| 摘要: |
| 为了在α稳定分布噪声的环境下获得清晰的跳频信号时频图，提出一种基于分数低阶SPWVD(Smoothed Pseudo Wigner-Vile Distribution)与形态学滤波相结合的跳频信号时频图修正算法。首先，根据接收到的多跳频信号建立跳频信号的模型和α稳定分布噪声模型；然后，采用低阶SPWVD变换抑制时频图中脉冲噪声；最后，根据形态学滤波处理方法对残留噪声进一步抑制进而得到清晰时频图。理论分析和仿真结果表明，所提算法在广义信噪比为-5 dB时仍可以得到清晰可靠的跳频信号时频图，并且基于时频图的参数估计性能优良。 |
| 关键词: 跳频信号 α稳定分布 分数低阶平滑伪WVD 形态学滤波 参数估计 |
| DOI： |
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| 基金项目: |
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| Time-frequency pattern modification of frequency hopping signals under impulse noise |
| JIA Wei |
| (Institute of Computer Science,Neijiang Normal University,Neijiang 641002,China) |
| Abstract: |
| In order to obtain a clear time-frequency pattern of the frequency hopping(FH) signal in alpha stable distribution noise,a time-frequency image modification algorithm based on Fractional Lower Order Smoothed Pseudo Wigner-Vile Distribution(FLOSPWVD) and morphological filtering is proposed.Firstly,the FH signal model and the alpha stable distribution noise model are established according to the received signals.Secondly,the FLOSPWVD transform is used to suppress the impulsive noise in time-frequency pattern.Finally,the morphological filtering method is used to further suppress the residual noise and obtain a clear time-frequency pattern.Theoretical analysis and simulation results show that the proposed algorithm can obtain a clear and reliable time-frequency pattern when the generalized signal-to-noise ratio(GSNR) is -5 dB,and the performance of the parameter estimation based on time-frequency pattern is excellent. |
| Key words: frequency hopping(FH)signal alpha stable distribution fractional lower order SPWVD(FLOSPWVD) morphological filtering parameter estimation |
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