Sharp Kabushiki Kaisha Corporation

Chitoku Kiyonaga

Kengo Sudoh

An error correction apparatus for reproducing data that have been multi-encoded with error correcting codes and recorded on a recording medium, and for correcting errors contained in the reproduced data through decoding the same. The apparatus includes: a reproducing circuit for reproducing the data encoded and recorded on the recording medium; a memory for storing the reproduced data; an error correction circuit adapted to correct errors of the data with the error correcting codes from the lowest to the highest levels in due order, for detecting that correction is impossible at the highest level and at an intermediate level between the lowest and the highest levels and for outputting a first and a second correction incapability detecting signals, respectively; and a controller responsive to the first and second correction incapability detecting signals for controlling the reproduction circuit, the memory and the error correction circuit. The controller controls the respective circuits to repeat error correction processing for the same data either until the errors are eliminated or until the retry number exceeds a certain limit number. Thereafter, the controller repeats the error correction processing up to the highest level either until the total retry number reaches a predetermined upper limit or until the errors are completely eliminated.

Error correction apparatus for reproducing data multi-encoded with error

A magnetic recording/reproduction device is disclosed that records data while forming serially a plurality of recording tracks on a magnetic tape. Each of the plurality of recording tracks have a plurality of data blocks recorded of the same bit length. Each of these plurality of data blocks includes a track data indicating the number of the track to be recorded and a synchronizing data indicating a synchronizing signal. The magnetic recording/reproduction device includes circuits for extracting the synchronizing data and the track data from each of the data blocks reproduced immediately after recording, a circuit for counting the number of synchronizing data extracted from the read out data blocks, a circuit for detecting a time period interval of synchronizing data for each recording track, a circuit for extracting track data from the read out data blocks, and a circuit for comparing the extracted track data with an expected data for each recording track. A circuit for making determination whether each data block is correctly recorded onto a corresponding recording track is implemented to make determination of data being correctly recorded only when the outputs of the circuit for comparison, the circuit for detecting the time interval, and the circuit for counting satisfy a certain condition.

Recording/reproduction apparatus with error detection capability

In a DAT (digital audio tape) recorder in which data is recorded and reproduced in a helical scanning system by using a rotary head, a magnetic tape is firstly wound back for usual reproduction when performing reverse reproduction. Data thus reproduced is once memorized in a memory, and data is outputted in the reverse sequence of the reproduction sequence from the memory. In this kind of reverse reproduction movement, the total sum of the number of data in each recording area is obtained by detecting the number of data thereof when winding back the magnetic tape. Winding back is stopped when this total sum exceeds the memory capacity of the memory. After that, usual reproduction is carried out and data after the next recording area of the recording area in which the total sum exceeds the capacity of the memory is memorized one after another in the memory. Therefore, it is possible to vary the distance of winding-back of the magnetic tape according to the number of data recorded in the recording areas, thereby causing the memory to be very effectively utilized.

Apparatus and method for reproducing data of a recording medium

A data recording/reproducing apparatus can record/reproduce digital data because a parity check code is added to the data at the time of recording. The original data can be reproduced through error correction even though part of the data is lost at the time of reproducing. In the present recording and reproducing apparatus, data immediately after being recorded is read and the number of errors is detected by a parity check code. When the number of errors in the data is equal to or greater than a predetermined reference value, the data is re-recorded in another unit recording area. By setting the reference value at a value less than the maximum number of errors which can be corrected by parity check codes, data can be re-recorded without apprehension that the errors cannot be corrected because the increased number of errors has been caused by deterioration of the recording state of the unit recording area due to repetition of reproducing operations.

Data recording/reproducing apparatus

When recording digital data on a recording medium, digital data is divided into information units of digital data which are further divided into recording units to be recorded on the recording medium. The digital data is recorded in the recording medium together with identification information to specify the information unit of the recording unit. When reproducing, the digital data which has been reproduced from the recording medium is temporarily stored in a memory unit whose capacity is more than one information unit. After the stored digital data reaches a capacity of at least one information unit or more, the digital data is outputted from the memory unit in the information unit format. Furthermore, when the reproducing operation is discontinued, a controller stored the identification information of the recording unit to be reproduced next, and the digital data of the recording unit to be recorded next is subsequently reproduced on the basis of the identification information when re-starting the reproduction and is stored in the memory unit, thereby causing the reproducing operation to become more reliable.

Method and apparatus for recording and reproducing of a recording medium

A magentic tape, a second end identifying part at a predefined distance from the end position of the magnetic tape in a direction toward the beginning of the tape. This second end identifying part is separate from an existing first end identifying part. When data is recorded on such a magnetic tape, the second end identifying part is first detected by an end detecting device, and then the residual data stored in a memory before the second end identifying part is detected are recorded in a recording area located between the second end identifying part and the first end identifying part. This makes it possible to record all data left within the memory before reaching the first end identifying part, that is, before the recording areas of the magnetic tape become full.

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Higashihiroshima, Japan

Chitoku Kiyonaga