JPS6093680A - Rotary head type pcm magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To reduce noise due to the clogging of a head or flow of a tape in a travelling direction by arranging data of an odd sample group and an even sample group in each scanning and rearranging an even sample adjacent to a sample in the odd sample group to a separate position in the same even sample group to record the rearranged sample. CONSTITUTION:An analog signal from an input terminal 1 is converted into a digital signal Wn through a low pass filter 3 and an A/D converter 4 and the digital signal Wn is written in a memory circuit 5. An encoding circuit 6 reads out a necessary smaple in the memory 5, generates a correction code Cn and writes the correction code Cn in the memory 5. The digital signal Wn and the correction code Cn are read out in each frame in an order shown in the figure. On the basis of the reading, interleaving processing is executed. The read out signal Wn and code Cn are inputted to a modulator 7 and recorded in a magnetic tape by heads 9, 10 through an alteration switch 8. The digital signal Wn is divided into an odd sample group and an even sample group and four samples and an error correction word Cn are contained in one frame. The number ln shows the n-th frame.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a rotating head type PCM magnetic recording/reproducing device, and in particular, converts an information signal into a digital signal and converts the information signal into a digital signal by scanning/scanning it diagonally or vertically with a rotating head. The present invention relates to improvements in data interleaving in a rotary head type PCVM recording and reproducing apparatus for recording and reproducing data on a magnetic tape.

[Prior Art] A rotating head type PCM 11 recording and reproducing device converts an audio signal into a digital signal and records and reproduces it on a magnetic tape using a rotating head, but this type of device generally uses an error correction code. It will be done. The purpose of the error correction code is to correct data errors that occur during recording and reproduction of magnetic tape, and to reproduce high-quality audio signals.

However, if the number of errors exceeds the correction capability and cannot be corrected, correction processing such as interpolation by taking the average value of previous and subsequent data is performed. Further, errors on magnetic tapes are often burst errors, and in order to improve the performance of error correction codes, interleaving (crossing) processing is performed to disperse error data. As mentioned above, if the error cannot be corrected, correction processing is performed, but
An effective method with a simple circuit is mean value interpolation. In order to perform average value interpolation, the data before and after must be correct data. Therefore, when interleaving is performed, the data of the odd sample group and the data of the even sample group are separated as much as possible.

FIGS. 1 and 2 are diagrams showing magnetization patterns recorded on a magnetic tape by a conventional rotary head type PCM magnetic recording/reproducing device.

In the following explanation, a two-head helical scan rotating head type PCM recording and reproducing apparatus will be considered as an example.

In FIGS. 1 and 2, data is divided into an odd sample group a and an even sample group a. The amount of interleaving is often determined by considering the error burst length and the correction ability of the error correction code. There are things that are side by side, or things that are the opposite. In FIG. 2, one scanning section is divided into equal parts and an odd sample group a and an even sample group are arranged.

It is assumed that the check data for error correction is appropriately contained in the odd sample group a and the even sample group a. These interleavings are effective against common errors.

However, when recording and playing back the same magnetic tape repeatedly,
The magnetic powder on the magnetic tape gradually peels off. At that time, it often happens that one head catches magnetic powder, in other words, causes instantaneous clogging, while the other head is able to perform normal playback. In such cases, the conventional rotating head type PCMt! ! The magnetization pattern of the optical recording/reproducing device has the disadvantage that it is impossible to interpolate the average value of the data before and after the data is correct, and a noise that is easy to hear is generated.

[Summary of the Invention] Therefore, the main object of the present invention is to arrange data of an odd number sample group and an even number sample group for each scan, and furthermore, to solve the above-mentioned conventional drawbacks. Head clogging can be avoided by rearranging and recording within a group of even (odd) samples so that even (odd) samples that occur adjacent to any sample in the group are recorded at positions as far away as possible. It is an object of the present invention to provide a rotating head type PCM magnetic recording/reproducing device which generates less noise even when scratches of various widths occur in the tape running direction.

The above objects and other objects and features of the present invention will become more apparent from the detailed description given below with reference to the drawings.

[Embodiment of the Invention] FIG. 3 is a diagram showing a magnetization pattern according to an embodiment of the present invention, FIG. 4 is a diagram also showing a signal grid, and FIG. 5 is a diagram showing details of the magnetization pattern. It is a diagram. Third
In the figure, the data of the odd sample group a and the even sample group A are arranged alternately for each scan. That is, such a magnetization pattern can be realized by making equal the total number of data of odd sample groups or even sample groups and redundant data such as error correction codes in one Skillen length and interleaving.

Next, the sample arrangement in the odd sample group aL13 and the even sample group will be explained. Figure 4 shows the formation of a transmission signal when 64 samples are recorded on a magnetic tape with a 2 scan length.
indicates the nth generated sample, and 0 indicates an error correction word. Various methods have already been considered for the direction in which the error correction word Qn is generated, and since they are directly related to the present invention, they will not be discussed here. As shown in Figure 4, samples W are arranged in a 16x4 matrix.
0 is divided into an odd numbered sample group and an even numbered sample group, and four vertically arranged samples and an error correction word Wn constitute one frame, and are serially transmitted in frame units.

Incidentally, in indicates the n-th frame, and 16 frames from j-+s are recorded on a magnetic tape having a length of 2 scans.

FIG. 5 shows the arrangement on the magnetic tape in frame units, where xl indicates the width of the tape and x2 indicates the maximum burst length from the tape edge without continuous interpolation. The first scan has an odd numbered sample group shown in Figure 4, the first +1 scan has an even numbered sample group shown in Figure 4,
In the first +1st scan, the odd sample group generated after the odd sample group recorded in the first scan is recorded. The feature of this recording method is that it is recorded separately into an odd number sample group and an even number sample group, and the even number sample group is recorded in Qz from approximately the center of one scan in descending order of frame number.
, (L-... is recorded as 6, and when the top edge of the tape is reached, 10 + fl + 2... is recorded as 6 from the bottom edge of the tape. Adopting such a recording method Therefore, even if the signal from one head is lost due to head clogging, continuous sample errors will not occur.Also, even if a burst error occurs in the tape running direction with a width of 'IC, X 2' Consecutive sample errors do not occur.If the error exceeds x2, 11 gardens, 6
A continuous error occurs in 1. When recording α frames in one scan,
It becomes X+/α. In practice, 200 to 300 frames are recorded, which prevents consecutive sample errors for bursts up to half the width of the tape.

Next, a rotary head type PCM magnetic recording/reproducing device that enables data arrangement as described above will be explained.

FIG. 6 is a schematic block diagram of an embodiment of the present invention.

Next, the configuration and operation of an embodiment of the present invention will be described with reference to FIG.

The recording system is composed of an input terminal 1, a low-pass filter (LPF) 3, an A/D converter 4, a memory circuit 5, an encoding circuit 6, a modulator 7, a first changeover switch 8, and heads 9 and 10. . An analog signal is input to input terminal 1,
This analog signal is given to a low pass filter 3 and band limited. The output of the low-pass filter 3 is given to an A/D converter 4 and converted into a digital signal Wn. The converted digital signal W0 is applied to the memory circuit 5 and written into the memory in the arrangement shown in FIG. 4 described above. An encoding circuit 6 provided in association with the memory circuit 5 reads the necessary samples in the memory, generates a correction code On, and writes this to the memory. Then, the digital signal Wn and the correction code On are read out frame by frame in the order 1j' shown in FIG. That is, interleaving processing is performed by this succession. The read digital signal WO and correction code Cn are input to the modulator 7.

The modulator 7 converts the digital signal wn and the correction code On into data suitable for recording on a recording medium, and the data is recorded on a magnetic tape by two heads 9 and 10 via a first changeover switch 8. Note that the first changeover switch 8
is for switching the circuit connected to the head during recording and playback.

Next, the configuration of the reproduction system and its operation will be explained. The reproduction system mainly consists of the second changeover switch 11 and the ll1i device 1.
2, memory circuit 13, decoding circuit 14, and D/A converter 15
, a low-pass filter 16 , and an output terminal 17 . The signals read from the two heads 9 and 10 mentioned above are applied to the second changeover switch 11 via the first changeover switch 8. This second changeover switch 11 is for applying the output signals of the heads 9 and 10 to the ** device 12 as one signal system. The demodulator 12 returns the input signal to the original digital signal and supplies it to the memory 13. Memory 13 writes the vIll signal. That is, the recording signal shown in FIG. 5 mentioned above is written while the memory address of the memory circuit 13 is controlled so that the arrangement shown in FIG. 4 is obtained during reproduction. And memory circuit 1
A decoding circuit 14 provided in connection with 3 reads out necessary samples from memory and performs error correction. The corrected samples in memory are stored in W by an address circuit (not shown) included in memory circuit 13.

, Wt, Ws..., W64 and are interleaved and read out sequentially. The read sample is given to the D/A converter 15 and converted into an analog signal. This analog signal is further applied to a low-pass filter 16, band-limited, and output from an output terminal 17. The clock generation circuit 19 provides necessary lock pulses to each section of the recording system and reproduction system.

In the above embodiment, the case of one channel was explained, but the VV is not limited to this, and also in the case of two channels.
+ L I W+ Let m be W, and W2 L IW2.
can be applied by setting W2 . . . , and can also be applied to a large number of channels in the same way.

Further, in the above-described embodiment, an example was shown in which samples in an even numbered sample group were rearranged, but samples in an odd numbered sample group may be rearranged.

[Effects of the Invention] As described above, according to the present invention, the data of the odd sample group and the even sample group are distributed for each scan, and the generation times of the odd samples and even samples of adjacent tracks are adjacent to each other. Since the data in the tape are recorded at positions far apart from each other in the tape width direction, data for one scan may be lost due to a clogged head, and data extending in the tape running direction, which has a width of approximately 1/2 the tape width, may occur. It is possible to obtain reproduced sound with less noise even for bursts.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a magnetization pattern recorded on a magnetic tape by a conventional two-head helical scan type rotary head type PGM magnetic recording/reproducing apparatus. FIG. 2 is a diagram similarly showing another example. FIG. 3 is a diagram showing a magnetization pattern according to an embodiment of the present invention. FIG. 4 is a signal configuration diagram according to an embodiment of the present invention. FIG. 5 is a diagram showing details of a magnetization pattern according to an embodiment of the present invention. FIG. 6 is a schematic block diagram of an embodiment of the present invention. In the figure, 3.16 is a low-pass filter, 4 is an A/D
conversion circuit, 5.13 is a memory circuit, 6 is an encoding circuit, 7
1 is a modulator, 8 and 11 are changeover switches, 9 and 10 are heads, 12 is a demodulator, 14 is a decoding circuit, and 15 is a D/A converter. Procedural amendment (spontaneous) July 1970//Date Commissioner of the Patent Office 1, Indication of the case 1, Iku (1+145 g -2020
No. 89 No. 2, Name of the invention Rotating head type PCM magnetic recording and reproducing device 3, Relationship with the person making the amendment case ↑1°, II blasphemy (to the representatives of I and Hitoshi Katayama Part 4, 61 of the drawings of the agent! 1 6. Details of the amendment as shown in the attached sheet.

Claims (1)

[Claims] Converting an information signal into a digital signal, n (n is an integer)
A rotating head type PC that records and reproduces digital signals on a magnetic tape by sequentially scanning diagonally or vertically with a rotating head.
In the Mfl-like recording and reproducing apparatus, means for dividing the digitized information signal into an odd number sample group and an even number sample group, a rearranging means for rearranging the order of the samples within each group, and a means for rearranging the order of the samples in each group, and sequentially dividing the digitized information signal into the odd number sample group and the even number sample group each time scanning is performed. A recording/reproducing means for alternately recording and reproducing data of even-numbered sample snoring is provided, and an arbitrary sample in the odd-numbered sample group and an adjacent sample in the even-numbered sample group are recorded and reproduced at positions separated in the tape width direction. Rotating head type P featuring
CM magnetic recording and reproducing device.