宽带接收中的信号分离技术研究

【作者】 刘焱；

【导师】 唐斌；

【作者基本信息】 电子科技大学 ， 信息获取与探测技术， 2006， 硕士

【摘要】 宽带信号接收时,窄带信号伴随宽带信号进入宽带数字接收机的概率较大。从多信号中分离出各信号是宽带数字接收的关键技术之一。因此,宽、窄带信号分离及其参数估计备受雷达和电子对抗领域的广泛关注。本文以线性调频(Liner Frequency Modulated, LFM)信号为主要研究对象,从时域、频域和时频域三个方面研究了宽窄信号的分离方法。论文的主要工作如下:1.分析了现代电子侦察环境下的信号特征,讨论了混叠信号类型。在时域、频域、时-频域分别研究了混叠信号特征。2.基于分数阶Fourier变换,改进一种欠采样条件下的宽带与窄带信号分离与参数估计方法。该方法先估计信号的调频斜率,并在分数阶Fourier变换域进行滤波实现多信号分离,最后对欠采样信号解频率模糊估计初始频率,解决了分数阶Fourier变换分离信号的二维搜索问题。3.研究了一种基于信号自相关的宽、窄带LFM信号分离方法。基于多个同时到达信号经过相关运算后的包络特征,对信号分段处理,并通过数据拟合,得到各个原信号。4.借鉴“CLEAN”快速谱估计方法的思想,研究了一种基于频域“CLEAN”的信号分离方法,该方法通过逐一解线调和频域滤波完成多信号分离。更多还原

【Abstract】 As receiving the wide band radar signals by a wide band digital receiver, it has great probability of receiving the narrow band radar signals at the same time. The technologies of signal separation and parameter estimation are the most important technologies of the wide band digital receiver. Therefore, it is widely concerned on separating signals from the aliasing signals and estimating the parameters of the signals in the various complicated electromagnetic circumstance. In this dissertation, it is focused on the LFM (Liner Frequency Modulated) signals, and the technology of separating the wide band signal from the narrow band signal in time domain, frequency domain and the time-frequency domain respectively are researched. The main works of this dissertation are included:1.The signal characteristics under modern electronic reconnaissance environment are analyzed. It’s pointed out that wideband digital receiver must satisfy wide monitoring band. The types and characters of aliasing signals are given and researched in time domain, frequency domain and the time-frequency domain respectively.2.Based on the fractional Fourier Transform (FrFT), a method, which separates and estimates parameters under the signals sub-sampled condition, is presented. After modulation rate roughly estimated using the signal with its delay version production and Newton’s iterative method,signals are filtered and separated in the fractional Fourier Transform domain. Finally, the initial frequencies of the sub-sampled LFM signal are estimated unambiguously. It is solved the problem of the two-dimensional searches in separating signals using FrFT.3.Based on the auto-correlation theory, a method, utilized to separate the wide band signals from the narrow band signals and to estimate the parameters is researched. The envelopment characters of LFM signals correlated in time domain are analyzed. Using the leap character of the envelopment, the aliasing signals are processed in subsection and the original signals are reconstructed by data fitting.4.A method based on the CLEAN algorithm is researched. In this method, the更多还原