Bit error analysis in a multimode communication system with optical transmission

Instruments for measuring error rates and error structures were developed to determine the transmission quality of the digital multimode experiment system of the Heinrich-Hertz-Institut in Berlin. The instruments enable in-service operation with pseudo-random sequencing or set data patterns. The results of more than 1400 hours of tests of high-rate switching devices, 12 repeaters and 32 km of fibre lines showed a mean error rate of 10-9 (excluding errors appearing in bursts). The error structure analysis showed bit errors to occur predominantly in the optical transmission lines.