一、引言多年来,西德在大力发展井下采掘机械化的同时,致力于全矿井通讯设备的改进。他们想研制一种通讯装置,监控人员通过该装置可以在任何时间、任何条件下实现他们之间及他们与中心站的通讯联络。他们首先考虑到无线电通讯。但是,井下条件不利于电磁波的传播,使他们遇到困难。由于衰减和反射,就大大缩短了传输 I. INTRODUCTION Over the years, West Germany has been devoting itself to the improvement of all-mine communications equipment while vigorously developing underground mining mechanization. They want to develop a communication device that enables supervisors to communicate between them and their central station at any time, under any condition. They first consider radiocommunication. However, the downhole conditions are not conducive to the spread of electromagnetic waves, so that they encounter difficulties. Due to attenuation and reflection, the transmission is greatly reduced