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Abstract

An optical transmission system (SYS), e.g. a cable television distribution network, contains at least one transmitting device (SEN), an optical transmission network (NET) and a number of receiving devices (EMP). In order to transmit analog electrical signals, e.g. television signals in the MHz range in such an optical transmission system, the analog electrical signals are first digitized in accordance with the pulse-duration modulation method (PDM) and are then routed to an electro-optic modulator (MOD). An optical pulse source (PULS) generates optical pulses whose repetition frequency rate is higher by the factor of 100 at least than the 3-dB cutoff frequency of the analog electrical signals, e.g. 10 GHz. The optical pulses are modulated with the digitized signals in the electro-optic modulator (MOD) and are then transmitted to the receiving devices (EMP). Only an optical-to-electrical converter OE and a passive electrical low-pass filter (TP) are required to recover the analog electrical signals. The modulated optical pulses from different transmitting devices (SEN) can be transmitted in the optical time-division multiplex method to increase the transmission capacity.

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