傅里叶望远镜部分周期信号解调及对成像的影响

为了解决傅里叶望远镜高功率短脉宽激光只能包含部分周期信号的难题,本文提出多脉冲拼接技术并对其基本原理和应用范围进行深入研究.首先介绍高功率短脉宽激光与声光移频器移频带宽之间的矛盾,进而引出利用傅里叶望远镜传统时间解调公式进行部分周期信号解调存在的困难.然后给出多脉冲拼接技术的基本理论,推导出理想情况下移频频率、脉冲重复率和脉宽满足的拼接条件.进而详细分析移频频率稳定性和脉冲重复率稳定性对多脉冲拼接成像结果的影响,并通过计算机仿真研究一般情况下脉宽变化对多脉冲拼接成像结果的影响.最后得出移频频率和脉冲重复率对成像无影响,激光脉宽变化小于25%仍可识别目标轮廓的结论.

Demodulation of Part Period Signal of Fourier Telescope and Effects for Imaging

In order to settle the problem of high power short pulse laser of Fourier telescope including part period of signal, the technique of multiple pulse segment was first put forward and its basic principle and application was also first studied. Firstly, the conflict between high power short pulse laser and band width of acousto-optic frequency shifter was introduced, and then the difficulty that part period signal was demodulated by conventional time demodulation formula of Fourier telescope was put forward. Secondly, the basic principle of multiple pulse segment was given and the condition of segment between shifting frequency, pulse repetition and pulse width under ideal instance was deduced. Thirdly, the effects of stabilization of frequency shifting and pulse repetition on imaging results of multiple pulse segment were analyzed and the effects of changing pulse width on imaging results of multiple pulse segment under usual condition were studied by computer simulation. At last, the conclusion was acquired that shifting frequency and pulse repetition had no effects on imaging and the figure of object could also been identified under the condition of laser pulse changing less than 25%.