基于FPGA和AD等相位距移相的光栅数字细分法  

Grating scale subdivision based on FPGA and AD converter using digital equidistant phase shift method

作　　者：刘建阳[1] 唐臻宇[1] 耿海翔[1] 

机构地区：[1]四川大学物理科学与技术学院,成都610064

出　　处：《微计算机信息》2010年第32期105-106,104,共3页Control & Automation

摘　　要：针对目前用CPU实现全数字光栅细分法和用移相电阻链、电压比较器实现的模拟光栅细分法在光栅细分上的广泛应用,提出了一种用FPGA和AD模数转换器件实现光栅数字细分的新方法。光栅输出的两路相位差900的正弦信号,经过AD转换后得到两路正弦信号数字量,对其分别乘以一定比例系数再进行相加减,实现正弦信号的数字等相位距移相。移相后的多路正弦信号在FPGA器件里进行数字电平比较后,得到不同相移的多路方波信号。对这多路移相方波进行一定的逻辑与运算,输出两路正交方波,将这两路正交方波通过普通的带四细分光栅计数器实现光栅细分。Digital method of using CPU and analog method of using resistor chain,voltage comparator are widely used in the grating scale subdivision recently,this paper give a new design digital way depending on FPGA and AD converter to solove the problem.Put the two way phase difference of 900 signals which are generateed by grating scale through AD converter to get its two way digital value,subtract or plus these digital value with a proper proportion to get sine singal phase shift.After use FPGA as a voltage comparator to process the multiplexed sine signals which have been phase shifted to get square waves out of phase.Then,perform the logic and between these square signals to get two way orthogonal square waves.At last,send the orthogonal square waves into the grating scale with four subdivision function to get the final subdivision result.

关 键 词：FPGA AD 数字等相位距移相 光栅尺 数字细分 

分 类 号：TH741.6[机械工程—光学工程]