非线性调频信号参数估计算法

Parameters Estimation of Nonlinear FM Signals

分析了非线性调频 (NLFM)信号参数估计问题 ,提出了利用二次相位差分使相位降阶 ,使 NLFM信号的参数估计转化为成熟的正弦波频率估计 ,而 NLFM信号参数估计算法从三维搜索简化为三次一维搜索 ,既减少了计算复杂度 ,又有利于工程实现 ;另外从正弦波频率估计问题出发推导出对信号参数 a3估计的最佳相关延迟量为 2 T/7,同时还考虑了延迟相关对信号信噪比的影响 ,发现一次延迟相关信号信噪比至少下降 3 d B,两次延迟相关至少下降 7d B,而且信噪比越小 ,下降越多 ,因此该算法适用于高信噪比条件。仿真结果表明 ,该算法在较高的信噪比条件 (RSN>2 d B)

The problem to estimate the parameters of the complex nonlinear FM signals is discussed. This problem is converted into estimating the frequency of sine wave through delay and correlative operation and the optimum delay of estimating a 3 is 2T/7 . The signal noise ratio after delay and the correlative operation are analyzed and the loss of signal noise ratio is larger than 3 dB, so the algorithms can be used when the signal noise ratio of input signal is higher than 2 dB. Simulational results prove that the algorithms have a good performance.