Abstract: A method and apparatus for recording and reading information in the form of a track of pit and land areas on an optical digital disc record carrier. The information is first encoded from symbol blocks of data bits into symbol blocks of channel bits to which are added merging bits selected so as to minimize the d.c. unbalance or digital sum value of the channel bits. Those parts of the stream of channel bits for which the d.c. unbalance does not meet predetermined criteria are subjected to selective scrambling to correct such unbalance prior to recording. During read-out the correctively scrambled parts of the recovered symbol blocks of data bits are descrambled in an inverse manner. Information identifying such parts is recorded with the channel bits. The invention also relates to a record carrier on which information has been so recorded.

Abstract: A multiphase electric machine whose stator winding is disposed in an air gap between a smooth stator wall and the rotor. The coils of the stator winding are wound stepwise in such a way that per coil the field variation in the direction of movement of the rotor is substantially sinusoidal and the winding has a constant thickness.

Abstract: A pivoting mirror device for pivoting a pivoting mirror about two mutually perpendicular pivoting axes under the influence of electric control signals, in particular for a video player which reads information from a video disk with the aid of a light beam using optical means, the mirror being journalled so as to be pivotable to all sides and the device comprising electro-dynamic drive means which include permanent magnets and control coils for controlling the pivoting movements. The mirror is supported near its center, while permanent magnetic positioning means which co-operate with permanent magnetic means which are connected to the mirror continually subject the bearing to pressure.