A High-Resolution Subdivision System of Frequency Difference Interference Signal Transformed by Phase Integral Operation

Abstract

The invention relates to a phase integral operation transformation frequency difference interference signal high-resolution subdivision system. A reference signal processing circuit and a measurementsignal processing circuit respectively complete photoelectric detection transformation, amplification, filtering and shaping of the measurement signal and the reference signal and then output two paths of square wave digital signals. One path of signals are transmitted to a phase discriminator to perform frequency doubling direction discrimination so as to output add and subtract digital pulse signals changing along with phase. The phase discriminator performs frequency doubling direction discrimination and outputs the add and subtract digital pulse signals changing along with phase to a counter. The counter transmits the integer of the frequency difference interference signals to a programmable processor. Meanwhile, the other path of signals are inputted to a high-resolution phase detection group, high-resolution phase detection is performed on the frequency difference interference signals and then the decimal of the frequency difference interference signals is transmitted to the programmable processor through a bus, and the integer pulses and the decimal data are calculated and processed to be outputted through the bus mode. The system has the characteristics of fast measurementspeed, high resolution and high reliability.

Description

technical field [0001] The invention belongs to the technical field of photoelectric detection, and relates to a phase detection method of a heterodyne interferometer, in particular to a high-resolution subdivision system of a frequency difference interference signal applied to a phase integral operation transformation, which can be widely used in ultra-large-scale integrated circuit processing equipment and precision machine tools On-line in-position measurement, error correction and control etc. Background technique [0002] Heterodyne interferometer is the most commonly used long-distance measuring instrument in the industry, and is widely used in on-site measurement, error correction and control of various precision machine tools and large-scale integrated circuit processing equipment. Theoretically, if the output signal of the heterodyne interferometer is not subdivided, the final measurement accuracy can only reach half of the wavelength of the light source. With the ...

AI Technical Summary

Problems solved by technology

The principle of the commonly used subdivision method based on phase-locked frequency multiplication is that the signals of the measurement channel and the reference channel are simultaneously phase-locked and frequency-multiplied, and the frequency-multiplied pulse related to the displacement is obtained after digital demodulation. It can also directly enter the motion control to achieve high-precision positioning control, but the frequency and tracking bandwidth of frequency multiplication phase-locking are limited, and the control of digital demodulation is limited by high-frequency work

The digital phase detection subdivision method based on pulse filling is also limited by many factors, so the improvement of measurement accuracy is extremely limited

Images