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线性调频(LFM)信号是在雷达、声纳中应用广泛的一类非平稳信号。要准确分析LFM信号,需要了解它的时频局部特性。目前,在信号处理领域,傅里叶变换研究很成熟,应用比较广泛,但它无法表述信号的时频局部特性,因此限制了它在LFM信号研究中的作用。而分数阶傅里叶变换(FRFT)是一个线性积分运算,非常适合处理线性调频(LFM)信号。选适当的旋转角度进行FRFT,LFM信号会呈现出能量的聚集,幅度会出现明显的峰值。高斯白噪声在FRFT域上不会出现能量的聚集。基于此,本文给出了一种利用FRFT实现LFM信号的白噪声滤除方法。仿真结果证实了该方法的有效性。
Linear Frequency Modulation (LFM) signals are a class of non-stationary signals that are widely used in radar and sonar. To accurately analyze the LFM signal, you need to understand its time-frequency local characteristics. At present, the Fourier transform is very mature and widely used in the field of signal processing. However, it can not express the time-frequency local characteristics of the signal and therefore limits its role in the research of LFM signals. Fractional Fourier Transform (FRFT), on the other hand, is a linear integral operation that is well suited for processing Linear Frequency Modulated (LFM) signals. Select the appropriate rotation angle for FRFT, LFM signal will show the accumulation of energy amplitude will be obvious peak. Gaussian white noise does not accumulate on the FRFT domain. Based on this, this paper presents a white noise filtering method using LFM LFM signal. Simulation results confirm the effectiveness of this method.