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根据国家广电部规划:天上一颗星(通讯卫星),地上一张网(有线电视网),将全国电视普及到千家万户每个角落,因而有线电视应运而生,并且以雨后春笋般的速度迅速发展。我国目前有线电视网的干线传输系统有300MHz、450MHz、550MHz、750MHz、800MHz等5种,目前国内采用的主要是前3种。由于有线电视与广
According to the planning of the State Radio and Television Department: One satellite in the sky (communications satellite) and one network on the ground (cable television network) will popularize the national television to every corner of every household and thus cable television emerges as the times require, and at a mushroomed speed Rapid development. At present, China’s cable television network trunk transmission system has 300MHz, 450MHz, 550MHz, 750MHz, 800MHz and other five kinds, the current domestic use is mainly the first three. Due to cable television and wide