摘要：讨论了平行光付立叶变换系统与会聚光付立叶交换系统的空间带宽积的不同计算方法，比较了两者的特点与数量关系，给出的计算实例表明，空间带宽积在优化激光粒度仪设计中占有中心地位。

关键词：付立叶变换（F．T）光学系统;空间带宽积;信息处理能力;

Abstract：The different calculating methods of spatial - bandwidth between two kinds of F-T optical system, parallel light and convergent light, have been discussed. A sample of calculation shows that it is important in design of laser particle sizer

Key words：F-T optical system;spatial- bandwidth;information capacity