JPS5965906A - Multi-channel recording and reproducing device - Google Patents

Abstract

PURPOSE:To reduce probability by which synchronizing patterns of plural tracks make an error simultaneously due to drop-out, by dispersing the synchronizing patterns on a tape, when recording and reproducing an analog signal of a voice, etc. CONSTITUTION:One example of a recording format on a tape is shown. In this example, a case of recording to eight multi-tracks is shown. For instance, when width of a tape is 1/8 inch (3.2mm.), width of one track becomes about 400mum. For instance, in case when length of one frame is about 4.8mm., it will do that recording is executed at a distance of >=1/4 of one frame (L). In this case, synchronization of a CH1 and a CH5 forms a line on a vertical line. As for a circuit, 21-26 show shift registers using a flip-flop, and a step number of the shift register is selected as mentioned below. In case when length of one frame of one channel is N bit, it will do that the step number of the shift register 21 and 24, 22 and 25, and 23 and 26 to N/4, N/2 and 3N/4, respectively.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a multi-channel magnetic recording/reproducing device, and the present invention relates to a multi-channel magnetic recording/reproducing device. This invention relates to a recording and reproducing circuit that reduces the probability that synchronization patterns will be erroneous at the same time.

[Prior art]

Recently, a digital processing (PCM) method has been adopted for recording and reproducing analog signals such as audio. As shown in FIG. 1, this system records and reproduces digital signals on a magnetic tape by converting analog signals such as input audio into analog/digital (A/D) L and using a multi-channel magnetic head.

1 is an input terminal, 2 is an A/D converter, 3 is a digital processing circuit, 4 is a multi-channel recording head, 5 is a magnetic tape, 6 is a multi-channel playback head, 7 is a playback processing circuit, and 8 is a D/D/D/D converter. A converter, 9 is an output terminal.

FIG. 2 shows a circuit for recording and reproducing one screen of a video signal as a still image on a tape. 10 is a video signal input terminal, 11 is an A/D converter, 12 is a one-frame memory, 13 is a digital processing circuit, and 14 is a multi-channel recording head. The input video signal is several M
Since it is a high frequency (Hz), it cannot be directly recorded on magnetic tape. For this reason, one frame of A/D conversion is temporarily stored in a memory, read out at low speed, and recorded on tape. For playback, playback multi-channel head 1
5, the signal is detected and stored in the one frame memory 16. 17 is a digital processing circuit that reads signals from the frame memory at high speed and converts them into digital-to-analog converters (D
/A) Convert to analog signal at 18 and output.

An example of the recording format recorded on the magnetic tape 5 used in these devices is shown in FIG. A digital signal is divided in parallel for each certain data to configure multiple channels, and a synchronization pattern (hereinafter referred to as 5YN) is applied to the data of each channel.
C) is added and recorded. As shown in the figure, 8
Considering the case of channels, one frame consists of a synchronization pattern (SYNC) and a data section (DATA), and tapes of channels 1 to 8 are recorded in parallel.

Then, an error correction code (hereinafter referred to as ECC) is added to deal with data loss due to dropout, and a method of dispersing and recording data (interleaving) is used to further improve the correction ability. For example, Figure 4 (A
) shows the data structure of CI-I 1, and the data structure of several bits or tens of bits (hereinafter referred to as words) D1~
D4 and all error correction codes ECC for these, (
Disperse as shown in B). By arranging and recording in this manner, the ability to correct burst errors due to dropouts is greatly improved. For example, if the original error correction ability is capable of correcting a one-word error, the fourth
Even if there is a dropout as shown in Figure (B), errors are dispersed as shown in Ic (C) by performing inverse interleaving on the playback side. Therefore, if there are five or less consecutive errors, all errors can be corrected.

However, in order to correctly perform the operations described above, the location of the data must be accurately known. That is, it is necessary to correctly reproduce the synchronization pattern (8YNC).

If 5YNC cannot be detected correctly, there will be problems such as erroneous correction or erroneous decoding of correct data.

Therefore, concentrating <8YNC in one place in Figure 3 is a big problem because errors in jDsYNc can occur simultaneously in multiple channels due to dropouts due to poor mechanical contact with the magnetic tape head9. I understand.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the probability that 8YNC of a plurality of tracks will be incorrect at the same time due to dropout by distributing the 8YNC pattern on the tape.

[Embodiments of the invention]

Hereinafter, the gist of the present invention will be explained in detail with reference to Examples.

Figure 5 shows one of the recording formats on tape according to the present invention.
An example will be shown in which recording is performed on eight multi-tracks. For example, if the tape width is 178 inches (3,2
wn ), the width of one track is approximately 400 μm. For example, if the length of one frame is about 4.8, it is good to record at least one-fourth of one frame (L) apart, as shown in FIG. In this case, the synchronization of CHl and CR2 are aligned on a vertical line. By recording in this way, two or more 8YNCs will not be mistaken at the same time for dropouts with a diameter of 0.6 mm or less on the tape.

The present invention is not limited to the above-mentioned track widths and frame lengths, and may be appropriately modified for recording.

In addition, if the length of one frame is sufficiently long compared to the track width, it is simply divided by the number of tracks as shown in Figure 6.
All you have to do is shift the location by just that. It can be seen that if the synchronization pattern 5YNC is recorded in this arrangement, the probability that a plurality of 5YNCs will be lost at the same time due to dropout is greatly reduced.

FIG. 7 shows an example of how the arrangement shown in FIG. 5 can be recorded by circuit means. 21 to 26 indicate shift registers using flip-flops, t, -rzJ, and the number of stages of the shift register is selected as follows. The length of one frame of one channel is eN bits.The number of stages in shift registers 21 and 24 is N/4.The number of stages in shift registers 21 and 25 is N/2.
．． The number of stages 23 and 26 may be set to 3N/4.

FIG. 8 shows the structure of a multi-channel head which is another means for realizing the recording shown in FIG. 5. If the head gaps G of the multi-channel head 30 are arranged in a stepped manner as shown in the figure, and the signal of CH'8 is recorded as is, the recording on the tape will be as shown in FIG. 5.

Further, in order to perform recording in the arrangement shown in FIG. 6, it is sufficient to simply shift the head. Furthermore, for simplicity, as shown in FIG. 9, the head carried in a straight line by the head gap may be tilted in the tape running direction.

FIG. 10 shows an example of a circuit for reproducing data arranged as shown in FIG. 5 and restoring it to the original arrangement. The output of the reproduction multi-channel head 40 is amplified and then input to shift registers 41-46.

This shift register is configured to provide a delay opposite to that of recording. That is, shift registers 41 and 44 have a delay of 3N/4, and shift registers 42 and 45 have a delay of N/4.
2 and a delay of N/4 in shift registers 43 and 46 to return the data as shown in FIG.

By dispersing the 5YNC as shown in FIGS. 5 and 6, the probability that the 8YNC of a plurality of channels will be incorrect at the same time can be greatly reduced, but there are also the following advantages.

For example, consider the case where an error correction code is added to data (words) in the width direction of a track as shown in FIG. In this example, the data channels are CHI to CH7.
shall be used for CH311m error correction. ECC error correction code for words D1 to D7
ECCl0.1 for DIl-D17. ...
...and... At this time, the ability of the error correction code is such that the error of one word in one data block (Di to D7 and ECC1) can be corrected. When recording is done side by side as shown in Figure 11, if a dropout occurs over 4 words (D35°D36.D45.D46) as shown in the figure, two errors will occur in each corrected block. It becomes impossible to correct. In contrast, an embodiment of the present invention is shown in FIG. 12, but the error occurs for the same dropout in D35. D45. D6. It can be seen that the value is D16. If this is rearranged to its original state during playback, there will be one error in one block as shown in FIG. As a result, the error is 1 within each corrected block.
Since it is a word rhyme, all errors can be corrected.

Furthermore, if the 5YNCs of a plurality of tracks are not mistaken at the same time, erasure correction is possible.

In other words, all the data of one track in which 5YNc is incorrect can be regarded as erroneous, and correction can be made using only other data.

If the 5YNC of two or more tracks is incorrect at the same time, all data on these tracks must be treated as an error. The probability of making a mistake can be significantly reduced, and the effect of dispersing data can also improve error correction ability.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a device that records and reproduces audio as a multi-channel digital signal.
A block diagram of an apparatus for recording and reproducing one frame as a digital signal in a multi-channel manner. Figure 3 is an example of a conventional recording format on a tape in the apparatus shown in Figures 1 and 2. Figure 4 is an example of an error recording format. Figure 5 is a diagram showing the state in which data is interleaved for correction and then restored.
1 of multi-channel recording formats according to the present invention
For example, FIG. 6 shows another embodiment of the recording format according to the present invention, FIG. 7 shows an example of a circuit that cannot be realized by the entire recording circuit shown in FIG. 5, and FIG. An example of realizing the recording shown in FIG. 9 with the structure of a multi-channel head, FIG. Figure 10 shows an example of a circuit for reproducing the recorded data shown in Figure 5 and restoring it to its original arrangement. Figure 11 shows the data format when an error correction code is added to the data in the width direction of the tape. FIG. 12 is a diagram showing the recording pattern on the tape when recording is performed according to the present invention, and FIG. 13 is a diagram showing the recording pattern on the tape when recording is performed according to the present invention. FIG. 1 % 2 Figure 13 CHl -' Go to Figure 4 CI (+- (A) Figure 5) F Figure ■3 Figure q

Claims (1)

[Claims] 1. In a multi-channel recording and reproducing device that records and reproduces digital information on a tape-shaped magnetic recording medium by attaching synchronization patterns to each of a plurality of channels, the synchronization patterns for each channel are recorded while being shifted. A multi-channel recording and reproducing device characterized by: 2. The multi-channel recording and reproducing apparatus according to claim 1, characterized in that the amount of deviation of the synchronization patterns is set to be one integer fraction of the synchronization pattern period between the synchronization patterns of adjacent channels. 3. The multi-channel recording and reproducing apparatus according to claim 1, wherein the error correction code of one channel is added to other channels.