光纤脉宽调制多路电视传输技术

Pulse--width modulation for fiber--optic transimission of multiplex radio frequency TV signals

本文研究了采用脉宽调制(PWM)方式来实现光纤多路电视信号传输,通过频谱分析,论证了根据自然采样原理实现脉宽调制的方法,不仅可以消除传统调制方式中存在的非线性失真,而且减小了边带分量的干扰,还具有解调简单、适于多路传输的优点。在此基础上,本文提出了一种用于CATV系统的脉定调制光纤多路电视传输方案,并为实现该方案进行了线路设计和传输试验。试验的结果表明,采用PWM方式实现2路V道电视信号的直接传输是可能的。

This paper makes researches on pulse-width modulation which can be used to realize. the fiber-optic transmission of multiplex TV signals. The spectrum of PWM signals is ana- lysed and it is demonstrated that the natural sampling PWM method can not only eliminate distortion existing in the conventional modulation way, but also reduce sideband frequency components interference. Demodulation for PWM signals is simple and suitable to multiplex transmission. On the basis of these characteristics, the paper presents a pulse-width modulation plan in which multiplexing TV images transmission is available to optical fiber CATV systems. Circuits for the plan realization are designed and transmission tests are made. The result illustrates that two TV signals in the V channel can be carried directly through an optical fiber in a pulse-width modulation way.