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电视图像信号在从发射到收视的传输过程中,由各组成部件中的振荡器引入的相位噪声所产生的干扰在模拟传输系统中表现为:屏幕上出现的亮度、长短和宽窄都随机变化的杂乱水平条纹,与CTB的干扰图像很相似。在现有的某些MMDS系统中,这种干扰明显可见。在数字传输系统中则表现为增加误码率,使系统能维持正常工作的载噪比阈值因之显著增高,因而对相噪电平的指标要求是评价各种数字调制制式刚坚性(robustness)的主要测试项
TV image signal During the transmission from transmission to viewing, the interference caused by the phase noise introduced by the oscillators in the components appears in the analog transmission system as the brightness, length, width and width appearing on the screen vary randomly Messy horizontal stripes, similar to the CTB interference image. In some existing MMDS systems, this interference is clearly visible. In the digital transmission system, it shows the increase of the bit error rate and the significant increase of the carrier-to-noise ratio which can maintain the normal operation of the system. Therefore, the requirement of the phase noise level is to evaluate the robustness of various digital modulation systems ) The main test items