A wiper system for vehicles, having at least one wiper lever assembly that has at least one wiper arm and that has a first pivot lever that can be coupled in a manner fixed against relative rotation to a stationary first shaft and a second pivot lever that is freely rotatable about a stationary second shaft, is proposed. The device operates simply, autonomously and independently and is provided with a simple structure. If the RF signal has a level equal to a comparator level, the bit-detecting section 4 outputs channel-bit data having logic level 0 or 1 in accordance with whether the sum of the amplitudes of the two RF signals respectively preceding and following that RF signal is higher or lower than the comparator level.