JPH04195803A - Helical scan system magnetic tape storage device - Google Patents

Abstract

PURPOSE:To enable verification even with a small diameter drum by fitting a reproducing only magnetic head at a different height from a recording only magnetic head in the heightwise direction of a rotary drum. CONSTITUTION:The magnetic heads 101 and 102 in one pair are specified as their respective double azimuth magnetic heads, and one double azimuth magnetic head 101 out of the pair is used exclusively for recording, the other double azimuth magnetic head 102 being used exclusively for reproducing. Then, the height of the head 102 having its height (m)-(n) is fitted downward in the heightwise direction of the rotary drum 103 by 1/2 of a head cap width Tw of the head 101 as against the height (k)-(l) of the head 101. Consequently, immediately after a recording track is recorded and formed by the head 101A(101B), this track is scanned and reproduced by the head 102A(102B). By this method, there is no problem of cross talk of a recording signal to a reproducing circuit, and the verification is feasible even on a small diameter drum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a helical scan type magnetic tape storage device for recording digital data, and in particular to a helical type magnetic tape storage device suitable for verifying with a small diameter rotating drum. The present invention relates to a scan type magnetic tape storage device.

[Conventional technology]

Helical scan type magnetic tape storage devices have a higher recording density than fixed head magnetic tape storage devices, and are therefore widely used in fields such as VTRs that require large amounts of information. In addition, with the recent development of VTR technology, home VTRs have been produced in large quantities and at low cost.
Its spread is remarkable.

An application of this VTR technology is the DAT (Digital Audio Tape Recorder), which records and plays PCM signals such as music on a magnetic tape stored in a cassette case.
There is. This DAT records and reproduces digital signals, and has a rotating drum equipped with a pair of recording/reproducing magnetic heads.The rotation speed is 200 rpm, the diameter is 30 mm, and the angle at which the magnetic tape is wound around the rotating drum is approximately 90 degrees. It has a function (high-speed search function) that allows you to play and access the magnetic tape while running it at high speed.
Suitable as an external recording device for computers. This D
If AT technology is used, conventional fixed head MT (
It is possible to realize a magnetic tape storage device that has a large capacity, can be accessed at high speed, and is inexpensive compared to a magnetic tape storage device.

Here, the track format of DAT is shown in Figure 13 (a
). The recording track of the DAT is divided into a plurality of recording areas, as shown in FIG. 2A, and various signals are recorded in each of the divided areas. A PCM signal area (PCM) is placed in the center of the recording track, ΔTF areas (ATF-1, ATF-2) on both sides, and subcode areas (SUB-1, 5UB-2) outside of it.
is placed. Furthermore, margin areas are arranged on both sides.

In the PCM signal area, digital data obtained by adding an error correction code to I) CM data obtained by converting a musical tone into PCM is recorded.

In the subcode area, you can search for a program and a specific position within the program, such as Start ■D indicating the start position of the program (song, etc.), the program number indicating the program number, and the time from the start position of the program. Search information etc. for the purpose are recorded.

A tracking control signal for causing the magnetic head to correctly scan the recording track during reproduction is recorded in the ATF area.

The margin area is an area for absorbing the instability of the touch immediately after the magnetic head contacts the magnetic tape or just before the magnetic head leaves the magnetic tape, and usually a PLL signal (4.7 MHz) is recorded therein.

In this way, various signals are divided into areas and recorded, so as shown in FIGS. 13(b) and (C), PCM
The so-called rewriting of the signal or subcode alone
Dubbing is possible. This is also one of the reasons why it is suitable as an external storage device for computers.

When this DAT is applied to an external recording device of a computer, an important issue is how to ensure the reliability of data recording and reproduction.

In DAT as well, if an error occurs in the reproduced data, an abnormal sound will be reproduced, so a check word is added to the information word consisting of multiple data (symbols) and recorded. is used to perform error correction processing that detects and corrects data errors.

However, there is a limit to this error correction ability, and 2.
If no playback output is obtained from one of the two magnetic heads, only half of the data to be played will be played back, which will not only seriously impede the playback sound but also make playback impossible. There is a possibility that it will become.

For this reason, among the sampled data, odd number data is recorded and reproduced using one magnetic head, and even number data is recorded and reproduced under the other magnetic head, so that the data is completed in two tracks, and error correction is performed. By completing the code structure for one track, and even if no reproduction output is obtained from one magnetic head, the original analog signal can be reproduced by average value interpolation using the reproduction output from the other magnetic head. It is possible.

The average value interpolation as described above is effective if the data to be handled is a data string in which adjacent data have a strong correlation, such as a music signal.

However, in information such as programs and various data handled by a computer, there is no strong correlation between adjacent data, and missing data cannot be restored by mean value interpolation.

Therefore, when realizing a magnetic tape storage device such as an external storage device for a computer using such AT technology, from the viewpoint of ensuring recording on the magnetic tape,
In order to avoid erroneous recording due to defects in the magnetic tape or the intrusion of foreign matter, check whether recording is normal. For this reason, as shown in FIG. 14(a), a first pair of magnetic heads arranged at an angular interval of 180 degrees and having mutually different azimuth angles, and a first pair of magnetic heads that run perpendicularly to the first pair of magnetic heads are arranged on the rotating drum at an angular interval of 180 degrees. a second pair of magnetic heads arranged at an angular interval of lso degrees and having different azimuth angles from each other; the first and second pairs of magnetic heads are dedicated for recording and reproduction, respectively; The second pair of reproducing magnetic heads immediately reproduces the recording track recorded by the first pair of recording magnetic heads, and the recording data recorded by the first pair of recording magnetic heads and the second pair of recording magnetic heads are immediately reproduced. The reliability of the recorded data is improved by comparing the reproduced data reproduced by a pair of reproducing magnetic heads to verify whether it has been accurately recorded.

Furthermore, when recording data such as music and video, it becomes possible to simultaneously monitor recording and reproduction.

Examples of verification using the helical scan method include JP-A-63-69074 and JP-A-63-1.714.
There is an example in No. 04.

Similar to the above-mentioned DAT, the winding angle of the magnetic tape around the rotating drum is approximately 90 degrees, and the indexing angle of the magnetic head is also 90 degrees, so two magnetic heads, a recording magnetic head and a reproducing magnetic head, , the time for simultaneous contact with the magnetic tape is extremely short, making it possible to perform the above-described verification without the problem of crosstalk of the recorded signal to the reproducing circuit.

In addition, as shown in FIG. 14(b), in order to downsize the mechanism, the diameter of the rotating drum was set to 1.5 mm, which is 1/2 of the above-mentioned rotating drum, and the rotation speed was 200 rpm.
In some cases, the magnetic heads are arranged at angular intervals of 1.80 g, and the magnetic tape is wound around the rotating drum at an angle of approximately 180 degrees.

[Problem to be solved by the invention]

In order to save space, magnetic tape storage devices are desired to be small. Therefore, it is conceivable to downsize the device by using the aforementioned small diameter drum. but,
In the small-diameter drum mentioned above, the magnetic tape is wound at an angle of approximately 180 degrees, so if the magnetic heads are arranged at 90-degree intervals like in a conventional rotating drum, the recording magnetic head and the reproducing magnetic head The two magnetic heads of
Since there is approximately 90 degrees of time for simultaneous contact with the magnetic tape, there arises a problem of crosstalk of the recorded signal to the reproducing circuit, making correct verification impossible.

SUMMARY OF THE INVENTION An object of the present invention is to provide a compact and highly reliable helical scan type magnetic tape storage device that solves the above-mentioned problems and makes it possible to perform verification even on a small diameter drum.

[Means to solve the problem]

The second purpose is to run a magnetic tape helically wound around a rotating drum equipped with a pair of magnetic heads arranged at an angular interval of 180 degrees, and to sequentially scan and tilt the magnetic tape diagonally. In a helical scan magnetic tape storage device that records digital signals so as to form magnetic tracks, each of the pair of magnetic heads is a double azimuth magnetic head, one of the double azimuth magnetic heads of the pair is used only for recording, and the other double azimuth magnetic head is used exclusively for recording. A double azimuth magnetic head is used exclusively for reproduction, and the reproduction magnetic head is attached at different heights in the height direction of the rotating drum with respect to the recording magnetic head, and the recording magnetic head transmits digital signals to the magnetic tape. This is achieved by providing a control circuit that cuts off the recording current supplied to the recording magnetic head during periods other than the recording period.

[Effect]

A magnetic tape is wound helically around a rotating drum equipped with a pair of magnetic heads arranged at an angular interval of 180 degrees, and the magnetic tape is run in a helical manner, and the magnetic tape is sequentially scanned diagonally to form an inclined magnetic track. In a helical scan type magnetic tape storage device for recording digital signals, each of the pair of magnetic heads is a double azimuth magnetic head, one double azimuth magnetic head of the pair is dedicated for recording, and the other double azimuth magnetic head is used for reproduction. The reproducing magnetic head is attached at a different height in the height direction of the rotating drum than the recording magnetic head, and the reproducing magnetic head is used for a period other than the period in which digital signals are recorded on the magnetic tape by the recording magnetic head. is controlled to cut off the recording current supplied to the recording magnetic head, so that the two magnetic heads, the recording magnetic head and the reproducing magnetic head, alternate at an angular interval of 180 degrees.
and after the recording magnetic head has recorded one track,
The time during which the reproducing magnetic head scans the recorded track and the two magnetic heads, the recording magnetic head and the reproducing magnetic head, contact the magnetic tape at the same time is extremely short;
Verification as described above is possible without the problem of crosstalk of the recording signal to the reproduction circuit.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1(a) is a schematic view of the vicinity of a rotating drum according to a first embodiment of the present invention, viewed from above.

101 is a recording magnetic head, and 102 is a reproducing magnetic head, each of which is a double azimuth magnetic head. The recording magnetic head 101 is composed of a magnetic head 101A having an azimuth angle of +20 degrees and a magnetic head 101B having an azimuth angle of -20 degrees. The reproducing magnetic head 102 includes a magnetic head 102A having an azimuth angle of +20 degrees and a magnetic head 102B having an azimuth angle of -20 degrees. That is, the recording magnetic head l0IA and the reproducing magnetic head 1゜2A, and the recording magnetic head l0IB and the reproducing magnetic head 102.
B have the same azimuth. 1.03 is diameter 15
The recording magnetic head 101 and the reproducing magnetic head 102 are arranged on the rotating drum 103 at an angular interval of 180 degrees. The magnetic tape 104 is wound around the rotating drum 103 at an angle of 180 degrees and runs.

The rotation speed of the rotating drum 103 is 4000 ppm.

, a recording magnetic head 101 and a reproducing magnetic head 10
2 are set in a height relationship as shown in FIG. 1(b). That is, for the height of the recording magnetic head 101 -1, the height m-n of the reproducing magnetic head 102 is 1/2 of the spacing gap width Tw of the recording magnetic head 101,
It is attached downward in the height direction of the rotating drum 103.

FIG. 2 is a diagram showing the scanning positional relationship on the magnetic tape 104 of each head attached with the above-mentioned height relationship. FIG. 5A is a diagram showing the scanning positional relationship of each head during recording. As mentioned above, the recording magnetic head 101
The height of the reproducing magnetic head 102 with respect to the height of Tw
/2, since it is attached downward in the height direction of the rotating drum 103, the recording magnetic head 10], A (IOIB
) immediately after recording and forming the recording track 203, the reproducing magnetic head 102A (102B) scans and reproduces the recording track 203.

FIG. 5B is a diagram showing the scanning positional relationship during playback or post-recording. Reproducing magnetic head 102B (102
Δ) is positioned at the center of the recording track 202 by l-racking control based on the amount of crosstalk of the ATF signals reproduced from the recording tracks 201 and 203 on both sides of the recording track 202 being scanned, the reproducing magnetic head 102B (102A) is the recording magnetic head 101 that scans next. A (IOIB) scans so that the left end of the head gap coincides with the left end of the recording track 203.

In the above embodiment, the track width scanned by the reproducing magnetic head during recording is wider than the track width scanned during normal reproduction. Therefore, during verification, the reproduced signal level is higher than during normal reproduction, resulting in a good S/N ratio and a low data error rate. Therefore, even if it is determined that recording is good at the time of verification, it may turn out to be defective during playback, and there may be cases where verification cannot be performed correctly.

FIG. 3 is a schematic view of the vicinity of the rotating drum according to the second embodiment of the present invention viewed from above, and a diagram showing the relationship between the heights of the magnetic helads.

The recording magnetic head 101 and the reproducing magnetic head 102 are
The height relationship is set as shown in FIG. 3(b).

That is, the height m-n of the reproducing magnetic head 102 is Tw/with respect to the height of the recording magnetic head 101 -1
2 + T p (Tw: head gap width of the recording magnetic head 101, Tp: recording track pitch) is attached below the rotating drum 103 in the height direction.

FIG. 4 is a diagram showing the scanning positional relationship on the magnetic tape 104 of each head attached with the above-mentioned height relationship. FIG. 5A is a diagram showing the scanning positional relationship of each head during recording. The recording magnetic head 101 and the reproducing magnetic head 102 are mounted on the reproducing magnetic head 102B (10
2A) scans and reproduces the recording track 202. In this case, since the track width scanned by the reproducing magnetic head during recording is the same as the rack width scanned during normal reproduction, verification can be performed accurately.

FIG. 5B is a diagram showing the scanning positional relationship during playback or post-recording. Reproducing magnetic head 102B (102
A) depends on the amount of crosstalk of the ATF signals reproduced from the recording tracks 201 and 203 on both sides of the recording track 202 being scanned. The recording magnetic head 10113 (IOIA) that scans next to the head 102B (102A) scans the left end of the head gap so that it coincides with the left end of the recording track 204.

FIG. 5 is a schematic view of the vicinity of a rotating drum according to a third embodiment of the present invention viewed from above, and a diagram showing the relationship between the mounting heights of the magnetic heads.

The recording magnetic head 101 and the reproducing magnetic head 102 are
The height relationship is set as shown in FIG. 5(b).

That is, the height m-n of the reproducing magnetic head 102 is T w
/ 2 + 2 T p, and is attached downward in the height direction of the rotating drum 103.

FIG. 6 is a diagram showing the scanning positional relationship on the magnetic tape 104 of each head attached with the above-mentioned height relationship. FIG. 5A is a diagram showing the scanning positional relationship of each head during recording. Recording magnetic head l0IB (IOIA
) immediately after recording and forming the recording track 204, the reproducing magnetic head 102B (102A) starts recording on the recording track 202.
will be scanned and played back. In this embodiment as well, since the track width scanned by the reproducing magnetic head during recording is the same as the track width scanned during normal reproduction, verification can be performed accurately.

FIG. 5B is a diagram showing the scanning positional relationship during playback or post-recording. Reproducing magnetic head 102B (102A
) is positioned at the center of the recording track 202 by tracking control based on the crosstalk amount of ATF signals reproduced from the recording tracks 201 and 203 on both sides of the recording track 202 being scanned, the reproducing magnetic head 102B (102A The recording magnetic head l0IA (IOIB) that scans next after > will scan the left end of the head gap so that it coincides with the left end of the recording track 205.

Here, in the case of the second embodiment, the mounting height of the magnetic head is Tw/2+3Tp, Tw/2+5Tp, Tw/
2+7Tp... may be closed, and in the case of the third embodiment, Tw/2+4Tp, Tw/2+6Tp, Tw/2+8
A similar effect can be obtained even if Tp... is used.

FIG. 7 is a diagram showing an embodiment around the recording/reproducing circuit.

In the figure, reference numeral 410 denotes a recording signal amplifier, which is composed of a recording signal amplifier 410A, a recording signal amplifier 4], and OB. 420 is a reproduced signal amplifier; the reproduced signal amplifier 420
A, a reproduced signal amplifier 420B, a head changeover switch 421, and an output buffer 422.

436 is a recording signal amplifier control circuit, 437 is a reproduction signal amplifier control circuit, and 438 is a rotary transformer.

The operations of the recording signal amplifier control circuit 436 and the reproduction signal amplifier control circuit 137 are controlled by the timing generation circuit 424.

These operations will be explained together with an operation timing diagram.

FIG. 8 is an operation timing chart when the rotating drums of the first and third embodiments described above are used.

FIG. 5A is a diagram showing the timing at which each magnetic head contacts the magnetic tape 104, and shows the timing at which each magnetic head contacts the magnetic tape 104.
The reference point is the point at which the magnetic tape 104 begins to be scanned,
The rotation angle of the rotating drum 103 is assumed to be 0 degrees.

First, the operation during recording will be explained together with the operation timing diagram of the recording/reproducing circuit during recording shown in FIG.

In the figure, timing 1 is when the recording magnetic head 10
1Δ is the timing when the magnetic tape 1.04 is in contact with the magnetic tape for a 180 degree section. Here, the timing generation circuit 424
The recording signal amplifier control circuit 436 turns on the recording signal amplifier 41OA and turns off the recording signal amplifier 410B, and the reproduction signal amplifier control circuit 437 turns on the reproduction signal amplifier 420A and the reproduction signal amplifier 4.
20B is turned off. The recording signal is recorded by recording signal amplifier 4.
10A, and the magnetic tape 1 is amplified by the recording magnetic head 10IA via the rotary transformer 438.
Recorded on 04.

Timing 2 is the timing when the reproducing magnetic head 102A is in contact with the magnetic tape 104 for 180 degrees. Here, in the timing generation circuit 424, the recording signal amplifier control circuit 436 turns off the recording signal amplifier 410A and the recording signal amplifier 410B, and the reproduction signal amplifier control circuit 437 turns off the reproduction signal amplifier 420A.
is turned on, the reproduction signal amplifier 420B is turned off,
Further, the head changeover switch 421 is switched to the A side. At timing 1, the recording magnetic head l0I
The recorded data recorded on the magnetic tape 104 by A is reproduced by the reproducing magnetic head 102A, and is transmitted to the reproduced signal amplifier 42O via the rotary transformer 438.
A is amplified by A.

Timing α is the time from when the reproducing magnetic head 102A performs 108 degree section reproduction at timing 2 until when the recording magnetic head 10IB comes into contact with the magnetic tape 104. This is a recording magnetic head], O
This is caused by the distance between IA and the recording magnetic head 101B. Although this timing is extremely short,
The timing generation circuit 424 absorbs the timing deviation.

The timing generation circuit 424 waits for this time to elapse, starts the operation of the recording signal amplifier 420B, and enters the next timing 3.

Timing 3 is the timing when the recording magnetic head 101B is in contact with the magnetic tape 104 for a 180 degree period. Here, the timing generation circuit 424 causes the recording signal amplifier control circuit 436 to turn off the recording signal amplifier 410A and turn on the recording signal amplifier 410B, and also causes the reproduction signal amplifier control circuit 437 to turn on the reproduction signal amplifier 420A and The reproduced signal amplifier 420B is turned off. The recording signal is amplified by the recording signal amplifier 410B, and recorded on the magnetic tape 104 by the recording magnetic head 101B via the rotary transformer 438.

Timing 4 is the timing when the reproducing magnetic head 102B is in contact with the magnetic tape 104 for a 180 degree period. Here, in the timing generation circuit 424, the recording signal amplifier control circuit 436 turns off the recording signal amplifier 410A and the recording signal amplifier 410B, and the reproduction signal amplifier control circuit 437 turns off the reproduction signal amplifier 420A.
is turned off, the reproduction signal amplifier 420B is turned on,
Further, the head changeover switch 421 is switched to the B side. At timing 3, the recording magnetic head l0I
The recorded data recorded on the magnetic tape 1.04 by B is reproduced by the reproducing magnetic head 1.02B,
The reproduced signal amplifier 4 via the rotary transformer 438
20B.

Here, timing 4 is equal to timing 1 and timing α
In that section, recording and reproducing operations are performed simultaneously, and crosstalk of the recorded signal to the reproducing circuit occurs, making verification impossible. However, normally the distance between the two bed gaps of a double azimuth head is 3.
001tm, and the distance is 15mm in diameter.
The angle of the rotating drum of mm is about 2 degrees, whereas the angle of the margin area is about 10 degrees, so there is no problem even if verification becomes impossible.

Next, the operation during reproduction will be explained together with the operation timing diagram during reproduction shown in FIG. 4(C).

At timing 1, the timing generation circuit 424 controls the recording signal amplifier 41 by the recording signal amplifier control circuit 436.
0A and the recording signal amplifier 410B are turned off,
The reproduced signal amplifier control circuit 437 turns off the reproduced signal amplifier 420A and the reproduced signal amplifier 420B. (The reproduction signal amplifier control circuit 437 may turn on either the reproduction signal amplifier 420A or the reproduction signal amplifier 420B.) At timing 2, the timing generation circuit 424 controls the recording signal amplifier control circuit 436 to turn on the recording signal amplifier 420A or the reproduction signal amplifier 420B. amplifier 41
OA and recording signal amplifier 410B are turned off,
The reproduced signal amplifier control circuit 437 turns on the reproduced signal amplifier 420A, reproduced signal amplifier=! 120B is turned off, and the head changeover switch 42] is turned off.
Switch to A side. Recorded data recorded on the magnetic tape 104 by the recording magnetic head 101A is reproduced by the reproducing magnetic head 102A, and is amplified by the reproduced signal amplifier 42OA via the rotary transformer 438.

At timing α and timing 3, the timing generation circuit 424 controls the recording signal amplifier 41OA and the recording signal amplifier 4 by the recording signal amplifier control circuit 4.36.
10B is turned off, and the reproduction signal amplifier control circuit 437
As a result, the reproduced signal amplifier 42OA and the reproduced signal amplifier 420B are turned off. (The reproduction signal amplifier control circuit 437 may turn on either the reproduction signal amplifier 42OA or the reproduction signal amplifier 420B.) At timing 4, the timing generation circuit 424 controls the recording signal amplifier control circuit 436 to turn on the reproduction signal amplifier 42OA or the reproduction signal amplifier 420B. signal amplifier 41
0A and the recording signal amplifier 410B are turned off,
The reproduced signal amplifier control circuit 437 turns the reproduced signal amplifier 4.20A off and the reproduced signal amplifier 420B on, and also turns the head changeover switch 421 on.
Switch to side B. Recorded data recorded on the magnetic tape 104 by the recording magnetic head 10IB is reproduced by the reproducing magnetic head 102B, and is amplified by the reproduced signal amplifier 420B via the rotary transformer 438.

Next, the operation during post-recording (here, post-recording in the PCM area will be taken as an example) will be explained together with the operation timing diagram during post-recording shown in FIG. 4(d).

At timing 1, the timing generation circuit 424 controls the recording signal amplifier 41 by the recording signal amplifier control circuit 436.
0A is turned on only in the PCM area section where there is recording data, the recording signal amplifier 410B is turned off, and the reproduction signal amplifier control circuit 437 turns the reproduction signal amplifier 4
2OA and the reproduced signal amplifier 420B are turned off. The recording signal (PCM area only) is recorded by recording signal amplifier 4.
The recording magnetic head 10A is amplified by the recording magnetic head 10A through the rotary transformer 438, and is recorded by the recording magnetic head 10A on the magnetic tape 104, overlapping the PCM area of the recording track that has already been recorded, and the data in the PCM area is rewritten. It will be done.

At timing 2, the timing generation circuit 424 controls the recording signal amplifier 41 by the recording signal amplifier control circuit 436.
OA and recording signal amplifier 41OB are turned off,
The reproduction signal amplifier control circuit 437 turns the reproduction signal amplifier 42OA on, the reproduction signal amplifier 420B off, and switches the head changeover switch 421 to the A side. Recorded data in areas other than the PCM area of the recording tracks on the magnetic tape 104 that have already been recorded, and new recording in the PCM area that was rewritten on the magnetic tape 104''2 by the recording magnetic head 101A at timing 1. The data is reproduced by the reproduction magnetic head 102A, and amplified by the reproduction signal amplifier 420A via the rotary transformer 438. Further, among the reproduced signals amplified by the reproduced signal amplifier 420A, a tracking control signal within the ATF area is transmitted to a tracking control circuit (not shown) to perform tracking control.

At timing 3, the timing generation circuit 424 controls the recording signal amplifier 41 by the recording signal amplifier control circuit 436.
0A is turned off, the recording signal amplifier 410B is turned on only in the PCM area, and the reproduction signal amplifier control circuit 437 turns the reproduction signal amplifier 42OA and the reproduction signal amplifier 420B off. Recording signal (P
CM area only) is amplified by the recording signal amplifier 410B, and is recorded by the recording magnetic head 10IB via the rotary transformer 438, overlapping the PCM area of the recording track already recorded on the magnetic tape 104, and the PCM Area data can be @ exchanged.

At timing 4, the timing generation circuit 424 controls the recording signal amplifier 41 by the recording signal amplifier control circuit 436.
The OA and the recording signal amplifier 410B are turned off, the reproduction signal amplifier control circuit 437 turns the reproduction signal amplifier 420A off, the reproduction signal amplifier 4.20B is turned on, and the head changeover switch 421 is set to the B side. Switch to J recording data in areas other than the PCM area of the recording tracks that have already been recorded on the magnetic tape 104 and new recording in the PCM area rewritten on the magnetic tape 104 by the recording magnetic head 1oIB at timing 3. The data is reproduced by the reproducing magnetic head 102B, and transmitted to the reproduced signal amplifier 4.20B via the rotary transformer 438.
is amplified by Further, among the reproduced signals amplified by the reproduced signal amplifier 420B, a tracking control signal within the ATF area is transmitted to a tracking control circuit (not shown), and tracking control is performed.

FIG. 9 is an operation timing chart when the rotating drum of the second embodiment described above is used. In this case, with respect to the operation timing shown in FIG.
Then, the operating order of the reproducing magnetic head 102B is reversed.

In the above description, the magnetic tape is wound around the rotating drum at an angle of 180 degrees, but the angle is not limited to this.

For example, as in the fourth embodiment shown in FIG. 10(a),
A similar effect can be obtained even when the magnetic tape is wound around a rotating drum having a diameter of 20 mm at an angle of 135 degrees. In this case, the rotation speed of the rotating drum 103 is 30
00 rpm. FIG. 6B is a diagram showing the relationship between the mounting heights of the magnetic heads in this embodiment, and shows that the reproducing magnetic head 102 is Tw with respect to the recording magnetic head 101.
/ 2. It is attached downward in the height direction of the rotating drum 103. This mounting is not limited to this height relationship, and may be mounted as in the second and third embodiments described above.

FIG. 11 is an operation timing diagram of the recording/reproducing circuit according to the embodiment shown in FIG. 10. In this example, since the magnetic tape is wound around the rotating drum at an angle of 135 degrees,
The recording magnetic head 101 and the reproducing magnetic head 102 are
Verification can be performed without contacting the magnetic tape 104 at the same time.

As described above, according to these embodiments, the recording magnetic head 101 and the reproducing magnetic head 102 are each double azimuth magnetic heads, and are arranged on the rotating drum 103 at an angular interval of 180 degrees. Since the reproducing magnetic heads 102 are installed at different heights in the height direction of the rotating drum 103, verification can be performed even on small-diameter rotating drums such as 15 mm in diameter and 20 ROM. Further, during post-recording, the left end of the head gap of the recording magnetic head 101 coincides with the left end of the M+- rack, so post-recording can be performed without reducing the recording track immediately before post-recording.

FIG. 12 is a system block diagram of a helical scan type magnetic tape storage device according to the present invention. It is connected to a host computer (not shown) through a 5C5I (small size computer system interface) 401.

First, the operation during recording will be explained.

During recording, the RA controlled by the system microcomputer 412
The M controller 402 receives data sent from the host (programs and various data handled by a computer, data digitized from analog signals such as music, video, etc.).
is stored in the RAM 403, read out again, and sent to the signal processing circuit 404. The signal processing circuit 4.04 generates an error correction code using the error correction circuit 4.05, and stores the data signal and the error correction code in the RAM 406. Here, this error correction code is a duplex Reed-Solomon code, similar to the conventional DAT.

Next, this data signal, error correction code, and subcode data generated in subcode processing 411 are read out according to the recording format, subjected to predetermined modulation, and
A tracking control signal and a synchronization signal generated by a TF signal generation circuit 408 are added by a multiplexer 409.

Subsequently, as described above regarding the operation timing, the recording data generated by the multiplexer 409 is recorded on the magnetic tape 104 at the timing when the recording magnetic heads 10IA and 101B are scanning the magnetic tape 104.

The recording format is based on the conventional DAT recording format; data is recorded in the PCM signal area, block numbers, frame numbers, etc. are recorded in the subcode area, and ATF area is
The l-racking control signal and synchronization signal generated by the TF signal generation circuit 408 are recorded.

The rotation speed of the rotating drum 1.03 is detected and the speed is controlled, and the phase of the tack pulse is controlled so that it is synchronized with an internal reference signal.The rotation of the rotating drum 1.03 is controlled to a constant speed by the drum control circuit 433. It is driven to run at a constant speed by a capstan motor 434 whose rotation is controlled at a constant speed by a capstan control circuit 432, and data is recorded by the recording magnetic heads 10IA and 101B based on the tack pulse.

Furthermore, at the timing when the reproducing magnetic heads 102A and 102B are scanning the magnetic tape 104, the recorded data is immediately reproduced to verify whether it has been accurately recorded. That is, verify is performed.

Next, the operation during playback will be explained.

During reproduction, the reproduction magnetic heads 102A and 102B feed back to the capstan motor 434 based on the tracking control signal in the ATF area recorded at both ends of the data signal, and output the signal while performing capstan servo. Play. The reproduced signal is amplified by a reproduced signal amplifier 420, and a waveform equalization circuit 421 corrects characteristic deterioration in the high frequency region of the magnetic head and magnetic tape, and then input to a data strobe circuit 422 to obtain data and a clock. From this signal, a synchronization signal detection circuit 423 and a timing generation circuit 424 detect a synchronization signal and generate a timing signal, and a demodulation circuit 425 demodulates the data. In the signal processing circuit 426, an error correction circuit 427 performs an error detection and correction operation, and after the corrected data signal is stored in the RAM 403, it is sent to a host computer (not shown) via the 5C5I 401.

Next, the operation during dubbing will be explained.

Tracking control during dubbing is the same as during playback.
This is tracking control using a tracking control signal within the TF area.

The capstan motor 434 is operated based on the tracking control signal in the AT'F area recorded at both ends of the data signal reproduced by the reproduction magnetic head 1.02.
The capstan servo is operated by feedback. When the reproduction magnetic head 102 is positioned at the center of the recording track being scanned by tracking control based on the crosstalk of the tracking control signals in the ATF area reproduced from the recording tracks on both sides of the recording track being scanned, the above-mentioned As shown in FIG.
The recording magnetic head 101B that scans next after No. 2 scans the left end of the head gap to coincide with the left end of the next recording track.

In this state, the recording magnetic head 101 is connected to the magnetic tape 1.
04, recording data is recorded on the magnetic tape 104 as explained above regarding the operation timing. At this time, the recorded data exists only in the PCM signal area or subcode area, not in the ATF area, and the ATF area is not rewritten. As a result, data other than the tracking control signal can be rewritten, that is, post-recording has been performed.

Also, during dubbing, verification is performed in the same way as during recording.

〔Effect of the invention〕

According to the present invention, each of the pair of magnetic heads is a double azimuth magnetic head, one double azimuth magnetic head of the pair is dedicated for recording, the other double azimuth magnetic head is dedicated for reproduction, and the reproducing magnetic head teeth,
The recording magnetic head is mounted at different heights in the height direction of the rotating drum, and during periods other than the period in which the recording magnetic head records digital signals on the magnetic tape, the recording magnetic head is Since the supplied recording current is controlled to be cut off, the two magnetic heads, the recording magnetic head and the reproducing magnetic head, have an angular interval of 1
Alternately at 80 degrees, and after the recording magnetic head has covered one track Ml, the reproducing magnetic head scans the already recorded track, and the recording magnetic head and the reproducing magnetic head
The time that the two magnetic heads contact the magnetic tape at the same time is extremely short, and verification is possible without the problem of crosstalk of recorded signals to the reproducing circuit.

[Brief explanation of the drawing]

1(a) and 1(b) are schematic diagrams of the rotating drum and its periphery seen from above in the first embodiment of the present invention, and a diagram showing the height relationship of the mounting of the magnetic head, and FIG. 3A and 3B are diagrams showing the scanning positional relationship of the head on the magnetic tape according to the first embodiment, and FIGS. FIG. 4 is a diagram showing the height relationship of the mounting of the magnetic head, FIG. 4 is a diagram showing the scanning positional relationship of the magnetic head on the magnetic tape according to the second embodiment, and FIGS. 5(a) and (b)
) is a schematic view of the periphery of the rotating drum of the third embodiment of the present invention viewed from above and a diagram showing the height relationship of the mounting of the magnetic head, and FIG. FIG. 7 is a diagram showing the scanning position relationship according to the embodiment; FIG. 7 is a diagram showing the peripheral area of the recording and reproducing circuit; FIG. 8 is a diagram showing the operation timing of the recording and reproducing circuit according to the first and third embodiments; FIG. 10(a) and 10(b) are schematic diagrams showing the vicinity of the rotating drum of the fourth embodiment of the present invention viewed from above, and magnetic 11 is a diagram showing the operation timing of the fourth embodiment of the recording/reproducing circuit, FIG. 12 is a system block diagram of the magnetic tape storage device, and FIG. 13 is a diagram showing the height relationship of the head mounting. FIG. 14, which is a diagram showing the track format of the DAT, is a schematic view of the vicinity of a conventional rotating drum viewed from above. 101 magnetic head for recording, 102 magnetic head for reproduction, 103 rotary drum, 104 magnetic tape.

Claims (1)

[Claims] 1. A magnetic tape is wound in a helical manner around a rotating drum equipped with a pair of magnetic heads arranged at an angular interval of 180 degrees, and the magnetic tape is sequentially scanned diagonally. In a helical scan magnetic tape storage device that records digital signals by forming inclined magnetic tracks, each of the pair of magnetic heads is a double azimuth magnetic head, and one double azimuth magnetic head of the pair is dedicated for recording; A helical scan type magnetic tape characterized in that the other double azimuth magnetic head is dedicated for reproduction, and the reproduction magnetic head is attached at a different height in the height direction of a rotating drum than the recording magnetic head. Storage device. 2. In the helical scan magnetic tape storage device according to claim 1, the recording current supplied to the recording magnetic head is controlled during a period other than the period in which the recording magnetic head records digital signals on the magnetic tape. A helical scan type magnetic tape storage device characterized by being equipped with a control circuit that shuts off.