摘要:
A method and system for preventing cross-talk during reproduction of data recorded on a high density recording medium. The method includes the steps of receiving signals from at least three consecutively parallel information tracks on a recording medium, determining first and second cross-talk coefficients representing a degree of cross-talk between the three parallel information tracks, filtering the first and second cross-talk coefficients, correcting the cross-talk between the first, second, and third information tracks in accordance with the first and second cross-talk coefficients, forming a difference between the first and second cross-talk coefficients and integrating this difference to generate a track following correction signal, and repeating the above steps for each of the information tracks on the recording medium.
摘要:
System for recording/writing on a recording medium in which there are distributed, on the tracks, groups (G0) of tracks with positive continuous components and groups (G1) of tracks with negative continuous components. In reading, the values of the different signals are integrated for each track. Then, on the one hand, a first addition circuit S1 adds up the results of integration of the first tracks of each group of tracks and, secondly, a second addition circuit S2 adds up the results of integration of the last tracks of each group of tracks. A comparison circuit (CD) compares the results of additions of the two addition circuits to correct the track-following operation.
摘要:
System for recording/writing on a recording medium in which there are distributed, on the tracks, groups (G0) of tracks with positive continuous components and groups (G1) of tracks with negative continuous components. In reading, the values of the different signals are integrated for each track. Then, on the one hand, a first addition circuit S1 adds up the results of integration of the first tracks of each group of tracks and, secondly, a second addition circuit S2 adds up the results of integration of the last tracks of each group of tracks. A comparison circuit (CD) compares the results of additions of the two addition circuits to correct the track-following operation.
摘要:
A process for reading binary information written on a carrier. The carrier has at least one track and the binary information is written onto the carrier at a frequency Fbit. The process includes the step of reading binary information at the sampling frequency F.sub.e to form a succession of successive read samples SAM(k) of the same track. SAM(k) is the read sample of order k, each read sample having a phase .phi.(k) lying between 0 and 2.pi.. The method further includes a step of interpolating to make it possible to calculate an interpolated sample I(k) with phase equal to .pi. which corresponds to read sample SAM(k) on the basis of the read sample and on the i+j read samples which bracket the original read sample SAM(k) such that:I(k)=a.sub.k-i SAM(k-i)+ . . . +a.sub.k SAM(k)+ . . . +a.sub.k+j SAM(k+j)The coefficients have values which depend on the chosen law of interpolation and a step of validation makes it possible to generate an information item intended to validate or invalidate the interpolated sample. The process is especially useful for the reading of binary information written on a large number of tracks.
摘要:
The invention relates to a system for reading a magnetic medium having several tracks of data which can be read in parallel with a detection device having at least as many detectors as there are tracks, making it possible to read simultaneously and at regular intervals a sample of data on each track. This system furthermore includes a processing circuit configured to receive each sample of data to be processed from each track together with sample of a first adjacent track and sample of a second adjacent track and to calculate the cross-talk affecting the sample of data to be processed due to the adjacent tracks. An integration circuit configured to receive the cross-talk value calculated by the processing circuit, integrates these values at each read time, and at subsequent read times. The systems also include a relative track-following control circuit configured to receive the result of integration of the integrator circuit and to supply a track-following control signal for the detection device.
摘要:
A clock circuit for the reading of sequential information elements includes a phase-locked loop for the control of the controlled oscillator. In the case of a reading system with n tracks, the phase computation circuit, the digital filter and the controlled oscillator each include as many memories (delay circuits R 1.1, . . . R 2.1, . . . R 3.1, . . . ) as there are samples of information elements (or information tracks) to be processed almost simultaneously. The invention finds particular application in the reading of high-density recording media.
摘要:
A reading head has odd and even elemental areas for reading corresponding odd and even information segments that alternate to make up a frame of information on a record medium. The odd elemental areas provide a train of sequential odd information segments, each odd segment having cross-talk associated with the neighboring even segments which are on either side thereof when it is read from the record medium. Similarly, the even elemental areas provide a train of even information segments, each even segment having cross-talk associated with the odd segments which neighbored it on either side when it is read from the record medium. To correct for such cross-talk in both signal trains, both are fed to each of two cross-talk correcting circuits. These circuits derive needed adjacent segment information as to the cross-talk producing adjacent segments from one of the trains being fed thereto so as to process the segments of the other train being fed thereto for cross-talk correction.
摘要:
The invention relates to a laser device comprising a number of fibre amplifiers (3) delivering a number of optical waves, which is supplied by an oscillator (1) that delivers a signal wave, characterized in that said device comprises: a coherent source (4) emitting a coherent wave at a wavelength approximately equal to that of the signal wave and the propagation direction of which is inclined to the propagation direction of the optical waves output by the fibre amplifiers; means for making the coherent wave interfere with the optical waves output by the fibre amplifiers, and generating an interferogram consisting of an array of fringes; interferogram detection means (7), the relative positions of the fringes transcribing an inter-fibre phase law; a spatial phase modulator (2); and processing/display means (6) for processing the detected phase law and for displaying it on the spatial modulator, said spatial modulator being positioned so as to be able to be read by the signal wave and thus generate a phase-modulated signal wave selectively at each of the fibre amplifiers, compensating for the phase shifts induced by said fibre amplifiers.
摘要:
The invention relates to a method and system reading data recorded in the form of tracks on a magnetic recording medium. The recorded data is read by a row of read heads greater in number than a number of data tracks. The system of the invention does not require the read heads to follow the data tracks when reading recorded data, and allows a magnetic tape to be read even if the positions of the data tracks relative to the read head positions are unknown. The reading system of the present invention finds particular application in the area of reading high density recorded magnetic tapes.
摘要:
The magnetic head of the invention is composed of several micro-heads each of which comprises, on a substrate (2'), a garnet (3') and two pole pieces (7, 8) separated by a narrow air-gap (9).