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针对FRFT-TDCS应对多分量LFM干扰信号时的变换阶次选择问题,提出了一种以寻求最大可用带宽为标准的FRFT-TDCS最优阶次选择算法。首先分析了LFM干扰信号在FRFT域内不同阶次下的频谱分布特征,对其能量聚焦时的展宽、位置以及幅值进行了量化;然后通过预设门限对不同变换阶次时的干扰频谱进行标记并统计,选择使可用子载波个数最多的变换阶次作为系统最优阶次;最后对CSK解调模型进行推导,得出了系统误码率与基函数自相关函数之间的关系,证明了增加系统可用子载波个数可以降低误码率。仿真结果表明,该方法在应对多分量LFM干扰时,可以自适应确定系统最优阶次,降低基函数的峰值和均值,提高发射波形的LPI、LPD性能,有效降低系统误码率。
Aiming at the problem of FRPS-TDCS transform order selection when dealing with multi-component LFM interference signals, an optimal FRFT-TDCS order selection algorithm based on seeking the maximum available bandwidth is proposed. Firstly, the spectral characteristics of LFM interference signals at different orders in the FRFT domain are analyzed, and their broadening, position and amplitude during energy focusing are quantified. Then the interference spectra of LFM interference signals at different transformation orders are marked by the preset threshold And chooses to make the transform order with the largest number of available subcarriers as the optimal order of the system. Finally, the CSK demodulation model is deduced, and the relationship between the system error rate and the autocorrelation function of the basis functions is obtained. Increasing the number of available subcarriers in the system can reduce the bit error rate. The simulation results show that the proposed method can adaptively determine the optimal order of the system and reduce the peak and mean of the basis functions in response to the multi-component LFM interference. This method can improve the LPI and LPD performance of the transmitted waveform and effectively reduce the system bit error rate.