SYSTEM ZUM MESSEN DER TRANSMISSIONSEIGENSCHAFTEN VON LICHTLEITERN

摘要

The system comprises a laser (10) launching short adjustable light pulses into one end of the light guide (11); a light deflector (12) for picking up the backscattered light from the guide and feeding it to a detector (13), a control unit including a timing unit (15) to control the laser and the detector; and a multichannel analyzer connected to the detector and the control and timing unit. The analyzer includes a plurality of storage cells or channels - each representing a time interval, the length of which is determined by the required resolution - for integrating in said plurality of parallel channels the digitized signals received from the detector and in which said plurality of parallel channels represent a time window. The system also comprises means (14) for adjusting the output power of the laser so that the received backscatter or reflected light in an actual time window exhibits an optimum intensity as defined in this context; means (14) for making corrections for the implied digital overflow introduced by the optimizing process; and means (14) for linking together data sets from measurements in mutually overlapping time windows to achieve, by a linear regression operation, a correct transmission of measurement data from one time window to a following one and to make corrections for background level and for different output powers of the laser.