Digital frequency-modulation continuous wave interference laser driving and signal processing method and circuit

Abstract

The invention provides a digital frequency-modulation continuous wave interference laser driving and signal processing method and circuit. The method is characterized by firstly, periodically readingdriving signal waveform data by a microprocessor through using a table look-up method, converting into an analog signal by a DAC, after being amplified by an amplification circuit, passing through a voltage-controlled current source so as to drive a semiconductor laser to generate a laser; then, converting an interference signal formed by the laser after passing through an interferometer into an electrical signal by a photoelectric detector, filtering and removing a noise via a preprocessing circuit, and converting into a periodic digital signal synchronized with the modulation period of a driving signal by the ADC; and finally, acquiring the frequency or the initial phase of a frequency modulation interference signal by the microprocessor according to the digital signal in the same periodthrough a digital phase discrimination algorithm. Through certain circuit implementation, the method and the circuit are compared with an analog frequency-modulation continuous wave interference laser driving and signal processing method and circuit, laser linear frequency modulation is easily acquired, the laser is prevented from being damaged, and high precision and large dynamic range measurement are realized.

Description

Technical field: [0001] The invention relates to the field of frequency modulation continuous wave laser interferometry, in particular to a digital frequency modulation continuous wave interference laser drive and signal processing method and circuit. Background technique: [0002] Frequency-modulated continuous wave laser interferometry is a new laser measurement technology that has emerged recently. It modulates the laser frequency in a linear form. The beat frequency interference signal, the frequency and initial phase of the beat frequency signal are related to the optical path difference of the two beams of light. Frequency-modulated continuous wave laser interference is different from traditional single-frequency laser interference. The beat-frequency interference signal obtained by frequency-modulated continuous wave interference is a dynamic signal. Therefore, it is very easy to subdivide the phase, determine the direction of phase change, and count the entire cycle....

AI Technical Summary

Problems solved by technology

Therefore, using an analog circuit, not only the initial phase measurement accuracy of the interference signal is low (0.1 microns), but also the dynamic range of the interferometer is small (30 mm)

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