Synthetic Wavelength Of Laser Interference Nano Measurement System And Its Signal Processing Method

As the most important part of Laser interferometer, signal processing has becoming very popular in the science and technology domain. In the Laser interferometer, metrical precision decided by the way of signal processing. In order to measure the nanometer scale, must subdivide the interference fringes, subdividing precision decides metrical precision. So, nowadays, the research about laser interferometers is focus on the subdividing technology.This dissertation based on the "A Novel Nanometer Measurement Method Based on the Principle of Interferometric Fringe Subdivision by use of a Synthetic Wavelength"(Project of NSFC), studied the nanometer measurement apparatus Based on the novel interference fringe subdivision theory using synthetic wavelength, the potential subdivision factor can be reached up to 1/440000, improved on the structure of this system. At the next steps, I paid more attention at signal processing system. Analyzed the integral counting errors and the correct combine between integral counting and fractional counting; gave a novel integral counting method which can subdivide one interference fringe to eight counting parts; analyzed some disadvantageous situations when counted the fringes very carefully and then, proposed a novel signal processing method that combined integral and fractional counting. Finally, I designed a signalprocessing system use CPLD.