Abstract: A magnetic tape recorder for video recording and video playback with a one head drum and a head support plate. According to the invention the head support plate is point supported and spring attached to a base plate. The head support plate is movable around two rotation axes and is actuated with an electromagnetic drive means. The one motion cooperates with a dynamic track following circuit for providing dynamic height level correction of the head and allows to capture tracks during replay, which deviate from the parallel inclined position or, in case of a course of the track deviating from the tape recording speed resulting in a trick palyback. The motion around the other axis allows a controlled and regulated azimuth offset of the neighboring tracks during playback, which are recorded with continuously alternating azimuth angle.

Abstract: An analog digital conversion is provided for two color difference signals, for example for a recording according to a timeplex method. The color difference signals are adjusted in their amplitude at the input of the analog digital converter such that the modulation range of the analog digital converter is always fully used independent of the original amplitude of the color difference signal. The amplitude is restored back to its original value after a digital to analog reconversion. This results in an improvement of the signal to noise ratio during the transmission. The amplification provided to the various signals can be controlled by comparator circuits comparing the signal level with a reference signal.

Abstract: Step-up switching regulator power supply device comprising, connected between the poles of a rectifier circuit supplied by an isolating voltage step-down transformer and loaded by a first filter capacitor, and inductance and the collector-emitter path of a first switching transistor of NPN type, a first diode whose anode is connected to the junction of the inductance and to the collector of said transistor and whose cathode is connected to a second filter and storage capacitor supplying a voltage at its output which supplies a horizontal deflection circuit of a television receiver.This horizontal deflection circuit which comprises in cascade a horizontal oscillator, a driver stage and an output stage, forms an integral part of the circuit controlling said first transistor and determines the repetition period of the switching, because it is started under an initial voltage slightly less than the unregulated input voltage of the device.

Abstract: A power control circuit for controlling the base current to a switching transistor connected in series with a primary winding of a switching transformer in which a logic circuit controls first and second amplifiers which respectively supply base current to and absorb base current from the switching transistor. The logic circuit blocks base current flow whenever the current flow through the transistor or a secondary winding of the transformer exceeds predetermined values in accordance with timing pulses.

Abstract: An improved sweep generator circuit suitable for deflection circuits in television receivers conventionally includes a condenser chargeable through a resistance to establish the sweep. A resistive voltage divider and a threshold comparator circuit are each arranged parallel to the condenser. The comparator circuit is triggerable to establish a low impedance discharge path across the condenser when the charging voltage across the condenser exceeds a normal reference voltage from the voltage divider. The frequency of the generator is made variable in response to a synchronization frequency within predetermined limits by shunting a resistance of the voltage divider by a control resistance through an electronic switch that is triggerable by the sync pulse train.