effective aperture

Sound as the most effective physical means of long-range underwater detection and communication. Currently international and domestic has developed a variety of sonar equipment ( such as side-scan sonar, synthetic aperture sonar, self-propelled variable depth sonar, etc.) for detecting underwater targets.

声是水下远距离探测、通讯的最有效的物理手段，目前国际国内已发展装备了各种声纳（如侧扫声纳、合成孔径声纳、自航式变深声纳等）用于探测水下目标。

Determination of effective aperture and estimation of truncation energy in synchronous three-channel optical system for laser warning

同步三通道激光告警光学系统有效孔径的确定及截获能量的估算

The effective aperture of a lens, controlled by a diaphragm.

光圈快门:由光圈控制的镜头的有效进光口.

· Theoretical analysis shows that there is a limitation for the array gain loss in an ocean multipath environment that exists more than 1 effective normal modes, which is an advantage for the application of a large-aperture line array.

理论分析表明，浅海多途环境中，当简正波号数大于1号时，阵增益下降存在极限，这对长线阵的应用是有利的。

Effective Feature Extraction Algorithm for Spotlight Synthetic Aperture Radar Images

一种有效的聚束式合成孔径雷达图像特征提取算法