"The high frequencies make the bats' sonar beam very focused and short-ranged, " he said.
“高频率声波使得声音束很集中，周期很短。” 他说。
2
The F is used for short range anti-submarine purpose around the carrier and depends on its own AQS-13F suspensory sonar to detect the submarine.
型则用于航母周围的短距反潜，主要依赖其AQS-13F悬吊声纳探测雷达。
3
On the base of the active sonar theory, This thesis provide active ultrasonic detecting system that application in low-speed moving object of short-range in shallow sea surroundings.