研究多径信道存在多普勒频移时,即“双扩展”效应下单阵元被动时反的信号检测性能.采用多普勒频移理论推导发现多径信道下接收信号频移由所有对应到达阵元的声线频率漂移组成,从而影响时反的聚焦效果,因而提出了“频反”、“时反”的方法.通过全相位分析及chirpz变换的仿真结果表明当声源频率为12kHz,初始相位为60°时,改进方法可使时反后的接收信号主频恢复为12kHz,而且同相叠加形成聚焦效果,且主频初始相位为300°.%Based on existence of Doppler frequency shift in the multi-path channel which named of "dual expansion" effect, the signal detection performance of passive time reversal by single hydrophone was discussed. Derivation through the Doppler frequency shift theory leads to the conclusion that the shifts of reception signals consist of all sound rays reaching the hydrophone due to multi—path channel, which affect the focus performance of time reversal, and so the methods of "frequency reversal" , and "time reversal" were raised. The simulation result shows that the method can recovery the dominant frequency of reception signals when the source dominant frequency is 12kHz through full—phase analysis and chirpz transformation, and make focus effect by same composed phase that is 300 degrees of dominant frequency when source initial phase is 60 degrees.
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