中文摘要：

为了提高无合作目标的相位式激光测距系统的稳定性和精度,并简化测距系统,设计了一种相位式激光测距系统的发射和接收电路。采用了双频调制、直接数字频率合成器（DDS）、差频测相技术等原理。进行了理论的研究、分析和实际的电路实验。利用DDS产生的正弦波信号进行调制发射,并且对非合作目标反射回来的激光信号进行接收、调理,并进行数据处理。在设计中,优化了系统的调制发射电路,采用新的光电探测器和高压偏置电路,增加简单实用的自动增益控制（AGC）模块等。实验结果表明,该测距系统简单有效,具有较高的测量精度和稳定性。

英文摘要：

In order to improve the stability and accuracy of the phase laser rangefinder for non-cooperative target,an improving transmitting and receiving circuits are designed.Its principle includes dual-frequency modulation,direct digital synthesizers（DDS）,phase-shift technology and so on.Theoretical research,analysis and experiments are carried out.Sine wave generated by DDS is modulated and transmitted.The laser signal reflected from non-cooperative target is received.Modulator and transmitter circuits of the system are optimized.New electro-optic detector and high-voltage bias circuit are used.The experimental result shows that the ranging system is simple and effective,and has high accuracy and stability.