| 摘要 |
PURPOSE:To measure a distance of 10-100m with high accuracy, by irradiating a measuring object with two kinds of difference frequency outputs obtained from two laser oscillators and setting a distance on the basis of the min. coincidence distance among distances calculated from the phase difference with reflected beam and the difference frequency outputs. CONSTITUTION:The difference frequency omega1=omega11-omega12 of the oscillation frequencies omega11, omega12 of a laser oscillator 11 and a variable frequency laser oscillator 12 is allowed to irradiate an object 5 to be measured and the phase difference phi of transmitting and receiving waves is taken out from an operation amplifiers 9 in the form of cosphi and sinphi to calculate the distance. L1 of the object according to formula. The frequency of the oscillator 12 is changed to omega13 and the distance L2 of the object is similary calculated from omega2=omega11-omega13. Further, LM is set as the distance of the object when the min. coincidence distance L0 of the distance L1, L2 forming fomulae LM<LO and LO<l is present to the interval (l) 1/2 the least common multiple of C/omega1 and C/omega2. |
