Circuit Research Of Grating Signal Processing Based On FPGA

Grating measurement technology in industry has been rapidly developed in the field of metrology, and grating sensor are widely used in the measurement of line displacement and angular displacement. There are many methods about grating signal processing, such as the traditional circuit, microcontroller or field programmable gate array (FPGA) and so on. With the development of electronic technology, grating signal processing circuit is researched toward the direction of digital, using programmable logic array circuit and the programming language to achieve the desired functionality. Currently, using FPGA to design circuit has become the most effective and the best method. In recent years, the grating signal processing using CPLD / FPGA technology has become a trend. In this article the grating signal processing circuit based on FPGA will be achieved.This paper briefly describes the basics of grating, and grating measurement principle is explained in detail as well as the Moire fringe signal of electronic subdivision. It describes the development and application of FPGA, and analyses the development process about FPGA and the hardware description language Verilog HDL.Using the Field Programmable Gate Array,a kind of grating signal processing circuit in Coordinate Measuring Machine(CMM) is proposed in this paper.The main contents are researched as follows:1.FPGA is the core to achieve the functions of four fold-frequency multiplication,discerning direction and counter about grating signals. The circuit design principles of four fold-frequency multiplication,discerning direction and counter are described in details.The entire circuit of the hardware design is expressed by the language of Verilog HDL.The simulation results show that not only the design achieves the targets of circuit design,also the resource is saved, and the program is easy to modify.2. Through the USB interface circuit, the data being collected will be uploaded to computer to complete data storage transfer and so on. The USB communication interface has high-speed in transmitting data. It can Plug and Play and supports multi-mode transmission. In the design , CH372 interface chip is chosed.In this topic the design of FPGA-core chip has been completed.The functions of four fold-frequency multiplication, discerning direction and counter about grating signals has been achieved. the USB interface circuit has been analyzed .we select the appropriate interface chip for it.