接收孔径可以有效地改善无线光通信链路的误码率性能。文章从孔径平均效应出发，比较了圆环接收孔径和圆形接收孔径的平均因子差异，进而分析了其对通信系统误码率的影响。仿真结果表明：当接收孔径D＜8 cm时，两种形状的孔径平均因子存在较大差异，误码率的相对误差较大；而当D≥8 cm时，两种形状的孔径平均因子基本相等，误码率的相对误差较小，基本上可以忽略。

Receiving aperture can effectively improve the BER performance of optical wireless communication links. Starting with the averaging effect of apertures, this paper compares the averaging factor differences between annular apertures and circular apertures and analyzes their impacts on the system BER. The simulation results reveal that, when receiving aperture diameter D＜8 cm, there are fairly great differences between the averaging factors of the two shapes of apertures and the relative errors of the BER are fairly large. However, when D≥8 cm, their averaging factors are basically identical and the relative errors are little or negligible.