A study on real time measuring microscopic movements in sinusoidal phase modulating interferometry using a laser diode

레이저 다이오드를 이용한 정현파 위상변조 간섭에 의한 실시간 극미세 진동 측정에 관한 연구

A now signal precessing system for real time displacement measurement in sinusoidal phase modulating interferometry is described. Although sinusoidal phase modulating interferometry is effective in measuring with high accuracy the displacement of an object, conventional signal processing takes along time. In this method, detection of the object's displacement is easily achieved by sampling the interference signal at those times that satisfy certain conditions and by processing the sampled signals with electric circuits in real time. the delay time of this signal processing system is < 45 $\mu$s. Specially in this paper we describe all electronic circuit and optical system design