JP2546189B2 - Rotating head type magnetic reproducing apparatus and signal processing circuit used therefor - Google Patents

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 magnetic reproducing apparatus for converting an information signal into a digital signal and reproducing the information recorded on a magnetic tape by scanning it obliquely or vertically by a rotary head. The present invention relates to a signal processing circuit, and more particularly, to improvement of data interleaving.

[0002]

2. Description of the Related Art A rotary head type PCM magnetic recording / reproducing apparatus converts an audio signal into a digital signal and records / reproduces on / from a magnetic tape by a rotating head. An error correction code is generally used in this type of apparatus. . The purpose of the error correction code is to correct a data error associated with recording / reproduction of a magnetic tape and reproduce a high-quality audio signal. However, when the number of errors exceeds the correction capability and the correction cannot be performed, a correction process such as interpolation by taking the average value of the preceding and following data is performed. Further, an error on the magnetic tape is often a burst error, and in order to improve the capability of the error correction code, the interleave process is performed to disperse the error data. As described above, when the error cannot be corrected, the correction process is performed, but the method effective with a simple circuit is the mean value interpolation. The data before and after must be correct in order to perform mean value interpolation. 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.

1 and 2 are conventional rotary head type PCs.
It is a figure which shows the magnetization pattern recorded on a magnetic tape by the M magnetic recording / reproducing apparatus. In the following description, a rotary head type PCM recording / reproducing apparatus of a two-head helical scan will be considered as an example. In FIG. 1 and FIG. 2, the data is two channels A and B,
Further, it is divided into an even sample group a and an odd sample group b. That is, a of A + B is an even sample group of A channel and B channel, and Aa is an even sample of A channel only. Further, S indicates the head scanning direction, and D indicates the tape running direction. The amount of interleaving is often determined in consideration of the burst length of an error, the correction capability of an error correction code, etc., and as shown in FIG. There are those that are lined up, or the opposite.

[0004]

FIG. 2 shows an even-numbered sample group a and an odd-numbered sample group b arranged side by side by equally dividing one scanning section. When such interleaving is performed, if one head momentarily clogs with the magnetic powder that has fallen off, that is, in the state where the reproduction signal from one head is lost, continuous data However, there is a drawback in that it is impossible to perform mean value interpolation, and noise that tends to be heard is generated.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and includes a first region located in the front half portion of each track from the vicinity of the track center to the track longitudinal direction. At least a second region located in the latter half part is provided, and the first region is from the 0th to m-
The first area has m sub areas (m is a natural number), and the second area has m sub areas from 0 to m−1 from the center of the track to the other end. Arranges digital signals of a plurality of words, arranges digital signals input within a unit time in the first and second areas of the first and second tracks, and is first input within the unit time. When the input order of words is 0, a first word group consisting of a plurality of 4n-th (where n is an integer) input words is placed in the first area of the first track, and the 4n + 1-th input word group is input. A second word group consisting of a plurality of words having an input order of 4n + 2nd plural words, and a third word group consisting of a plurality of words having an input order of 4n + 2th plural words having an input order of 4n + 3rd plural words. Fourth consisting of words
The word groups of are arranged in the second area of the first track,
Within each area, a digital signal reproduced from a magnetic tape in which each word is repeatedly arranged in the sub areas from No. 0 to m-1 according to the input order for each word group corresponding to each area, is reproduced. Since the outputs are rearranged in order, the probability of continuous error and the probability of concentrated data loss are lowered, and a rotary head type magnetic reproducing device capable of reproducing accurately without causing a large error, and the same. A signal processing circuit used for is obtained.

[0006]

In the rotary head type magnetic reproducing apparatus and the signal processing circuit used for the same according to the present invention, the probability of continuous erroneous data and the probability of concentrated data loss occurring are reduced to reproduce accurately without causing a large error. You can

[0007]

First, prior to the description of the embodiments of the present invention, 2
The principle of the rotary head type magnetic recording / reproducing apparatus of the channel will be described as an example. FIG. 3 is a magnetization pattern diagram on a tape recorded by a two-channel rotary head type PCM magnetic recording / reproducing apparatus. As shown in the figure, the characteristic of interleaving by the rotary head type magnetic recording / reproducing apparatus of the present invention is that even-numbered sample data groups and odd-numbered sample data groups of the same channel are separated for each scan and in the head scanning direction. It is to place it in a position.
By arranging in this way, even if the signal of either one of the two heads is lost due to the head clogging as described above, at least one of the even sample group and the odd sample group in the same channel is One side always obtains a signal, so continuous sample errors do not occur. Also, for burst errors in the tape running direction with a certain width from the edge of the tape, up to half the width of the tape in the figure, either the even sample group or the odd sample group in the same channel has no signal. Obtained,
There are no consecutive sample errors in the same channel.

FIG. 4 is a diagram showing another example of the magnetic pattern. Also in this example, the even-numbered sample group and the odd-numbered sample group of the same channel are arranged at positions separated for each scanning and in the scanning direction, and it is possible to cope with the same signal loss as in the example of FIG.

Next, a rotary head type PCM magnetic recording / reproducing apparatus for recording / reproducing the above magnetic pattern will be described. FIG. 5 is a schematic block diagram of a configuration example of an apparatus that enables recording and reproduction of the magnetic pattern of FIG. 3 or 4. The configuration and operation will be described below with reference to FIG. The recording system includes a 2-channel input terminal 1, a low-pass filter (LPF) 2 for band limitation, an analog-digital (A / D) conversion circuit 3 for converting an analog signal into a digital signal, and a digital signal temporarily. A memory circuit 4 for storing, a coding circuit 5 for adding codes for error correction and error detection to the digital signal, a modulation circuit 6 for modulating the coded digital signal,
Recording amplifier 7 and first switch 8 for selecting a head
And the heads 9 and 10.

An analog signal of two channels, L and R, is input to the input terminal 1 and each band is limited by the low pass filter 2. The output of the low pass filter 2 is A
It is given to the / D conversion circuit and converted into digital signals WLn and WRn. Here, n represents the order of sampling,
The L and R two-channel analog signals are sequentially sampled, and both channels are alternately output as digital signals such as WL0, WR0, WL1, WR1, WL2, WR2. The digital signals WLn and WRn are given to the memory circuit 4 and sequentially written in the memory by a memory address control circuit (not shown) included in the memory circuit 4. This memory address control will be described later in detail. An encoding circuit 5 provided in association with the memory circuit reads out a necessary sample in the memory to generate a correction code and writes it in the memory. Then, the digital signal and the correction code are sequentially read by the memory address control circuit described above. The read digital signal is input to the modulation circuit 7, converted into data suitable for recording on the magnetic tape, and amplified by the recording amplifier 7,
Recording is performed on the magnetic tape by the two heads 9 and 10 via the first changeover switch 8. The first changeover switch 8 is for changing over 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 9 and 10, a second changeover switch 11, a reproducing amplifier 12, a demodulation circuit 13 for demodulating a reproduced digital signal, a memory circuit 14 for temporarily storing the demodulated digital signal, and an error correction. A decoding circuit 15 for detecting an error, a digital-analog conversion circuit 16 for converting a decoded digital signal into an analog signal, a low-pass filter 17, and a 2-channel output terminal 18. Two heads 9 and 1
The signal read from 0 is applied to the second changeover switch 11 via the first changeover switch 8. The second changeover switch 11 is for applying the output signals of the heads 9 and 10 to the reproduction amplifier 12 as a signal of one system. The reproduced digital signal is amplified by the reproduction amplifier 12,
The signal is supplied to the demodulation circuit 13, is returned to the digital signal before being modulated, and is supplied to the memory circuit 14. The memory circuit 14 writes this digital signal. Memory circuit 14
In the decoding circuit 15 provided in relation to, the necessary samples are read from the memory and error correction and detection are performed.
The corrected samples in the memory are sequentially read from the memory by the memory address control circuit as described above, and D /
The signal is given to the A conversion circuit 16, converted into an analog signal, band-limited by the low-pass filter 17, and output terminal 1
It is output from 8.

The clock generation circuit 19 supplies the necessary clock pulse to each part of the recording system and the reproducing system. An example of the means for performing the above-described data interleaving will be specifically described in relation to the memory circuits 4 and 14 shown in FIG. FIG. 6 shows a memory block diagram which enables such data interleaving. In the figure, the number of samples recorded in two scans is 32 for each of the L and R channels.
The numbers in the horizontal direction indicate memory addresses in units of columns (hereinafter referred to as frame addresses), and the numbers in the vertical direction indicate memory addresses in units of rows (hereinafter referred to as sample addresses). In the recording system, as described above, WL0, WR0,
The samples which are A / D converted and sent sequentially as WL1, WR1, ... Are written in the memory while controlling the addresses by the memory address control circuit so as to have the arrangement shown in the figure. That is, writing is performed sequentially with the sample address set to 0 and the frame address set to 0, 8, 12, 4, ..., When the frame address becomes 7, and the sample of WR7 is written, the sample address is updated by 1 and the frame is read again. Writing is sequentially performed while controlling the address.

In this way, the samples are arranged in a 4 × 16 matrix, but at this time, the even sample groups and the odd sample groups of each channel are already separated. The matrix of this sample is encoded by the encoding circuit of FIG. 5, but the encoding is omitted because it is not the gist of the present invention. Here, CLn and CRn are used in units of frames as correction words for errors. Reading from the memory takes 4 vertical samples and 1 error correction word
Words are regarded as one frame and are sequentially transmitted frame by frame. That is, the frame address is set to 0, the sample address is sequentially updated to 0, 1, 2, ..., When the error correction word is transmitted at 4, the frame address is updated to 1 and similarly sent. The data up to the frame address 7 is included in one scan, and the data of the entire memory is completed in two scans. The data thus transmitted has a pattern as shown in FIG. 3 on the tape, and as described above, a signal loss of one scan or a burst error in the tape running direction of half the width of the tape from the tape edge occurs. In this case, continuous sample error does not occur and the mean value interpolation can be corrected.

When obtaining the magnetization pattern as shown in FIG. 4, it is possible to appropriately change the address control of the sample writing to the memory as described above. In the above description, an example of two channels is shown, but a plurality of channels of three or more can be similarly realized. In FIG. 7, A,
The magnetic tape pattern state in the case of four channels B, C and D is shown, and this shows the tape pattern recorded by the method of one embodiment of the present invention. In this embodiment, only the even sample groups of the four channels A, B, C and D are arranged on the first track and only the odd sample groups are arranged on the second track, but in this case as well. 1 as in the case of 2 channels
Even if a scan signal is lost and a burst error occurs in the tape running direction, which is half the tape width, from the tape edge, errors in consecutive samples do not occur in each channel, and average value interpolation is possible.

Further, in the above example, the device for the audio signal is described, but it can be used for the device for which the correction by the mean value interpolation is effective, for example, the device for the image signal, and the digital signal can be used. It goes without saying that the signal recording / reproducing system can be applied to systems other than the PCM system.

[0016]

As described above, according to the rotary head type magnetic reproducing apparatus and the signal processing circuit used for the same according to the present invention, the first half of each track is located in the front half of the track from the vicinity of the track center. The second region has at least a region and a second region located in the latter half part, and the first region has m (m is a natural number) sub-regions 0 to m−1 toward the track center. 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, and a digital signal input in a unit time is When arranged in the first and second areas of the first and second tracks and the input order of the word input first in the unit time is 0th, the input order is 4nth (n is an integer) ) The first group of words In the first region of the serial first track,
A second word group consisting of a plurality of words having an input order of 4n + 1 is located in the first area of the two tracks and has an input order of 4n.
The third word group consisting of + 2nd plural words is in the second area of the second track, and the fourth word group consisting of 4n + 3rd plural words in the input order is the second track of the first track.
Reproduced from a magnetic tape which is arranged in each area, and in each area, each word is repeatedly arranged in the sub areas from 0 to m-1 according to the input order for the word group corresponding to each area. Since the digital signals are rearranged in a predetermined order and output, a signal train reproduced from a recording track having a specific recording pattern as in the present invention by a helical scan by a rotary head can be easily obtained. It is possible to rearrange the signal sequence into the signal sequence and output the signal sequence, and it is possible to obtain an effect that a large continuous error is unlikely to occur and accurate reproduction can be performed.

[Brief description of drawings]

FIG. 1 is a magnetization pattern state diagram of a conventional example.

FIG. 2 is a magnetization pattern state diagram of a conventional example.

FIG. 3 is a magnetization pattern state diagram by a two-channel recording / reproducing system for explaining the principle of the present invention.

FIG. 4 is a state diagram of a magnetization pattern by a two-channel recording / reproducing system for explaining the principle of the present invention.

5 is a schematic block diagram of the 2-channel recording / reproducing system of FIG.

FIG. 6 is a memory state diagram of FIG.

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

[Explanation of symbols]

1: Input terminal, 2: Low pass filter, 3: A / D conversion circuit, 4: Memory circuit, 5: Encoding circuit, 6: Modulation circuit, 7: Storage amplifier, 8: First changeover switch, 9: Head , 10: head, 11: second changeover switch, 1
2: reproduction amplifier, 13: demodulation circuit, 14: memory circuit,
15: Decoding circuit, 16: D / A conversion circuit, 17: Low pass filter, 18: Output terminal, 19: Clock generation circuit

Claims (2)

(57) [Claims] 1. A device for scanning a diagonal track formed on a recording medium to reproduce a digital signal, wherein each track is located in the first half portion of the track longitudinal direction from the vicinity of the track center. And at least a second region located in the latter half portion, the first region has m sub-regions 0 to m-1 (m is a natural number) toward the track center, and the second region is There are m sub-regions 0 to m-1 from the center of the track to the other end, and a plurality of words are arranged in each sub-region, and digital signals for a unit time are first and second. In a rotary head type magnetic reproducing apparatus for reproducing the data distributed in each area of the two tracks, rearranging them in a predetermined order and outputting the same, the digital signals for the first and second two tracks are used as a unit. Arrange digital signals The reproduction signal processing means, which has a memory capable of storing the digital signal reproduced within the unit time, and the output order of the words output first from the reproduction signal processing means. when was the 0th, the first word group including a plurality word reproduced from the first region of the first track to the 4n-th (n is an integer), a plurality reproduced from the first region of the second track a plurality of second word groups of words 4n + 1 th, the third word group including a plurality of word reproduced from the second region of said second track to 4n + 2 th, reproduced from the second region of said first track 4th word group consisting of words, 4n + 3rd , 1 word sequentially
The memory is controlled so as to repeatedly output each word, and in each area, each word is sequentially targeted to the word group corresponding to each area from the sub areas from 0 to m-1 according to the output order. A rotary head type magnetic reproducing device characterized in that the memory is controlled so as to repeatedly output. 2. 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, wherein each track is located in the longitudinal direction from near the center of the track. At least a first area located in the first half and a second area located in the second half are provided, and the first area is m sub areas (m is a natural number) from 0 to m-1 toward the center of the track. And the second area is from the center of the track to the other end from 0 to m
-1 number m of sub-regions, digital signals of a plurality of words are arranged in each sub-region, and each sub-region corresponds to the unit time distributedly arranged in each of the first and second two tracks. A signal processing circuit for a rotary head type magnetic reproducing device which rearranges and outputs the digital signals in a predetermined order. The digital signals are rearranged in units of the digital signals for the first and second tracks. A signal processing unit for outputting the digital signal for the unit time, the signal processing unit including a memory control unit for controlling an input / output operation of a memory capable of storing the digital signal for the unit time, When the output order of the word output first from the signal processing means is 0th, the memory control means includes a first word composed of a plurality of words reproduced from the first area of the first track. 4n word group
The second (n is an integer), the second word group consisting of a plurality of words reproduced from the first area of the second track is 4n + 1th, consisting of a plurality of words reproduced from the second area of the second track. The third word group is output 4n + 2th, and the fourth word group consisting of a plurality of words reproduced from the second area of the first track is repeated 4n + 3th sequentially one word at a time so as to be output from the signal processing means. In addition to controlling the memory, in each of the areas, targeting a word group corresponding to each area, the words are output in order from 0 to m-1.
A signal processing circuit for a rotary head type magnetic reproducing device, characterized in that the memory is controlled so as to sequentially output one word at a time from sub-areas up to the first sub area.