【摘要】 在全光异步CDMA通信系统中 ,引入两个光硬件限幅器是有效减小多用户干扰及PIN光电检测过程暗电流噪声的一种方案。实际上 ,引入两个光硬件限幅器同样可以减小系统中的其他噪声 :APD光电检测过程中的散粒噪声、暗电流噪声、背景光影响、消光比影响及热噪声。本文在系统中存在上述噪声及多用户干扰 ,APD光电检测器噪声作高斯近似下 ,对系统误码性能进行了理论分析及计算机数字仿真。分析和计算机数字仿真结果表明 :引入两个光硬件限幅器不仅可以有效地减小多用户干扰 ,还可以减小APD噪声、背景光影响、消光比影响及热噪声对系统性能的影响 ,从而提高系统的误码性能更多还原

【Abstract】 In all optical asynchronous CDMA communication system,multi user interference and PIN dark current noise can be reduced by introducing double optical harder limiters In practice,other noise in the system can be reduced by introducing double optical harder limiters also,such as:APD shot noise,APD dark current noise,background light and thermal noise In this paper,Performance of the system is analyzed theoretically under the assumption of Gauss distribution of APD output and in the presence of multi user interference and noise mentioned above Computer digital simulations are also given The results of both analysis and simulation show that the introduction of double hard limiter not only can reduce the influence of multiuser interference,but also can reduce the noise in the system,therefore can improve system performance更多还原