加三角窗的频谱校正  

Spectrum correction with a triangular window

作　　者：张强[1,2] 张频[3] 张明童[1] 

机构地区：[1]上海师范大学建筑工程学院,上海201418 [2]同济大学结构工程与防灾研究所,上海200092 [3]江西农业大学国土资源与环境学院,南昌330045

出　　处：《振动与冲击》2009年第2期96-98,共3页Journal of Vibration and Shock

基　　金：上海师范大学科研基金项目(SK200746);上海大学生创新活动计划项目

摘　　要：频谱校正是抑制快速傅里叶变换的栅栏效应和频谱泄漏的有效方法,但是加三角窗的频谱校正尚无文献报导。针对三角窗,给出了两种频率校正方法。第一种方法利用主瓣内的最高和次高谱线,但是需要数值法求解非线性方程。第二种方法利用最高谱线左右两侧两条谱线,它存在显式解。利用单频实正弦的仿真信号对两种算法的频率、幅值和相位等恢复精度进行了考核。结果表明:1)两种方法都显著优于传统的简单谱线近似法;2)负频率的泄漏是影响精度的重要因素。The spectrum correction is a promised approach to overcome the picket fence effect of the fast Fourier transform(FFT);however the formula for the case of triangular windowing is not yet available from references.Two approaches were proposed here to the triangular window case.The first one makes use of the first and second highest spectral lines,but needs iteration to solve a nonlinear equation numerically.The second one makes use of the second and third highest spectral lines that locate at two sides of the first highest spectral line.The simulation examples show that both approaches have much better performance than the conventional direct readings from the spectral lines and the error can be ascribed to the interference from the negative frequency component.

关 键 词：频谱 快速傅里叶变换(FFT) 泄漏 栅栏效应 窗函数 三角窗 

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]