| 分数阶Fourier变换在水声信号处理中的应用研究 |
投稿时间：2018-03-15 修订日期：2018-04-15  点此下载全文 |
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| 中文摘要:线性调频（LFM）信号瞬时频率随时间呈线性变化，当干扰噪声与其强耦合时，经典的滤波方法难以有效的滤除噪声。针对水声通信中采用LFM信号作为载体时滤波效果不明显的问题，提出了一种改进的分数阶Fourier变换（FRFT）滤波方法。水听器接收到的LFM信号在最佳变换域经FRFT变换后，同时对期望信号进行FRFT变换，系数修正后再对信号进行窄带滤波处理。仿真结果表明，在信噪比高于-15dB时,新算法能够有效的实现信噪分离，还原出信号。 |
| 中文关键词:线性调频信号 水声通信 分数阶Fourier变换 窄带滤波 |
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| Application of Fractional Fourier Transform to Underwater Acoustic Signal Processing |
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| Abstract:The instantaneous frequency of Linear Frequency Modulation(LFM) signal varies linearly with time. It contains the characteristic of time-frequency coupling and the classical filtering methods are difficult to separate noises from signal effectively. Aimed at poor filtering capability of narrow-band signal in underwater acoustic communication which used LFM signals as carrier signals, an improved Fractional Fourier Transform (FRFT) filtering method is proposed. The LFM signal which received by the hydrophone is transformed by FRFT in optimal transform domain. The desired signal is also subjected to FRFT transformation. After the coefficient is modified, the signal is narrow-band filtered. Through the simulation results, when the Signal Noise Ratio(SNR) is higher than -15dB, the new algorithm can separate noises from signal and restore the signal effectively. |
| keywords:Linear Frequency Modulation signal underwater acoustic communication Fractional Fourier Transform separate noises from signal |
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