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无线电信道常常属时变信道。其衰落现象是随机的,其中由多径传播引起的选择性衰落特别引人注意,因为它对地面无线电中继系统,特别是对高速数字无线电中继系统的影响较大,因此探讨数字无线电系统对选择性衰落敏感程度的测量方法具有重大现实意义。根据近几年来的研完成果,IEC于1984年3月提出了一个实验室测量方法〔1〕,征求各IEC成员国的意见,以便成为数字无线电系统对选择性衰落敏感程度的标准测量方法。本文旨在阐述这种IEC提出讨论的测量方法本身以及如何借助测量的结果来比较精确地估计实际数字无线电中继电路中断时间,供国内有关厂所参考。本文第三部分在修正Vasant K的关于τo 公式的基础上,将M.En-shiller和Vasant K等人的工作进行了结合。
Radio channels are often time-varying channels. The fading phenomenon is random, of which selective fading due to multipath propagation is particularly noticeable as it has a significant impact on terrestrial radio relay systems, especially for high-speed digital radio relay systems. Therefore, it is discussed that digital radio systems It is of great practical significance to measure the sensitivity of selective decline. According to the research done in recent years, the IEC proposed a laboratory measurement method [1] in March 1984 to solicit the opinions of various IEC member states in order to become the standard measurement method for the sensitivity of digital radio systems to selective fading. The purpose of this paper is to explain how the measurement method proposed by IEC is discussed and how to estimate the actual interruption time of the digital radio relay circuit with the help of the measurement results for reference by the relevant factories in China. The third part of this article combines the work of M.En-shiller and Vasant K et al. On the basis of modifying Vasant K’s formula for τo.