数字相位测距仪信号源的研究与设计

在相位激光测距仪中,信号初始相位的相对稳定性对测距仪的测量精度非常重要.对于如何得到全同步的主振信号、本振信号、差频参考信号以及填充脉冲,给出了采用单片机控制频率合成器(DDS)直接数字频率合成芯片,直接滤波以及FPGA软件模拟DDS原理三种不同的方案,最后对这三种方案进行了比较.直接滤波法实现起来简单且成本较低,适合测量精度不是很高的系统.另外两种方案可用于测量精度较高的系统,但是成本较高.

Research and Design of Signal Fountain in Digital Phase Range Finder

The initial phase relative stability of signal is very important to digital phase range finder. Three feasible methods are introduced to keep the coherence of main oscillate signal, root oscillate signal and referenced minor frequency signal. The first is gaining sine wave from square wave by direct filter. The second is the application of direct digital synthesizer technique controlled by SCM. The last is gaining sine wave by means of simulation DDS on a piece of FPGA. The three methods are compared. We can get the conclusion that cost price of a system based on the scheme of direct filter is low and realization is simple, but it is not suitable for high precision measurement systems. The system based on the other two schemes can reach higher precision but need higher cost.