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近来,对于陆地移动通信的需求已迅速增长。而无线频谱中,可用频率严重缺少。对于未来移动无线电的发展所需增加的信道,最有前途的方法之一是缩窄无线电信道。日本在400MHz频段已建立了采用12.5kHz间隔窄带调频发射的陆地移动通信。其研究结果已在CCIR报告319—5(MODI)中介绍。本文讨论日本在800MHz频段采用12.5kHz信道间隔的陆地移动通信,并建议修正报告319—5(MOD I)。
Recently, there has been a rapid increase in demand for land mobile communications. In the wireless spectrum, there is a serious shortage of available frequencies. One of the most promising ways to increase the number of channels needed for the future development of mobile radios is to narrow the radio channels. Japan has established land mobile communications using narrow band FM transmissions at 12.5 kHz intervals in the 400 MHz band. The results of this study are described in CCIR Report 319-5 (MODI). This article discusses Japan’s land mobile communications using 12.5 kHz channel spacing in the 800 MHz band and recommends Modification Report 319-5 (MOD I).