High-speed Signal Processing Of Laser Interferometer

With the enhancement of China’s independent innovation capability andadvanced manufacturing technology, we achieved rapid development in ultra-fineprocessing, nano-materials research, integrated circuits and micro-electromechanicalsystems (MEMS) device manufacturing, and other high-tech industries. There is anurgent need to establish a unified measure nanometer measurement standards andtraceability system because of these high-tech industries are based onnano-technology. In order to achieve the national benchmark traceability nano moneytransfer system, China Institute of Metrology developed a wide range ofnano-geometries baseline measurement device.The development of a high-speed signal processing laser interferometer system isdesigned after research. New subdivision algorithm, and identified the fringe countingalgorithm, as well as a new means of communication is researched in the systemimplementation. The signal processing speed of measurement basis device has beengreatly improved. The main text of the content and results as follows:1．Signal processing architecture, the main part of the analysis of a wide range ofnano-device geometry measurement basis, to design a computer plus FPGA (fieldprogrammable gate array) signal processing system, used in laser interferometersignal processing. Among them, the AD8620used in the system to achieve the reversesignal, analog filtering, etc.; using the AD7622data acquisition parallel transfer toFPGA; using FPGA core device digital filtering, control data acquisition, and defenseto the fringe counting signal segments, hardware check table; using ARM chip toreceive data from the FPGA, and control TCP/IP hardware cores and other chipnetwork communication, parallel data communication, SPI serial communication;using RS232serial communication MAX3232CSE achieve.2．Hardware circuit design, including the photoelectric conversion circuit,signal conditioning circuits, data acquisition circuits, network communication circuitdesign and implementation; well on ARM programming, FPGAprogramming, etc., to achieve control of data acquisition in the software, digital filtering, serialcommunications, network communications, PC display.3．Electronic subdivision algorithm, to improve the measurement resolutionoptical octave and phase electronic subdivision, innovative design phase subdivisionalgorithm, as well as innovative designs and argue the fringe counting algorithm.Paper’s innovative work mainly included the following three points:1) analysis of multiple subdivision algorithm, and to improve the phase subdivisionalgorithm used to accelerate the speed signal processing, reducing the occupied FPGAresources.2) using a new fringe counting, to argue algorithms from the original hardware circuitsimplification, counting more reliable and stable, the sensitivity of the debate alsomentioned that the hardware configuration more flexible.3) using a communication network, the relative ratio of the previous PCI parallelcommunication, the communication speed, the circuit is more simplified, betterstability..