Abstract: A real-time magnetic digital video disk recording system has been developed for applications in on-line digital imaging systems and off-line fast access image storage and retrieval buffers. The disk recorder uses new high density recording technology and Winchester computer drive technology in a unique peripheral configuration which is fully synchronized to video system timing, provides for flexible formatting, achieves fast random access to a large video image file, and eliminates the need for complex data controllers. The recorder includes two independent actuator and head assemblies for alternately recording successive video fields on separate tracks on separate zones A and B of a disk stack. Movement of one of the actuators and head assemblies is controlled and occurs within a field time to skip tracks containing media flaws to achieve real time digital video recording.
November 15, 1982
Date of Patent:
March 18, 1986
Digital Engineering, Ltd.
David J. Hedberg, Edward P. Denta, Jr., Victor E. Jo Chiong
Abstract: An information recording and reproducing apparatus wherein a light beam is applied onto an optical disk having pits previously formed in optical manner thereon. A tracking signal is detected from the light beam which has been modulated by the pits, and information is recorded by applying a record beam modulated by an information signal onto an area between one pit and the succeeding pit while tracking is effected by using the tracking signal.
Abstract: An FM demodulating circuit demodulates a frequency-modulated signal of a predetermined channel of frequency-modulated signals of respectively different channels, where the frequency-modulated signals are obtained by frequency-modulating carriers of respectively different frequencies by information signals of respectively different channels and transmitting the frequency-modulated signals in a mutually multiplexed state. The FM demodulating circuit has a demodulated output characteristic such that a frequency at which a differential value describing the slope of a demodulated output characteristic curve becomes maximum, is substantially equal to a center frequency of the frequency-modulated signal of the above predetermined channel, and a frequency at which the differential value becomes minimum is equal to a center frequency of a frequency-modulated signal of a channel other than the above predetermined channel.
Abstract: The invention provides an optical head for writing-reading a disk by means of at least a focussed radiation. This apparatus has at least one track, this track having evenly spaced apart grooves. An optical head using a motor having a fixed magnetic circuit with an air-gap in which a mobile assembly moves is provided. A magnetic circuit is additionally used which has a magnetic access and radial tracking circuit having at least one core intersecting all the grooves. The mobile assembly is formed of two actuators. The first of these actuators providing access to and radial tracking of the track. The second provides focussing of the light radiation on this track. There is a flexible fixing device connecting together these two actuators, along with a guide comprising friction sliding elements flexibly mounted on the radial and access actuator and allowing the actuator to slide over the core of the magnetic access and radial tracking circuit.
Abstract: An optical memory device comprises a modulator for modulating a laser beam in accordance with recording data, an objective lens for focusing the output light beam from the modulator on a recording medium, a sensor arranged in the far field of the objective lens, and a judging circuit for detecting an erroneous writing operation in accordance with an output from the sensor and the recording data. The sensor has a square detecting surface divided into four segments by lines which form angles of .+-.45.degree. with respect to the direction of relative movement between the recording medium and the focused light beam. The difference between the sums of outputs from two pairs of opposing segments is supplied to the judging circuit.
Abstract: A reproduced color video signal processing circuit in a rotary recording medium reproducing apparatus reproduces a recorded signal from a rotary recording medium which is recorded with a composite color video signal in which a carrier chrominance signal is frequency-converted into a low frequency band and multiplexed using a common frequency band within a part of a frequency band of a luminance signal, and levels of the carrier chrominance signal and a color burst signal are controlled according to the level of the carrier chrominance signal with respect to the color burst signal.
Abstract: An automatic tracking apparatus, by which a tracking condition of reproducing heads and a recorded track can be automatically adjusted. This apparatus has a rotary heads, an envelope detector, and a filter. A tracking error signal is generated by detecting the envelope of a video signal which does not contain chrominance signal components, the video signal being derived from the rotary heads. As a result, the tracking error signal includes only the luminance signal but does not include the signal from the next track. Therefore, the envelope signal is a good tracking error signal which is only responsive to the signal level of the objective track.
October 8, 1982
Date of Patent:
October 22, 1985
Matsushita Electric Industrial Co., Ltd.
Abstract: A digital video tape recorder (VTR) for use with an NTSC, PAL or SECAM television signal includes a reference signal generating circuit which generates a reference signal having a frequency of 13.5 MHz; a first frequency dividing circuit (1/45045) for use with an NTSC television signal; a second frequency dividing circuit (1/45000) for use with a PAL or SECAM television signal; and a switch which supplies a first or second frequency control signal to a magnetic recording head for recording a pulse of the control signal at the lower edge of a magnetic tape for each of successive, parallel tracks extending obliquely on the magnetic tape in which a television signal is recorded. A discriminator circuit detects whether the television signal to be recorded is NTSC, PAL or SECAM format and controls the switch to supply the appropriate frequency control signal to the magnetic recording head.
Abstract: An apparatus reads and/or records information on a disc by means of a light beam, which disc rotates about an axis of rotation, and is driven by a drive spindle which is journalled in a spindle support, an objective 1 being moved along two parallel guides by means of a slide in a radial direction relative to the axis of rotation. All parts of an opto-electronic system for producing the light beam and for effecting a conversion between optical and electrical modulation may be arranged on the slide but may alternatively form part of a stationary opto-electronic system. At least the spindle support or the stationary opto-electronic system is supported by at least one of the guides, for example by means of supports and which are formed with locating stops which cooperate with the guides 9A and 9B.
March 4, 1983
Date of Patent:
October 1, 1985
U.S. Philips Corporation
Gerardus L. M. Jansen, Alexander Vorspaget
Abstract: A tracking information detecting device for recording a video signal together with a pilot signal on one track of a magnetic disc and detecting tracking information at the time of reproduction. In this device, the pilot signal has a predetermined frequency at least ten times that of the horizontal synchronizing signal. The pilot signal is recorded in such a manner that its phase is displaced with respect to the horizontal synchronizing signal at every track. The horizontal synchronizing signal is displaced at every track at the time of reproduction of the recorded video signal, and the phase difference between the horizontal synchronizing signal and the pilot signal is detected as the tracking information.
Abstract: In a light spot control signal generating device, a light spot is irradiated on a recording medium having tracks on which information is recorded. In order to jump the light spot from a track being scanned thereby to an adjacent track, a signal representative of light quantity of reflection or transmission of the light spot and a track error signal are detected. The two signals are used to judge whether the light spot has passed through an edge of the track. The track error signal is also used to detect a signal representative of an instant at which the light spot is present at the middle point between adjacent tracks, and this signal is used as a timing signal for changing the polarity of a control signal applied to a spot light deflector.
Abstract: A focus servo system for an optical video disc player. A pair of signals generated by two pairs of photo-cells are supplied to an adder and a differential amplifier, an output signal of the adder is supplied to a first comparator and an output signal of the differential amplifier is supplied to a second comparator. When an output signal of the adder reaches a reference voltage of the first comparator, a focus servo pull-in range is detected. Thereafter, when an output signal of the differential amplifier reaches a reference voltage of the second comparator, a stable operation condition of the focus servo system is detected and a servo system loop is closed so that a malfunction is prevented.
Abstract: An information reproducing apparatus having a tracking servo control loop for causing an information reading unit including device for detecting a tracking error signal for tracking an information bearing track on a disc, to track the information bearing track in accordance with the tracking error signal so as to reproduce information in accordance with an information signal read by the information reading unit. A circuit for extracting a discrimination signal for discriminating a negative feedback region of the tracking error signal is provided so that a tracking servo control loop is closed in the negative feedback region.
Abstract: Method and apparatus for the recording onto a recording medium and playback of digital data, such as digitally encoded audio data, such that the recording medium is playable on either of two different commercial television format video type players. For example, according to the present invention an optical disc having digitally encoded audio data recorded thereon may be playable on either a PAL compatible or an NTSC compatible optical video disc player with minimal modification of the player.
Abstract: In a magnetic recording apparatus for frequency multiplexing and recording a frequency-modulated luminance signal, a chrominance signal, a frequency-modulated audio signal and a pilot signal on a magnetic tape, the signal level of the frequency-modulated luminance signal is adjusted by a first signal level adjuster, and the chrominance signal, the pilot signal and the frequency-modulated audio signal are mixed and then subjected to signal level adjustment by a second signal level adjuster. The signal levels of the four signals can be adjusted by the two level adjusters.
Abstract: In a magnetic recording and/or reproducing apparatus of the kind in which the azimuth angles of recorded signals in adjacent tracks on a magnetic recording medium are made different with each other so as not to require a guard band and having a rotary head assembly including at least a pair of magnetic transducing heads, each having the head width larger than the track width, when a portion of an audio signal on the magnetic medium is re-recording, an identification information signal is recorded on a predetermined track in connection with the first or last track for which the re-recording is required so that signal deterioration and noise caused by track width fluctuation or variation is compensated for.
Abstract: A programmable time code generator utilizes a synchronous parallel-to-serial data converter for conversion of time code in parallel form into serial form. The resulting longitudinal time code is suitable for recording on magnetic tape in synchronism with an information signal. The time code generator can be readily adapted for various video recording formats, such as NTSC, PAL, PAL-M, SECAM, etc., as well as for synchronous time code generation in other types of recording. In addition, the frequency of the generated longitudinal time code can be changed in a simple manner to be adapted for recording at various tape speeds which are different from the normal playback speed.
Abstract: In a data recording/reproducing apparatus, a DC motor is provided for rotating an optical disk. A recording/reproducing head is driven to move over the disk linearly in the radial direction of the disk, thereby defining a plurality of data-storing tracks on the disk. A motor control section is provided for controlling the rotation of the disk so as to change the angular velocity of the disk when the head tracing is changed among the track groups. While the head is tracing the tracks included in the same track group, the rotation of the disk is made constant so that the disk rotates at a constant angular speed.
Abstract: A tracking control system is used for a magnetic recording and/or reproducing apparatus in which a magnetic head relatively scans a magnetic recording medium to record and/or reproduce an information signal thereon and/or therefrom. The tracking control system comprises a circuit for supplying a tracking reference signal to the magnetic head together with the information signal. The reference signal supplying circuit supplies the tracking reference signal to the magnetic head so that the magnetic head is positioned at a position where the recorded position of a tracking reference signal on both sides of the tracks adjacent to a certain track is positioned successively shifted respectively to the track longitudinal direction with respect to the tracking reference signal recorded position at the certain track.
Abstract: The data recovery procedure for errors caused by track occlusion as a result of adjacent track misregistration or head sensitivity to the low frequency content of adjacent tracks is effected by reading and storing the information from the adjacent tracks and thereafter erasing the adjacent tracks either on centerline or with the transducer offset toward the intermediate track of interest. The track of interest can then be read with the transducer aligned with the track centerline and at varying positions of offset. If this sequence of rereads fails, the erase step can be repeated with greater amounts of offset toward the intermediate track to further reduce inband interference and the reread sequence also repeated.
December 27, 1982
Date of Patent:
May 7, 1985
International Business Machines Corporation