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: Recording or reproducing unit for a plate-shaped information medium including an improved autobalancer for compensating an unbalance. The autobalancer for compensating an unbalance is arranged in the hold-down for a plate-shaped information medium at a diameter greater than an inside scanning diameter, required for scanning, of the information medium and is formed by at least one disc in a circularly running groove forming the means for compensating an unbalance.

Abstract: The present invention relates to an apparatus for reading and/or writing data markings of an optical recording medium having data markings arranged along a track and header markings arranged laterally offset with respect to the center of this track. The apparatus has a signal conditioner, a header identification unit and a switch unit driven by the latter. The object of the invention is to enable data and header markings to be read out with the lowest possible error rate. For this purpose, the apparatus according to the invention has a threshold value forming unit and a storage unit with at least two storage locations, in which case, by means of the switching unit, the input of the storage unit can be connected to the output of the threshold value forming unit and the output of the said storage unit can be connected to a threshold value input of the signal conditioner. The apparatus according to the invention is suitable for reading from or writing to optical recording media such as a DVD-RAM, for example.

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: An optical scanning device having an improved response characteristic, for use in an apparatus for optically reading or writing information in one or more tracks on a recording medium. The object of the invention is to provide an optical scanning device which, without any electronic compensation means, very largely avoids resonance peaks and has an improved response characteristic. According to the invention, this object is achieved by a retaining plate which supports the objective lens of the scanning device via bearing elements and has at least one cutout, which separates the mounting points, in the surface which holds the bearing elements for the objective lens holder. The field of application of the invention is optical scanning devices having an improved response characteristic for use in equipment for reading or writing information on an optical recording medium, such as a CD, DVD, a CD or DVD which can be written to, or else a magneto-optical recording medium, for example.

Abstract: A method for recovering a video signal uses an adaptive equalizer, the characteristics of which are adjusted to the conditions of a transmission channel by using the digital data signals that are concomitantly transmitted in addition to the analogue signal components in a video signal. This adjustment is then used for analogue signal components of the video signals. A teletext signal can advantageously be used for the adjustment.

Abstract: In one embodiment, data are converted, with the aid of corresponding rules and headers, into data having a fixed block length in such a way that, with the CTL bit definition, no clashes with known data structures of the CTL track such as VISS and VASS occur. The effect achieved by this is that any desired data can be stored on the control track.

Abstract: In order to reproduce the audio signal which has been recorded as an FM audio signal in the slanted tracks of a recording medium in tape form by means of read/write heads arranged on a rotating head drum, it is possible to use PLL circuits which are designed as FM demodulators and in each case form a phase-locked loop with a VCO. FM demodulators of this type generally operate satisfactorily e.g. in video recorders with improved audio signal recording, but there is the risk of the frequency of the VCO of the respective FM demodulator drifting when the read/write head assigned to it leaves the wrap-around region of the recording medium on the head drum and only being able to be synchronized with the FM audio signal when the said head re-enters the recording medium.

Abstract: A device for rotating inside of a disk player and/or recorder a disk shaped data carrier which takes into account that the rotating disk may be eccentered from an imposed rotation axis. Side moving means allow the rotating disk and the fixing means to which the disk is removably fixed, to move inside said player and/or recorder in a rotation plane substantially perpendicular to an axis of rotation of said fixing means. The rotating disk and the fixing means go into a gyroscopic movement inside the player. A plurality of examples to realize the invention are described.

Abstract: The mains filter comprises coils with windings which are arranged on substrates, for example conventional thin printed circuit boards, as conductor tracks. A coil can comprise one or more substrates, which are in contact with one another in the case of a plurality of substrates. In the centre, the substrates have an opening through which a core is passed. With an appropriate number of windings, one substrate is sufficient for one winding, so that only one substrate per coil is required for the mains filter. The two substrates for the two coils can be of identical design, in particular, the input and the output for a coil being arranged on a substrate in the region of opposite corners. The core used can be a narrow E/E core or E/I core, so that the space requirement for the filter on a circuit board is very low.

Abstract: Analyzing steps are used for automatic aspect format detection in digital video pictures. A black bars analyzing step is performed wherein for each possible aspect format (14:9, 16:9, 2:1) a top and/or bottom area is defined and checked for whether a black bar is present. A center analysis also is performed to check whether an active picture area is present. A horizontal transition analysis determines whether a horizontal border between a dark area and the active part of the picture is present, and then a format choice is made and the picture aspect format is selected. The method can control zoom operation in a TV receiver with a 16:9 picture tube or can control the recording function of a video recording device, in combination with the appropriate apparatus.

Abstract: A photodiode detection circuit is used to automatically identify a type of photodiode circuit connected to it. The photodiode circuit comprises at least a photodiode. Once the type of photodiode circuit has been identified by applying a current to it and evaluating a voltage occuring at an input of the detection circuit the photodetection circuit adapts itself to it, e.g. a reverse biasing voltage is/isn't applied to the photodiode of the photodiode circuit. The result is a photodiode detection circuit which uses a forward or a reversed biased photodiode. The photodiode detection circuit is now in a state to measure light falling on the photodiode. The detection circuit may be part of a light intensity monitoring and controlling circuit which allows to regulate the intensity of a laser beam in an optical disk reading/recording device.

Abstract: A circuit for correction of deflection errors in a television set, in which a correction current having alternate forward-sweep and flyback periods is supplied to a correction coil for an error parameter. An amplitude of the correction current is reduced during a time window which corresponds to the flyback period and in which no visible picture is displayed.

Abstract: The switched-mode power supply comprises a transformer, a switching transistor connected in series with a primary winding of the transformer, a primary-side control circuit and a secondary-side regulating stage. The regulating stage is coupled to a coupling element for transiting a regulating signal from the secondary side to the primary side. A first switch is situated between the control input of the switching transistor and a primary-side operating voltage, and a second switch is situated between the regulating stage and a secondary-side operating voltage, with the two operating voltages being able to be disconnected using a single control signal. In this case, the isolating element transmits both the regulating information for the primary-side control circuit and the turn-off signal for the first switch. If the second switch is turned off by the control signal, the regulating stage and the optocoupler become completely currentless and consume no further power.

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 circuit arrangement with a digital controller for operating an electric motor and a method for starting an electric motor are disclosed. Electric motors require a considerably higher current immediately after they have been switched on and during the running-up phase because of the inductance of the motor windings. In order to increase the control sensitivity of the controller for the normal operation, the control range of a digital controller is switched over into a higher current range for the running-up phase. For the normal operation of the motor, the control range of the controller is switched back again into a lower current range. As a result, the control sensitivity of the controller is completely available for the normal operation of the motor.

Abstract: Television receivers are increasingly making use of digital signal processing. Present-day television receivers use a line-coupled clock system in this case, since this produces an orthogonal pixel array for signal processing on the picture screen. The disadvantage of such a clock grid resides in its problematical generation, in particular when video recorders are used as signal source. According to the invention, video signals are digitized and processed by means of a free-wheeling system clock made from a quartz oscillator. In order not to have to use large buffer memories, the vertical deflection is synchronized with the input signal, but the number of lines per field or frame is varied.

Abstract: A signal processing method for an analogue picture signal is proposed. In this case, the analogue picture signal originates from a computing unit (10) in which the signal was generated digitally in accordance with a graphics standard such as, for example, EGA or VGA and was subsequently converted into analogue form. The method consists in subjecting the analogue picture signal to analogue/digital conversion at a first chosen sampling frequency, after which the sampled picture is then investigated for picture disturbances, in order to determine a corrected sampling frequency. Further measures relate to the determination of the optimum sampling phase and the determination of the exact position of the active picture relative to the horizontal and/or vertical synchronization pulses.

Abstract: A dual wavelength optical pickup head in which as many same parts as possible are used as well to direct light beams incident than light beams reflected from a reflective layer of an optical disk. The reuse of as many parts as possible allows to and a second wavelength emitted by a first and a second light source to an optical disk, a dual focus lens objective for focusing said light beams on a layer of said optical disk and a single detector which allows to detect light beams of either said first or said second wavelength.

Abstract: In an OFDM system, the so-called self-noise component, which represents that noise component of the respective carrier which is caused by the carrier itself and is mapped onto itself, can be estimated and corrected by shifting all the carriers back in the receiver by multiplication by a factor which is determined by averaging. The so-called external-noise component, which is caused by adjacent carrier interference from the so-called leakage effect of the Fast Fourier transform (FFT2) used in the receiver for demodulation cannot be corrected using this method. In addition to the demodulation FFT, a further FFT (FFT1) is used in the receiver to estimate the self-noise component (&psgr;e). The estimated self-noise component is used to reproduce the orthogonality between the carriers by correction before the demodulation FFT, to thereby prevent crosstalk. The additional FFT (FFT1) may have a shorter length than the demodulation FFT (FFT2), so that the additional complexity is negligible.