Abstract: An optical fiber test unit and a method of operating it. The test unit has a laser with a computer controlled excitation current input. To take a measurement, the laser is turned on for a period of time which is approximately equal to twice the propagation time through the fiber. The laser is then turned off and the reflected signal is recorded. This signal is displayed and contains discontinuities which indicate discontinuities in the fiber. The unit provides good dynamic range, but is able to make measurements more rapidly than a conventional OTDR. It is therefore well suited for scan testing of fiber optic cable bundles.

Abstract: In a method and apparatus for scanning a fiber optic network, a light source emits optical pulses into an optical fiber under test. A detector detects reflected light for each of the optical pulses and converts the reflected light into an electrical signal for each of the optical pulses. A sampling circuit samples the electrical signal for each of the optical pulses to generate sets of sample data points associated with the respective optical pulses. A signal processor is programmed to ensemble average the sets of sample points with each other to generate a merged set of avenge sample points. The signal processor then compresses the merged set of average sample data points to obtain a current set of trace data points. The data compression is preferably accomplished using "boxcar" time-avenging of the sample points. The current set of trace data points is compared with a reference set of trace data points stored in memory to determine whether or not a fault exists in the fiber under test.