Abstract: In a receiver unit, a synchronous pull-in circuit is formed. The synchronous pull-in circuit is comprised of a transversal filter having a roll-off characteristic (roll-off filter), a timing discriminator for extracting a timing signal contained in a received signal and a decision part for detecting a phase deviation between the thus extracted timing signal and an internal clock by which the receiver unit itself is synchronized. The roll-off filter is provided with a plurality of taps, the tap coefficients of which are varied in accordance with the phase deviation, so that said timing signal is synchronized with the internal clock.