频谱校正的复比值法  

Spectrum correction based on the complex ratio of discrete spectrum around the main-lobe

作　　者：陈奎孚[1] 王建立[2] 张森文[3] 

机构地区：[1]中国农业大学理学院,北京100083 [2]邢台职业技术学院,河北邢台054035 [3]暨南大学应用力学研究所,广东广州510632

出　　处：《振动工程学报》2008年第3期314-318,共5页Journal of Vibration Engineering

摘　　要：为了抑制快速傅立叶变换(FFT)栅栏效应,已经发展了多种幅值比校正法。但是研究发现:这种方法对于实信号在有些条件下,甚至会比从FFT离散谱线直接读出的误差更大。其原因是由于实信号中负频率成分对正频率谱峰的干扰。为了抑制这种干扰,给出了复比值校正方法和复合复比值法。前者直接利用复数频谱进行校正,后者根据前者在最高谱线与其左右相邻的谱线各校正出一个频率,然后对这两个频率加权平均。仿真算例表明:复比值法对负频率成分的干扰不敏感;而复合复比值法性能优于Quinn算法。It is first reported here that the MR approach may not always increase accuracy for a real-valued signal. Some exceptional examples presented here demonstrate that, under some special circumstance, the results from the MR approach are even worse than the plain readings from the FFT spectral lines. Two approaches were proposed. The first one makes use of the ratio of complex spectrum （RCS）, and the second one, composite RCS based approach, which interpolates the right-side and left-side results of the spectral peak from the first approach. The noise-free examples show that the composite RCS approach is significantly less sensitive to the negative frequency component than the MR approach. The Monte Carlo simulation shows that it is superior to the Quinn＇s algorithm.

关 键 词：信号处理 频谱 快速傅里叶变换(FFT) 栅栏效应 谱泄漏 

分 类 号：TN911.6[电子电信—通信与信息系统] O329[电子电信—信息与通信工程]