采用 S 变换和支持向量机进行电能质量扰动的分类识别。作为连续小波变换和短时傅立叶变换的发展,S 变换引入了宽度与频率成反向变化的高斯窗,具有与频率相关的分辨率。由于 S 变换具有良好的时频特性,因而非常适合于进行电能质量扰动...采用 S 变换和支持向量机进行电能质量扰动的分类识别。作为连续小波变换和短时傅立叶变换的发展,S 变换引入了宽度与频率成反向变化的高斯窗,具有与频率相关的分辨率。由于 S 变换具有良好的时频特性,因而非常适合于进行电能质量扰动信号特征提取。首先通过 S 变换进行扰动信号特征提取,然后构造支持向量机分类树进行扰动分类。算例表明该方案具有分类准确率高,对噪声不敏感,训练样本少等优点,是电能质量扰动识别的有效方法。展开更多
This paper presents a new method for the detection and parameter estimation of multicomponent LFM signals based on the fractional Fourier transform. For the optimization in the fractional Fourier domain, an algorithm ...This paper presents a new method for the detection and parameter estimation of multicomponent LFM signals based on the fractional Fourier transform. For the optimization in the fractional Fourier domain, an algorithm based on Quasi-Newton method is proposed which consists of two steps of searching, leading to a reduction in computation without loss of accuracy. And for multicomponent signals, we further propose a signal separation technique in the fractional Fourier domain which can effectively suppress the interferences on the detection of the weak components brought by the stronger components. The statistical analysis of the estimate errors is also performed which perfects the method theoretically, and finally, simulation results are provided to show the validity of our method.展开更多
The fractional Fourier transform is a generalization of the classical Fourier transform, which is introduced from the mathematic aspect by Namias at first and has many applications in optics quickly. Whereas its poten...The fractional Fourier transform is a generalization of the classical Fourier transform, which is introduced from the mathematic aspect by Namias at first and has many applications in optics quickly. Whereas its potential appears to have remained largely unknown to the signal processing community until 1990s. The fractional Fourier transform can be viewed as the chirp-basis expansion directly from its definition, but essentially it can be interpreted as a rotation in the time-frequency plane, i.e. the unified time-frequency transform. With the order from 0 increasing to 1, the fractional Fourier transform can show the characteristics of the signal changing from the time domain to the frequency domain. In this research paper, the fractional Fourier transform has been comprehensively and systematically treated from the signal processing point of view. Our aim is to provide a course from the definition to the applications of the fractional Fourier transform, especially as a reference and an introduction for researchers and interested readers.展开更多
文摘采用 S 变换和支持向量机进行电能质量扰动的分类识别。作为连续小波变换和短时傅立叶变换的发展,S 变换引入了宽度与频率成反向变化的高斯窗,具有与频率相关的分辨率。由于 S 变换具有良好的时频特性,因而非常适合于进行电能质量扰动信号特征提取。首先通过 S 变换进行扰动信号特征提取,然后构造支持向量机分类树进行扰动分类。算例表明该方案具有分类准确率高,对噪声不敏感,训练样本少等优点,是电能质量扰动识别的有效方法。
文摘This paper presents a new method for the detection and parameter estimation of multicomponent LFM signals based on the fractional Fourier transform. For the optimization in the fractional Fourier domain, an algorithm based on Quasi-Newton method is proposed which consists of two steps of searching, leading to a reduction in computation without loss of accuracy. And for multicomponent signals, we further propose a signal separation technique in the fractional Fourier domain which can effectively suppress the interferences on the detection of the weak components brought by the stronger components. The statistical analysis of the estimate errors is also performed which perfects the method theoretically, and finally, simulation results are provided to show the validity of our method.
基金supported by the National Natural Science Foundation of China(Grant Nos.60232010 and 60572094)the Teaching and Research Award for 0utstanding Young Teachers in Higher Education Institutions of M0E,P.R.C.the Ministerial Foundation of China(Grant No.6140445).
文摘The fractional Fourier transform is a generalization of the classical Fourier transform, which is introduced from the mathematic aspect by Namias at first and has many applications in optics quickly. Whereas its potential appears to have remained largely unknown to the signal processing community until 1990s. The fractional Fourier transform can be viewed as the chirp-basis expansion directly from its definition, but essentially it can be interpreted as a rotation in the time-frequency plane, i.e. the unified time-frequency transform. With the order from 0 increasing to 1, the fractional Fourier transform can show the characteristics of the signal changing from the time domain to the frequency domain. In this research paper, the fractional Fourier transform has been comprehensively and systematically treated from the signal processing point of view. Our aim is to provide a course from the definition to the applications of the fractional Fourier transform, especially as a reference and an introduction for researchers and interested readers.
