JPH0242686A - Rotary head type magnetic recording and reproducing device and system for recording and reproducing - Google Patents

Abstract

PURPOSE:To execute a satisfactory reproduction and to eliminate necessity to increase a clock rate by executing correction with a mean value interpolation even when a signal omission is generated. CONSTITUTION:The samples of plural channels L and R are divided into an even sample group (a) and an odd sample group (b) for each channel, the even sample group (a) and odd sample group (b) of the same channel are alternately arranged for each scanning, they are arranged separately from each other in a tape T width direction, and simultaneously, an error correcting code is prepared and arranged to be completed to data contained in one scanning. For such a reason, even to the signal omission of one scanning and a burst error in the tape T traveling direction having a large width in the tape width direction, the correction by the mean value interpolation can be executed. Thus, a reproduced sound and a reproduced image with a small noise can be obtained, and moreover, the sound and image not to need the increase of the clock rate at the times of encoding and decoding can be obtained even in such a case.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a rotary head type recording/reproducing device and its recording/reproducing method, and in particular to interleaving (interleaving) of digitized data, and interleaving (interleaving) of digitized data, and interleaving of data occurring during recording/reproducing. This relates to something that uses an error correction code to correct errors in data.

[Conventional technology]

Conventionally, as an example of this type of device, there is a rotary/rad type PCM recording and reproducing device that converts an audio signal into a digital signal and records and reproduces it on a magnetic tape using a rotary head. Generally, error correction codes are used in such devices to correct errors in data that occur during recording and playback, and if the number of errors exceeds the correction capability and cannot be corrected, the average value of the previous and subsequent data is taken and interpolated. Correction processing such as

Since errors on magnetic tape are often burst errors, it is effective to perform interleaving processing to randomize error data in order to fully utilize the ability of error correction codes.

In the above-mentioned correction processing, a method with a simple circuit and low noise is average value interpolation, but for this, the data before and after must be correct, so the data of the odd sample group and the adjacent even sample group Interleaving is performed to place the data at positions as far apart as possible.

In the following explanation, two channel signals will be treated as an example.
Let's consider a rotating head type PCM recorder with a helical scan head. Figure 1 shows a conventional rotating head type PCM.
FIG. 3 is a diagram showing a magnetization pattern recorded on a magnetic tape by a recorder. In the figure, T represents the magnetic tape, S represents the head scan direction, D represents the tape running direction, R represents two channels, a represents an even sample group, b represents an odd sample group, and P represents an error correction code group. It shows. In this example, as an interleaving method that arranges the even sample group and the odd sample group at separate positions as described above, samples that can be included in one scan are divided into an even sample group and an odd sample group, and these are divided into error correction code groups. This method places the P on both sides. If such interleaving is performed, even if a burst error Y of approximately half the width of the tape shown in the figure occurs, continuous sample errors will not occur, making it possible to perform average value interpolation.

However, in this conventional method of interleaving,
If one head becomes momentarily clogged with magnetic powder that has fallen off, that is, if the reproduction signal from one head is missing or has deteriorated significantly, errors will occur in consecutive samples. This method has the disadvantage that it is not possible to perform average value interpolation, resulting in audible noise.

[Summary of the invention]

The present invention has been made in view of the above-mentioned conventional problems.The present invention divides information signals of a plurality of channels into an even sample group and an odd sample group for each channel, and By arranging the sample groups alternately for each scan and at separate positions in the tape width direction, and by encoding the error correction code so that it is completed within one scan, head clogging and certain width corrections can be avoided. A rotary head type magnetic recording/reproducing device and its recording/reproducing method that can perform good reproduction even in the case of burst errors in the tape running direction and do not require an increase in the clock rate when correcting errors even in such cases. is intended to provide.

[Embodiments of the invention]

FIG. 2 shows a rotating head type PCM which is an embodiment of the present invention.
FIG. 2 is a diagram of a magnetization pattern on a tape recorded by a magnetic recording/reproducing device. The symbols in the figure are the same as those in FIG. In interleaving by the apparatus of the present invention, odd sample groups and even sample groups of the same channel are arranged alternately in each adjacent scan and at positions separated from each other in the width direction of the tape. With such an arrangement, even if the aforementioned one-scan signal loss occurs, continuous sample errors will not occur in each channel, so correction can be performed by means of average value interpolation.

Hereinafter, as an example of the present invention, the tape is wrapped at an angle of 90°.
The configuration and operation of the two-head helical scan rotary head type PCM recorder will be explained. FIG. 3 is a block diagram of this recorder, and FIG. 4 is a timing diagram showing the operation of the memory circuit included in the block diagram.

In FIG. 4, WT is the write period to memory, EN
is the encoding period, RD is the reading period from memory, D
E indicates the decoding period.

In Figure 3, the recording system includes a two-channel input terminal 1, a low-pass filter (LPF) 2, a sample-hold (S/H) circuit, and an analog-digital (A/D) circuit.
Conversion circuit 3, memory circuit 4, recording system memory address control circuit 5, encoding circuit 6, modulation circuit 7, recording amplifier 8, first switch 9, heads 10 and 11
It consists of

Two channels of LR analog signals are input to the input terminal 1 and band-limited by the LPF 2, respectively. LPF2
The output of is given to the S/H and A/D conversion circuit 3, and the digital signal WL,..., w, (n=0.1, 2...
) is converted to Here, n indicates the sampling order, and the signals of the two channels L and R are sampled alternately.

WR, WL, . . . are sequentially output. This signal is applied to the memory circuit 4 and sequentially written to addresses on the memory specified by the recording system memory address control circuit 5. The samples stored in the memory circuit 4 are successively outputted in the necessary order by the recording system memory address control circuit 5 and provided to the encoding circuit 6. The encoding circuit 6 generates error correction codes and error detection codes, and writes them into the memory circuit 4.

The information signal and the error correction code are sequentially read out by the recording system memory address control circuit 5 and applied to the modulation circuit 7. The memory circuit 4 is practically divided into two systems;
While one system of memory is writing samples, another system of memory is encoding and reading. This situation is shown in FIG. 4. Since recording and reproducing is performed on two heads by winding a 90'' tape, there are alternating 90'' signal recording and reproducing sections and 90 DEG pause sections. i.e. 9
The signal recording/reproducing period of 0''' corresponds to the recording/reproducing of one scan.Of the two scans of signals sampled in the WT period of Fig. 4 Tol, one scan is read out in the next RD period. The signal is first encoded in the EN period and read out in the RD period, and then the remaining signal for one scan is encoded in the next EH period and read out in the RD period.

The signal read from the memory is converted by the modulation circuit 7 into a data string suitable for recording on a magnetic tape, amplified by the recording amplifier 8, and then sent to the two heads 10 and 11 via the first changeover switch 9. recorded on magnetic tape. In addition,
The first changeover switch 9 operates to change over the circuit connected to the head during recording and playback.

Next, the configuration and operation of the reproduction system will be explained.

The reproduction system includes heads 10 and 11, a second changeover switch 12, a reproduction amplifier 13, a demodulation circuit 14, a memory circuit 15, a reproduction system memory address control circuit 16, a decoding circuit 17, and a correction circuit 18. , digital-analog (
D/A) conversion circuit 19 and low pass filter (LPF)
20, and a two-channel output terminal 21.

The second changeover switch 12 is for applying the output signals of the heads 10 and 11 to the reproduction amplifier 13 as one signal 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 1, and are supplied to the demodulation circuit 14. The demodulation circuit 14 converts the signal back into a digital signal before being modulated and modulated, and provides it to the memory circuit 15 . This digital signal is sent to the reproduction system memory address control circuit 16.
The data are sequentially written into the memory circuit 15 by the following steps.

Further, the memory address control circuit 16 reads out necessary samples from the memory circuit 15 and provides them to the decoding circuit 17. The decoding circuit 17 performs error detection and correction using an 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, and the errors are detected but cannot be corrected. Corrections such as the above-mentioned mean value interpolation are performed on the samples that are not present. The memory operation during reproduction is shown in FIG. 4 (To). WT
The samples of one scan reproduced during the period are written to the memory circuit 15 and are stored in the next 90° gap period (denoted by DE).
decoded and held in memory.

The remaining one scan of samples is written to memory during the next WT period and decoded during the next DE period.

Samples for two scans that have been decoded are read out during the RD period. The memory circuit 15 is divided into two systems, and while one memory is writing and decoding, the other memory is reading, as in the case of recording.

The corrected and corrected samples are sent to the D/A conversion circuit 1.
The signal is converted into the original analog signal at step 9, unnecessary frequency components are removed at LPF 20, and then outputted from output terminal 21.

The lock pulse generating circuit 22 functions to provide necessary input/output to each section of the recording system and reproduction system.

Next, memory circuits 4 and 15 in the block shown in FIG.
A detailed explanation of this and the detailed sample arrangement on the tape will be explained below.

FIG. 5 shows a memory configuration diagram in one embodiment of the present invention. In the figure, W, W□ indicate the nth sample of the upper channel and R channel, respectively, CL, l, CRn+Pn are error correction codes, and E, l□7 is the vertical direction. This indicates the number of a frame consisting of four samples of the information signal and a correction code. Further, the horizontal numbers fa indicate memory addresses in frame units (hereinafter referred to as frame addresses), and the vertical numbers sa indicate memory addresses in row units (hereinafter referred to as sample addresses). A indicates data recorded within one scan, and the memory is composed of data for two scans, in this case 32 samples of each information signal LR and 26 words of an error correction code. WL+II WI during recording
The samples given as QI WLll . . . are stored in the memory by controlling the memory address so that they become the array shown in the figure. At this time, the even number sample group a and the odd number sample group a are separated for each channel.

Next, 'LOI' L2. which should be recorded first. l
L4+1, j! □+ lR3+ ll! in
Ill? Coding is performed on the 8×4 matrix-like samples, and error correction codes P0 to P4 and CLO,
z, CL4. C.

Generate C□, CR31CR5I C117.

There are many types of error correction codes, and the encoding methods are also different, but since these are not the gist of the present invention, they will be omitted.

The encoded data of frame addresses O to 8 are sequentially read out frame by frame in the order of the frame number, and the error correction code frame t! ,. It is read out after frame number 3 and recorded on the tape so that it falls between Takehari and L5. After the reading of one scan is completed, the samples of the remaining one scan are similarly encoded and recorded in the next scan. That is, consecutive samples in each channel are distributed into two scans, but the error correction code is completed for one scan of data recorded on the tape and does not span two scans.

During playback, data is written into the memory frame by frame, which is the opposite of when recording, and after correction using an error correction code, WL,
, WR, , WL, . . . are sequentially read out. As mentioned above, since the error correction code is completed in one scan, when the data of one scan is read, that scan can be decoded.

This operation is as explained in Figure 4. If the code spans two scans, after the two scans' worth of data is complete, the two scans' worth of decoding must be performed in the next 90° gap interval. On the other hand, in this method, decoding can be performed for each scan, so the lock rate required for encoding and decoding does not increase even if two scans of data are interleaved.

FIG. 6 is a diagram of a magnetic pattern recorded on a tape by the memory configuration of FIG. 5. In the figure, Xl indicates the width of the tape, and X2 indicates the width of the burst error that can be interpolated with the mean value.

In this example, the error correction code frames CP0, β,.

The read address is controlled during recording so that it is located in the center of one scan, but it may be placed anywhere within the scan.

As mentioned above, with the magnetic pattern shown in Figure 6, continuous sample errors will occur even if a one-scan signal loss occurs or a burst error occurs from the tape edge in the tape running direction with a width of about half the tape width. Since there is no difference, average value correction is possible.

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 shown in FIG.

Although the above description deals with the case where information signals of two channels are handled, the present invention is applicable to the case where information signals of a plurality of channels are handled.

Further, in the above example, a device that targets audio signals has been described, but it is possible to target all signals for which correction by mean value interpolation is effective.

It goes without saying that the present invention can also be applied to systems other than the PCM system as digital signal recording and reproducing systems.

〔Effect of the invention〕

As described above, according to the present invention, samples of a plurality of channels are divided into even sample groups and odd sample groups for each channel, and even sample groups and odd sample groups of the same channel are alternately arranged for each scan. , they are arranged apart from each other in the tape width direction, and the error correction code is generated and arranged so as to be completed for the data included in one scan. Even burst errors in the tape running direction, which have a large width, can be corrected by mean value interpolation, and reproduced sound and images with less noise can be obtained, and even in such cases, the clock rate during encoding and decoding can be reduced. This results in something that does not require an increase in .

[Brief explanation of the drawing]

FIG. 1 is a state diagram of a magnetization pattern according to a conventional rotary head type recording/reproducing device, FIG. 2 is a state diagram of a magnetization pattern according to an embodiment of the present invention, and FIG. 3 is a schematic block diagram of an embodiment of the present invention. FIG. 4 is a timing diagram showing the operating 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, and FIG. FIG. 7 shows a state diagram of a magnetization pattern showing a frame arrangement on a tape according to an embodiment. FIG. 7 shows a state diagram of a magnetization pattern according to another embodiment of the present invention. In the figure, 1 is an input terminal, 2 is a low-pass filter on the recording side, 3 is a sample hold and analog-digital conversion circuit, 4 is a memory circuit on the recording side, 5 is a recording system memory address control circuit, 6 is an encoding circuit, 7 is a modulation circuit;
8 is a recording amplifier, 9 is a first changeover switch, 10 and 11 are heads, 12 is a second changeover switch, 13 is a playback amplifier, 14 is a demodulation circuit, 15 is a playback side memory circuit,
16 is a reproduction system memory address control circuit, 17 is a decoded signal, 18 is a correction circuit, 19 is a digital-to-analog conversion circuit, 20 is a reproduction side low-pass filter, 21 is an output terminal,
22 indicates a clock generation circuit. The same reference numerals in the figures indicate the same or corresponding parts. Engraving of drawings (no changes to content)

Claims (5)

[Claims] (1) In a rotary head type magnetic recording and reproducing device that records and reproduces digital signals of two channels, first and second, while forming diagonal tracks on a recording medium, a digital signal disposed within said one track. an encoding means for encoding a signal to generate a redundant signal for error control; and an encoding means for encoding a signal to generate a redundant signal for error control; All the samples for the two channels are placed in the first and second two tracks, and the even and odd samples of the same channel are placed in the two tracks, respectively. rearranging the samples so that they are recorded on different tracks and at positions separated in the longitudinal direction of the tracks, and including all the redundant signals in the track containing the digital signal that generated the redundant signal, a signal processing means for supplying the digital signal and the redundant signal; a recording means for sequentially recording the digital signal and the redundant signal supplied from the signal processing means on a recording medium; recorded on the recording medium; a reproduction means for scanning a track and reproducing two channels of digital signals; and a reproduction signal processing means for receiving the signal supplied from the reproduction means and rearranging the order of samples in the order of the original samples for each channel in units of two tracks. each track includes a first area located near the center of the track;
at least a second area and a third area located on both sides of the first area, and either the even-numbered or odd-numbered samples of the first channel are concentrated in the second area of the first track. Recording and reproducing, one of the even-numbered or odd-numbered samples of the second channel is placed in the third area of the first track, and the other one of the even-numbered or odd-numbered samples of the second channel is placed in the third area of the first track. In the second area of two tracks, the other one of the even-numbered or odd-numbered samples of the first channel is recorded and reproduced in the third area of the second track, and At least a portion of the redundant signal for error control is the first signal of the first track.
at least a portion of the redundant signal for error control for the digital signal of the second track is transmitted to the first digital signal of the second track.
A rotary head type magnetic recording/reproducing device characterized by recording and reproducing information in respective areas. (2) In a rotary head magnetic recording device that records digital signals of two channels, first and second, while forming diagonal tracks on a recording medium, the digital signals arranged in one track are An encoding means that performs encoding to generate redundant signals for error control; All the samples for the two channels are placed in the first and second two tracks, and the even-numbered samples and odd-numbered samples of the same channel are placed in the two tracks, respectively. The digital signal is rearranged so that the samples are recorded on different tracks and at positions spaced apart in the longitudinal direction of the track, and the redundant signal is all included in the track containing the digital signal that generated the redundant signal. and a recording means for sequentially recording the digital signal and the redundant signal supplied from the signal processing means on a recording medium, each track being located near the center of the track. at least a first area, and a second area and a third area located on both sides of the first area, and the second area of the first track includes either an even-numbered sample or an odd-numbered sample of the first channel. one of the even-numbered or odd-numbered samples of the second channel is recorded in a third area of the first track, and the other of the even-numbered or odd-numbered samples of the second channel is recorded. In a second area of the second track, the other one of the even-numbered or odd-numbered samples of the first channel is recorded in a third area of the second track, and At least a portion of the redundant signal for error control is the first signal of the first track.
at least a portion of the redundant signal for error control for the digital signal of the second track is transmitted to the first digital signal of the second track.
A rotary head type magnetic recording device characterized by recording in a region. (3) In a rotary head magnetic reproducing device that reproduces digital signals of two channels, first and second, while sequentially scanning diagonal tracks formed on a recording medium, each of the tracks has a plurality of channels near the center of the track. It has at least one region, a second region and a third region on both sides thereof, and samples of two channels for unit time are divided into the first and second regions.
At least a part of the redundant signal is recorded in the second and third areas of the track, and at least a part of the redundant signal is consolidated and distributed in the first area of each track for error correction or error detection that is completed in each track. A device for reproducing a signal, comprising: a reproducing means for reproducing a signal while scanning the track; a decoding means for performing error correction or error detection in units of signals for one track; and an error correction or error detection process. and reproduction signal processing means for rearranging and outputting samples for each channel in units of digital signals for two tracks, the first and second, and outputting either the even-numbered or odd-numbered samples of the first channel. is reproduced from a second area of the first track, one of the even-numbered or odd-numbered samples of the second channel is reproduced from the third area of the first track, and one of the even-numbered or odd-numbered samples of the second channel reproducing the other one of the odd-numbered samples from a second area of the second track; reproducing the even-numbered or odd-numbered samples of the first channel from a third area of the second track; and arranging the order of the samples. A rotary head type magnetic reproducing device characterized by changing output. (4) In a rotary head magnetic recording system in which digital signals of the first and second channels are recorded while forming diagonal tracks on a recording medium, each track is formed in a first area located near the center of the track. and a second region and a third region respectively located on both sides of the first region, and divides the samples of two channels input within a unit time into the even-numbered input sample and the odd-numbered sample for each channel. The input samples are separated into two channels, and all the samples for the two channels are sent to the second track of the first and second tracks.
and arranged in a third area, one of the even-numbered or odd-numbered samples of the first channel is placed in the second area of the first track, and either the even-numbered or odd-numbered samples of the second channel are placed in the second area of the first track. one of the even-numbered or odd-numbered samples of the second channel is placed in the second region of the second track; one of the even-numbered or odd-numbered samples of the second channel is placed in the second region of the second track; The other one of the samples is hard recorded in the third area of the second track, and all the redundant signals for error control of the digital signal arranged in one track are within that track and at least the redundant signal is recorded in the third area of the second track. A rotary head magnetic recording system characterized in that a part of the signal is recorded in the first area. (5) In a rotary head magnetic reproducing system in which digital signals of the first and second channels are reproduced while sequentially scanning diagonal tracks formed on a recording medium, each of the tracks has a plurality of channels near the center of the track. one area, and at least a second area and a third area on both sides thereof, samples of two channels for a unit time are arranged in the second and third areas of the first and second two tracks, and each A method for reproducing what is recorded in a first area of each track by compiling at least a part of redundant signals for error control that are completed in each track, the redundant signal being recorded in the first area of each track, the redundant signal being recorded in the first area of each track. Error correction or error detection is performed using the method, and either the even-numbered or odd-numbered samples of the first channel are processed using the first and second two tracks on which the error correction or error detection processing has been performed as a unit. from the second area of the first track; one of the even-numbered or odd-numbered samples of the second channel from the third area of the first track; and the even-numbered or odd-numbered samples of the second channel. the other one of the even-numbered or odd-numbered samples of the first channel is played back from the second area of the second track, and the other one of the even-numbered or odd-numbered samples of the first channel is played back from the third area of the second track, and the sample order for each channel is A rotating head magnetic reproducing system that rearranges and outputs the information.