, the waves are modulationaJ unstable if the conditions are not satisfied.展开更多
A new SO1 high-voltage device structure with nonuniform thickness drift region （n-uni SOl） and its optimiza- tion design method are proposed. Owing to the nonuniform thickness drift region, the electric field in the...A new SO1 high-voltage device structure with nonuniform thickness drift region （n-uni SOl） and its optimiza- tion design method are proposed. Owing to the nonuniform thickness drift region, the electric field in the SOl layer is modulated and the electric field in the buried layer is enhanced, resulting in an enhancement of breakdown voltage. An analytical model taking the modulation effect into account is presented to optimize the device structure. Based on the analytical model, the dependencies of the electric field distribution and breakdown voltage on the device parameters are investigated. Numerical simulations support the analytical model. The breakdown voltage of the n-uni SOl LDMOS with n = 3 is twice as high as that of a conventional SO1 while its on-resistance maintains low.展开更多
基金The National Natural Science Foundation of China(No.61375028,61673108)China Postdoctoral Science Foundation(No.2016M601696)+2 种基金Qing Lan Projectthe Program for Special Talent in Six Fields of Jiangsu Province(No.2016-DZXX-023)Jiangsu Planned Projects for Postdoctoral Research Funds(No.1601011B)
文摘To promote the performance of the traditional multichannel filter bank which leads to speech quality degradation,an efficient design method of the non-uniform cosine modulated filter bank（CMFB） based on the audiogram for digital hearing aids is proposed. First, a low-pass prototype filter is designed by the linear iterative algorithm. Secondly,the uniform CMFB is achieved on the basis of the principle formulas. Then, the adjacent channels of a uniform filter bank which have low or gradual slopes are merged according to the trend of audiogram of the hearing impaired person. Finally,the corresponding non-uniform CMFB is obtained. Simulation results show that the signal processed by the proposed filter bank is similar to the original signal in a time-domain waveform and spectrogram without significant distortion or difference. The speech quality results show that the personal evaluation of speech quality（PESQ） of non-uniform CMFB is 35% higher than that of the traditional design, and the hearing-aid speech quality index（HASQI） increases by about 40%.
基金Supported by the National Natural Science Foundation of China under Grant No.60772023 the Open Fund of the State Key Laboratory of Software Development Environment under Grant No.BUAA-SKLSDE-09KF-04+2 种基金Beijing University of Aeronautics and Astronautics,by the National Basic Research Program of China (973 Program) under Grant No.2005CB321901the Specialized Research Fund for the Doctoral Program of Higher Education under Grant Nos.20060006024 and 200800130006Chinese Ministry of Education
文摘With the aid of computation, we consider the variable-coefficient coupled nonlinear Schrodinger equations with the effects of group-velocity dispersion, self-phase modulation and cross-phase modulation, which have potential applications in the long-distance communication of two-pulse propagation in inhomogeneous optical fibers. Based on the obtained nonisospectral linear eigenvalue problems （i.e. Lax pair）, we construct the Darboux transformation for such a model to derive the optical soliton solutions. In addition, through the one- and two-soliton-like solutions, we graphically discuss the features of picosecond solitons in inhomogeneous optical fibers.
文摘A Korteweg-de Vires-type （KdV-type） equation and a modified Nonlinear Schrodinger equation （NLSE） for the dust lattice wave （DLW） are derived in a weakly inhomogeneous dust plasma crystal. It seems that the amplitude and the velocity of the dust lattice solitary waves decay exponentiaJly with increasing time in a dust lattice. The modulational instability of this dust lattice envelope waves is investigated as well. It is found that the waves are modulational stable under certain conditions. On the other hand, the waves are modulationaJ unstable if the conditions are not satisfied.
文摘A new SO1 high-voltage device structure with nonuniform thickness drift region （n-uni SOl） and its optimiza- tion design method are proposed. Owing to the nonuniform thickness drift region, the electric field in the SOl layer is modulated and the electric field in the buried layer is enhanced, resulting in an enhancement of breakdown voltage. An analytical model taking the modulation effect into account is presented to optimize the device structure. Based on the analytical model, the dependencies of the electric field distribution and breakdown voltage on the device parameters are investigated. Numerical simulations support the analytical model. The breakdown voltage of the n-uni SOl LDMOS with n = 3 is twice as high as that of a conventional SO1 while its on-resistance maintains low.
