WDM系统中改进的Q值在线检测方法

提出了一种改进的Q值在检测方法，指出可以使用不同的门限电平分别对空号和传号进行判决，并引入噪声系数征高速光纤通信系统信号噪声的幅度变化范围，相应地修正了空号和传号均方差的计算表达式，基于改进的方法设计了实验方案，采用数字信号处理芯片（DSP）技术开发了Q值测试板并进行了模拟测试，在一定噪声范围内，测试结果与理论认值吻合得较好，相比干现有的Q值在线检测方法，改进的方法更精确地表示了传输信号的信噪比，具有更好的实用性。

Improved on-line Q-factor measurement method in wavelength-division-multiplexing systems

The principle of an improved method for on line Q factor measurement is presented, describing that the space levels and the mark levels can be decided respectively by different thresholds. By introducing a coefficient that denotes the intensity of noise in high speed optical communication systems, the expressions for calculating the root mean square deviation of spaces and marks are modified. Based on the novel method presented, an experiment scheme by the digital signal processor (DSP) approach is designed and a Q factor testing board is developed. The simulating results coincide with the theoretical values when the optical noise amplitude vibrating in a practical range. With the improved method the signal to noise ratio (SNR) of practical systems can be measured more accurately than previously published ones.