Abstract: A method and device are revealed for scanning a radiation-sensitive layer (2) of a rotating carrier (4) with a constant linear velocity by means of a radiation beam (5) which is directed towards the carrier (4) by an optical system (6) which is radially movable relative to the carrier (4). A velocity-pulse generator (10) generates clock pulses (Ps) of a frequency (fs) proportional to the angular velocity of the carrier (4). A clock generator (25) generates clock pulses (Pk) of constant frequency (fk). In response to every clock pulse (Pk) a sum value (Sw) is corrected by a first correction value (DEC). In response to every velocity pulse (Ps) the sum value is corrected by a second correction value (INC) having a sign opposite to that of the first correction value. The angular velocity (W) of the record carrier is controlled to a value for which the average of the sum value (Sw) remains constant.

Abstract: A method and apparatus for scanning a rotating optical disc record carrier with a radiation beam which forms a scanning spot on the carrier and which is moved radially relative thereto. Pulses are generated at a frequency proportional to the angular velocity of the carrier, and clock pulses are generated at a constant frequency differing from and preferably higher than that of the velocity pulses. In response to each velocity pulse an accumulator is incremented by a first correction value (INC) and in response to each clock pulse the accumulator is decremented by a second correction value (DEC). The angular velocity of the record carrier is controlled to maintain a constant value of the average of the sum output of the accumulator over the intervals between successive velocity pulses, and the correction values are adjusted so that the ratio thereof is maintained proportional to the radial distance between the scanning spot and the axis of rotation of the carrier.

Abstract: A device for displaying variable quantities on the viewing screen of a cathode-ray tube by means of deflection coils which are energized by a number of deflection amplifiers coupled to different supply voltages, the deflection amplifier with the lowest supply voltage serving for signal components with the lowest frequencies and that with the highest supply voltage for the signal components with the highest frequencies. This results in a substantial reduction in power consumption.