Linear frequency modulation(LFM)signal is a signal form widely used by radars. Since the traditional instanta⁃neous frequency measurement(IFM)system is unable to analyze the internal frequency structure of LFM signal,which can influence the frequency measurement accuracy of LFM signal,the fundamental of IFM is introduced briefly,and the frequency ambiguity reso⁃lution method of IFM system with multi-channel phase discriminators is analyzed. Based on this,the model of processing the LFM signal by IFM system was established,and the reason why frequency measurement error of LFM signal is generated by IFM system was analyzed. The results of theoretical analysis were simulated and verified,which provided a theoretical reference for IFM technology in engineering application.%线性调频（LFM）信号是当前雷达广泛应用的一种信号形式。传统的瞬时测频（IFM）系统无法分析LFM信号的内部频率情况，所以会影响对LFM信号的测频准确性。通过简要介绍IFM的基本原理，分析了多路鉴相器组合的IFM系统的解频率模糊方法。在此基础上建立IFM系统处理LFM信号的模型，分析了引起IFM系统对LFM信号测频误差的原因。通过对理论分析结果进行仿真验证，为工程实际中的瞬时测频技术提供了理论参考。
展开▼
