一种CPM信号频率成形脉冲盲估计算法
doi: 10.3724/SP.J.1146.2008.01560
A Blind Estimation Algorithm of the Frequency-Shaping Pulse of CPM-Signal
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摘要: 频率成形脉冲是连续相位调制(CPM)信号解调所必需的调制参数,由脉冲形状和脉冲长度两个参数共同决定。该文利用CPM信号的自相关特性,深入分析了CPM信号调制参数与自相关函数之间的内在联系,并在此基础上提出了一种频率成形脉冲的盲估计算法。该算法首先实现脉冲形状的盲识别,然后将CPM信号的调制指数调整为整数,最后通过自相关函数中非零值的个数来实现脉冲长度的盲估计。计算机仿真结果与分析表明,该算法实现简单,能够在任意调制阶数和调制指数下有效估计出频率成形脉冲。Abstract: Frequency-shaping pulse is one of the essential modulation parameters for the demodulation of Continuous Phase Modulation (CPM), and it is determined by the pulse shape and pulse length. In this paper, based on the features of the auto-correlation of CPM-signal, an in-depth study is proposed on the internal relationship of the modulation parameters and the auto-correlation function of CPM-signal. Then a blind estimation algorithm of frequency-shaping pulse is developed. First, the pulse shape is identified; second, the modulation index of the CPM-signal is adjusted to an integer; Finally, the pulse length is estimated using the number of non-zero value of auto-correlation function of CPM-signal. The simulation study shows that the proposed algorithm has the ability to provide a good estimation of frequency-shaping pulse of CPM-signal with any arbitrary modulation order and modulation index. In addition, the algorithm design is computation efficient and thus facilitates hardware implementation.
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