JPH0991904A - Information recording medium and information recording / reproducing method thereof - Google Patents

Abstract

(57) Abstract: A tracking error signal and a track number signal of an information recording medium are reproduced from a common signal recording portion,
The area occupied by the recording portion is reduced to increase the density of the information recording medium. A servo burst portion is provided corresponding to each information recording track. The servo burst unit 13 is
The servo burst portions 13 corresponding to the information recording tracks 12 are arranged such that the positions in the traveling direction are sequentially different according to the arranged order, and the center of the servo burst portion 13 in the width direction is 1/2 track pitch from the center line of the information recording tracks 12. It is in a displaced position. The clock signal 15 and the index signal 16 that determine the signal reproduction timing of the servo burst unit 13 are recorded on the clock track 14. Servo burst section 13
The tracking error signal can be obtained from the amplitude of the reproduction signal, and the track number where the head is currently located can be obtained from the timing of the reproduction signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium and an information recording / reproducing method thereof, and more particularly, to an information recording medium capable of reducing a track pitch of an information recording track and improving its information recording density, and The present invention relates to an information recording / reproducing method therefor.

[0002]

2. Description of the Related Art In a computer system, information stored in a memory such as a hard disk is backed up in case of memory damage or transferred to another computer so that the information can be recorded on an information recording medium such as a magnetic tape. The operation of storing in is generally performed. A streamer is a typical example of a recording medium used for such a purpose. The streamer is, for example,
It is a recording medium in which a 1/4 inch magnetic tape is stored in a cartridge. The streamer is provided with a number of information recording tracks parallel to the tape running direction, and a magnetic head arranged opposite to this is moved in a direction orthogonal to the running direction to position the magnetic head on a predetermined track. Then, the information is recorded / reproduced.

In recent years, in order to increase the amount of information and reduce the size and weight of the information recording medium, there has been a strong demand for streamers to improve the linear recording density and track density. However, in the streamer, the head is moved by open loop control using a step motor, and there is no means for correcting an error due to meandering of the tape. Therefore, there is a limit to the reduction of the track pitch to increase the track density.

[0004]

Recently, new techniques for recording / reproducing streamers have been proposed. In this technique, three head gaps are provided in the magnetic head, and one of them is used to read the servo pattern recorded in the central portion of the tape to detect a tracking error and control the head position. However, this method has a problem that the cost of the driving device is high because a special head is required, and that a dedicated area for recording the servo signal is required and the data recording area is pressed.

On the other hand, in hard disk devices, conventionally, there is known a technique for detecting tracking error and performing tracking control by a method called sector servo or sample servo. This is a method of recording servo signals intermittently on data tracks,
In addition to the burst signal for detecting the tracking error, a signal for identifying the track number is required. Therefore, if this method is directly applied to a streamer, a large area is required for recording servo signals, and a sufficient information recording area cannot be secured, which hinders high density recording.

In view of the above, the present invention uses a servo burst signal that can obtain both a tracking error signal and a signal for identifying a track number, and uses this to control the position of the head to reduce the recording area. An object of the present invention is to provide an information recording medium that can be reduced and a recording / reproducing method therefor.

[0007]

The information recording medium of the present invention corresponds to a plurality of information recording tracks that extend in parallel with the running direction of the information recording medium and on which information is recorded / reproduced, and each of the information recording tracks. An information recording medium having a plurality of servo burst portions each having a predetermined signal recorded therein and having an information recording surface, wherein the servo burst portions are sequentially arranged in a traveling direction according to an arrangement order. It is characterized in that they are arranged differently.

[0008] Here, the term "record /
"Playback" generally includes recording or playback as well as recording and playback. The term “recording / reproducing head” includes a recording / reproducing head and a reproducing-only head.

The shape of the information recording medium of the present invention is not particularly limited and includes, for example, a band-shaped magnetic recording medium as well as a magnetic disk and the like. Further, the recording / reproducing method is not limited to the magnetic recording method.

An information recording / reproducing method according to a first aspect of the present invention is an information recording / reproducing method for the above-mentioned information recording medium, which is obtained by reproducing two servo burst signals adjacent to each other. The intensities of the respective reproduced signals are compared with each other,
Based on the comparison, the deviation of the position of the recording / reproducing head from the center of the information recording track is detected, and the position control of the recording / reproducing head is performed based on the deviation.

Further, in the information recording / reproducing method of the second aspect of the present invention, in addition to or instead of the above method, the clock signals after the index signal is detected are counted, and a plurality of servo signals are detected. The track on which the recording / reproducing head is currently located is detected based on the count value of the clock signal at the time when the amplitude of the reproduction burst signal obtained by reproducing the burst signal is large.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The information recording medium of the present invention is provided with a servo burst part containing a servo burst signal corresponding to each information recording track, and the servo burst parts are sequentially arranged in the traveling direction according to the arrangement order. Arranged differently. In a preferred example of the present invention, the center of the servo burst portion corresponding to each information recording track in the direction orthogonal to the traveling direction is not on the center line of the information recording track but at a position displaced from it by 1/2 track pitch. .

Based on the above structure, the recording / reproducing head running on a certain information recording track continuously reproduces the signals of the two servo burst portions adjacent to the track. In this case, these two servo burst signals are reproduced as signals having different amplitudes according to the deviation of the position of the recording / reproducing head from the center line of the information recording track.

The timing information for detecting the amplitude of the servo burst signal can be obtained by the reproduction result of the servo burst signal itself or the clock signal formed from the reproduction result of the information recording signal. Instead of this, one clock track in which a clock signal is recorded is provided on the information recording medium, and the clock signal can be reproduced from this, and in this case, a more stable clock signal can be obtained. In the clock track, it is preferable to superimpose and record a clock signal having a predetermined cycle for indicating the position of each servo burst signal in the traveling direction and an index signal indicating the reference position in the traveling direction.

When the information recording medium is provided with a clock track on which a clock signal and an index signal are recorded, the number of pulses of the clock signal generated after detecting the index signal is counted, and at the time when the servo burst signal is detected. Based on the count value of the clock signal of
Detect the track number where the playhead is located.

In order to record / reproduce information on / from the above information recording medium, a recording / reproducing head is used to reproduce a servo burst signal, and a tracking error of the head is detected based on the amplitude comparison of two consecutive servo burst signals. To detect. By correcting and controlling the head position according to the tracking error signal, the recording / reproducing head can be accurately positioned at the center of the information recording track despite the track position fluctuation due to meandering or the like.

Specifically, when the recording / reproducing head actually records / reproduces information on one information recording track, the servo burst signals of two servo burst portions adjacent to this information recording track are continuous. Is reproduced, and by comparing the amplitudes of both servo burst signals,
Detecting the positional deviation (tracking error) of the head from the information recording track. By controlling the head position so that the amplitudes of both servo burst signals are equalized, the recording / reproducing head can be accurately positioned at the center of the information recording track.

[0018]

FIG. 1 is a schematic plan view showing an information recording medium according to an embodiment of the present invention. This figure shows the arrangement of each recording area in a tape-shaped recording medium configured as a streamer, for example. A large number of information recording tracks 12 are arranged on the tape-shaped recording medium 11 in parallel with the running direction and at a predetermined track pitch. Servo burst portions 13 are periodically provided corresponding to the respective information recording tracks 12, and four servo burst signals in pulse form are recorded in each servo burst portion 13 at regular intervals. The center of the servo burst portion 13 in the tape width direction is located at a position separated from the center line of the corresponding information recording track 12 by ½ of the track pitch. Further, the servo burst portions 13 as a whole are sequentially staggered in the medium traveling direction according to the arrangement order, and this shift amount is the same as the recording length of each servo burst portion 13.

By shifting the servo burst portion 13 stepwise in the running direction of the information recording medium, the timing at which the servo burst signal is detected in the reproduced signal causes
It is possible to determine the information recording track on which the recording / reproducing head is currently traveling. Here, an example in which the servo burst portions are arranged in a staircase will be described, but the same effect can be obtained even if the servo burst portions have a diagonal pattern.

One clock track 14 is provided in the center of the recording medium 11 in the width direction, and a clock signal 15 forming a pulse train and an index signal 16 which is a periodic single pulse are recorded in the clock track 14. Has been done. The clock signal 15 determines the reproduction time of the servo burst signal and is recorded at the same timing as the timing of the servo burst signal. The index signal 16 is recorded so as to be inserted between two specific clock signals 15. Information recording track 12
Are divided into two groups, an upper half and a lower half, with the central clock track 14 in between, the upper half group at the time of normal rotation of the tape, and the lower half group at the time of reverse rotation of the tape, respectively. Recorded / played back.

The recording / reproducing apparatus for the above information recording medium includes an information recording track 12 and a servo burst section 13.
There is provided one information recording / reproducing head for recording / reproducing the signal of 1) and one clock reproducing head for reproducing the signal in the clock track 14.

FIG. 2 is a schematic diagram showing a waveform reproduced from the recording medium of FIG. 1 in correspondence with information recording tracks. FIG. 7A is a timing chart of the signal obtained by full-wave rectifying the signal output from the information recording / reproducing head, and FIG. 7B is obtained by peak detection of the signal output from the clock reproducing head. FIG. 3C shows a partially enlarged plane of the information recording track 12 in which the traveling direction position is made to correspond to the signals of these timing charts. As shown in FIG. 7C, these figures show a state where the traveling position 17 of the magnetic gap of the information recording / reproducing head is slightly deviated from the center position of the information recording track 12.

The clock signal S ₁₅ is a pulse that is repeatedly reproduced, for example, every 1 μsec. The index signal is
It is output when it is sandwiched by two burst signals reproduced when the information reproducing head is positioned on the information recording track 12 which is closest to the clock track 14. That is,
The index signal is generated at the center time of the reproduction time of two specific burst signals, and is output as a pulse indicating the reference time inserted between the two corresponding clock pulses.

Reproduced signal S from each servo burst unit 13
Reference numeral ₁₃ includes four pulse-like signals that are generated every 1 μsec in synchronization with the clock signal S ₁₅ on the clock track. Each servo burst portion 13 is recorded at a time of 4 μsec with respect to the servo burst portion 13 adjacent thereto. Therefore, as shown in FIG. 2A, when the reproduction signal S ₁₂ from the information recording track is once interrupted from the information recording / reproducing head at a certain track position, two servos adjacent to this track are Each of the four pulsed signals from the burst section is continuously reproduced.

The time when the two servo burst signals corresponding to each information recording track 12 are output can be obtained by counting the number of pulses of the clock signal after the index signal is detected. That is, the track number at which the recording / reproducing head is currently located can be specified by a numerical value obtained by dividing the count value of the clock signal at the time when the servo burst signal appears by 4. Further, since the signals of two adjacent servo burst portions are reproduced at a time interval of 4 μs, the amount of positional deviation of the information recording / reproducing head from the center line of the information recording track can be obtained by calculating the amplitude difference. You can

FIG. 3 shows an example of a circuit for obtaining a head position signal (track number signal) from a signal recorded on a clock track and a servo burst signal. The signal output from the clock reproducing head 20 is amplified by the amplifier 21 and then separated and reproduced by the decoding circuit 22 into the clock signal “a” and the index signal “b”, and the pulse number of the clock signal “a” is counted. 23. The counter 23 displays the index signal "
It is reset by b "and returns to zero, and the signal" c "excluding the lower 2 bits is output as a track number signal.

On the other hand, the signal output from the information recording / reproducing head 30 is amplified by the amplifier 31, and then only the frequency component of the burst signal is extracted by the filter 32. The extracted servo burst signal “d” is converted into a digital signal “f” by extracting each pulse “e” by the four sets of sample-and-hold circuits 33 and AD converters 34 corresponding to each. Signal processing circuit (DSP)
25.

The time point at which the amplitude of the servo burst signal should be measured is given by the four track numbers "g" output from the DSP 25. These numbers are
The corresponding four comparators 24 compare with the track number signal "c" obtained from the counter 23, and each comparison circuit 24 outputs a coincidence signal "h" when they coincide with each other. Each sample and hold circuit 33 samples one corresponding burst signal pulse at the time when the coincidence signal "h" is generated.

Track number "g" output by the DSP 25
Is given in the following procedure according to the three modes required for head positioning, namely, the tracking mode, seek mode and search mode.

The tracking mode is applied when the track number on which the information recording / reproducing head is located has already been given. In the tracking mode, the DSP 25 compares the count value of the counter corresponding to two consecutive burst signals detected at a certain time with the count value of the counter corresponding to two consecutive burst signals detected thereafter. . If any of the subsequently detected count values is greater than any of the previously detected count values, the actual track position is 1 from the initially given track position.
This means that the track position signal internally moved is increased or decreased because it means that the track position signal has moved by more than the track pitch. At this time, in the servo-on state in which it is instructed to position the information recording / reproducing head on the center line of the information track, an instruction to move the head position so that the amplitudes of two burst signals detected later become equal. give.

The seek mode is a state in which the information recording / reproducing head is moving from the initial track position to another track position. In the seek mode, the DSP 25 outputs the track number corresponding to the count value of the counter at the time when the burst signal is expected to appear when the head is positioned on the target track or the track numbers before and after it. This locates the target track position and places the head at that track position.

The search mode is applied when the current track position of the information recording / reproducing head is unknown. DS
In the search mode, P25 sequentially increments the track number to search for a position at which the currently output burst signal is stably reproduced. As a result, the current track position of the head is specified.

In the above embodiment, the case where the present invention is applied to a magnetic tape device called a streamer has been described, but the present invention can also be applied to other types of recording devices such as magnetic disks. Further, although the case where the clock signal and the index signal are reproduced by using the dedicated clock reproducing head has been described, a PLL circuit or the like is adopted,
It is also possible to generate the clock signal from the burst signal or the information reproduction signal. In this case, the index signal can be generated using the ID signal indicating the track number recorded on the information recording track.

The present invention has been described above based on its preferred embodiments. However, the information recording medium and the information recording / reproducing method of the present invention are not limited to the configurations of the above-mentioned embodiments but the above-mentioned embodiments. An information recording medium and various information recording / reproducing methods which are variously modified and changed from the configuration of the embodiment are also included in the scope of the present invention.

[0035]

In the information recording medium of the present invention, the servo burst signal obtained from the servo burst portion arranged corresponding to the information recording track and arranged so that the traveling direction positions are sequentially different according to the arrangement order. As a result, both the tracking error and the track number are detected, so that the recording area can be reduced as compared with the conventional recording medium which obtains them from another signal. As a result, the density of the information recording medium can be increased.

Further, even when the clock track is provided, it suffices to provide a single clock track shared by all the information recording tracks, so that the area required for this can be small.

Further, according to the information recording / reproducing method of the present invention, a signal relating to a tracking error and / or a track number can be obtained from the servo burst part of the information recording medium, and the information recording / reproducing for the recording medium can be performed. Can be used with equipment.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an information recording medium of one embodiment of the present invention.

FIG. 2A is a timing chart of a signal obtained by full-wave rectifying a signal output from an information recording / reproducing head,
(B) is a timing chart of the pulse signal obtained by peak detection of the signal output by the clock reproducing head,
FIG. 7C is a partially enlarged plan view of the information recording track in which the signals in these timing charts are associated with the positions in the traveling direction.

FIG. 3 is a circuit diagram of a signal processing circuit that obtains a head position signal from a servo burst signal.

[Explanation of symbols]

 11 Tape-shaped recording medium 12 Information recording track 13 Servo burst part 14 Clock track 15 Clock signal 16 Index signal 17 Magnetic gap running position 20 Clock reproducing head 21 Amplifier 22 Decoding circuit 23 Counter 24 Comparator 25 Signal processing circuit (DSP) 30 Information Recording / reproducing head 31 Amplifier 32 Filter 33 Sample and hold circuit 34 A / D converter

Claims (6)

[Claims] An information recording medium extends in a direction parallel to a traveling direction of the information recording medium,
Information recording having a plurality of information recording tracks on / from which information is recorded / reproduced and a plurality of servo burst portions arranged corresponding to the respective information recording tracks and recording predetermined signals on an information recording surface The information recording medium according to claim 1, wherein the servo burst parts are arranged such that positions in a traveling direction are sequentially different according to an arrangement order. 2. The center of the servo burst portion in the direction orthogonal to the traveling direction is located at a position apart from the center line of the corresponding information recording track by 1/2 of the track pitch of the information recording track. Information recording medium described. 3. A clock track extending parallel to the information recording track, the clock track corresponding to a clock signal sequentially recorded at a predetermined interval in the traveling direction and a reference position in the traveling direction. The information recording medium according to claim 1, further comprising an index signal. 4. An information recording / reproducing method for an information recording medium according to claim 1, wherein each reproduction signal is obtained from signals of two servo burst parts adjacent to each other. Are compared with each other, the deviation of the position of the recording / reproducing head from the center of the information recording track is detected based on the comparison, and the position of the recording / reproducing head is controlled based on the deviation. Information recording / playback method. 5. An information recording / reproducing method for an information recording medium according to claim 3, wherein the clock signal after the index signal is detected is counted and a plurality of servo burst signals are reproduced. Based on the count value of the clock signal at the time when the amplitude of the reproduced burst signal is large,
An information recording / reproducing method for detecting the track where the reproducing head is currently located. 6. The strength of each reproduction signal obtained from the signals of two servo burst parts adjacent to each other is compared with each other,
6. The information recording / reproducing method according to claim 5, wherein a deviation of the position of the recording / reproducing head from the center of the information recording track is detected based on the comparison, and the position of the recording / reproducing head is controlled based on the deviation.