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在整个通信技术中,数字信号的传输日益重要,以致出现了有关在特定传播条件下移动通信所用传输方法的问题。本文以中继通信和卫星通信使用的数字信号传输法的一般情况为基础,对陆上移动通信所出现的特殊传播条件进行了比较性的分析。其中对多径传播的局部作用,以及它对通信信号传输速度的影响进行了探索,并定义了影响传播的最重要的物理参数。最后,根据目前的技术状况,确定了迄今己在模拟方式中使用的频分复用法是陆地移动通信中传送数字信号最好的方法。
The transmission of digital signals has become increasingly important throughout the communications technology, resulting in problems with the transmission methods used for mobile communications under certain propagation conditions. Based on the general situation of digital signal transmission method used in relay communication and satellite communication, this paper makes a comparative analysis of the special propagation conditions that occur in land mobile communication. Among them, the local effect on multipath propagation and its influence on the transmission speed of communication signals are explored, and the most important physical parameters affecting propagation are defined. Finally, based on current state of the art, it is confirmed that the frequency division multiplexing used so far in analogue mode is the best way to transmit digital signals in land mobile communications.