Research And Development Of The Grating Signal Electronic Subdividing System

Grating measurement technology is a high precision measurement technology based on counting the Moiréfringes created by the grating moving. And the subdividing of the grating signal is one of the most economical and effective method to improve the precision grade of the measurement technology. The paper is applying itself to research and manufacture electronic subdividing system for grating signal on the basic of grating signal's characteristic and subdividing technology.At first, on the basis of systematical analyzing of the internal and external applied status of grating measurement technology, the paper is centering on the research fruit and the development trend of the electronic signal subdividing technique. In the part of theory research, the generation principle and signal's characteristic of moiréfringes is being introduced, and then explain the concept of signal subdividing and the application meaning of the theory. After the theory explanation, the paper illuminates some mainstream signal subdividing methods which are being used widely in engineering, and compares them by some technical aspects in detail. Combining with the technique requirement of our project, we chose the best one by making the scheme with further improvement, and plant it in the system design.The core of electric subdividing hardware system is the Altera's CPLD EPM7128. The design uses just one chip to take on the jobs of subdividing data processing and system logic control. Circuit's highly integrity makes the system becoming more reliable, by the time with more simple hardware structure. The USB interface module is used for communicate with the upper computer, because of its flexibility and broad applications. In software design, the program is designed by VHDL language. By using the techniques such as Hiberarchy Design and Finite State Machine, each module has its own independence function, and the process of program is under an efficient and reliable way.By the experiment, the subdividing data output from the E2PROM which is select by 8 bit address signal convert by ADC is accuracy and reliable. The electric subdividing system equipped with strong resolving ability for phase- shifted grating signal. The fruit of the research can be greatly applied in the engineering project and production, and it will dramatically improve the grating measurement precision.