基于FRFT窄带滤波的LFM信号研究

随着分数阶傅里叶变换域窄带滤波技术的不断应用与发展,对分数阶域窄带滤波带宽的研究将变得尤为重要。研究了分数阶傅里叶变换域窄带滤波带宽与滤波后信号之间的关系,并以信号的失真度为准则,分析了分数阶域窄带滤波带宽的临界值。理论分析和仿真结果表明:线性调频信号经过分数阶域窄带滤波后信号的相位没有发生改变,信号的幅度为辛克函数积分的形式。为保证LFM信号频率信息不丢失,分数阶域窄带滤波的带宽必须不小于LFM信号在分数阶域幅度谱的主瓣宽度。为分数阶域滤波带宽的选取提供了参考标准。

Study of LFM Signal Based on FRFT Domain Narrowband Filter

With the application and development of FRFT domain narrowband filter technology,so the study of FRFT domain narrowband filter bandwidth will become particularly important. In this paper the relationship between the FRFT domain narrowband filter bandwidth and the signal after filtering are studied and the fractional domain narrowband filter bandwidth threshold with the signal distortion as a criterion is analyzed. The theoretical analysis and simulation results show:By the FRFT domain narrowband filtering the phase of linear frequency modulation signal has no changing and the amplitude of linear frequency modulation signal is the form of the integration of Sinc function. And In order to ensure the LFM signal frequency information integrity the bandwidth of the fractional domain narrowband filter must be no less than the main lobe width of LFM signal amplitude spectrum in fractional domain and provides a reference standard for the fractional domain filtering bandwidth selection.