Abstract: A multichannel digital magnetic recording apparatus comprises a plurality (N) of modulating circuits (41 to 4N) and timing circuits (51 to 5N). Digital signals (Z1 to ZN) undergo modulation in the modulating circuits in accordance with a modulation system of a detection window Tw. The modulated signals (A1 to AN) are converted into pulse current trains by the timing circuits and then delayed such that the respective pulse currents do not occur simultaneously. Accordingly, a power capacity required of a voltage source for writing the signals by means of thin film magnetic heads (71 to 7N) is considerably decreased.

Abstract: A magnetic recording system transmits data edge information and clock signals through a rotary transformer. From the signals derived from secondary side of the transformer the data is reconstructed from the edge information and retimed using the clock signals. A record amplifier is D.C. coupled to a recording head for good pulse response. The amplifier can be a differential one with a pulsed current source for still better pulse edge response.

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: An apparatus for re-recording a new digital signal in a track on a magnetic record medium which has a previously recorded digital signal in the track, the digital signal being arranged in data blocks each containing a sync signal, a data signal, an error correction code signal, and an error detection code signal, comprises a reproducing circuit which reproduces each digital signal recorded on the magnetic record medium, a code generating circuit which supplies a discriminating code signal for each of the data blocks, and a recording circuit which re-records the new digital signal and the respective discriminating code signals in the track on the magnetic record medium.

Abstract: A system for detecting and recording disturbances, e.g., transients, in periodic signals, wherein the system has a delay memory for storing sampled digital signal values of the periodic signals, is disclosed. In order to reduce the amount of data needed to be recorded, the sampled digital values are interim-stored in a read/write memory, from which the samples are read out each period of the periodic signal via an address control. The interim stored digital samples, which are the samples for the period of the periodic signal existing in time immediately preceding the present period, along with the samples from the present period, are fed to a digital comparator. The digital comparator compares the samples for the two signal periods, and depending on whether the samples differ by a predetermined threshold, generates a start or stop signal to an output device coupled to the delay memory for recording the occurrence of the disturbance.

Abstract: A device for reading magnetically recorded patterns on a magnetic recording medium includes a first system for causing a light beam polarized in a predetermined direction to enter the recording medium, a second device for relatively varying the ratio of the polarized component in the predetermined direction and the polarized component in a direction perpendicular thereto, of the light of said light beam reflected or transmitted by the recording medium, and a third device including a photodetector and an amplifier for amplifying a detection signal, the third device being for detecting the light beam from the second means and reading the recorded patterns on the magnetic recording medium, the second device being set so that the SN ratio of the detection signal becomes maximum.

Abstract: A magnetic tape transport for recording digital data. The tape transport is selectively operable in either a parallel write mode for recording concurrently along multiple tracks in a standard format or a high density serial write mode for recording along one track at a time, the multiple tracks being recorded in sequence in a serpentine format. The transport uses standard multitrack read and write heads with each head having N transducers, where N is a positive integer greater than 1, supplemented by an additional multitrack read head or write head with N/2 transducers for N even or (N-1)/2 transducers for N odd, so that for either direction of tape movement, the tape will first pass a write head and then a read head. When moving in a first direction (forward) the tape will move past the write head and then past the first read head.

Abstract: A capacitance detector for detecting the information recorded in the form of a series of microscopic pits on a capacitance disc record. The detector comprises, within an outer conductor, a dielectric support, an oscillator having a first line conductor on the support for generating microwave energy, a coaxial resonator having a second line conductor on the dielectric support, the second line conductor being coupled to the electrode of a capacitance detection stylus. Means are provided for inductively coupling the microwave energy from the oscillator to the resonator. This coupling means comprises a loop having a first section inductively coupled with said first line conductor and a second section inductively coupled with said second line conductor, and a capacitor connected from an intermediate point between the first and second sections to ground, so that the microwave energy coupled to the second line conductor is modulated in amplitude with capacitance variations corresponding to the microscopic pits.

Abstract: The angular velocity of an information element contained in the precut track of an information carrier disk is controlled by means of a concentric circular ring located internally with respect to the precut track and constituted by mark zones uniformly spaced in angular sectors. A light beam is projected onto the circular ring and the emergent beam is modulated as a function of the mark zones and blank zones which form the circular ring. Errors arising from eccentric displacement of the track can thus be corrected and the rate of travel of information can be controlled in relation to the reading or recording light beam.

Abstract: An apparatus to improve the positioning accuracy of an actuator in a disc system. The apparatus provides for accelerating and braking the actuator at appropriate times during positioning operations in order to accurately position the actuator at a selected track on the disc. In addition, in order to maintain positioning accuracy in the presence of run-out, provision is made for detecting the occurrence of run-out by comparing positioning accuracy at spaced time intervals and blocking actuator braking at those times when it would be counter-productive to positioning accuracy.

Abstract: A tape recorder motor circuit includes an automatic shutoff circuit and a motor servo circuit formed by a constant current circuit section, a bridge circuit, and an amplifier section. The constant current circuit section is connected to a power source through a switching transistor which is controlled by the automatic shutoff circuit. The amplifier section of the motor servo circuit is connected in a substantially direct manner to the power source, not through the switching transistor.

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: 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: A detecting device for detecting abnormality in the tape travel, comprises detectors for detecting capstan rotation pulses which have a frequency in accordance with the rotational speed of a capstan which drives and causes a tape to travel, supply reel rotation pulses which have a frequency in accordance with the rotational speed of a supply reel which pays out the tape, and take-up reel rotation pulses which have a frequency in accordance with the rotational speed of a take-up reel which takes up the tape, and a detecting circuit supplied with the three kinds of rotation pulses, for detecting abnormality in the tape travel and for producing an abnormality detection signal which indicates that an abnormality has been detected in the tape travel.

Abstract: A method and apparatus is provided for recording and reproducing television or other broad band signals with an altered time base effect so as to provide, for example, in the case of television signals, slow motion, faster than normal motion, stop motion or reverse motion. To provide slow motion replay of television signals, successive fields of the signal are recorded separately on a plurality of magnetic mediums, and at predetermined head-to-medium writing speeds, and are played back at substantially the same head-to-medium writing speeds. On playback, each field is repeated a number of times depending upon the time base effect desired. Reverse motion is provided by reversing the order of replay of the fields.

Abstract: Damaging head crashes are prevented in a disk drive system by providing a specially chosen RC network between the head position control servo and the head actuator. The values of the RC network are chosen in conjunction with the servo output voltage so that, without detracting from head access time, the maximum head velocity will be limited to a value which will prevent damaging head crashes even when a fault occurs in the system.

Abstract: A data recording and reproducing apparatus promotes error-free and speedy exchange of data between separate recording media. When desired primary data is to be recorded on a master recording medium, secondary data is added to the primary data in order to detect and correct data errors. The primary and secondary data are recorded on the master recording medium in a plurality of series which differ in recording sequence from each other. The primary data is reproduced from the master recording medium together with the secondary data for the different series at the same time, regardless of their recording sequences. The reproduced primary data is allowed for error check and correction based on the secondary data and is recorded in the slave recording medium.

Abstract: A tracking servo system for a magnetic recording and reproducing apparatus uses a flexible magnetic disk having thereon at least first, second and third tracks each of which includes a data track portion and a pair of servo track portions located on both sides of the data track portion. Tracking signals having different frequencies are recorded on the first, second and third servo track pairs. Servo and data heads are formed in a unitary structure. When the data head records an information signal on the second data track portion or reads out the recorded information signal therefrom, the servo head reads out the tracking signals recorded on the first and third servo track portions.

Abstract: A method and device for reproducing coded programs in which an incomplete program is recorded on one medium and a program having an algorithm for completing the program on the first medium is provided on a second medium. Upon correction of the first program by the algorithm of the second program to record on a third medium, data corresponding to the number of times of operation of the program on the second medium is updated on the second and/or the first medium, to enable accounting of the number of times the program on the first medium has been reproduced.

Abstract: A digital data capture window extension circuit utilizing a matched pair of signal detection subcircuits that are activated during alternate cycles of a master read clock. The interleaved operation of the paired subcircuits permits each subcircuit to detect and process an incoming data signal, resulting in an effective overall processing rate twice that of prior art circuitry. The invention therefore permits the reading of data at a high rate using a system clock of the same frequency as the incoming data.