摘要
目前的CATV网络不仅要传输一般的模拟信号,而且要能够传输QAM调制的数字信号。重点分析了数字CATV网络中数字频道和模拟频道的相互影响以及QAM调制的原理,讨论了在发射机端激光器削波对数字信号的影响,并给出了仿真结果。分析结果表明,QAM信号的误码率和QAM信号的光调制度、削波失真系数以及削波失真与高斯噪声之间的比例等都有密切的关系,激光器削波将严重恶化数字QAM信号的误码率。
The CATV network has to transmit both traditional analog signal and digital QAM signal. The mutual influence of analog channel and digital channel in digital CATV network is discussed,and the principle of QAM modulation presented in this paper. The discussion indicates that the bit error rate （BER） of the QAM signal is influenced by the optical modulation depth of the QAM signal,the clipping coefficient,the rate of clipping distortion and the Gaussion noise. And the clipping distortion would seriously deteriorate the BER of QAM.
出处
《通信技术》
2009年第12期19-21,共3页
Communications Technology
