Abstract: A frequency converter circuit has at least two outputs that are respectively connected to a load, in particular an induction coil. A first output is operated at a first switching frequency and a second output is simultaneously operated at a second switching frequency that is different from the first, in such a way that noise having a frequency generated by the superposition of the first switching frequency and the second switching frequency is produced. The frequency converter circuit is operated in such a way that the frequency of the noise is lower than a first cutoff frequency and/or is higher than a second cutoff frequency.

Abstract: The present invention relates to a Parking brake (1) which is connected to at least two brake cables (60), in particular for a parking brake system of motor vehicles, comprising: an actuator (30; 130) with linking means to which the at least two break cables (60) are coupled at linking places and an operation means (5, 10) configured and connected to the actuator (30; 130) such that it can change the distance between the linking places in a controlled manner whereby a relative movement of the linking places to each other or away from each other is enabled. Preferably, the parking brake (1) comprises a set of gears (10) and an electric motor (5) for generating and transmitting a rotation wherein the rotation is transformed into a linear movement by means of an actuator (30; 130). The parking brake (1) according to the invention assures a uniform operation of the respective brakes and a comfortable control with reduced efforts for adjustment and maintenance.