Deutsche Thomson-brandt Gmbh

Jurgen Kaaden

Gerhard Reiner

Klaus Oldermann

Dietmar Uhde

Peter Mahr

Erich Geiger

Franz Bigge

Ernst F Schroder

Heinz-Werner Keesen

Fritz Weisser

Hans-Joachim Platte

Jens Spille

Hermann Link

Edgar Wursthorn

Christof Stumpf

Rolf Schiering

Paul A Gillot

Bruno Weihs

Bernhard Otto

Hartmut Schandl

An information storage medium has at least a longitudinal bundle comprising three servo tracks (3, 4, 5). The bundle is arranged in consecutive tracking units (T(N)) of a determined longitudinal length. Surfaces of said servo tracks present either a first or a second characteristic (6, 7) and vary in size and distribution inside the tracking units. The bundles may contain longitudinally stored identification information. Methods for obtaining tracking signals indicating a transversal offset between a reading head and the bundle and for retrieving identification information are disclosed. Also methods for obtaining tracking units in which transversal tracking code is combined with distinct information are described.

Combined longitudinal and transversal tracking

A method of controlling track following in a recorder which uses recording in oblique tracks of a magnetic tape without inactive areas between the tracks and wherein data gaps occur in the useful data sequence due to the change of tracks includes the step of filling the time period containing the data gaps with a predetermined sequence of cyclical modifications of code words representing amplitude and degree increments of a symmetrical train of oscillations. A sequence of code words is used to produce incremental portions of the train of symmetrical oscillations whereby a number of incremental portions forms a complete train of symmetrical oscillations. The code words are modified in synchronism with the clock rate at which the useful data of the recorder are clocked.

Method for the control of track following in a recorder

Multitrack tape device using a movable magnetic head with a planar

In digital, magnetic and optical storage systems for audio/video/data, a Viterbi detector is extended by a control output, and a PLL is controlled by a variable delay line at the output or inside of the PLL.

Signal processing system for digital signals

Method and apparatus for recording a digital signal wherein the recording rate is higher than the available data rate. In such a situation, the available excess recording capability is used for extending the playing time by the existing storage capacity of a magnetic tape is better utilized. In the present embodiment, playback time is increased by use of a constant tape transport speed with part-segmented helical track recording and a bidirectional recording operation during recording and replay.

Method and apparatus for the recording of signals

A cassette for use with a recording apparatus comprises: a housing for a recording medium, the housing having a first surface and side walls, the recording medium being accessible through one of the side walls; at least a part of a chip card affixed to the housing, forming a second surface of the housing and closing the cassette, the chip card part having a memory formed integrally therewith and externally accessible contacts; and, the contacts of the chip card being positioned on the second surface to be engageable by corresponding contacts in the recording apparatus when the cassette is inserted therein. One of the side walls has an access door for the recording medium and the second surface forms an upper wall of the housing as defined by the access door. The part of the chip card forming the second surface of the housing has a marking position at which light transmissivity can be controlled. The marking position can be rendered non transmissive to light to prevent recording.

Cassette including a recording medium for a recording apparatus

A time coding system of high resolution for a digital audio and video recording system is disclosed. Various methods of structuring: time code for recording are disclosed which enable time code reading at high tape transport speeds to facilitate automatic search/forward and reverse. A time and control code generator for video recording and replay use comprises a pulse generator generating a pulse having a television frame frequency repetition rate. A source of a time code signal is related to the television frame frequency, and comprises data bits representing hours minutes seconds and frames. A pulse position modulation means is coupled to the pulse and in response to the data its representing hours minutes seconds, modulates a trailing edge of the pulse to a first position responsive to the data bits having a logical 1 value and modulates the trailing edge to a second position responsive to the data bits having a logical 0 value. A generating is means coupled to the data bits representing frames and generates a first signal frequency responsive to the frame data bits having a logical 0 value and a second signal frequency responsive to the frame data bits having a logical 1 value. The second frequency is double the first frequency. The first and second frequencies are added symmetrically to the trailing edge to maintain the modulated positions.

Method of helical scan magnetic tape recording

Method for determining the position in a cassette recorder

In a calibration operation mode of a magnetic tape recorder for helical track recording, employing the R-DAT standard, a first magnitude of a pilot signal reproduced in a first magnetic head from a pilot signal recorded in a center track with respect to the first magnetic head is obtained. A second magnitude of a pilot signal reproduced in a second magnetic head from a pilot signal recorded in a center track with respect to the second magnetic head is also obtained. A ratio between the first and second magnitudes is calculated and stored prior to normal playback mode of operation. During normal playback mode of operation, the stored ratio is used for normalizing a first difference signal, between crosstalk pilot signals that are reproduced in one of the first and second magnetic heads relative to a second difference signal, between crosstalk pilot signals that are reproduced in the other one of the first and second magnetic heads. The first and second difference signals are applied to a capstan motor for reducing a head-track misalignment error.

Head track alignment arrangement in a magnetic tape recorder

A digital signal, such as obtained during playback from a DAT machine, includes a first component containing e.g. the audio content and a second component containing error recognition code. A signal processor derives in accordance with the second component an error signal representative of errors in the digital signal. A microcomputer then calculates an error rate signal. The error rate signal may be visually displayed or the error rate signal may be applied to the pre-amplifier circuits in the playback transducer stage to minimize the errors.

Apparatus relating to the reproduction of error encoded digitally

Several signal sources that produce corresponding digitally coded signals are coupled to a selection circuit. A microprocessor controls signal selection switches that select one of the signal sources in accordance with a priority schedule, provided that the signal source produces a signal at a frequency that is within a predetermined range of frequencies. The selected signal is then recorded in a tape recorder or forwarded to a signal reproducer device. To test whether a given signal source generates a signal at a frequency that is suitable for recording or reproducing purposes, the digitally coded signals from that source is coupled to an input of a phase-lock-loop circuit (PLL). When the signal causes a lock-in condition in the PLL, that signal source is then selected. If the lock-in condition does not occur, the test is applied to another signal source that is next in the priority schedule.

Signal selection arrangement

The invention concerns a videorecorder with a rotating head drum (KT) that has video heads (K1 & K2) with a magnetic tape (B) looped partly around them mounted on it, with at least one pulse generator (M) mounted on the head drum, with at least one sensor (S) that generates a head-shift signal that switches from one video head to the other, and with a control head (KK) for scanning the vertical-synchronization signal during playback. In the playback mode the time between the signal supplied to the sensor and the vertical-synchronization signal is measured and compared with a reference, and a criterion for controlling the position in time of the head-shift signal is derived from the comparison.

Videorecorder with rotating head drum and video heads

A track readjustment arrangement for a video magnetic tape recorder in which at least two magnetic heads travel across the direction of motion of the magnetic tape, for the purpose of scanning signals that are recorded on the tape. The magnetic heads are carried on a rotatable head wheel, and they have air gaps with an azimuth angle that alternates mirror-inverted around the central axis of the wheel. The phase errors that may occur in the signals scanned by the magnetic heads are from the horizontal sync pulses. The magnetic heads provide individually control parameters that are derived from the magnitude and direction of the phase errors. The head wheel is axially varied and reset as a function of the control parameters.

Track-readjusted magnetic-tape recorder with transverse tracking

Method of determining the elapsed and/or still available playing time of

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.

Growing community of inventors

Villingen-Schwenningen, Germany

Jurgen Kaaden