分数阶Fourier变换对多分量Chirp信号中心频率的分辨能力  

Resolution Ability of Fractional Fourier Transform in Multi-component Chirp Signal Center Frequency

作　　者：刘锋[1,2] 黄宇[1] 陶然[2] 王越[2] 

机构地区：[1]烟台海军航空工程学院电子工程系,山东烟台264001 [2]北京理工大学信息科学技术学院,北京100081

出　　处：《兵工学报》2009年第1期14-18,共5页Acta Armamentarii

基　　金：国家杰出青年科学基金资助项目(60625104);国家部委预研资助项目(4100102020111002040105)

摘　　要：研究了当多个同调频率的Chirp信号相近时,分数阶Fourier变换(FRFT)对中心频率的分辨能力问题。从FRFT在数值计算中对中心频率的估计区间出发,推导出了对中心频率的分辨能力表达式,根据偏微分方程进一步分析了采样时间、采样频率和信号调频率对分辨能力的影响。计算机仿真结果表明,当采样频率为400 MHz,采样时间为2μs;信号调频率的大小不超过100MHz/μs时,FRFT对中心频率的最小分辨力与调频率约成凹形抛物线关系,并且大于2 MHz.The resolution ability of fractional Fourier transform（FRFT）in the center frequency was studied,when multi-component Chirp signal had only one Chirp-rate.From the estimation sector of the center frequency in the FRFT＇s numerical calculation,the center frequency＇s resolution ability expression was deduced.Based on partial differential equation,the influence of the sampling time,sampling frequency and Chirp-rate upon the resolution ability were analyzed further.The computer simulation results indicate that the smallest resolution ability of center frequency has the cave parabola relationship about with Chirp-rate and is greater than 2 MHz,when the sampling frequency is 400 MHz,sampling time is 2 μs and the value of Chirp-rate is no more than 100 MHz/μs.

关 键 词：信息处理技术 分数阶FOURIER变换 CHIRP信号 信号检测 中心频率 分辨力 

分 类 号：TN971[电子电信—信号与信息处理] TN974[电子电信—信息与通信工程]