A practical approach to the development of a transversal filter for equalization in an optical Gbit/s transmission system
When the transfer-function of an optical transmission system for Gbit/s application is not given analytically and when the signal distortion is not too severe a transversal filter for equalizing can be simulated easily. It consists of a few passive components and an appropriate oscilloscope. Tap gains and tap delays of a filter to be realized after simulating can be obtained easily from the setting of the simulating filter. The circuit of the realized filter is given. Comparing the signals taken behind the simulation transversal filter and the realized filter a good agreement can be observed. By means of a 50 Omega input amplifier in the receiver and a succeeding transversal filter the transmission of 2.24 Gbit/s signals over 21 km single-mode fibre was possible. The measured bit error rate was less than 10-9.