METHOD AND APPARATUS FOR CONTROLLING RECIPROCATION OF MOVABLE MIRROR FOR PHOTOACOUSTIC FOURIER TRANSFORM SPECTROSCOPY

摘要

A method and apparatus for controlling thereciprocation of a movable mirror of an interferometer usedin an interferometric spectrophotometer are disclosed,wherein a frequency dividing ratio corresponding to adesired reciprocating speed of the movable mirror is setand then a pulse signal from an oscillator is divided atthe frequency dividing ratio for producing afrequency-divided signal which in turn is compared with aninterference signal from a control interferometer toproduce an error signal for controlling the reciprocatingspeed of the movable mirror based on this error signaluntil the desired reciprocating speed is reached.Preferably, the frequency dividing ratio can be varied by acentral processing unit, for example, so that the user isable to freely change the reciprocating speed of themovable mirror to conform to the type of a detector used,thereby enabling a measurement under optimum conditions.