Multivac 的Level set包，包括 narrow band level set方法和fast marching方法的全部源代码。

对实际采集的舰船辐射噪声进行了demo谱分析，分别采用了窄带解调和宽带解调两种方式，得到了较清晰的轴频和叶频信息。-use narrow-band and broad-band methods to demodulate the ship-radiated noise which is actually colleted, there can see clear axle frequency and blade frequency in the demo spectrum.

窄頻段的邊界耦合，將所需參數輸入，可以看出其響應曲線-Coupled Boundary narrow band, the required input parameters, you can see the response curve