本文提出了充分利用有限频谱资源的频率规划分配原则。针对双频系统给出了按1.25MHz50个信道分段的无三阶互调频率分配方案,频谱利用率可达100％。一、做好频率规划,充分有效地利用有限频率资源由于历史原因,我国移动通信用的超短波频率的使用情况存在很多问题。在频率分配上缺乏全面规划;多半是孤立地按部门按单位指配给固定的专用频率;很少考虑同一地区各单位备部门之间的关系和不同地区的频率复用问题。这样就容易产生严重的邻道干扰、互调干扰和同频干扰。为了避免相互干扰,就得将一些信道舍弃不用或设置较宽的保护带,浪费了宝贵的 This paper proposes the principle of frequency plan allocation that makes full use of limited spectrum resources. For the dual-band system, there is no third-order intermodulation frequency allocation scheme based on 1.25MHz50 channel segments, and the spectrum utilization rate can reach 100%. First, do a good job of frequency planning, full and effective use of limited frequency resources Due to historical reasons, China’s mobile communications with the use of ultrashort frequency there are many problems. There is a lack of comprehensive planning of frequency allocations; most of them are assigned to fixed dedicated frequencies by departments and units in isolation; seldom consider the relationship between departments in different parts of the same region and the frequency reuse in different regions. This will easily lead to serious adjacent channel interference, intermodulation interference and co-channel interference. In order to avoid mutual interference, it is necessary to discard some of the channels or set a wider protective tape, wasting valuable