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同频干扰 目前,有线电视在我国部分地区处于与无线电视同时并存的状况。有线电视用户希望节目套数更多些,内容更丰富些,无线电视观众却又希望无线电视的发射频道更多些,信号更强些。因此有线电视台和无线电视台为尽可能地满足观众的要求,而且从经济造价和传输损耗方面考虑,有线电视和无线电视的播出频道都选择在VHF波段。尽管CATV系统可以用增补频道传输信号,但由于普通电视接收机特别是黑白电视机需将信号变换后方能收看,且数量也有限,于是在VHF波段存在CATV系统与无线电视同频道播出的情况。如果对CATV系统不
Co-channel interference At present, the cable TV in some areas in China in the coexistence with the wireless TV situation. Cable TV users expect more programs and richer content, while wireless viewers hope more of the channel will be broadcast and the signals will be stronger. Therefore, cable TV stations and wireless television stations to meet the requirements of the audience as much as possible, and in terms of economic costs and transmission losses, cable and wireless television broadcast channels are selected in the VHF band. Although the CATV system can use the additional channel to transmit signals, since ordinary television receivers, especially black-and-white TV sets, need to convert the signals to be able to watch and have limited numbers, there is a case where the CATV system and the radio channel are broadcast on the same channel in the VHF band . If the CATV system is not