Digital Transmission Systems

Feedback equalization is employed for digital repeaters of transmission systems having twisted-wire pairs, in order to reduce intersymbol interference while minimizing near-end crosstalk gain. Previously the incoming signal was selectively amplified at the higher frequencies in order to negate intersymbol interference, with subsequent near-end crosstalk gain. According to the present invention the intersymbol interference element of an incoming signal is cancelled, prior to amplification in an adder by a compensation signal derived from the output signal of a regenerator and a retimer. An output stage serves to amplify and shape the resultant signal to a form suitable for transmission. The compensation signal comprises the inverted output of a filtering and scaling network.