中文摘要：

实信号经过傅里叶变换后有一半频谱是负频率成分,着重分析了负频率成分对频谱中极低频、极高频等极端频率信号频谱的干涉影响并给出了典型工程示例。仿真分析结果表明,由于负频率成分影响,对于极端频率信号的参数估计,即使采用现有离散频谱校正方法也存在着较大的误差。鉴于开展针对极端频率信号的频谱分析与校正方法研究具有重要的理论意义和工程实用价值,对近年来出现的计及负频率影响的频谱分析与校正方法的原理、适用范围、优缺点等进行了分析和比较,并展望了其主要的发展方向。

英文摘要：

Half of signal spectrum is negative frequency component after FFT.The interferential influence which roots in negative frequency to extreme frequency such as ultra low frequency and ultra high frequency is analyzed and some typical example signals in engineering is given.Simulation result shows that there exists great error while estimating the parameters of extreme frequency,even if discrete spectrum correction method is adopted.So it has great theoretical significance and practicality to study the parameter estimation and spectrum correction approach for extreme frequency which result from engineering applications.The analyses and comparisons are made to account for the estimation principle,application scope and features of current algorithms with the influence of negative frequency component,and main possible research directions are tipped.