JPH0877761A - Magnetic recording / reproducing device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method that is effective for high-speed search and does not increase redundancy in a magnetic tape recording / reproducing apparatus. A collective address information block SAB0, which is a combination of two address information blocks AB0 and AB1, has the same block length as the data block DB0. [Effect] Since the block length of the address information block is shorter than that of the data block, the address information block can be easily reproduced even during high-speed running. Since it is not necessary to shorten the data block length, redundancy does not increase. Since the block lengths of the data block and the collective address information block are the same, the periodicity of the sync signal is maintained, and the sync signal can be easily detected in normal reproduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of recording tape position information on a helical track in an apparatus for recording / reproducing digital signals with a rotary head and a magnetic tape.

[0002]

2. Description of the Related Art In a magnetic tape device for a VTR or a computer, there is an example of a recording / reproducing device for recording information indicating a position on the tape (hereinafter referred to as address information) together with image information and digital data. By using the address information, editing of the VTR, cueing of the image, positioning of the magnetic tape device for a computer, etc. can be performed with high accuracy. Television Society Journal Vol. 44, No. 1
2, pp. As described in 1713 to 1716 (1990) and the like, a time code is used as address information in a VTR for business use, a voice recorder, and the like. Normally, the time code is assigned a continuous value for each frame of image information. When cueing to a certain position on the tape, the time code to be reproduced is referred to, the positional relationship is judged from the deviation from the time code corresponding to the cueing position, and the tape running is controlled.

In a VTR or a magnetic tape device having a rotary head, when the tape is run at a high speed, the state of the playback signal is such that the playback head travels across the helical track, so that the signal on the track is partially Will be played. In the format in which the address information is recorded on the helical track, it is necessary that the signal partially reproduced during high-speed traveling includes the address information.

Usually, when recording a digital signal,
In addition to recording data, a sync signal indicating a signal processing unit delimiter is recorded. Therefore, in order to reproduce the address information during the high speed search, it is necessary to accurately detect the sync signal.

[0005]

It can be said that the higher the search speed supported by the apparatus, the higher the performance of the search function. As the tape running speed becomes higher, the locus of scanning by the reproducing head deviates from the inclination angle of the helical track, so that the range in which one track is continuously scanned becomes narrow. If the scanning range is smaller than the block containing the address information, the address information cannot be read.

Therefore, it is conceivable to shorten the block length of the address information in order to cope with the high speed search. However, if the block length is shortened, the number of blocks per track increases, so that the ratio of the additional signals such as the synchronization signal and the error correction code, which are simultaneously inserted in each block, to the data increases, and the redundancy increases.

An object of the present invention is to provide a digital signal recording / reproducing apparatus having a rotary head, which is compatible with high speed search and has a low redundancy format.

[0008]

To this end, a block containing digital data and a block containing address information are separated, and only the block length of address information is shortened. However, when the block length of the data and the block length of the address information are different, the intervals of the synchronization signals added to the heads of the respective blocks are not constant. Therefore, in the case of detecting or protecting the sync signal during normal reproduction, there is an inconvenience that complicated processing is required as compared with the condition that the cycle in which the sync signal appears is constant.

Therefore, a collective block in which several address information blocks are collected is constructed, and the block length is made to match the block length of data so that the periodicity of the synchronizing signal is maintained. At this time, if it is not possible to match the collection length of the address information blocks and the data block length due to the relationship between the data block length and the address information data amount, add an arbitrary signal to the address information as a dummy. To form an aggregate block and match the block length of the data.

[0010]

The block length of the address information can be shortened by collecting the address information blocks to form a collective block and matching the same with the data block length, so that the address information can be easily read even at high speeds and synchronization can be achieved. Since the periodicity of the signal is maintained, it is possible to easily detect and protect the synchronization signal in normal reproduction. Further, it is not necessary to shorten the block length of data, and additional signals other than data such as synchronization signals per track do not increase, so that redundancy does not increase.

[0011]

FIG. 4 is a diagram showing a configuration example of a magnetic tape running system for realizing the present invention. RH is a recording head PH is a reproducing head, 1 is a drum, 2 is a magnetic tape, 3 is a tape guide, 4 is a drum motor, 5 is a capstan motor, 6
Is a capstan, 7 is a pinch roller, 8 is a drum pulse generator, 9 is a capstan frequency generator,
10 is a servo controller, 11 is a drum control signal, 1
2 is a capstan control signal, 13 is reproduction level information, 1
4 is a recording signal, 15 is a reproduction signal, X is a drum rotation direction,
Y is the tape running direction, DPG is the drum pulse signal, CF
G is a capstan frequency signal, and RT is a rotary transformer.

FIG. 5 shows an outline of the tape recording pattern of the magnetic tape 2. T is a track, 21 is a data recording area,
Reference numeral 22 is an address information recording area. The track T is recorded by the recording head RH and reproduced by the reproducing head PH. If this example is a magnetic tape device for a computer, the data recording area 21 is a recording area containing user data. The address information recording area 22 is a recording area containing address information.

Further, in this embodiment, the address information recording areas 22 are arranged on the track T at regular intervals.
In the case of arranging at a constant interval, the address information may be generated at a constant cycle in the recording circuit, which has an advantage that it can be realized with a simple circuit configuration.

Next, the components of FIG. 4 and their operation will be described.

The magnetic tape 2 is wound around the drum 1 about 180 degrees by the tape guide 3. The recording head RH and the reproducing head PH are installed on the side surface of the drum 1, and the recording head RH and the reproducing head PH are rotated by the rotation of the drum 1.
Scans on the magnetic tape 2. The positions of the recording head RH and the reproducing head PH are in a relation in which the locus scanned by the recording head RH at the time of normal reproduction or recording is scanned by the reproducing head PH after the drum 1 makes a half rotation. During recording, the recording signal 14 passes through the rotary transformer RT and the recording head R
It is supplied to H and the track T is recorded on the magnetic tape 2.
At the time of reproduction, the reproduction head PH scans the track T recorded on the magnetic tape 2 to output the reproduction signal 15 through the rotary transformer RT.

The operations of the drum 1 and the magnetic tape 2 are controlled by the servo controller 10. The servo controller 10 is mainly a microcomputer, an interface circuit and an AD.
It is composed of peripheral circuits such as converters.

The servo controller 10 drives the drum motor 4 to rotate the drum 1 in the rotation direction X. The magnetic tape 2 has a capstan 6
The servo controller 10 drives by driving the capstan motor 5 while being sandwiched between the pinch roller 7 and the pinch roller 7. During recording or normal reproduction, the magnetic tape 2 runs in the tape running direction Y.

The servo controller 10 controls the rotation of the drum 1 and the tape operation. Servo controller 10
Although not shown, has a reference signal that oscillates at a constant cycle inside, and performs control by comparing this with a signal related to the control target.

The drum 1 needs to rotate at a constant speed. The drum pulse signal DPG is generated by the drum pulse generator 8 at a constant rotation position every time the drum 1 makes one rotation. The servo controller 10 gives a drum control signal 11 to the drum motor 4 to control the rotation of the drum 1 so that the drum pulse signal DPG is always generated at a constant timing with respect to the reference signal.

The magnetic tape 2 needs to run at a target speed. The capstan frequency signal CFG generated from the capstan frequency generator 9 has a frequency proportional to the rotation speed of the capstan 6. Further, since the rotation speed of the capstan 6 is proportional to the tape speed, the servo controller 10 can detect the tape speed by measuring the frequency of the capstan frequency signal CFG. As a result, the servo controller 10 outputs the capstan control signal 12 to the capstan motor 5 so that the capstan frequency signal CFG has a frequency corresponding to the target tape speed.
To drive.

Further, the servo controller 10 performs tracking control so that the reproducing head PH scans the track T. When the rotational phase of the capstan 6 is changed while the tape is running at the speed corresponding to the normal reproduction, the reproduction head PH and the track T are deviated from each other in tracking state. The servo controller 10 detects the tracking state from the reproduction level information 13. The reproduction level information 13 indicates the amplitude level of the reproduction signal 15, and when the amplitude level is maximized, the reproduction head PH moves to the track T.
Can be determined to be tracking accurately. The servo controller 10 performs tracking control by changing the capstan control signal 12 and controlling the rotation phase of the capstan 6 so that the reproduction level information 13 becomes maximum.

FIG. 2 shows an example of the structure of a recording circuit for generating the recording signal 14. 31 is recording user data, 32 is encoder, 33 is recording data, 34 is reproduction search information, 35 is address information generation, 36 is recording address information, 37 is synchronization signal generation, 38 is synchronization signal, 39
Is a synthesizer, and 40 is a recording amplifier.

FIG. 3 shows an example of the structure of a reproducing circuit for processing the reproduced signal 15. 41 is a reproduction preamplifier, 42 is an equalizer, 43 is data discrimination, 44 is envelope detection, 45 is sync signal detection, 46 is a decoder,
47 is reproduction user data, and 48 is address information detection.

Next, the configurations and operations of the recording circuit and the reproducing circuit will be described.

Recorded user data 31 transferred from the outside such as a computer for storage on the magnetic tape 2 of the apparatus.
The signal processing such as rearrangement of signals and addition of error correction code is performed by the encoder 32 to generate recording data 33. The address information generator 35 generates address information indicating the position information of the tape, but the position information needs to have a continuous value in the arrangement order of the tracks recorded on the tape. Therefore, in the case of continuously adding to the already recorded track, the reproduction address information 34 of the already recorded track is referred to and the recording address information 36 is generated based on the reproduction address information 34. The sync signal generator 37 generates a sync signal 38. The synchronization signal 38 indicates a block unit of signal processing. The recording data 33, the recording address information 36, and the synchronizing signal 38 are combined by the combiner 39, and further amplified by the recording amplifier 40 to generate the recording signal 14.

After the reproduction signal 15 is amplified by the reproduction preamplifier 41, the equalizer 42 compensates the change in the frequency characteristic of the magnetic tape 2 during recording and reproduction. Furthermore, the data discrimination 43 generates a clock synchronized with the level change timing of the input signal, and the data discrimination of the input signal is performed based on this. Further, the output of the equalizer 42 produces reproduction level information 13 in which the DC potential changes according to the amplitude level of the reproduction signal 15 by the envelope detection 44. As described above, the reproduction level information 13 is input to the servo controller 10 and used for detecting the tracking state.

The sync signal detector 45 detects the sync signal included in the output of the data discriminator 43 from the conditions of signal pattern matching and periodicity. When the sync signal is correctly detected, the signal processing unit can be recognized based on it, so that the user data and address information can be restored. The decoder 46 performs the reverse operation of rearranging the data by the encoder 32 at the time of recording and the error correction process by the added error correction code, and outputs the reproduced user data 47.

The address information detector 48 extracts a signal corresponding to the address information based on the detection of the synchronizing signal, and outputs the content as the reproduction address information 34 to the address information generator 35 as described above.

FIG. 1 shows an example of the data arrangement relationship of the recording signal 14, the reproduction signal 15 and the track T, which is a feature of the present invention. SY0 to SY3 are synchronization signals, DA0 and DA1 are data, and AD0 and AD1 are address information. Sync signals SY0 to SY3, data DA0 and DA1,
The address information AD0 and AD1 are respectively generated from the synchronizing signal 38, the recording data 33, and the recording address information 36 in the recording circuit of FIG. Alternatively, the synchronization signal SY2 can be realized with a simpler configuration if it is generated from the recording address information 36 instead of the synchronization signal 38.
The portion of the data arrangement shown in FIG. 1 corresponds to the portion including the address information recording area 22 in the track T of FIG.

Here, a combination of the synchronization signal SY0 and the data DA0 is called a data block DB0. The data recording area 21 of FIG. 5 is composed of a collection of data blocks DB0. Further, the synchronization signal SY1 and the address information AD
A combination of 0s is called an address information block AB0, and a combination of the synchronization signal SY2 and address information AD1 is called an address information block AB1. The address information recording area 22 of FIG. 5 is composed of a collection of address information blocks, and in this example, two address information blocks AB
It consists of 0 and AB1. Further, the two address information blocks AB0 and AB1 are collectively referred to as a collective address information block SAB0.

At this time, in the present invention, the data block DB
0 and the collective address information block SAB0 have the same block length. As a result, the synchronization signals SY0, S
Since Y1 and SY3 have a fixed cycle, there is an effect that the synchronization detection method of the synchronization signal detection 45 becomes easy during normal reproduction. Further, the synchronization signal SY2 is not recognized as a synchronization signal if the synchronization detection protection process of periodically opening the detection window is performed, so there is no problem.

Unlike normal reproduction, during high speed search,
In the sync signal detection 45, sync detection protection is not performed. The reproducing head PH scans across the track T except during normal reproduction. The range in which one reproducing track is scanned over one track T becomes narrower as the tape speed becomes faster. Therefore, the shorter the block length, the better the data reproduction at high speed.
In this example, since the block length of the address information block is half that of the data block, the address information may be reproducible even if the tape speed becomes high and the data block cannot be regenerated.

FIG. 6 shows a recording signal 14 which is a feature of the present invention.
3 shows an example of the data arrangement relationship between the reproduction signal 15 and the track T. AD0 'and AD1' are address information, D is dummy data, AB0 'and AB1' are address information blocks, and SAB0 'is a collective address information block.

Also in this case, since the block lengths of the data block DB0 and the collective address information block SAB0 'are the same, the periodicity of the synchronizing signals SY0, SY1, SY3 is maintained. In this example, address blocks AB0 'and AB
This is the case where even if 1'is combined, it does not match the block length of the data block DB0, and dummy data D is added to form a collective address information block SAB0 '. The dummy data D is arbitrary data, and it is conceivable to apply data having no meaning to the contents simply for the purpose of adjusting the block length.

FIG. 7 shows a recording signal 14 which is a feature of the present invention.
3 shows an example of the relationship between the data arrangement of the reproduction signal 15 and the data of the track T. ASY0 and ASY1 are address information synchronization signals, AD0 "and AD1" are address information, and AB.
0 ″ and AB1 ″ are address information blocks, and SAB0 ″ is a collective address information block.

Since the block lengths of the data block DB0 and the collective address information block SAB0 "are the same, the periodicity of the synchronizing signals SY0, SY1 and SY3 is maintained. The characteristic of this example is the address information dedicated synchronizing signal. The synchronization signals ASY0 and ASY1 are used as address information AD0 "
And AD1 "in combination with address information block AB
0 ″ and AB1 ″ are configured. As a result, the synchronization signal S deviating from the periodicity as shown in the examples of FIGS.
Since there is no Y2, the sync signal will not be erroneously detected even if the sync detection protection process is not performed. In addition, it is possible to easily determine whether this is a data block or an address information block depending on the difference in the synchronization signal.

Instead, it is necessary to detect the signal pattern of the address information synchronization signals ASY0 and ASY1 when performing synchronization detection during high-speed search, and it is necessary to change the signal pattern detected by the synchronization signal detection 45 depending on the operating state.

FIG. 8 shows a recording signal 14 which is a feature of the present invention.
3 shows an example of the relationship between the data arrangement of the reproduction signal 15 and the data of the track T. ID0 to ID2 are identification signals, AD
10 and AD11 are address information, AB10 and AB11 are address information blocks, DB10 is a data block, S
AB10 is a collective address information block.

The identification signals ID0 to ID2 determine the contents of the block including the identification signals. The identification signal ID0 is a signal pattern indicating a data block, and the identification signals ID1 and I
D2 is a signal pattern indicating that it is an address information block.

Also in this example, since the block lengths of the data block DB10 and the collective address information block SAB10 are the same, the synchronizing signals SY0, SY1, SY3 have a certain periodicity.

At the time of high speed search, the signal pattern of the sync signal is the same for both the data block and the search information block, so that the process in the sync signal detection 45 becomes easy. Further, by checking the contents of the identification signals ID0 to ID2 after detecting the synchronization signal, the contents included in the block can be easily determined.

[0042]

According to the present invention, in the digital signal recording / reproducing apparatus using the magnetic tape of the helical track system, the block length of the address information block is shorter than that of the data block and the periodicity of the synchronizing signal is maintained. It is effective for high-speed search and can be executed without problems in sync signal detection in normal reproduction.

[Brief description of drawings]

FIG. 1 is a structural diagram of a recording signal according to an embodiment of the present invention.

FIG. 2 is a block diagram of a recording circuit that generates a recording signal.

FIG. 3 is a block diagram of a reproducing circuit for reproducing a recording signal recorded on a magnetic tape.

FIG. 4 is a block diagram of a configuration for controlling running of a magnetic tape.

FIG. 5 is a diagram illustrating a recording track pattern of a magnetic tape.

FIG. 6 is a structural diagram of a recording signal according to another embodiment of the present invention.

FIG. 7 is a structural diagram of a recording signal according to another embodiment of the present invention.

FIG. 8 is a structural diagram of a recording signal according to another embodiment of the present invention.

[Explanation of symbols]

1. Drum, 2. Magnetic tape, 21. Data recording area,
22. Address information recording area, 35. Address information generation, 37. Synchronous signal generation.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Fujita, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside the Video Media Research Laboratory, Hitachi, Ltd. (72) Inventor Seikan Imagawa 292, Yoshida-cho, Totsuka-ku, Yokohama Hitachi, Ltd. Visual Media Research Center

Claims (5)

[Claims] 1. A recording head, a reproducing head, a means for bringing a magnetic tape into contact with the recording head and the reproducing head, a means for moving the magnetic tape, and a sync signal for indicating a boundary between signal processing units. Means, means for adding the synchronization signal to data to generate a data block, means for generating address information indicating position information on the magnetic tape, and address information block for adding the synchronization signal to the address information Means for generating a recording signal by combining the data block and the address information block, a means for supplying the recording signal to the recording head, and a means for obtaining a reproduction signal from the reproducing head. In the device, the block length of the data block is formed by forming an aggregate block including the address information block. A magnetic recording / reproducing apparatus comprising means for forming the aggregate blocks having the same length. 2. The magnetic recording / reproducing apparatus according to claim 1, further comprising means for forming the aggregate block from two or more address information blocks. 3. A means for generating an address information synchronizing signal for the address information, and a means for adding the address information synchronizing signal to the address information to generate an address information block. 1. The magnetic recording / reproducing device according to any one of 1 and 2. 4. The magnetic recording / reproducing apparatus according to claim 1, further comprising means for adding identification information for identifying the contents of the block to the data block and the address information block. 5. A means for recording two or more aggregate blocks on one track, and a means for recording two or more aggregate blocks on the track at regular intervals. 1. The magnetic recording / reproducing apparatus according to any one of 1 to 4.