光纤AM CATV外调制发射机中组合二次失真CSO的控制

Control of composite second order distortion in externally modulated transmitter for optical fiber AM CATV

提出了一种易于实现的调制器偏置点控制方案,对其进行了理论分析,导出了误差信号的表达式,并进行了计算。实验结果表明,理论分析与实验相符。采用该方案,对于PAL/D550MHz的电视系统,能够将发射机的CSO指标控制在-65dBc以下,满足实际使用的要求。

In this paper we present a novel control loop for biasing the modulator in order to elimintare even order distortion.The theoretical analysis and deducing are given.On this scheme ,in a real PAL/D550MHz CATV transmission experiment ,all the channels' CSO is less than-65dBc.