时域相乘,频珐卷积。所以x(t)的频谱 =X1YuX2的卷积; X1的w起点=-110pi,Zhong点=110pi; X2的w起点=-120pi,Zhong点=120pi; 卷积后w=-230pi~230pi,Ji最高频率 按230pi计算,最小采样频率ws=460pi