For underwater acoustic positioning system based on measurement of time_delay, range ambiguity appears when pulse's propagating time is longer than its repetitionperiod.
基于时延测量的水声跟踪定位系统，当信号传播时延大于脉冲重复周期时，就会出现距离模糊。
2
At present stage in China, tourism in rural areas is one for leisure, with the characteristics of short period, short trip, low consumption and repetition.
我国现阶段乡村旅游属于休闲旅游，有短时、短途、低消费、重复的特征。
3
In contrast to traditional shipbuilding mode, this method can sharply lower the rate of repetition and material wasting in pipe design and arrangement period.