一种新型的全数字锁相环

该文提出了一种实现全数字锁相环的新方法。在基于该方法实现的全数字锁相环中,一种数字比例积分控制的设计结构取代了传统的一些数字环路滤波控制方法。通过线性近似,该文推导出该锁相环系统的数学模型,并进一步对该系统的局部动态特性进行了讨论。理论分析表明这种新型的全数字锁相环具有很宽的锁相范围,并且在不同被锁频点的局部范围内都具有相同的稳定形式,锁相跟踪达到稳定的时间与被锁信号的周期成正比。由于充分利用了鉴相脉冲宽度所包含的相位误差信息,同时又引入了积分控制,使锁相环的跟踪响应速度得到提高。仿真实验进一步验证了理论分析的结论。该文锁相环采用数字电路方式实现,其性能可以通过比例和积分控制参数进行调节,因而简化了设计过程,便于应用在电机调速系统、有源滤波器和静止无功补偿器等领域。

水下目标轨迹测量处理系统的设计与实现

应用成熟的信号处理技术和单片机技术研制水下目标测量处理机,处理机具有目标测量和动态静态模拟仿真功能,处理机的所有参数能由计算机设置,计算机软件采用Visual C++编程,软件功能齐全,人机界面好,完成跟踪定位、事后处理、系统自检、模拟仿真等功能。

Phase control of ellipsometric interferometer for nanometric positioning system

Development in industry is asking for improved resolution and higher accuracy in dimensional metrology. In this paper,we proposed a control displacement method based on a polarization ellipsometirc interferometer and phase-locked loop technique. The proposed principle was set up. The experimental results of step and step displacements with a step value of 5 nm were presented. We also analyzed the resolution,the potential minimal displacement of the established system. The results show that the position error induced by the ellipticty deviation of the light beam becomes negligible thanks to our signal processing circuit with high-order filter. This method could be useful for many applications in nano dimensional metrology and semiconductor industry.