一种具有高稳定相位差的成像雷达频率源

An Imaging Radar Frequency Source with High Stable Phase Difference

针对微波频率源相位抖动以及频率不稳定等因素导致高分辨成像雷达成像效果差的问题,分析了频率源稳定性对运动补偿精度的影响,设计并实现了一种具有高稳定相位差的基于时钟同步校准技术的双路直接数字频率合成(DDS)频率源。通过多次DDS芯片时钟的同步校准,得到脉间相位稳定的双路调制脉冲。试验结果表明:该双DDS频率源的输出信号同步延时误差在500 ps以内,脉间相位差均值稳定在2°以内,相位差标准差不大于1.5°,满足高分辨成像雷达对频率源的相位稳定性要求。

Aiming at the problem of the poor imaging effect of high-resolution imaging radar caused by phase jitter and frequency instability of microwave frequency source,the influence of the stability of the frequency source on motion compensation accuracy is analyzed.A dual-channel direct digital synthesis(DDS)frequency source based on clock synchronization calibration technology with high stable phase difference is designed and implemented.By synchronizing calibrations the clock of DDS chip multiple times,a dual-channel modulated pulse with stable phase between pulses is obtained.The test results show that the output signal synchronization delay error of the proposed dual-DDS frequency source is less than 500 ps,the mean phase difference between pulses is less than 2°,and the standard deviation of phase difference is less than 1.5°,which meets the phase stability requirement of high-resolution imaging radar for the frequency source.