Abstract: The invention relates to a reproduction or recording apparatus for different optical recording media, which differ for example with regard to their storage density, are scanned by different means and have a photodetector arrangement that is jointly used for the different recording media and scanning means, which arrangement provides a photodetector signal which is independent of the absolute light power level of the laser diodes. For generating the photodetector signal which is independent of the absolute light power level of the laser diodes, a switch for changing over the sensitivity of the photodetector is provided, which switch is controlled by the modulator for generating a uniform light power with a laser diode. A connecting line to the basic apparatus and corresponding terminals for controlling the switch are advantageously obviated as a result.

Abstract: The invention relates to an optical scanning device for apparatuses for recording and/or reproducing information on optical recording media, which is suitable in particular for recording and/or reproducing information at high speed, such as, for example, the scanning of a DVD at a twelve-fold speed. According to the invention, the optical scanning device has a lens holder which is formed by a hollow body and whose side walls are arranged such that they run at an angle to a connecting point with its elastic support. The thus hexagonally formed lens holder has advantageous air chambers and an enlarged distance from the lens, and also an elastic support deviating from a parallel guide, which lead to a low degree of lens tilting, improved guidance properties and a natural resonance behaviour which is necessary for scanning at high speed. The field of application relates to the production of scanning devices for optical recording media which are provided for recording and/or reproducing information at high speed.

Abstract: A tape recorder, having a reading device for a magnetic tape, is set up to read out simultaneously a number of data tracks recorded in parallel on the magnetic tape. Stored on the magnetic tape in the vertical direction relative to the data tracks is additional information which can be sensed as a whole in specific tape positions by the reading device. The additional information can contain information on the state of the tape. Such a tape recorder can read the information on the state of the tape immediately after the insertion of a magnetic tape cassette without the need for the magnetic tape to be transported to and fro.

Abstract: Tape recorder having a group of write heads which are arranged like a matrix in rows and columns, with each write head assigned in one row line and in one column line, and having a driver circuit for passing current through the row and column lines. A write head magnetizes a magnetic tape permanently only when its associated row and column lines have currents applied to them causing magnetic fields that reinforce one another in the magnetic tape. A common row return line is provided to which all the row lines are connected and a common column return line is provided to which all the column lines are connected.

Abstract: A method for tracking control of a head unit with respect to data tracks on a magnetic tape determines a first tracking signal and a second tracking signal from control tracks recorded on the tape. The data tracks are divided into successive data sections, each of which is subdivided into an initial region and a useful region. A first control track extends over the entire length of the data section. In addition to this, a second control track is provided in the initial region of each data section. A first tracking signal is generated from the first control track and a second tracking signal is generated from the first and second control track. A difference signal is generated and stored, which is based on a comparison of the first and second tracking signal. A tracking control signal applied to an actuator adjusting the head unit is generated from the second tracking signal when the second tracking signal is available.

Abstract: Magnetic tape recording apparatus comprising a plurality of recording heads for recording digital signals onto a magnetic tape, the recording heads being arranged in a matrix-type structure; and a control unit for electrically compensating for different magnetic properties of the recording heads, the control unit comprising controllable current sources connected to each of the recording heads; at least one non-volatile memory in which is permanently stored individually determined and pre-set magnetizing current values individually corresponding to a particular recording head; and common controller circuit for selectively activating the current sources and the current values stored in the non-volatile memory in dependence on the digital signals to be recorded, wherein upon selection the recording heads are supplied with the stored values of the magnetizing current assigned to them.

Abstract: A method for controlling a phase relation between a head drum and a tape feed system, of a type wherein digital picture data is subdivided into blocks having an assigned pointer value each and wherein the pointer values define which part of the picture the block of picture data represents includes the steps of: incrementing or decrementing a location in a measured value with a corresponding pointer value with corresponding data block in a reproduced data stream, monitoring the content of the locations in the measured value store after a certain amount of reproducing time by means of determining the distance between pointer value regions which have been reproduced more often than the regions in-between, thereby taking into account the difference in reproducing frequency between the more often reproduced regions and the more seldom reproduced regions according to the measured value store entries, and determining a phase correction value for the control of the phase relation between the head drum and the tape fe

Abstract: Recording is carried out with time compression at an increased tape longitudinal speed and an increased head drum speed of rotation. Reproduction is carried out at a set tape longitudinal speed and at the same increased or slightly reduced head drum speed of rotation. Conversion into real time and the frequency position for real time reproduction are ensured by electronic memories into which the signal repeatedly generated by overscanning is written and from which it is read out during reproduction.

Abstract: A method for monitoring and adjusting a motor current in a disk data drive allows to adjust a rotation speed of a disk to be as high as possible in order to increase an overall performance of the disk data drive. It comprises measuring the value of the motor current fed to the motor for an actual value of the disk rotation speed, comparing the value of the motor current with a nominal value of motor current at the actual value of the disk rotation speed, increasing the disk rotation speed to a new actual value of the disk rotation speed if the value of the motor current is substantially equal to the nominal value of motor current.

Abstract: A head drum for a magnetic tape apparatus includes a stationary lower cylinder and a rotating upper cylinder on which at least one write/read head is securely arranged and interacts with a magnetic tape with an exchange of electromagnetic signals. Also provided are at least one amplifier which rotates together with an upper cylinder and amplifies the signals coming from the write/read head, and a rotating transformer for transferring electrical signals between the stationary lower cylinder and the rotating upper cylinder. Storage means for electrical energy arranged on the rotating upper cylinder is capable of supplying electrical power to all the electronic components rotating together with the upper cylinder. A controller is securely arranged on the rotating upper cylinder for monitoring the charge state of the storage means and controlling the duration of the energy transfer as a function of the charge state.

Abstract: The invention relates to a tracking device in which a position of a coil driven actuator is determined using a sensor coil. A reference signal 12 having a determined voltage and frequency is fed to a driven coil. A position of the coil driven actuator is proportional to a distance between the driving coil and the sensor coil. The sensor coil produces an alternating voltage induced by an alternating magnetic field emitted by the driving coil. The alternating voltage is used to determine the position of the actuator.

Abstract: It is known in the case of digital helical track recording and replay apparatuses for audio, video and general data to be recorded for pilot tones to be interleaved in the data tracks, for tracking. The interleaving can be carried out simultaneously with the data by frequency decoupling (a) or by superimposition (b). The invention is based on the object of providing a helical track recording and replay system which carries out tracking in a simple manner. According to the invention, the ATF signal is obtained in a filter module, which also carries out the rectification of the filtered-out pilot tones. The two DC voltage levels are interrogated and processed in the servo microcontroller, with A/D converters. Coupled to the rotation of the head drum, pulses are produced by the servo system which switch the ATF conditioning over between direct operation and tracking operation, so that evaluation is achieved by the microcontroller during the fast ATF burst phase.

Abstract: The invention relates to a device for positioning a first element relatively to a second element. The device according to the invention uses lifting means comprising a cam element and actuator means to actuate the cam element. The cam element has a plurality of contiguously arranged sectors with machined edges belonging to first and second interleaved groups. The machined edges are shaped such that a response of the lifting means to the actuator means has different values for sectors of said first and second group thereby providing alternately a coarse positioning and a fine positioning. The device may for example be used to position a multitrack magnetic tape and a magnetic writing/reading head relatively to each other.

Abstract: In the case of various recording systems based on the helical-scan method for magnetic tapes, a pilot-tone principle is used for tracking control, generally using two pilot tones which are recorded on the helical tracks respectively in series of four: pilot tone F1, no pilot tone, pilot tone F2, no pilot tone. Known methods for determining the pilot-tone amplitudes use narrow-banded band filters, a control signal being generated by forming the difference between the amplitudes. On account of the weak pilot tones, this requires very narrow-banded filters with good dynamic properties.According to the invention, a quadrature mixing has the effect of converting the two pilot tones into the baseband, whereby the filtering is performed in the low-pass range and a control signal can be derived from the difference between the pilot-tone amplitudes thus determined.

Abstract: The invention relates to a method for recording longitudinal track bundles on an information medium. The method involves recording tracking information in special tracks in said track bundles. The special tracks are contiguous between each other. When recording a new track bundle a recording and/or reading head may be positioned using tracking information contained in special tracks of a previously recorded track bundle. Several examples of patterns used for coding tracking information in the special tracks we described.

Abstract: A method for tracking control of a head unit with respect to data tracks on a magnetic tape determines a first tracking signal and a second tracking signal from control tracks recorded on the tape. The data tracks are divided into successive data sections, each of which is subdivided into an initial region and a useful region. A first control track extends over the entire length of the data section. In addition to this, a second control track is provided in the initial region of each data section. A first tracking signal is generated from the first control track and a second tracking signal is generated from the first and second control track. A difference signal is generated and stored, which is based on a comparison of the first and second tracking signal. A tracking control signal applied to an actuator adjusting the head unit is generated from the second tracking signal when the second tracking signal is available.