上行信道中QPSK调制技术的研究

Study on QPSK Modulation Techniques in Upstream Channel of HFC-CATV Networks

根据HFC网络上行信道的特性,建立了信道模型;分析了上行信道中存在的各种噪声对QPSK调制技术的影响。结果表明在C/N（传输信道载噪比）较低的情况下,采用QPSK调制方式,可以提高系统的抗干扰能力。

This paper establishes the channel model according to the properties of the upstream channel of HFC networks. It also studies how various noises in the upstream channel of HFC networks effects the modulation techniques of QPSK. It is demonstrated that when C/N is low, the anti-jamming ability of the system can be improved if QPSK is adopted.