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1.现代通信的“三多”特性 信息社会对通信的需求明显存在“三多”特性; ·通信制式多——调幅(AM)、调频(FM)、以及单边带调制(SSB)等。 ·工作频段多——高频(HF)、甚高频(VHF)、特高频(UHF)等。 ·传输形式多——语音、图像、数据、文本等。 “三多”特性导致了相应的通信系统及装备繁多,这就造成了它们之间的互通性、兼容性、
1. The “Three Versions” Characteristics of Modern Communications There are obviously “three multi-characteristics” in the information society for the demand of communication. • The communication systems include AM, FM and SSB. · Multi-frequency operation - HF, VHF and UHF. Transmission forms - voice, images, data, text and more. “Three more” features led to the corresponding communication systems and equipment, which resulted in interoperability between them, compatibility,