Abstract: When examining optical fibers it may be of interest to determine the location of a reflection point along the fiber. A process for time localization of reflected pulses is described, at least two reflected pulses being received, the first one of which originates from a predetermined reference point, the second one from a reflection point whose position is to be determined. According to the described process, the location of the reflection point along the fiber is determined roughly, and then a relatively narrow sampling window is laid around the roughly determined position. The sampling process is hereby concentrated around the reflected signal to provide for optimum utilization of the signal processing time for fine localization of the pulse. Also an apparatus for performing the process is described.