摘要:
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.
摘要:
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.
摘要:
The determination of the position of a tape thread-in and thread-out mechanism in a cassette recorder is carried out using contact paths together with a slider contact that form position switches. Output signals of the position switches are coupled via a resistor network that combines the output signals and produces an output signal on a single conductor. The resistor network output signal is coupled to an input of an analog -to-digital converter. To improve the reliability of determining the position of the mechanism without requiring the use of highly accurate resistors in the resistor network, the voltage value assigned to each individual position is measured at the output of the network during a calibration operation. The voltage values are stored in a memory and used as the desired values during normal operation.
摘要:
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.
摘要:
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.
摘要:
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. The application of the invention is envisaged for reproduction or recording apparatuses of different optical recording media in which a modulation of the laser current is provided for generating a uniform light power.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A tape recorder and/or a playback device for a multitrack tape utilizes a magnetic head having active parts for recording and/or reading microtracks with the active parts being arranged in a two-dimensional matrix within a substantially planar surface of the magnetic head. A pressure device assures contact between the microtracks and the active parts by acting on a backside surface of the tape opposite to the front side surface containing the magnetic head. A structure allows for positioning the magnetic head in front of either one of at least two macrotracks which bundle addressed microtracks. A portion of the tape surface is supported adjacent to the macrotrack bundling the addressed microtracks to prevent unwanted tape deformation.