echo return meaning in Chinese

回声返回
混响输入

The thesis reviews the theory which is the basis of synthetic aperture processing and introduces five algorithms of image reconstruction : the coherent addition provides a good opportunity for the real time sas ; the envelope processing can work when sonar echo returns lack phase coherence ; the i - q processing can reduce the sampling rate ; the broadband and ctfm processing are both aimed to increase the sas mapping rate
讨论了用于重构图象的五种算法，包括简单的可进行实时处理的相关合成法，可以在缺乏相位信息时使用的包络处理法，可以降低采样率、减少运算量、存储量的正交处理法，可以提高声纳运行速度，从而提高成象率的宽带处理法和ctfm法等五种算法。