As you move onto the more expensive zoom lenses, they maintain a constant aperture.

当你继续研究比较昂贵的变焦镜头时，你会发现它们有着恒定的光圈。

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By using the aperture synthetic wideband beamforming algorithm, the theory of designing the conventional filter is improved, and a wideband constant beamwidth is reached in the appointed bandwidth.

采用子阵合成式宽带波束形成方法，改进常规滤波器设计原理，使其可以在规定的带宽范围内获得一致的基阵指向性。

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The projection optics is designed for a constant field angle and entrance pupil. Thus image always fills entrance aperture and view field of the test optical system.

从光学指标的确定，结构、材料的选取到最终光学性能，阐述了准直投射光学系统的设计。

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