JPH04229466A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To facilitate the exact restoration of recording data at the time of data reproduction even if there is an error in the recording data by calculating the length and number of the drop-outs of reproduced waveforms and deciding whether a magnetic recording state is good or not. CONSTITUTION:The track of recorded signals is immediately reproduced by a head 102 for reproduction when the digital signals are recorded on a magnetic tape by a head 101 for recording. The recording data and the envelope of the signal part corresponding to the area of the error correction code thereof are extracted by an extracting means 104 at this time and the defect part of the envelope detected by a detecting means 105 is detected. The defect parts are regarded to be the defect of two blocks at each one point and are totaled by a defect block number totaling means 106. The widths of the defect parts are measured by a defect block number adding means 107 and a 1 is added to the totaled block number at every time when this width attains one block. The defect is decided by a deciding means 108 when the block number exceeds the block number of the area of the error correction codes.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION This invention relates to a magnetic recording and reproducing device, and in particular to a device called an R-DAT (rotating drum type digital audio tape recorder) that records digital data on a magnetic tape using a rotating head. This invention relates to a magnetic recording and reproducing device applied as a data recorder.

0002

[Prior Art] Conventionally, in the above-mentioned magnetic recording and reproducing apparatus, a magnetic tape is wound around a rotating drum on which a recording head and a reproducing head are arranged. A digital signal containing the data and its error correction code is recorded.

[0003] Then, the track of the recorded signal is immediately played back by a playback head, and the quality of the recording is determined based on the waveform state of the reproduced analog signal. When the analog signal level falls below a certain level for a certain period of time, a detection signal is output to determine whether the recording is good or bad (
(Refer to Japanese Patent Application Laid-Open No. 2-23577).

0004

[Problems to be Solved by the Invention] Generally, in the above-mentioned magnetic recording/reproducing apparatus, as mentioned above, during recording,
Since an error correction code is added to the recorded data, even if some errors occur during data recording, the errors can be corrected.

However, in determining the state of magnetic recording, if the quality of recording is determined simply by the period of the missing portion of the reproduced waveform as in the past, the amount of errors in the recorded data cannot be recovered by the error correction code. Even if the range is exceeded, it may not be possible to determine that the recording condition is defective, and in such a case, a problem arises in that the recorded data cannot be accurately restored during reproduction.

[0006] The present invention was made in consideration of the above-mentioned circumstances, and the length and number of gaps in the reproduced waveform are calculated to determine the quality of the magnetic recording state. Another object of the present invention is to provide a magnetic recording/reproducing device that can accurately restore recorded data during data reproduction.

[0007]

[Means for Solving the Problems] FIG. 1 is a block diagram showing the configuration of the present invention. As shown in this figure, in the present invention, a magnetic tape is wound around a rotating drum 103 on which a recording head 101 and a reproducing head 102 are arranged, and the recording head 101 writes data consisting of a plurality of blocks onto the magnetic tape. A digital signal including the area of the error correction code is recorded, and the track of the recorded signal is transferred to the playback head 1.
In a magnetic recording and reproducing device that immediately reproduces the analog signal by 02 and determines the quality of the recording based on the waveform state of the reproduced analog signal, the area of the recorded data and its error correction code is determined from the analog signal reproduced by the reproduction head 102. Extracting means 10 for extracting the envelope of the signal portion
4, a detection means 105 for detecting a missing part of the envelope extracted by the extraction means 104, and a detection means 105.
As a result of the detection, if there is a missing part, it is assumed that two blocks are missing in each place, and the missing block number aggregation means 106 counts up the number of missing blocks, and the width of the missing part detected by the detection means 105 is measured. Then, each time the width reaches one block, a missing block number adding means 107 adds 1 to the total number of blocks of the missing block number totaling means 106, and the number of missing blocks totaled by the missing block number totaling means 106 is calculated. , the magnetic recording/reproducing apparatus comprises a determining means 108 which determines that the recording state of the magnetic tape is poor when the number of blocks in the area of the error correction code exceeds half.

[0008]

[Operation] According to the present invention, when a digital signal including data consisting of a plurality of blocks and an area for error correction codes is recorded on a magnetic tape by the recording head 101, the track of the recorded signal can be reproduced. The recording head 102 immediately reproduces the data.

At this time, the extraction means 104 extracts the envelope of the signal portion corresponding to the area of the recorded data and its error correction code from the reproduced analog signal,
The detection means 105 detects the missing portion of the extracted envelope.

As a result of the detection by the detection means 105, if there is a missing part, it is assumed that two blocks are missing at each location, and the number of missing blocks is totaled by the missing block number counting means 106. In addition, the missing block number addition means 10
7, the width of the missing portion detected by the detection means 105 is measured, and each time the width reaches one block, 1 is added to the total block number of the missing block number totaling means 106.

[0011] Then, when the determining means 108 determines that the number of missing blocks counted by the missing block number counting means 106 exceeds half the number of blocks in the area of the error correction code, the recording state of the magnetic tape is poor. It is determined that

Therefore, if the number of missing blocks in the reproduced waveform is within the range in which recorded data can be accurately restored, that is, if it is less than half the number of blocks in the area of the error correction code, the recording condition is considered to be good. If the recorded data exceeds the range where it is impossible to accurately restore it, that is, if it exceeds half the number of blocks in the error correction code area, the recording condition is considered to be poor, so errors in the recorded data are always corrected to the extent that it can be restored. As a result, even if there is an error in the recorded data, the recorded data can be accurately restored during data reproduction.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on embodiments shown in the drawings. Note that this invention is not limited to this.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention. In this figure, 1 is a magnetic tape, 2
3 is a rotating drum, 3 is a recording amplifier, 4 is a recording signal processing circuit, 5 is a host interface, 6 is a host computer, 7 is a playback amplifier, 8 is an envelope detection circuit, 9 is a control microcomputer (hereinafter abbreviated as microcomputer) ).

The host computer 6 transmits a recording command to the microcomputer 9 via the host interface 5. Subsequently, recording data is input from the host computer 6 to the recording signal processing circuit 4 via the host interface 5. As shown in FIG. 3, the recording signal processing circuit 4 classifies the input recording data as follows.

That is, record data D (0, 0), record data D (0, 1), ..., record data D (0, N) from the 1st series to the N series are recorded as the 0th block, recording data D (1, 0), recording data D (1
, 1), ..., the recording data from the 1st series to the N series of the recording data D (1, N) are set as the first block, and the recording data D (M, 0), the recording data D (M, 1 ),...
, recording data D(M,N), the recording data from the 1st series to the N series is set as the Mth block, and so on.
Separate each block.

[0017] Then, one series of record data, record data D (0, 0), record data D (1, 0), . . .
Recorded data D(M,0) includes parity data as an error correction code, parity P(1,0), parity P(
2,0),..., recording data D(0,1) is added as parity P(10,0) and is two series of recording data.
, recorded data D (1, 1), ..., recorded data D (M,
1) has parity P(1,1), parity P(2,1
), . . . , parity P (10, 1) is added, and so on, parity data is added to each of the recorded data from the 1st sequence to the Nth sequence. Therefore, as a whole, parity P(1,0) to parity P(10,N) are added to recording data D(0,0) to recording data D(M,N), resulting in data for one track. .

When all the parities have been added in this manner, the record data to which parity has been added is outputted as a record signal from the record signal processing circuit 4, and this record signal is sent to the record amplifier 3 and the rotating drum 2. is recorded on the magnetic tape 1 via the .

As an example of the recording signal recorded on the magnetic tape 1 is shown in FIG. 4, recording data D (0,0), recording data D (0,1), . Data D(0,N),..., Parity P(1,N),...
..., parity P (10, N) for one track.

Next, the recorded data D is immediately reproduced by the reproduction head and inputted to the envelope detection circuit 8 via the rotary drum 2 and the reproduction amplifier 7.

FIG. 5 is a waveform diagram showing the processing state of the reproduced waveform. In the figure, the reproduced signal S is a signal that is reproduced by a reproduction amplifier 7 and input to an envelope detection circuit 8, and the signal E of the envelope detection window sets the data range when detecting the envelope of the reproduced signal S. This is a signal to do so.

Generally, in DAT, one block consists of 32 bytes. One track recorded on the magnetic tape 1 consists of a 128-block data area and a 68-block service area placed at both ends of the data area. Set the range to the part,
This is a signal for detecting the envelope.

The envelope detection signal K is a signal output from the envelope detection circuit 8, and is the envelope waveform of the reproduced signal S extracted by the signal E of the envelope detection window. The microcomputer input signal M is the microcomputer 9
This signal is input to the envelope detection signal K, and is obtained by waveform-shaping the envelope detection signal K.

The microcomputer 9 examines the input microcomputer input signal M, calculates the total amount of missing parts from the width and number of missing parts of the envelope, and determines whether the data is good or bad. That is, in detecting this missing part, even the smallest missing part of one block or less is considered as missing two blocks, and the number of missing blocks is totaled.

For example, in FIG. 5, when the reproduced signal S is a signal as indicated by A, it is assumed that the missing portion of the microcomputer input signal M is within three blocks. In this case, using the example of recorded data shown in FIG. 2, 10 parity blocks are added to each series of data from series 1 to series N. At this time, each recorded data from the 1st sequence to the Nth sequence can be restored if the error amount is up to 1/2 of the parity block, so the missing blocks can be up to 5 blocks (10 blocks divided by 2). If so, the data can be restored. Therefore, in this case, there are three missing blocks, which is less than five blocks, so that the recorded data can be accurately restored using the error correction code. Therefore, it is determined that the recording is good.

Further, when the reproduced signal S is a signal as shown by B, it is assumed that the missing portion of the microcomputer input signal M is a small missing portion, and there are four such small missing portions. Regarding this, even the smallest omission of one block or less is considered as two blocks missing, so if there are four missing parts, the calculation result is that eight blocks or less have been missing. Therefore, since 8 blocks is more than 5 blocks, the recorded data cannot be restored by the error correction code, and is determined to be a recording defect.

FIG. 6 is a flow chart showing the contents of the processing operation of the microcomputer 9. The microcomputer 9 first checks whether there is an envelope window (step 21), and if there is an envelope window, initializes the COUNT, EFLAG, and WIDTH memories (step 22). Next, a missing part of the envelope is detected (step 23), and if there is no missing part, EFLAG is set to "0" (step 24), which takes 1/10 of the time required to write one block, that is, 0.
Wait one block time (step 25), check whether there is an envelope window (step 26), return to step 23, and repeat.

In step 23, if there is a missing part, check whether EFLAG is "1" (step 2
7), if it is not “1”, add “2” to COUNT (
Step 28), set EFLAG to "1" (Step 29), and proceed to Step 25. Further, in step 27, if EFLAG is “1”, WIDTH is “1”.
” (step 30), and checks whether WIDTH is “9” or less (step 31). At this time, “
If it is less than 9", proceed to step 25 and wait for 0.1 block time again. If it is more than "10", 0.1 block is 1 block 10 times, so "1" is added to COUNT.
” is added (step 31), WIDTH is set to “0” (step 33), and the process proceeds to step 25.

In step 26, if there is no envelope window, in the example of the recorded data in FIG. 2, there are 5 parity blocks, so COU
It is checked whether NT exceeds "5", and if it is less than "5", the recording state is considered to be good and processing is continued (step 3).
5) If it exceeds "5", it is assumed that the recording state is poor and error processing is performed (step 36).

[0030] In this way, the length and number of gaps in the envelope of the reproduced signal are calculated to determine whether the magnetic recording condition is good or bad. In other words, the number of missing blocks in the reproduced waveform indicates whether the recorded data can be accurately restored. If the number of blocks is less than half of the number of blocks in the area of the error correction code, the recording condition is considered to be good. If the number exceeds half of the number, the recording condition is considered to be defective, and errors in the recorded data can always be corrected to the extent that they can be restored.This allows even if there is an error in the recorded data, it will not be corrected when the data is played back. Recorded data can be accurately restored.

[0031]

According to the present invention, when detecting a missing part from the envelope of a reproduced signal, the number of missing blocks is totaled from the number of missing parts and the width of the missing part, and the total number of missing blocks is calculated as follows: When the number of blocks in the error correction code area exceeds half, it is determined that the recording condition of the magnetic tape is poor, so errors in the recorded data can always be corrected to the extent that they can be restored. Therefore, even if there is an error in the recorded data, the recorded data can be accurately restored during data reproduction.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing the relationship between a recording signal and an error correction code.

FIG. 4 is an explanatory diagram showing an example of a recording signal recorded on a magnetic tape.

FIG. 5 is a waveform diagram showing a processing state of a reproduced waveform.

FIG. 6 is a flowchart showing the operation of the embodiment.

[Explanation of symbols]

1 Magnetic tape 2 Rotating drum 3 Recording amplifier 4 Recording signal processing circuit 5 Host interface 6. Host computer 7 Playback amplifier 8 Envelope detection circuit 9. Microcomputer

Claims (1)

[Claims] 1. A magnetic tape is wound around a rotating drum on which a recording head and a reproducing head are arranged, and the recording head generates a digital signal on the magnetic tape including an area of data consisting of a plurality of blocks and its error correction code. record and
In a magnetic recording/reproducing device that immediately reproduces a track of a recorded signal using a reproducing head and determines the quality of the recording based on the waveform state of the reproduced analog signal, recorded data and its an extraction means for extracting the envelope of a signal portion corresponding to the area of the error correction code; a detection means for detecting a missing part of the envelope extracted by the extraction means; 2 per
Missing block count counting means that counts the block as missing and counts the number of missing blocks, and missing block count counting means that measures the width of the missing portion detected by the detection means and each time the width reaches one block. 1 for the total number of blocks
When the number of missing blocks counted by the missing block number adding means and the missing block number counting means exceeds half of the number of blocks in the error correction code area, it is determined that the recording condition of the magnetic tape is poor. A magnetic recording/reproducing device comprising determining means for determining that there is a magnetic recording device.