说明：  水声目标识别34页图2-17仿真 分别使用仿真信号和实际船舶辐射噪声信号进行解调处理获得解调谱，以比较上述三种方法的解调效果。
(The simulation signal and the actual ship radiated noise signal are respectively used to demodulate and obtain the demodulation spectrum to compare the demodulation effect of the above three methods.)