两列等振幅相干波相向传播时叠加形成驻波.

振幅不大，稳定，方向清楚，不是驻波，而是向上波动，而且有空间,signal is clear, otherwise 振幅 too big, a lot of signals mixed together, as indicated by big spread between bid and ask as seen by market makers, then something is going on