多部VHF/UHF频段机载通信电台同址干扰影响分析

Analysis of co-site interference effect on VHF/UHF airborne radios

多部甚高频/特高频(VHF/UHF)频段机载通信电台在机上同时工作时,存在严重的自扰、互扰、串扰等同址干扰电磁兼容性问题。以3部VHF/UHF频段机载通信电台同机工作为例,分析了影响其通信效果的天线安装位置、空中电磁环境特性、杂散及互调等因素,并进行了空中实际测试;对空中电磁环境特性与地面电磁环境特性进行了比对,初步验证了通信电台发射机杂散辐射射频分量等相关指标优劣的重要性以及多部电台同频段与不同频段通信时带来的二阶互调、三阶互调的影响程度,有助于指导机载通信电台的电磁兼容设计。

When multiple Very High Frequency/Ultra High Frequency(VHF/UHF)airborne radios work simultaneously on the same airplane,there will be serious Electromagnetic Compatibility(EMC)problems of co-site interference,such as self-interference,intermodulation interference and crosstalk.Considering the case of three VHF/UHF radios on one airplane for air test,this paper analyzes the factors affecting the communication effect which contains antenna installation positions,air electromagnetic environment characteristics,spurious,intermodulation interference and others.After the comparison of electromagnetic environments between air and ground,the importance of the radio frequency components of spurious radiation and other related indicators of communication radio transmitters is preliminarily verified,and the influence degree of second-order intermodulation and third-order intermodulation caused by multi-radio communication in the same band or different bands is analyzed,which is helpful to guide the EMC design of VHF/UHF airborne radios.