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电子学报 ›› 2012, Vol. 40 ›› Issue (11): 2165-2170.DOI: 10.3969/j.issn.0372-2112.2012.11.004

• 学术论文 • 上一篇    下一篇

基于FRFT的线性调频信号欠采样快速检测方法

仇兆炀1, 陈蓉1,2, 汪一鸣1,2   

  1. 1. 苏州大学电子信息学院,江苏苏州 215006;
    2. 通信系统信息控制技术国家级重点实验室,浙江嘉兴 314001
  • 收稿日期:2012-02-27 修回日期:2012-05-25 出版日期:2012-11-25
    • 通讯作者:
    • 汪一鸣 女,1956年2月生于江苏省苏州市,苏州大学电子信息学院教授,博士生导师.研究方向为认知无线电、通信信号处理. E-mail:ymwang@suda.edu.cn
    • 作者简介:
    • 仇兆炀 男,1987年7月生于四川省成都市,苏州大学电子信息学院硕士研究生.主要研究方向为通信信号处理. E-mail:nerv2015@foxmail.com 陈 蓉 女,1983年10月生于江苏省镇江市,苏州大学电子信息学院博士研究生.主要研究方向为通信信号处理,信道编解码技术. E-mail:chrong@suda.edu.cn
    • 基金资助:
    • 国家自然科学基金 (No.60872003,61071214); 国防科技重点实验室基金 (No.9140C1301031001); 高等学校博士学科点专项科研基金 (No.20093201110005)

Fast Detection of LFM Signal Based on FRFT and Sub-Nyquist Sampling

QIU Zhao-yang1, CHEN Rong1,2, WANG Yi-ming1,2   

  1. 1. School of Electronics and Information Engineering,Soochow University,Suzhou,Jiangsu 215006,China;
    2. National Laboratory of Information Control Technology for Communication System,Jiaxing,Zhejiang 314001,China
  • Received:2012-02-27 Revised:2012-05-25 Online:2012-11-25 Published:2012-11-25
    • Supported by:
    • National Natural Science Foundation of China (No.60872003, 61071214); Key Laboratory of national defense science and Technology Foundation (No.9140C1301031001); Research Fund for the Doctoral Program of Higher Education of China (No.20093201110005)

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摘要： 采用分数阶Fourier变换对线性调频信号(Linear Frequency Modulation,LFM)进行检测与参数估计时,由于信号的特征未知,需要运用二维搜索方法确定分数阶Fourier变换的最佳旋转角度.该方法运算量巨大.为减少运算量,本文推导了欠采样前后LFM信号的分数阶Fourier变换最佳能量聚集旋转角度关系,证明了无噪LFM信号的调频率估计可以完全不受Nyquist采样定理的限制;通过推导分析欠采样含噪LFM信号在最佳分数阶Fourier域的信噪比,给出了欠采样倍数M对LFM信号检测的影响及其选取原则;最终提出一种基于欠采样理论的LFM信号快速检测方法.实验结果表明,当M选取合适时,利用原始信号的欠采样样本即可对LFM信号实现有效检测,快速确定其调频率.

关键词: 欠采样, 分数阶Fourier变换, 线性调频信号, 最佳旋转角度, 信噪比

Abstract: The relationship between the optimal rotation angle of fractional Fourier transform(FRFT)of the undersampled signal and that of the original signal was studied.It was proved that the chirp-rate of noiseless linear frequency modulation(LFM)signal can be estimated correctly even though the signal was undersampled.By deducing and analyzing the signal to noise ratio(SNR)in the optimal fractional Fourier domain,the impact of subsampling rate on detection of LFM signal was discussed.Finally,a novel method was proposed to realize fast detection of LFM signal.Simulation results show that when the subsampling rate is set properly,the detection and parameter estimation of LFM signal can be realized rapidly by applying FRFT to the undersampled signal.

Key words: sub-nyquist sampling, fractional Fourier transform, linear frequency modulation signal, optimal rotation angle, signal to noise ratio

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