基于分数阶Fourier变换的一种新的非均匀采样方法  

Novel Nonuniformly Sampled Method Based on Fractional Fourier Transform

作　　者：邹世杰[1] 刘锋[1] 

机构地区：[1]海军航空工程学院,山东烟台264001

出　　处：《现代电子技术》2009年第13期69-72,共4页Modern Electronics Technique

摘　　要：由于采样设备和被采样信号的限制,完全均匀采样是无法实现的,因此不得不进行非均匀采样。根据信号的时变特征,在信号的低频部分,用较低的频率对信号进行采样;在信号的高频部分,用较高的频率对信号进行采样。在此基础上,应用分数阶Fourier变换对非均匀采样Chirp信号进行分析,得到非均匀采样Chirp信号在分数阶Fourier变换域的频谱表达式,并分析其在分数阶域的频谱性质。该方法解决了整个采样时段内由于过采样造成的数据冗余性,满足了实时性要求,且具有较好的抗噪声能力。这里提出的非均匀采样方法满足了采样定理的要求,并得到了均匀采信号在分数阶域的频谱表达式。Because of confination of the sampling equipments and the sampled signals, complete uniform sampling can not be realized, so the signals must be sampled nonuniformly. According to the signal＇s timevariant feature, the signal is sampled by low sampling frequency in the signal＇s low - frequency part and by high sampling frequency in the signal＇s high - frequency part. The nonuniformly sampled Chirp signal is analyzed by fractional Fourier transform. The spectral expression of nonuniformly sampled Chirp signal in the fractional Fourier domain has been derived, and its fractional spectral property has been analyzed. This method solves the problem of redundant data because of oversampling in the whole sampling period,meets the real - time request and has better ability to resist noise. The innovation of this paper is that the proposed nonuniform sampling method meets the sampling theorem request,and the spectral expression of nonuniformly sampled signal in the fractional Fourier domain has been obtained.

关 键 词：非均匀采样 分数阶FOURIER变换 CHIRP信号 采样频率 分数阶谱 

分 类 号：TN911[电子电信—通信与信息系统]