摘要针对现有的复合调制信号参数估计方法在Alpha稳定分布噪声中性能严重退化的问题，提出了一种基于L-DFT(L-filter-based DFT)的线性调频与相位编码(Linear frequency modulation and binary phase shift keying，LFM-BPSK)复合调制信号参数估计方法。该方法首先定义了L-DCFT(L-filter based Discrete chirp-Fourier transform)，平方倍频法消除编码调相后，采用L-DCFT估计信号的起始频率和调制斜率；分析了循环自相关函数中脉冲出现概率增大的问题，提出了基于改进L-DFT和循环统计量的码速率估计方法。仿真结果表明，基于L-DFT的参数估计方法能有效抑制脉冲噪声，在强脉冲噪声中具有良好的参数估计性能。
Abstract：In order to solve the problem that the existing parameter estimation algorithm of hybrid modulated signals will significantly degrade in Alpha stable noise environment, an L-DFT (L-filter-based DFT) based algorithm for hybrid modulated signals combining binary phase shift keying (BPSK) with linear frequency modulation (LFM) parameter estimation is proposed. First the definition of L-DCFT (L-filter based Discrete chirp-Fourier transform) is proposed. Then the square frequency doubling method is applied to eliminate the binary phase modulation of the reconstructed signal, and the initial frequency and chirp rate are estimated by L-DCFT. The problem that the probability of appearance of pulses in cyclic autocorrelation is bigger than in the original observed signal is analyzed, and a symbol rate estimation algorithm based on modified L-DFT and cyclic statistics is proposed. Simulation results show that the L-DFT based method can suppress impulse noise efficiently and it offers superior parameter estimation performance in heavier impulse noise environment.
金 艳 朱敏 姬红兵. Alpha稳定分布噪声下基于L-DFT的LFM-BPSK复合调制信号参数估计[J]. 振动与冲击, 2015, 34(17): 38-43.
Jin Yan Zhu Min Ji Hong-bing. Parameter estimation of hybrid modulated signals combining BPSK with LFM based on L-DFT in Alpha stable noise environment. JOURNAL OF VIBRATION AND SHOCK, 2015, 34(17): 38-43.
[1] 彭智慧, 林明, 胡知非. 复合编码调制Frank/Costas雷达信号性能分析[J]. 科学技术与工程, 2013, 13(24): 7059-7065.
Peng Zhi-hui, Lin Ming, Hu Zhi-fei. The Performance Analysis of Hybrid Frank/Costas Waveform[J]. Science Technology and Engineering, 2013, 13(24): 7059-7065.
[2] 赵春晖, 马爽.脉冲噪声下基于Myriad滤波及分形盒维数的频谱感知[J]. 震动与冲击, 2012, 31(3): 84:87.
Zhao Chun-hui Ma Shuang, Liu Ming-qian. Spectrum sensing based on fractal box dimension and myriad filter under impulsive noise environment[J]. Journal of vibration and shock, 2012, 31(3): 84-87.
[3] 薛妍妍, 刘渝. LFM-BPSK复合调制信号识别和参数估计[J]. 航天电子对抗, 2012,28(1): 60-64.
Xue Yan-yan, Liu Yu. The recognition and parameter estimation of LFM-BPSK[J]. Aerospace Electronic Warfare, 2012, 28(1): 60-64.
[4] 宋军, 刘渝, 薛妍妍. LFM-BPSK复合调制信号识别与参数估计[J]. 南京航空航天大学学报, 2013, 45(2): 217-224.
Song Jun, Liu Yu, Xue Yan-yan. Parameter Estimation and Recognition of Hybrid Modulated Signal Combining BPSK with LFM[J]. Journal of Nanjing University of Aeronautics & Astronautics, 2013, 45(2): 217-224.
[5] 张超,袁彦霞.频率调制经验模态分解在轴承故障诊断中的应用[J].振动与冲击,2014,33(18):185-189.
Zhang Chao, Yuan Yan-xia, Application of frequency modulated EMD in bearing fault diagnosis[J].Journal of Vibration and Shock,2014,33(18):185-189.
[6] Gardner W A, Spooner C M. Detection and source location of weak cyclostationary signals: simplifications of the maximum-likelihood receiver[J]. IEEE Transactions on Communication, 1993, 41(6): 905-916.
[7] 林俊, 熊刚, 王智学. 基于时频分析的伪码与线性调频复合体制侦查信号的参数估计研究[J]. 电子与信息学报, 2006, 28(6): 1045-1048.
Lin Jun, Xiong Gang, Wang Zhi-xue. Study on Reconnaissance Signal Parameter Evaluation of PN and LFMBased on Time-Frequency Analysis[J]. Journal of Electronics & Information Technology, 2006, 28(6): 1045-1048.
[8] 熊刚, 杨小牛, 赵惠昌. 基于平滑伪Wigner分布的伪码与线性调频复合侦查信号的参数估计[J]. 电子与信息学报, 2008, 30(9): 2115-2119.
Xiong Gang, Yang Xiao-niu, Zhao Hui-chang. Parameter Estimation of Reconnaissance Signal Combined PN and LFM Based on Smoothed Pseudo Wigner Distribution[J]. Journal of Electronics & Information Technology, 2008, 30(9): 2115-2119.
[9] 张佳芬, 和小冬, 唐斌. 伪码-线性调频信号快速参数估计[J]. 电讯技术, 2009, 49(12): 100-103.
Zhang Jia-fen, He Xiao-dong, Tang Bin. A Fast Parameter Estimation Approach for Multiplicative Signal Combined PRBC and LFM[J]. Telecommunication Engineering, 2009, 49(12): 100-103.
[10] Yang Peng, Liu Zheng, Jiang Wen-li. Parameter estimation of multi-component chirp signals based on discrete chirp Fourier transform and population Monte Carlo[J]. Signal, Image and Video Processing, 2013, Doi: 10.1007/s11760-013-0552-0.
[11] 金艳, 低截获概率信号的循环平稳检测与参数估计[D]. 西安：西安电子科技大学, 2008.
[12] Djurovic I, Jubisa Stankvic L, Bohme F.J. Robust L-Esitimation Based Forms of Signal Transforms and Time-Frenquency Representations [J]. IEEE Transactions on Signal Processing, 2003, 51(7): 1753- 1760
[13] Djurovic I, Lukin V V, Roenko. A. A. Removal of -Stable Noise in Frequency Modulated Signals Using Robust DFT Forms [J]. Telecommunications and Radio Engineering, 2004, 61(7): 574-579.
[14] Djurovic I, Wang Pu, Ioana Cornel. Modification of the robust chirp-rate estimator for impulsive noise environment[J]. Signal Processing, 2010, 90(2010): 1730:1736.
[15] Djurovic I, Lukin V V. Robust DFT With High Breakdown Point for Complex-Valued Impulse Noise Environment[J]. IEEE Signal Processing Letters, 2006, 11(1): 25-28.
[16] Jin Yan, Ji Hong-bing. Robust symbol rate estimation of PSK signals under the cyclostationary framework[J]. Circuits Syst Signal Process, 2013. Doi: 10.1007/s00034-013-9639-7.
