the invention relates to an apparatus for processing a signal received via an information carrier . the apparatus comprises a receiving unit for receiving a signal from the information carrier , an equalizer for equalizing the signal thus received , and a signal processing device . the signal processing device has a first signal path including time delay means , a second signal path including differentiation means adapted to effect at least two differentiations with respect to time , a decision circuit , and a controllable switching element . the decision circuit is adapted to transfer a control signal , the decision circuit being adapted to supply a control signal which depends upon the signals on the outputs of the first signal path and the second signal path . depending on the action defined by the control signal the controllable switching element couples the output of the first signal path to the output of the controllable switching element or it couples the output of the second signal path to the output of the controllable switching element . the above - mentioned signal processing circuit reduces the influence of inter - symbol interference in the signal .