某机载雷达电信号异常调制的故障分析及设计改进

某机载雷达在试飞联调时,电信号中出现了固定频率的异常调制信号,影响到电性能。根据故障仅发生在振动环境下这一事实,得出异常调制与振动相关的初步结论。通过对雷达各主要组成部件的分析,发现天线单元固有频率与调制频率吻合的概率最高。对单元开展仿真分析和试验验证,得出最终结论:天线单元的固有频率落在载机随机振动的第1个高量级窄带内,从而引起电信号出现异常调制现象。对天线单元进行了设计改进,使其固有频率远离高能量窄带,电信号恢复正常。

Failure Analysis and Design Improvement for Abnormal Modulation Signal of an Airborne Radar

During the debugging process of an airborne radar, there is an abnormal modulation signal with steady frequency in the electrical signal. Based on the fact that the failure only occurs in vibration environment, a preliminary conclusion is made that the abnormal modulation is caused by vibration. By analyzing the primary components of the radar, it is found that the natural frequency of the antenna fits the modulation frequency with highest robability. By finite element analysis and experimental verification for the antenna, it is finally concluded that the abnormal modulation is caused by the fact that the natural frequency of the antenna is in the scope of the first high-level narrow-band of the random vibration of the airplane. Design improvement is conducted for the antenna to make its natural frequency far from the high-level narrow-band. Finally the electrical signal becomes normal.