Abstract: Disclosed is a record carrier for optically detectable data storage, apparatus for manufacturing such a record carrier and apparatus for recording and/or reproducing information on such a record carrier. The record carrier is provided with periodic track variations whose period corresponds to a frequency for which the power spectrum of the digitally coded information substantially exhibits a zero point. When scanned by a beam of radiation, the periodic track variations produce periodic modulation in the beam of a frequency corresponding to the period of the track variations in order to generate a clock signal of a frequency equal to the bit frequency during recording or reproduction.

Abstract: The target of a television camera tube comprises photoconductive material in the form of a regularly interrupted structure so that both the photoconductive material and parts of the signal electrode are accessible to the electron beam. The potential difference between the signal electrode and the cathode is adjusted so that during scanning, the signal electrode accepts a proportion of the beam current dependent on the local potential of the photoconductor surface, and the photoconductor is stabilized only during fly-back. The camera tube thus has an adjustable inherent amplification without increased inertia.

Abstract: A black-white or color television camera comprising a pick-up tube, provided with a signal electrode composed of separated strips. Prior to a line scan to be performed by an electron beam, the signal electrode strips are connected to a reference potential. After a scan the strips are through-connected successively through associated switches for supplying information. The switch outputs are alternatingly, in at least two groups through-connected and connected to at least two output leads. Always two stitches, which are connected to two adjacent strips are closed simultaneously. In this way it is avoided that a capacitive voltage distribution across the strips and switch inputs influence the picture signal obtained in a disturbing manner.

Abstract: A semiconductor device, in particular a target for use in a memory tube having an optical and electric input and an electric output, having a semiconductor plate of the silicon vidicon type, in which information in the form of charge is stored in an insulating layer present on the diodes and is read non-destructively by scanning a reading grating present on the insulating layer between the diodes by means of an electron beam.