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针对传统扫频干扰抑制方法存在信噪比损失大、输出信干噪比受输入干信比影响大导致同步性能不稳定、强干扰下频谱泄露严重等问题,提出了一种基于重叠变换的分数阶傅里叶域与时域联合干扰抑制技术.首先通过加窗、重叠分数阶傅里叶变换,提高干信比改善性能,降低信噪比损失;其次,通过弱化干扰与二次门限处理,在分数阶傅里叶域中尽可能多地抑制干扰能量,减小干信比对输出信干噪比的影响,最后,通过分数阶傅里叶域及时域联合干扰抑制,解决强干扰存在相位不连续造成分数阶傅里叶抑制后,时域仍残留干扰能量的问题.理论分析及仿真结果表明,本文所提方法对单个调频率多个周期扫频干扰和多个调频率扫频干扰均具有较好的抑制效果,尤其在高干信比下比传统方法性能改善明显.
Aiming at the problems of large loss of signal-to-noise ratio and large SINR of output signal-to-interference ratio (SINR) due to the large interference of input SINR, which leads to unstable synchronization performance and severe spectrum leakage under strong interference, a new algorithm based on overlap transform Order Fourier domain and time-domain joint interference suppression technology.Firstly, through windowing, overlapping fractional Fourier transform, improve the performance of dry-to-speech ratio to improve the performance and reduce the loss of signal to noise ratio.Secondly, through the weakening interference and quadratic threshold processing, In the fractional Fourier domain, the interference energy is suppressed as much as possible to reduce the effect of the interference ratio on the output signal to interference and noise ratio. Finally, through the fractional Fourier domain and time domain joint interference suppression, Theoretical analysis and simulation results show that the method proposed in this paper has a great deal of research on the multi-period frequency-swept frequency interference and multi-frequency frequency sweeping interference Has a better suppression effect, especially in the high dry letter than the traditional method to improve performance significantly.