Resonance of surface waves of a given length is shown to be possible over bed waves with synchronous , subharmonic, or ultraharmonic wave lengths.

针对定长入射流，得到一个自治动力系统，给出它的图。

The error estimation of the quasi-synchronous sampling harmonics anal-ysis and the method used for measuring the subharmonics of periodic signalsare also discussed.

文中还对测量误差作了析和估计,并介绍了测量数的一种方法。