| 摘要 |
The invention relates to a method and apparatus for measuring an optical distance with the aid of a light beam transmitter (2) which generates a continuous, coherent, electromagnetic beam, at least during a measuring process. This beam is split and transmitted along two beam paths (3, 4, 8, 7 and 3, 4, 5, 6, 7) and the two beams are brought together at a detector (10), where they are added one to the other. The transmitter (2) is caused to change its wave number in time during at least one sequence, in order to determine a discrepancy between the two beam paths. A phase shift corresponding to an instantaneous wave number is registered in an output signal from the detector (10). A measurement of the phase shift, and therewith the discrepancy, is obtained by measuring the number of occurrent interference fringes in a counter (10) and/or by measuring the time during a given sequence. The change in the wave number of the beam transmitted by the transmitter (2) is selected within a predetermined, accurately delimited wave number interval. The discrepancy is determined from the dependency of the phase change on the wave number change and/or the time. |
