为了改善数字调制识别在低信噪比下的识别性能,该文提出了基于瞬时信息的自适应小波阈值消噪的调制识别优化算法.该方法采用自适应小波阈值消噪算法对瞬时信息进行消噪以提高瞬时信息的信噪比,并在已有的两个特征参数σap和σdf的基础上,改进了特征参数Ra和Rσa,以降低判决门限设置的敏感度.仿真结果表明,即使在信噪比低达1 dB时,7种数字调制的成功识别率都达到96%以上.与已有算法相比,该优化算法具有实现简单、计算量小和极低信噪比下识别率高等优点.%An optimal algorithm based on adaptive wavelet de-noising is proposed to improve effectively the performance of digital modulation recognition under low Signal to Noise Ratio (SNR). An adaptive wavelet threshold de-noising filter is used to eliminate the noise in instantaneous information and improve the SNR. And two parameters Ra, Rσa are improved based on two existing parameters σap, σdf to reduce the sensitivity to noise threshold. Simulation results show that recognition probability of 7 types of digital modulation signals is all above 96％, even SNR is down to 1 dB. Compared with existing algorithm, the proposed algorithm is easy to implement,which has lower computational costs, higher recognition probability.
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