Dynamic magnetic information storage or retrieval – General processing of a digital signal – Data verification
Reexamination Certificate
1999-04-20
2001-10-02
Tran, Thang V. (Department: 2651)
Dynamic magnetic information storage or retrieval
General processing of a digital signal
Data verification
C369S053350
Reexamination Certificate
active
06297920
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to information reproduction apparatuses, and in particular, to an information reproduction apparatus for reproducing original information from a recording medium containing information divided into information units based on which errors can be detected.
2. Description of the Related Art
Information reproduction apparatuses for reproducing information recorded on a tape or disk recording medium include magnetic reproduction apparatuses that use a fixed magnetic head and magnetic tape to perform reproduction by dividing digital signals into blocks, and magnetic or optical reproduction apparatuses that use an optical pickup and optical disk or the like to perform reproduction by dividing digital signals into blocks.
In the magnetic reproduction apparatuses that use a fixed magnetic head and magnetic tape, when an error is detected from data in an information unit in a block used for reproduction, a portion of the magnetic tape on which the block is recorded is played while ignoring the block in which the error was detected and rewinding the magnetic tape, and this step is repeatedly performed until no errors are detected at all from information units in the block.
In the magnetic reproduction apparatuses, track width and the width of the information reading unit (hereinafter referred to as the “head tip”) of the magnetic head, has become smaller with recent increases in storage capacity of recording media for information reproduction apparatuses, and the intervals between tracks has decreased. Thus, it is difficult for the head tip to travel on the same track used when recording was performed, particularly when the magnetic tape slightly fluctuates perpendicular to the travelling direction of the magnetic tape.
In particular, in the case of the so-called “multihead-tip, multitrack” magnetic recording apparatus that uses a plurality of reproduction head tips to perform simultaneous reproduction from information units on a plurality of recording tracks, in contrast to the case of a single-head-tip, single-track magnetic recording apparatus, it is almost impossible for the tracking control to simultaneously position all the reproduction head tips so as to maintain correspondence with all the tracks having recordings.
Consequently, errors frequently occur in the information units in a block used for reproduction, and the duration and time elapse (hereinafter referred to as “block restoration time”) required to cancel information-unit errors in the block increases further. Accordingly, an information reproduction apparatus that rapidly and stably reproduces original information recorded on a recording medium is in great demand.
As described above, when the magnetic reproduction apparatuses using the fixed magnetic head and the magnetic tape detect an error from a block used for reproduction, they ignore the error-detected block and rewinding the magnetic tape, and this step is performed repeatedly until no errors are detected at all from information units in the block. However, this has a problem in that the block restoration time greatly increases because the repeated reproduction requires a very long time, depending on the conditions of the fixed magnetic head and the magnetic tape.
In addition, the number of times of the reproduction must be repeated varies depending on the conditions of the fixed magnetic head and the magnetic tape. As a result, time intervals of the restored block and restored blocks subsequent to the error-detected block are irregular. Therefore, a problem arises in that the repeated reproduction cannot cope with a case where original information must be restored by outputting reproduced information units at a predetermined cycle and in a predetermined order.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an information reproduction apparatus in which a block restoration time is even shorter than that in a conventional information reproduction apparatus, even if an error is detected from an information unit in a block used for reproduction, and a condition where information units must be output at a predetermined cycle and in a predetermined order is satisfied.
To this end, the foregoing object is achieved through provision of an information reproduction apparatus for reproducing original information, including an information reader for reading information as blocks composed of a plurality of information units for enabling error detection, from a recording medium on which information divided into the information units is recorded, and for performing control so that the information recorded on the recording medium is read from a selected position; a block storer for storing the blocks read by the information reader; an error detector for detecting an error in each information unit stored in the block storer; and an information corrector in which when an information-unit error in one of the blocks is detected by the error detector, the information corrector uses the information reader to perform re-reading from a position of the one block having the information-unit error, and the information corrector replaces the one block having the information-unit error by performing the re-reading of a corresponding information unit having no error, and outputs the corresponding information unit as reading information from the one block having the information-unit error.
Preferably, the block storer outputs the stored information units in an order recorded on the recording medium and at a predetermined cycle, and includes an output timing adjuster for restoring the original information.
The information reader may include a multiblock simultaneous reproducer for performing playback of the recording medium, on which a plurality of tracks composed of block lines are adjacently arranged.
The information reproduction apparatus may be either a magnetic reproduction apparatus or an optical reproduction apparatus.
According to the present invention, when errors are detected in information units in a block obtained by reproduction, an information reproduction apparatus greatly reduces a block restoration time to be less than that in a conventional information reproduction apparatus by using a block storer to store a block in which an error was detected; and using an information corrector to perform information correction, without simply performing repeated reproduction until no errors are detected. By providing a multiblock simultaneous reproducer to the information reproduction apparatus, the block restoration time can be greatly reduced.
In addition, by using an output timing adjuster, the information reproduction apparatus can cope with the case where the information units of original information must be output at a predetermined cycle and in a predetermined order when the original information is restored.
REFERENCES:
patent: 5251077 (1993-10-01), Saitoh
patent: 5349481 (1994-09-01), Kauffman et al.
patent: 5590112 (1996-12-01), Morishima
patent: 6055216 (2000-04-01), Shintani
High-density Magnetic Tape Recording by Non-tracking Method,T. Himeno and T. Katoku, Journal of Magnetism and Magentic Materials, Jun. 1994, pp. 255-261.
Towards the Multitrack Digital Video Tape Recorder, F. Maurice, J. Magn. Soc. JPN, vol. 15, No. s1 (1991), pp. 389-394.
Saito Kengo
Yamamoto Kuniko
Maioli Jay H.
Sony Corporation
Tran Thang V.
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