JPH05234265A - Rotary head type magnetic recording and reproducing, signal processing circuit and magnetic tape - Google Patents

Abstract

PURPOSE:To enable decoding smoothly the contents of information without omission of many continuous words even for the omission of one scan signal by allocating word groups corresponding to each region one by one repeatedly to sub-regions from 0th to (m-1)th according to the inputted order, in each region. CONSTITUTION:A signal read out from a memory in a modulation circuit 7 is converted to the string of data which adapts for recording in a magnetic tape, is amplified, and recorded in the tape from heads 10 and 11 via a changeover switch 9. Also, a region P is provided in the vicinity of the center of each track, a region Lb is provided on the first half from the region P in a longitudinal direction and a region Ra is provided on the later half from the region P by all means, and the region Lb has the sub-regions of 0th to (m-1)th facing to the center and the region Ra has sub-regions facing to the other end from the center. Also, each word in word groups corresponding to each regions is allocated to the sub-regions of 0th to (m-1)th one by one repeatedly according to the inputted order. Therefore, hindrance for decoding the contents of information caused by the omission of contents of information does not occur.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head type recording / reproducing apparatus, a signal processing circuit and a magnetic tape used therefor, and particularly to interleaving digitized data and generating during recording / reproducing. The present invention relates to one using an error correction code for correcting an error in data.

[0002]

2. Description of the Related Art Conventionally, as a device of this kind, there is a rotary head type PCM recording / reproducing device for converting an audio signal into a digital signal and recording / reproducing it on a magnetic tape by a rotary head. Generally, an error correction code is used in the above device to correct an error in data that occurs during recording / reproduction. A correction process such as turning on is performed. Since errors on the magnetic tape are often burst errors, it is effective to randomize the error data by performing interleaving processing in order to make full use of the ability of the error correction code.

In the correction processing as described above, the method with a simple circuit and less noise is the mean value interpolation. However, since the preceding and following data must be correct for this, the data of the odd sample group and its adjacent The interleaving is performed so that the data of the even sample groups to be arranged are arranged as far as possible from each other. In the following description, as an example, a two-head helical scan rotary head type P that handles two-channel signals
Consider a CM recorder. FIG. 1 is a diagram showing a magnetization pattern recorded on a magnetic tape by a conventional rotary head PCM recorder.

In the figure, T is a magnetic tape, S is a head scan direction, D is a tape running direction, and L and R are also shown.
Indicates two channels, a indicates an even sample group, b indicates an odd sample group, and P indicates an error correction code group. In this example, as an interleaving method for arranging the even sample group and the odd sample group at positions separated from each other,
This is a method in which the samples that can be included in the scan are divided into an even sample group and an odd sample group, and these are arranged with an error correction code group P interposed therebetween. If such interleaving is performed, even if a burst error Y of about half the width of the tape shown in the figure occurs, consecutive sample errors do not occur, so that average value interpolation is possible.

[0005]

SUMMARY OF THE INVENTION In the interleaving of such a conventional method, however, when one head is momentarily clogged with the magnetic powder that has come off, that is, a reproduction signal from the one head. However, in the case of missing or extremely deteriorated state, errors occur in consecutive samples, so that average value interpolation cannot be performed, and there is a drawback that noise that is audible to the ear is generated.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and includes a first region located near the track center of each track and a first region in the track longitudinal direction. Also has at least a second area located in the first half of the track and a third area located in the latter half of the track with respect to the first area, and the second area has m number 0 to m−1 toward the center of the track. The third region has m sub-regions 0 to m-1 from the center of the track to the other end, and each sub-region has a digital signal of a plurality of words. Digital signals for a unit time are arranged in the second and third areas of the first and second two tracks, and at least a part of the redundant signal for error control is arranged in the first area of each track. Of the first input word within the unit time When a force sequence was 0-th, first input order consists of 4n th plurality of words (n is an integer) 1
In the second area of the first track, the second word group consisting of a plurality of words having an input order of 4n + 1th in the second area of the second track, and the second word group consisting of a plurality of words of an input order of 4n + 2 A third word group is arranged in the third area of the second track, and a fourth word group consisting of a plurality of words having an input order of 4n + 3 is arranged in the third area of the first track, and in each area, Probability of continuous erroneous and concentrated data loss by repeatedly arranging each word in the sub-regions 0 to m-1 according to the input order for the word group corresponding to each region The purpose of the present invention is to obtain a signal processing circuit of a magnetic recording device having a low magnetic field. It is another object of the present invention to provide a magnetic reproducing apparatus signal processing circuit capable of reproducing a recorded signal based on the present invention with high accuracy and with little error. Furthermore, it is an object of the invention to obtain a magnetic tape on which data is recorded so that the data can be reproduced accurately.

[0007]

The magnetic recording device signal processing circuit according to the present invention can reduce the probability of continuous error and the probability of concentrated data loss. Further, the magnetic reproducing device signal processing circuit can reproduce the signal recorded according to the present invention with high accuracy and with little error. Further, according to the present invention, the magnetic tape can be a magnetic tape on which data is recorded so that the data can be reproduced with high accuracy.

[0008]

FIG. 2 is a magnetization pattern diagram on a tape recorded by a rotary head type PCM magnetic recording / reproducing apparatus according to an embodiment of the present invention. The symbols in the figure indicate the same as those in FIG. In the interleaving by the apparatus of the present invention, the odd sample group and the even sample group of the same channel are alternately arranged for each adjacent scan and arranged at positions separated in the width direction of the tape. Even if the signal loss of one scan described above occurs due to such an arrangement, consecutive sample errors do not occur in each channel.
Correction by average value interpolation is possible.

The structure and operation of a two-head helical scan rotary head type PCM recorder having a tape winding angle of 90 ° will be described below as an embodiment of the present invention. 4 is a timing diagram illustrating the operation of the memory circuit included in FIG. Fourth
In the figure, WT is a writing period in the memory, EN is a coding period, RD is a reading period from the memory, and DE is a decoding period. In FIG. 3, the recording system includes a 2-channel input terminal 1, a low-pass filter (LPF) 2,
Sample hold (S / H) circuit and analog-digital (A / D) conversion circuit 3, memory circuit 4, recording system memory address control circuit 5, encoding circuit 6, modulation circuit 7, and recording amplifier 8 And a first switch 9 and heads 10 and 11.

An analog signal of two channels of LR is input to the input terminal 1, and the band is limited by the LPF 2 respectively. The output of the LPF 2 is given to the S / H and A / D conversion circuit 3, and digital signals WLn, WRn (n = 0, 1,
2, ...). Here, n indicates the sampling order, and the signals of the two channels L and R are alternately sampled and sequentially output as WL0, WR0, WL1, .... This signal is given to the memory circuit 4 and sequentially written in the addresses on the memory designated by the recording system memory address control circuit 5. The samples stored in the memory circuit 4 are read out in a required order by the recording system memory address control circuit 5 and given to the encoding circuit 6. An error correction code and an error detection code are generated in the encoding circuit 6,
It is written in the memory circuit 4. The information signal and the error correction code are sequentially read by the recording system memory address control circuit 5 and given to the modulation circuit 7. The memory circuit 4 is practically divided into two systems, and while one system memory writes samples, the other one system memory performs encoding and reading. This is shown in Figure 4,
Since the recording / reproduction is performed by two heads by winding the 90 ° tape, a 90 ° signal recording / reproducing section and a 90 ° resting section are alternately present. That is, the 90 ° signal recording / reproducing period is 1
It supports recording and playback of scans. WT in FIG. 4 (b)
Of the signals for two scans sampled in the period of 1), the signal of 1 scan read in the period of the next RD is first encoded in the period of EN and is read in the period of RD, and then the remaining 1 The signals for the scan are encoded in the next EN period and read in the RD period.

In the modulation circuit 7, the signal read from the memory is converted into a data string suitable for recording on the magnetic tape, amplified by the recording amplifier 8, and then the two heads are passed through the first changeover switch 9. It is recorded on a magnetic tape from Nos. 10 and 11. The first changeover switch 9 operates to switch the circuit connected to the head during recording and during reproduction.
Next, the structure and operation of the reproducing system will be described. The reproducing system includes heads 10 and 11 and a second changeover switch 12
, Reproduction amplifier 13, demodulation circuit 14, and memory circuit 1
5, a reproducing system memory address control circuit 16, a composite circuit 17, a correction circuit 18, and a digital-analog (D / A) circuit.
A) Conversion circuit 19 and low-pass filter (LPF) 20
And a two-channel output terminal 21. Second
The changeover switch 12 is for applying the output signals of the heads 10 and 11 to the reproduction amplifier 13 as a signal of one system. The signals reproduced by the heads 10 and 11 are amplified by the reproduction amplifier 13 via the first changeover switch 9 and the second changeover switch 12, and are given to the demodulation circuit 14. In the demodulation circuit 14, the signal is returned to the digital signal before being modulated and is given to the memory circuit 15. This digital signal is sequentially written into the memory circuit 15 by the reproduction system memory address control circuit 16. Further, the memory address control circuit 16 reads out necessary samples from the memory circuit 15 and gives them to the composite circuit 17. The composite circuit 17 performs error detection and correction using the error correction code. The corrected samples in the memory are sequentially read out by the memory address control circuit 16 and given to the correction circuit. The samples in which an error is detected but which cannot be corrected are corrected by the above-mentioned average value interpolation. It The memory operation during reproduction is shown in FIG. 1 played during WT
The scan samples are written to the memory circuit 15, decoded during the next 90 ° open period (denoted by DE) and held in memory. During the next WT period, the remaining one-scan samples are written to the memory and decoded during the next DE period. The samples for the two scans for which decoding has been completed are read during the RD period. The memory circuit 15 is divided into two systems, and while one is writing and decoding, the other memory is reading, as in the case of recording.

The corrected and corrected sample is D /
The LPF is converted into the original analog signal by the A conversion circuit 19.
After the unnecessary frequency component is removed at 20, it is output from the output terminal 21. The clock pulse generation circuit 22 has a function of giving a necessary clock to each part of the recording system and the reproducing system. Next, a concrete description of the memory circuits 4 and 15 in the block shown in FIG. 3 and a detailed sample on the tape will be described. FIG. 5 shows a memory configuration diagram in an embodiment of the present invention. In the figure, WLn and WRn represent the nth sample occurring in the L channel and the R channel, respectively, as described above, CLn, CRn and Pn are error correction codes, and lLn and lRn are four vertical information signal samples. And the frame number composed of the correction code. Further, the horizontal number fa indicates a memory address in a frame unit (hereinafter referred to as a frame address), and the vertical number sa indicates a memory address in a row unit (hereinafter referred to as a sample address). Each A indicates data to be recorded in one scan, and the memory is composed of data for two scans, here 32 samples of each information signal LR and 26 words of error correction code. During recording, WL0, WR0, WL1,
The sample given as ... is stored in the memory by controlling the memory address so that the array shown in the figure is obtained. At this time, an even sample group a and an odd sample group b are provided for each channel.
And are separated.

Next, lL0, lL2, l to be recorded first
The 8 × 4 matrix sample of L4, LL6, LR1, LR3, LR5, LR7 is encoded and the error correction code P
0 to P4 and CL0, CL2, CL4, CL6, CR1, CR3, CR
5, CR7 is generated. There are many error correction codes, and the encoding method and the like are also different, but they are omitted because they are not the gist of the present invention. Coded frame address 0 to
The data of No. 8 are sequentially read in the order of frame numbers in frame units, and only the error correction code frame lP0 is La and Lb.
It is read after the frame number 3 so as to come in between and recorded on the tape. After the reading of one scan is completed, the same coding is performed on the remaining samples of one scan, and the samples are recorded in the next scan. That is, continuous samples on each channel are distributed to two scans, but the error correction code is complete for one scan of data recorded on the tape and does not extend to two scans. At the time of reproduction, data is written in the memory on a frame-by-frame basis and corrected using an error correction code, and then WL
0, WR0, WL1, ... are sequentially read. As described above, the error correction code can decode the scan when the data of one scan is read.

This operation is as described with reference to FIG. 4, and if the code extends over two scans, the data for two scans must be gathered, and then the decoding for two scans must be performed in the 90 ° open section. On the other hand, in the present method, since decoding can be performed for each scan, the clock rate required for encoding and decoding does not increase even if data interleaving for 2 scans is performed. FIG. 6 is a magnetic pattern diagram recorded on a tape having the memory configuration of FIG. In the figure, X1 indicates the width of the tape, and X2 indicates the width of the burst error that can be interpolated by the average value. In this example, the error correction code frames 1P0 and 1P5 are controlled so that the read address during recording is located at the center of one scan, but they may be placed anywhere in the scan. As described above, in the magnetization pattern shown in FIG. 6, continuous sample errors do not occur even when a signal loss of one scan occurs or when a tape running direction noburst error of about half the tape width from the tape edge occurs. Therefore, the average value can be corrected.

FIG. 7 is a diagram showing another example of the magnetization pattern according to the present invention. It is clear that this example also has the same effect as that shown in FIG. In the above description, the case of handling the information signals of two channels is shown, but it is applicable to the case of handling the information signals of a plurality of channels. Furthermore, in the above examples, the apparatus for the audio signal is described, but it is possible to cover all signals for which correction by the mean value interpolation is effective. As a digital signal recording / reproducing system, it goes without saying that a system other than the PCM system can be applied.

[0016]

As described above, according to the signal processing circuit of the rotary head type magnetic recording apparatus of the present invention, the first area located near the track center of each track and the tracks in the track longitudinal direction rather than the first area. It has at least a second region located in the first half and a third region located in the latter half of the track with respect to the first region, and the second region is m sub-regions 0 to m-1 toward the center of the track. The third region has m sub-regions 0 to m-1 from the center of the track to the other end, and a digital signal of a plurality of words is arranged in each sub-region, Minute digital signals are arranged in the second and third areas of the first and second tracks, and at least a part of the redundant signal for error control is arranged in the first area of each track. Of the first word entered in time When a force sequence was 0-th, first input order consists of 4n th plurality of words (n is an integer) 1
In the second area of the first track, the second word group consisting of a plurality of words having an input order of 4n + 1th in the second area of the second track, and the second word group consisting of a plurality of words of an input order of 4n + 2 A third word group is arranged in the third area of the second track, and a fourth word group consisting of a plurality of words having an input order of 4n + 3 is arranged in the third area of the first track, and in each area, Since the words are repeatedly arranged in the sub-areas 0 to m-1 in accordance with the input order for the word groups corresponding to the areas, the following effects are obtained. (B) A large continuous word loss does not occur even if the signal is lost in one scan. Therefore, the information is not concentrated and lost, and there is no problem in deciphering the content of the information. (B) Large continuous word loss does not occur even with a burst error in the tape running direction having a size of about half the tape width. (C) Even if a continuous error of a sub-region length or less at a distance of more than half the tape width occurs in the first and second tracks simultaneously, a large continuous error is unlikely to occur. Further, according to the rotary head type magnetic reproducing apparatus signal processing circuit of the present invention, it is possible to reproduce the signal recorded according to the present invention in which a large continuous error is unlikely to occur. Further, according to the magnetic tape of the present invention, regarding the reproduction of the data recorded in the present invention, there is an effect that the reproduction is unlikely to cause a large continuous error even if the tape is contaminated.

[Brief description of drawings]

FIG. 1 is a magnetization pattern state diagram of a conventional rotary head type recording / reproducing apparatus.

FIG. 2 is a magnetization pattern state diagram according to an embodiment of the present invention.

FIG. 3 is a schematic block diagram according to an embodiment of the present invention.

FIG. 4 is a timing diagram showing an operation state of a memory circuit included in an embodiment of the present invention.

FIG. 5 is a memory configuration diagram of a memory circuit included in an embodiment of the present invention.

FIG. 6 is a magnetization pattern state diagram showing a frame arrangement on the tape of the present invention.

FIG. 7 is a magnetization pattern state diagram according to another embodiment of the present invention.

[Explanation of symbols]

1 Input Terminal 2 Recording Side Low Pass Filter 3 Sample Hold and Analog-Digital Conversion Circuit 4 Recording Side Memory Circuit 5 Recording System Memory Address Control Circuit 6 Encoding Circuit 7 Modulation Circuit 8 Recording Amplifier 9 First Changeover Switch 10 Head 11 Head 12 Second selector switch 13 Reproduction amplifier 14 Demodulation circuit 15 Reproduction side memory circuit 16 Reproduction system memory address control circuit 17 Decoded signal 18 Correction circuit 19 Digital-analog conversion circuit 20 Reproduction side low-pass filter 21 Output terminal 22 Clock generation circuit

Claims (8)

[Claims] 1. A circuit which is applied to a rotary head type magnetic recording device for performing recording while forming diagonal tracks on a recording medium by sequentially inputting digital signals per unit time, each track being located near the center of the track. It has at least a first region, a second region located in the first half of the track in the track longitudinal direction with respect to the first region, and a third region located in the latter half of the track with respect to the first region, and the second region is located at the center of the track. There are m sub-regions from 0 to m−1 toward the other end, and the third region has m sub-regions from 0 to m−1 toward the other end from the track center. In a unit for rearranging and outputting the digital signals so that a plurality of words are arranged in the area, an encoding unit that encodes the digital signals to generate a redundant signal for error control, and the unit All the digital signals input within the time are output as signals to be distributed to the second and third areas of the first and second tracks, and the error control is performed in the first area of each track. And at least a part of the redundant signal for the unit time is arranged, and when the input order of the first word input in the unit time is 0th, the input order is 4nth (n is an integer) consisting of a plurality of words. 1 word group in the second area of the first track,
A second word group consisting of a plurality of words having an input order of 4n + 1 is placed in the second area of the second track, and the input order is 4
A third word group consisting of n + 2 th plurality of words is arranged in the third region of the second track, and a fourth word group consisting of 4n + 3 th plural words of input order is arranged in the third region of the first track. At the same time, in each area, the digital signal is output so that each word is repeatedly arranged one by one in the sub areas 0 to m-1 according to the input order for the word group corresponding to each area. A recording signal processing circuit for a rotary head magnetic recording device characterized by the above. 2. The recording signal processing circuit for a rotary head type magnetic recording apparatus according to claim 1, wherein said encoding means generates a code which is completed by one track. 3. A circuit applied to a rotary head type magnetic reproducing device for reproducing a digital signal by scanning an oblique track formed on a recording medium, each track being a first area located near the center of the track. And a second region located in the first half of the track with respect to the first region in the track longitudinal direction,
At least a third area located in the latter half of the track with respect to the first area is provided, a redundant signal for error control is arranged in the first area of each track, and the second area starts from number 0 toward the center of the track. The third area has m sub-areas of m-1 and the third area has m sub-areas of 0 to m-1 from the center of the track to the other end, and each sub-area has a plurality of sub-areas. A digital signal of a word is arranged, and the digital signal for a unit time is the second of the first and second tracks,
Decoding means for performing error detection or error correction of a reproduced signal by using a redundant signal reproduced from the first area in an arrangement in which those distributed in the third area are rearranged in a predetermined order and output, and an error. And a signal processing means for rearranging and outputting the digital signals in units of the first and second digital signals for which the detection or error correction processing has been performed, and the output of the word to be output first within the unit time. When the order is 0th, the first word group consisting of a plurality of words reproduced from the second area of the first track is output to the 4nth (n is an integer), and the second area of the second track is output. The second word group consisting of a plurality of reproduced words is output to the 4n + 1th position, and the third word group consisting of a plurality of words reproduced from the third area of the second track is arranged into a 4n + 2nd position. Outputs, and outputs a third fourth word group including a plurality of words which are reproduced from a region of said first track 4n + 3 th, in each region,
A reproduction signal for a rotary head type magnetic reproducing apparatus, wherein each word is repeatedly output one by one from the sub-areas 0 to m-1 in order of output, targeting a word group corresponding to each area. Processing circuit. 4. A reproducing signal processing circuit for a rotary head type magnetic reproducing apparatus according to claim 3, wherein said decoding means performs error detection or error correction in units of one track signal. 5. A digital signal sequentially input in a unit time is arranged so as to form an oblique track, and each track has a first region located near the center of the track and a first region in the track longitudinal direction from the first region. Also has at least a second area located in the first half of the track and a third area located in the latter half of the track with respect to the first area, and the second area has m number 0 to m−1 toward the center of the track. Has a sub-region,
The third area is 0 to m from the center of the track to the other end.
In a magnetic tape having m sub-regions of -1, each of which has a digital signal of a plurality of words, all the digital signals input within the unit time are the first and second. The input order of the first word input in the unit time is arranged in the second and third areas of two tracks, and at least a part of the redundant signal for error control is arranged in the first area of each track. Is the 0th,
A first word group consisting of a plurality of 4n-th (n is an integer) input order words is in the second area of the first track, and a second word group consisting of a 4n + 1-th order input word is the second word group. Input order is 4n in the second area of 2 tracks
A third word group consisting of + 2nd plural words is arranged in the third area of the second track, and a fourth word group consisting of 4n + 3rd plural words in the input order is arranged in the third area of the first track. In each area,
A magnetic tape in which each word is repeatedly arranged one by one in sub-areas 0 to m-1 according to an input order for a word group corresponding to each area. 6. The magnetic tape according to claim 5, wherein the redundant signal of each track is generated from a digital signal arranged on the track. 7. A magnetic tape in which digital signals of two channels, first and second, are arranged to form diagonal tracks, and each track is located near the center of the track.
At least a second region and a third region located on both sides of the region and the first region, respectively, and all samples of two channels for a unit time are in the second and third regions of the first and second two tracks. The even samples of the first channel are arranged in the second area of the first track, the odd samples of the second channel are arranged in the third area of the first track, and the even samples of the second channel are arranged in the first area. The second sample in the same sample order as the even samples of the channel.
In the second area of the track, the odd-numbered samples of the first channel are arranged in the third area of the second track in the same sample order as the odd-numbered samples of the second channel, and the first area of each track is arranged. The magnetic tape is characterized in that at least a part of a redundant signal for error control is arranged on the magnetic tape. 8. The magnetic tape according to claim 7, wherein the redundant signal of each track is generated from a digital signal arranged in the track.