The signal spectral leakage and fence effect are prone to take place during the power harmonic analysis by fast fourier transform(FFT) under asynchronous sampling.The inhibiting ability of classical window functions i...The signal spectral leakage and fence effect are prone to take place during the power harmonic analysis by fast fourier transform(FFT) under asynchronous sampling.The inhibiting ability of classical window functions is restricted by side-lobe behaviors. A new type window function called time domain mutual-multiplication window, is obtained by multiplication operation of several window functions. A novel approach of harmonic analysis is developed through analyzing performances of main-lobe and side-lobe of the new window. Simulation results show that the time domain mutual-multiplication window can significantly suppress frequency spectral leakage and improve the accuracy of harmonic parameter estimation.展开更多
1 Introduction That a laser beam is scattered from rough surfaces attracts many researchers. In1987, E. R. Mendez and K. A. O’Donnell first observed the enhanced backscatteringthat a laser beam (6328 A) was scattered...1 Introduction That a laser beam is scattered from rough surfaces attracts many researchers. In1987, E. R. Mendez and K. A. O’Donnell first observed the enhanced backscatteringthat a laser beam (6328 A) was scattered from a metal rough surface, whose most impor-tant feature is the high rms slope of the profile. Kirchhoff single scattering modeland small perturbation theory cannot be used to get this effect theoretically. Howev-展开更多
To reduce the side-lobe level of L-shaped expansion array and improve the output signal to interference and noise ratio(SINR),the algorithm of side-lobe constraint based on minimum variance distortionless response(MVD...To reduce the side-lobe level of L-shaped expansion array and improve the output signal to interference and noise ratio(SINR),the algorithm of side-lobe constraint based on minimum variance distortionless response(MVDR-SC)is proposed.Firstly,the approach of mixing diagonal loading and Mailloux-Zatman(DLMZ)is used to taper the covariance matrix of the expansion array.Then,the second order cone programming(SOCP)obtained by constructing a new matrix is used to control the beam side-lobe.Finally,the new adaptive weight numbers are constructed by adjusting the proportion between DLMZ and SOCP.Simulation results show that the MVDR-SC algorithm can effectively reduce the side-lobe of beamforming under the L-shaped expansion array and obtain a larger output SINR.At the same time,it has good robustness to the mutual coupling error.展开更多
文摘The signal spectral leakage and fence effect are prone to take place during the power harmonic analysis by fast fourier transform(FFT) under asynchronous sampling.The inhibiting ability of classical window functions is restricted by side-lobe behaviors. A new type window function called time domain mutual-multiplication window, is obtained by multiplication operation of several window functions. A novel approach of harmonic analysis is developed through analyzing performances of main-lobe and side-lobe of the new window. Simulation results show that the time domain mutual-multiplication window can significantly suppress frequency spectral leakage and improve the accuracy of harmonic parameter estimation.
文摘1 Introduction That a laser beam is scattered from rough surfaces attracts many researchers. In1987, E. R. Mendez and K. A. O’Donnell first observed the enhanced backscatteringthat a laser beam (6328 A) was scattered from a metal rough surface, whose most impor-tant feature is the high rms slope of the profile. Kirchhoff single scattering modeland small perturbation theory cannot be used to get this effect theoretically. Howev-
文摘To reduce the side-lobe level of L-shaped expansion array and improve the output signal to interference and noise ratio(SINR),the algorithm of side-lobe constraint based on minimum variance distortionless response(MVDR-SC)is proposed.Firstly,the approach of mixing diagonal loading and Mailloux-Zatman(DLMZ)is used to taper the covariance matrix of the expansion array.Then,the second order cone programming(SOCP)obtained by constructing a new matrix is used to control the beam side-lobe.Finally,the new adaptive weight numbers are constructed by adjusting the proportion between DLMZ and SOCP.Simulation results show that the MVDR-SC algorithm can effectively reduce the side-lobe of beamforming under the L-shaped expansion array and obtain a larger output SINR.At the same time,it has good robustness to the mutual coupling error.
