JP2555143B2 - Recording / reproducing circuit control method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical scan type magnetic tape storage device, and particularly to reproducing recorded data immediately and verifying whether or not the data is accurately recorded. The present invention relates to a control system of a recording / reproducing circuit of a helical scan type magnetic tape recording apparatus suitable for performing a so-called verify (read after write) operation.

[Conventional technology]

The helical scan type magnetic tape storage device has a higher recording density than that of a fixed head magnetic tape storage device, and is therefore widely used in a field requiring a large amount of information such as a VTR. Also, with the recent development of VTR technology, a large number of household VTRs are produced at low cost, and their spread is remarkable.

A DAT that records and reproduces musical sound PCM signals on a magnetic tape stored in a cassette case by applying this VTR technology.
(Digital audio tape recorder). This DAT is for recording and reproducing digital signals.The diameter of the rotating drum provided with a pair of recording / reproducing magnetic heads is 30 mm, and the winding angle of the magnetic tape around the rotating drum is as small as 90 degrees. Less damage to
Moreover, because it has a function (high-speed search function) that can be played back and accessed while running the magnetic tape at high speed,
Suitable as an external recording device for a computer. This DA
By using the T technology, it is possible to realize an inexpensive magnetic tape storage device that has a large capacity, can be accessed at high speed, and can be accessed as compared with a conventional fixed head type MT (magnetic tape) storage device.

Here, the track format of the DAT is shown in FIG. 8 (a).
Shown in The recording track of the DAT is divided into a plurality of recording areas as shown in FIG. 8 (a), and various signals are recorded in the respective divided areas. In the center of the recording track
A PCM signal area (PCM) is arranged, ATF areas (ATF-1, ATF-2) are arranged on both sides thereof, and subcode areas (SUB-1, SUB-2) are arranged outside thereof.

In the PCM signal area, digital data in which an error correction code is added to PCM data obtained by converting a musical sound into PCM is recorded.

The subcode area is used to search for a specific position within the program, such as the start ID indicating the start position of the program (song, etc.), the program number indicating the program number, the time from the start position of the program, etc. Search information and the like are recorded.

In the ATF area, a tracking control signal for correctly scanning the recording track by the magnetic head during reproduction is recorded.

As described above, since various signals are recorded in the divided areas, the so-called after-recording operation of individually rewriting the PCM signal or the sub-code is possible as shown in FIG. 8 (b). This is also one of the reasons why it is suitable as an external storage device of a computer.

Regarding the DAT track format mentioned above,
DA Conference Standard −
Final Draft- "DT-Digital Audio Tape Recorder System" (1987
April 22, 2016) (THE DAT CONFERENCE STANDARD −FI
NAL DRAFT- `` DAT-DIGITAL AUDIO TAPE RECORDER
SYSTEM ”1987, APRIL, 22).

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

Even in the DAT, if an error occurs in the reproduced data, an abnormal sound is reproduced.
As described in No. 59-215013, a check word is added and recorded to an information word consisting of a plurality of data (symbols), and at the time of reproduction, the check word is used to detect a data error. Error correction processing is performed.

However, this error correction capability is also limited, and due to the dropout of the magnetic tape and the clogging of the magnetic head due to the adhesion of magnetic powder, dust, etc. separated from the magnetic tape,
If reproduction output cannot be obtained from one of the two magnetic heads, only half of the data to be reproduced will be obtained, so that the reproduced sound will not be seriously disturbed.
There is a possibility that reproduction will become impossible.

Therefore, as described in the above-mentioned document and Japanese Patent Application Laid-Open No. 60-195703, among the sampled data, odd number data is recorded and reproduced by one magnetic head and even number data is recorded and reproduced by the other magnetic head. In this way, the data is completed in two tracks, and the error correction code structure is completed in one track, and even when no reproduction output is obtained from one magnetic head, the other magnetic head is used. With the reproduction output of, the original analog signal can be reproduced by average value interpolation.

The average value interpolation as described above is effective if the data to be handled is a data string having a strong correlation between adjacent data, 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,
Missing data cannot be restored by mean value interpolation.

Therefore, when implementing a magnetic tape storage device such as an external storage device of a computer using such DAT technology, from the viewpoint of ensuring recording on a magnetic tape,
In order to confirm whether the recording is normal, in order to avoid erroneous recording due to defects of the magnetic tape and intrusion of foreign matter, the first drums with different azimuth angles are arranged on the rotary drum at an angular interval of 180 degrees. A pair of rotary magnetic heads and a second pair of rotary magnetic heads arranged orthogonal to the first pair of rotary magnetic heads, which are also arranged at an angular interval of 180 degrees and have different azimuth angles, are provided. The first and second pairs of rotary magnetic heads are dedicated to recording and reproduction, respectively, and the recording tracks recorded by the first pair of rotary magnetic heads are immediately reproduced by the second pair of rotary magnetic heads, The recorded data recorded by the first pair of rotary magnetic heads and the reproduced data reproduced by the second pair of rotary magnetic heads are collated to verify whether or not they have been accurately recorded. If the data and do not match records the data to another location on the tape, the so-called verification is possible to improve the (read-after-write) the reliability of recording data by performing the operation considered. Examples of performing the verify operation by the helical scan method are described in JP-A-58-122606 and JP-A-61-139909.

Similar to the above-mentioned DAT, if the winding angle of the magnetic tape around the rotating drum is approximately 90 degrees, the indexing angle of the magnetic head is also 90 degrees, so there are two magnetic heads, a recording magnetic head and a reproducing magnetic head. However, the time to contact the magnetic tape at the same time is extremely short, and there is no problem of crosstalk,
The verify operation as described above can be performed.

[Problems to be Solved by the Invention]

As described above, in order to realize the so-called verify (read after write) operation of immediately reproducing the recorded data and verifying whether or not the data is correctly recorded, when the device is in the data recording state, The reproducing circuit may also be activated. However, if the recording circuit and the reproducing circuit are in the active state at the same time when the device is in the data recording state, the following problems occur.

Here, the timing at which the first pair of rotary magnetic heads traces on the magnetic tape, that is, the recording timing is the first timing, and the second pair of rotary magnetic heads traces on the magnetic tape. The present timing, that is, the reproduction timing is the second timing.

First of all, if the recording circuit and the reproducing circuit are simultaneously in the active state at the second timing when the second pair of rotary magnetic heads are tracing on the magnetic tape, as shown in FIG. , The recording circuit 410 → the rotary transformer 438 → the reproducing circuit 420 → the loop path 301 of the recording circuit 410 is formed,
The reproducing circuit 420 is oscillated, and the correct verify operation cannot be performed. This is a particular problem when both the recording circuit 410 and the reproducing circuit 420 are mounted in one IC 439 because both circuits are close to each other.

That is, as shown in FIG. 10, if the recording circuit and the reproducing circuit are both turned on at all the timings, the reproducing circuit is oscillated at the second timing and the correct verify operation cannot be performed.

Secondly, in order to solve the first problem, the first
At a first timing when the pair of rotary magnetic heads are tracing on the magnetic tape, the recording circuit is controlled to the active state, and the second pair of rotary magnetic heads are tracing the magnetic tape on the magnetic tape. At this timing, if the recording circuit is controlled to be in a stopped state in order to disconnect the loop path described above, the following problems occur during so-called after-recording when the PCM signal or subcode is rewritten.

At the time of after-recording, the above-mentioned AT reproduced by the second pair of rotary magnetic heads at the second timing.
While performing tracking control by the tracking control signal obtained from the F area, only the data area (PCM signal area or sub code area) except the ATF area is operated at the first timing by the first pair of rotary magnetic heads. rewrite. Further, during after-recording, the verify operation is performed at the second timing by the second pair of rotary magnetic heads as in the case of normal recording.

Here, in order to solve the above-mentioned first problem, at the first timing when the first pair of rotary magnetic heads are tracing on the magnetic tape, that is, at the recording timing,
When the recording circuit is controlled to be in the active state and the recording circuit is controlled to be in the stopped state at the second timing when the second pair of rotary magnetic heads are tracing on the magnetic tape, that is, the reproduction timing, for example, a PCM signal is generated. When rewriting the data in the area, as shown in FIG. 11, impulse noise is generated from the recording circuit when the operation control of the recording circuit is switched, and the noise is amplified by the reproducing circuit. The noise is transmitted to the tracking control circuit, and the tracking control circuit erroneously recognizes the noise as a tracking control signal and performs erroneous tracking control. This problem also occurs when rewriting the subcode area.

Further, at the time of verification, the recording track immediately after recording, that is, the recording track before overwriting is reproduced, so that the recording track width reproduced is wider than the recording track width reproduced during normal reproduction. Therefore, the reproduction signal level becomes higher than the reproduction signal level at the time of normal reproduction by the wider track width. On the other hand, in the reproducing circuit, in order to reduce the influence of disturbance noise on the reproduced signal, the amplification degree is usually set to the full dynamic range of the reproducing circuit during normal reproduction. Here, when the verify operation is performed by the amplifier circuit, as described above, the reproduced signal level is larger than the reproduced signal level at the time of normal reproduction by the wider track width, so that the reproduced circuit is saturated and the correct verify operation is performed. Can not be.

An object of the present invention is to provide a highly reliable magnetic tape storage device that solves the above problems.

[Means for solving the problem]

The above-mentioned object is to perform a so-called verify (read-after-write) operation of immediately reproducing recorded data and verifying whether or not the data is correctly recorded. At the first timing of tracing, the recording circuit is controlled to the active state, and at the second timing of the second pair of rotating magnetic heads tracing on the magnetic tape, the recording circuit is stopped. Controlling, at the first timing at which the first pair of rotary magnetic heads traces on the magnetic tape, the reproducing circuit is controlled to be in a stopped state for a transient response time of the recording circuit or longer. At a second timing when the second pair of rotary magnetic heads are tracing on the magnetic tape, controlling the reproducing circuit in an active state; At the second timing when the magnetic transfer head is tracing on the magnetic tape, the increment of the recording track width traced by the second pair of rotating magnetic heads is approximately equal to the increase of the recording track width traced during normal reproduction. It is achieved by controlling the amplification degree of the reproducing circuit by a value.

[Action]

When performing a so-called verify (read after write) operation of immediately reproducing the recorded data and verifying whether or not the data is correctly recorded, the first pair of rotary magnetic heads traces on the magnetic tape. The first
At the second timing, the recording circuit is controlled to the active state, and at the second timing when the second pair of rotary magnetic heads are tracing the magnetic tape, the recording circuit is controlled to the stopped state. At the second timing when the pair of rotating magnetic heads of (1) are tracing on the magnetic tape, the recording circuit and the reproducing circuit do not become active at the same time, and the loop path described above is not formed. Therefore, the correct verify operation can be performed.

Further, according to the above method, at the first timing when the first pair of rotary magnetic heads are tracing on the magnetic tape, the reproducing circuit is stopped for the transient response time of the recording circuit or longer. And the second pair of rotary magnetic heads are tracing the magnetic tape at the second timing, the reproducing circuit is controlled to the active state, so that the impulse noise generated when the operation control of the recording circuit is switched. Is not transmitted to the tracking control circuit, the tracking control will not be erroneous during after-recording.

Further, at the second timing when the second pair of rotary magnetic heads are tracing on the magnetic tape, the second
The pair of rotating magnetic heads is controlled so as to decrease the amplification degree of the reproducing circuit by a value approximately equal to the increase in the recording track width traced by the pair of rotating magnetic heads with respect to the recording track width traced during normal reproduction. The circuit is not saturated, and the correct verify operation can be performed.

〔Example〕

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

FIG. 1 is a diagram showing a so-called verify (read-after-write) operation of immediately reproducing recorded data and verifying whether or not it is recorded correctly.

FIG. 9A is a diagram showing a verify operation on the magnetic tape during normal recording. In the figure, 100 is a magnetic tape, 101A to D are recording tracks already recorded,
101E is a recording track that is just recording, 102 is an ATF area in which a tracking control signal for tracking control is recorded, 203A and 203B are rotary magnetic heads for recording, 2
Reference numerals 03C and 203D denote reproducing rotary magnetic heads. Also, in the figure, the rotary magnetic head for recording 203A is used for recording tracks.
The trace position of each magnetic head with respect to the recording track when 101A is recorded is shown. The trace order of the magnetic heads is 203A → 203C → 203B → 203D → 203A → .... Data is recorded by the recording rotary magnetic heads 203A and 203B,
The reproduction is performed by the reproducing rotary magnetic heads 203C and 203D.

Data is recorded at the timing when the recording rotary magnetic head 203A is tracing on the magnetic tape 100, and after the recording track 101G is recorded, the reproducing rotary magnetic head that is traced next to the recording rotary magnetic head 203A. 203C
Is the recording track recorded by the recording rotary magnetic head 203A.
The 101G is traced, the recording track 101G is reproduced, and the verify operation is performed.

FIG. 11B is a diagram showing the timing of the verify operation during normal recording.

Timing 1 is timing when the recording rotary magnetic head 203A traces on the magnetic tape 100. At this timing, the recording circuit is turned on and the reproducing circuit is turned off by the recording circuit control signal and the reproducing circuit control signal, and the recording data is recorded in the rotary magnetic head 20 for recording.
It is recorded on the magnetic tape 100 by 3A.

Timing 2 is the timing when the reproducing rotary magnetic head 203C traces on the magnetic tape 100. At this timing, the recording circuit is turned off and the reproducing circuit is turned on by the recording circuit control signal and the reproducing circuit control signal, and recording is performed by the recording rotary magnetic head 203A at the timing 1 on the magnetic tape 100. The recorded data thus reproduced is reproduced by the reproducing rotary magnetic head 203C.

Timing 3 is the timing when the recording rotary magnetic head 203B traces on the magnetic tape 100. At this timing, the recording circuit is turned on and the reproducing circuit is turned off by the recording circuit control signal and the reproducing circuit control signal, and the recording data is recorded in the rotary magnetic head 20 for recording.
It is recorded on the magnetic tape 100 by 3B.

Timing 4 is the timing when the reproducing rotary magnetic head 203D traces on the magnetic tape 100. At this timing, the recording circuit is in the OFF state and the reproducing circuit is in the ON state by the recording circuit control signal and the reproducing circuit control signal, and the recording is performed by the recording rotary magnetic head 203B at the timing 3 on the magnetic tape 100. The recorded data thus reproduced is reproduced by the reproducing rotary magnetic head 203D.

FIG. 6C is a diagram showing a verify operation on the magnetic tape at the time of so-called after-recording for rewriting data in the PCM signal area or the subcode area. In this embodiment, the operation at the time of after-recording the PCM signal area will be shown. In the figure, 101H to N are recording tracks that have already been recorded.
I am trying to rewrite the data in the PCM signal area from 1K.

The reproducing rotary magnetic head 203C is a reproducing rotary magnetic head.
When the recording track 101I is positioned at the center of the recording track 101I by the capstan servo by comparing the crosstalk amount of the tracking control signals in the ATF areas reproduced from the recording tracks 101H and 101J on both sides of the recording track 101I to be traced by 203C, The recording rotary magnetic head 203B, which is traced next to the rotary magnetic head 203C, traces the left end of the head gap of the recording magnetic head 203B in line with the left end of the recording track 101J.

When the recording rotary magnetic head 203B finishes tracing the recording track 101J, the reproducing rotary magnetic head 203D that traces next to the recording rotary magnetic head 203B, when the reproducing rotary magnetic head 203C reproduces the recording track 101I. This time, it will be positioned at the center of the recording track 101J as well.

In this way, the trace is advanced while the capstan servo is applied by the tracking control signal in the ATF area, and the reproducing rotary magnetic head 203D is one track before the recording track 101K in which the data in the PCM signal area is being rewritten. When the recording track 101J is completely traced, the recording rotary magnetic head 203A comes to a position where the left end of the head gap is traced so as to coincide with the left end of the recording track 101K. Therefore, if the recording rotary magnetic head 203A performs the recording operation only in the PCM signal area of the recording track 101K, only the data in the PCM signal area can be rewritten.

FIG. 6D is a diagram showing the timing of the verify operation at the time of so-called after-recording for rewriting the data in the PCM signal area or the sub-code area. In this embodiment, the operation at the time of after-recording the PCM signal area will be shown.

Timing 1'is the timing when the recording rotary magnetic head 203A traces on the magnetic tape 100. At this timing, the recording circuit is turned on and the reproducing circuit is turned off by the recording circuit control signal and the reproducing circuit control signal, and the recording data only in the PCM signal area is recorded on the magnetic tape by the recording rotary magnetic head 203A. 100
The data is recorded in the PCM signal area of the above already recorded recording track, and the data in the PCM signal area is rewritten.

Timing 2'is the timing when the reproducing rotary magnetic head 203C traces on the magnetic tape 100. At this timing, the recording circuit is in the off state and the reproducing circuit is in the on state by the recording circuit control signal and the reproducing circuit control signal, and the PCM signal of the already recorded recording tracks on the magnetic tape 100 is recorded. The recording data of the area other than the area and the new recording data of the PCM signal area rewritten by the recording rotary magnetic head 203A at the timing 1'are the reproducing rotary magnetic head.
Played by 203C.

Timing 3'is the timing when the recording rotary magnetic head 203B traces on the magnetic tape 100. At this timing, the recording circuit is turned on and the reproducing circuit is turned off by the recording circuit control signal and the reproducing circuit control signal, and the recording data only in the PCM signal area is recorded on the magnetic tape by the recording rotary magnetic head 203B. 100
The data is recorded in the PCM signal area of the above already recorded recording track, and the data in the PCM signal area is rewritten.

Timing 4'is the timing when the reproducing rotary magnetic head 203D traces on the magnetic tape 100. At this timing, the recording circuit is in the off state and the reproducing circuit is in the on state by the recording circuit control signal and the reproducing circuit control signal, and the PCM signal of the already recorded recording tracks on the magnetic tape 100 is recorded. The recording data of the areas other than the area and the new recording data of the PCM signal area rewritten by the recording rotary magnetic head 203B at the timing 3'are the reproduction rotary magnetic heads.
Played by 203D.

In the above embodiment, the reproducing circuit is turned off during the timing when the recording rotary magnetic head 203A or B is tracing on the magnetic tape 100. FIG. 6E is a timing chart at the time of verification in the embodiment in which the reproducing circuit is turned off for the transient response time of the recording circuit by the reproducing circuit control signal.

FIG. 2 is a side half view showing the structure of a rotary drum equipped with a magnetic head, FIG. 3 is a plan view showing the structure of a rotary drum equipped with a magnetic head, and FIG. 4 is a rotary view equipped with a magnetic head. It is a side view which shows the structure of a drum. 201 is a fixed drum, 202 is a rotating drum, and 203A and 203B are rotating drums 202.
The rotary magnetic heads for recording 203C and 203D fixed to the rotary magnetic heads for reproduction, 204 and 20 fixed to the rotary drum 202.
5 is a rotary transformer, 206 is a rotating shaft, 207 is a magnet which is a motor rotor, 208 is a motor stator coil, 2
Reference numeral 09 denotes a coil for detecting the motor rotation speed, a hall element for detecting the rotation phase of the magnet 207, and a hall element for detecting a pulse signal (hereinafter referred to as a tack pulse) generated once per one rotation of the motor. The detection substrate 210 to which is attached is a lead for helically winding the magnetic tape around the fixed drum 201.

 The rotary drum 202 is fixed to the rotary shaft 206.

Further, the rotary magnetic heads 203A, 203B, 203C, 203D are 90
The rotary magnetic head for recording 203A
And a rotary magnetic head for reproduction 203C, a rotary magnetic head for recording 20
3B and the rotary magnetic head for reproduction 203D have the same azimuth, respectively, and the rotary magnetic head for recording 203A and the rotary magnetic head for reproduction.
203C is +20 degrees, and the recording rotary magnetic head 203B and the reproducing rotary magnetic head 203D are -20 degrees.

The rotary magnetic heads 203C and 203D for reproduction are the rotary drum 202.
The spacers 211 are attached on the top. Since the indexing angle of each rotary magnetic head is 90 degrees, the rotary magnetic heads for recording 203A and 203B and the rotary magnetic head for reproduction 20 are used.
When the mounting step of 3C and 203D is zero, as shown in FIG. 5 (a), the reproducing rotary magnetic heads 203C and 203D track the recording tracks scanned by the recording rotary magnetic heads 203A and 203B. Scanning will be shifted by a half of the pitch Tp. Since there is a one-to-one correspondence between the mounting step of the rotary head and the scanning track pitch shift, the rotary magnetic heads for reproduction 203C and 203D are replaced with the rotary magnetic heads for recording 203A and
If the rotary magnetic heads for recording 203A and 203B are attached to the rotary magnetic heads 203A and 203B so as to be shifted downward by 3B, the reproducing rotary magnetic head 203C traces the recording track 101B as shown in FIG. 5B. Recording tracks 101 on both sides of
When positioned at the center of the recording track 101B by tracking control by the crosstalk amount of the tracking control signal in the ATF area reproduced from A, 101C,
As described above, the recording rotary magnetic head 203B to be traced next to the reproducing rotary magnetic head 203C traces the left end of the head gap of the recording track 101C in line with the left end of the recording track 101C. Further, the reproducing rotary magnetic head 203D to be traced next to the recording rotary magnetic head 203B has recording tracks 101B and 10 adjacent to both sides of the recording track 101C to be traced.
When positioned at the center of the recording track 101C by the tracking control by the crosstalk amount of the tracking control signal in the ATF area reproduced from 1D, as described above, the recording rotation that is traced next to the reproducing rotary magnetic head 203D is performed. The magnetic head 203A traces the left end of the head gap so as to match the left end of the recording track 101D.

FIG. 6 shows an embodiment around the recording / reproducing circuit of this apparatus. In the figure, 410 is a recording signal amplifier, 420 is a reproduction signal amplifier, 436 is a recording signal amplifier control circuit, 437 is a reproduction signal amplifier control circuit, and 438 is a rotary transformer. The reproduction signal amplifier 420 is composed of amplifiers 4201, 4202, 4203 and a magnetic head changeover switch 4204. Here, the recording signal amplifier 410 and the reproduction signal amplifier 420 are mounted in the recording / reproduction amplifier IC439.

First, the operation during normal recording will be described. At the timing (timing 1) when the recording rotary magnetic head 203A is tracing on the magnetic tape 100, the recording signal amplifier control circuit 436 and the reproduction signal amplifier control circuit 437 cause the recording signal amplifier 410 to be in the ON state and the reproduction signal amplifier 410. 420 is in the off state, and after the recording signal is amplified by the recording signal amplifier 410, the recording tape is amplified by the recording rotary magnetic head 203A via the rotary transformer 438.
Recorded above.

At the timing (timing 2) when the reproducing rotary magnetic head 203C traces on the magnetic tape 100, the recording signal amplifier control circuit 436 and the reproduction signal amplifier control path 4
The recording signal amplifier 410 is turned off and the reproduction signal amplifier 420 is turned on by 37.
At timing 1, the recording data recorded by the recording rotary magnetic head 203A is changed to the reproducing rotary magnetic head 20.
The signal is reproduced by 3C and amplified by the reproduction signal amplifier 420 via the rotary transformer 438. here,
As shown in FIG. 1 (a), a reproducing rotary magnetic head 203C.
Since the recording track 101E is traced immediately after the recording rotary magnetic head 203A records, a recording track having a wider width is traced than in the normal reproduction in which the recording track after being overwritten is traced. .
That is, the reproduction output of the reproducing rotary magnetic head 203C increases by the increase in the width of the recording track. Specifically, in DAT, the head gap of each rotary magnetic head is 21 μm, and the track pitch during normal playback (after overwriting) is 13.6.
The recording track width traced at the time of verification is 21− (21−13.6) /2=17.3 μm, and the reproduction output of the reproducing rotary magnetic head 203C is increased by 201 og (17.3 / 13.6) = 2.1 dB. At this time, the reproduction signal amplifier control circuit 437,
Control is performed so that the amplification degree of the reproduction signal amplifier 420 is reduced by an amount corresponding to the increase in the recording track width during normal reproduction.
That is, the amplification degree of the reproduction signal amplifier 420 is controlled to be reduced by about 2.1 dB.

At the timing (timing 3) when the recording rotary magnetic head 203B traces on the magnetic tape 100, the recording signal amplifier control circuit 436 and the reproduction signal amplifier control circuit 4
The recording signal amplifier 410 is turned on by 37 and the reproduction signal amplifier 420 is turned off by 37, and after the recording signal is amplified by the recording signal amplifier 410, it is passed through the rotary transformer 438 and by the recording rotary magnetic head 203B. It is recorded on the magnetic tape 100.

At the timing (timing 4) when the reproducing rotary magnetic head 203D traces on the magnetic tape 100, the recording signal amplifier control circuit 436 and the reproduction signal amplifier control circuit 4
The recording signal amplifier 410 is turned off and the reproduction signal amplifier 420 is turned on by 37.
At timing 3, the recording data recorded by the recording rotary magnetic head 203B is changed to the reproducing rotary magnetic head 20.
It is reproduced by 3D and amplified by the reproduction signal amplifier 420 via the rotary transformer 438. Further, as described above, the reproduction signal amplifier control circuit 437 controls so that the amplification degree of the reproduction signal amplifier 420 is reduced by the increase in the recording track width traced at this time with respect to the recording track width traced during normal reproduction. .

Next, the operation during the after record (PCM signal area) will be described.

At the timing when the recording rotary magnetic head 203A is tracing on the magnetic tape 100 (timing 1 '), the recording signal amplifier control circuit 436 and the reproduction signal amplifier control circuit 437 cause the recording signal amplifier 410 to be in the ON state and the reproduction signal. The amplifier 420 is in the off state, and after the recording signal is amplified by the recording signal amplifier 410, the recording is performed on the magnetic tape 100 by the recording rotary magnetic head 203A via the rotary transformer 438. It is recorded in the PCM signal area of the track and the data in the PCM signal area is rewritten.

At the timing (timing 2 ′) when the reproducing rotary magnetic head 203C traces on the magnetic tape 100, the recording signal amplifier control circuit 436 and the reproduction signal amplifier control circuit 437 cause the recording signal amplifier 410 to be in the OFF state and the reproduction signal. The amplifier 420 is in the ON state, and the recording data of the area on the magnetic tape 100 other than the PCM signal area of the already recorded recording track and the timing 1 '.
In, the new recording data in the PCM signal area rewritten by the recording rotary magnetic head 203A is reproduced by the reproducing rotary magnetic head 203C and is amplified by the reproduction signal amplifier 420 via the rotary transformer 438. Further, among the reproduction signals amplified by the reproduction signal amplifier 420, the tracking control signal in the ATF area is transmitted to a tracking control circuit (not shown), and tracking control is performed. Here, as shown in FIG. 1 (c), the reproducing rotary magnetic head 203C is a recording track.
Since 101E is traced immediately after recording by the recording rotary magnetic head 203A, it is rewritten by the recording rotary magnetic head 203A at timing 1'as compared with normal reproduction in which a recording track after being overwritten is traced. In the PCM signal area, a wide recording track is traced. That is, in the PCM signal area, the reproduction output of the reproducing rotary magnetic head 203C increases by the increase in the width of the recording track. Specifically, it increases by 2.1 dB as described above. Therefore, the reproduction signal amplifier control circuit 4
37 controls so that the amplification degree of the reproduction signal amplifier 420 is reduced by an increment of the recording track width traced at this time with respect to the recording track width traced during normal reproduction. That is, at the timing when the reproducing rotary magnetic head 203C traces the PCM signal area of the recording track 101E, the amplification degree of the reproducing signal amplifier 420 is controlled to be decreased by about 2.1 dB.

At the timing when the recording rotary magnetic head 203B traces on the magnetic tape 100 (timing 3 '), the recording signal amplifier control circuit 436 and the reproduction signal amplifier control circuit 437 cause the recording signal amplifier 410 to be in the ON state and the reproduction signal. The amplifier 420 is in the off state, and after the recording signal is amplified by the recording signal amplifier 410, the recording track already recorded on the magnetic tape 100 by the recording rotary magnetic head 203A via the rotary transformer 438. Is recorded in the PCM signal area and the data in the PCM signal area is rewritten.

At the timing (timing 4 ′) when the reproducing rotary magnetic head 203D traces on the magnetic tape 100, the recording signal amplifier control circuit 436 and the reproduction signal amplifier control circuit 437 cause the recording signal amplifier 410 to be in the OFF state and the reproduction signal. The amplifier 4200 is in the ON state, and the recording data of the area other than the PCM signal area of the recording track which has already been recorded on the magnetic tape 100 and the timing 3 '.
In, the new recording data in the PCM signal area rewritten by the recording rotary magnetic head 203B is reproduced by the reproducing rotary magnetic head 203D and is amplified by the reproduction signal amplifier 420 via the rotary transformer 438. Further, among the reproduction signals amplified by the reproduction signal amplifier 420, the tracking control signal in the ATF area is transmitted to a tracking control circuit (not shown), and tracking control is performed. Further, as described above, the reproduction signal amplifier control circuit 437 reproduces at the timing of tracing the PCM signal area by the increment of the recording track width of the PCM signal area traced at this time with respect to the recording track width traced during normal reproduction. The control is performed so as to reduce the amplification degree of the signal amplifier 420.

As described above, during recording or after-recording, the recording rotary magnetic heads 203A and 203B are
Timing 1 when tracing on the magnetic tape 100,
In 3, 1'and 3 ', the recording signal amplifier control circuit 436 is
At the timings 2, 4, 2 ', and 4'when the recording signal amplifier 410 is turned on and the reproducing rotary magnetic heads 203C and 203C are tracing on the magnetic tape 100, the recording signal amplifier control circuit 436 causes the recording signal amplifier Since the amplifier 410 is controlled to the off state, the reproducing rotary magnetic heads 203C and 203
Timing 2 when tracing on the magnetic tape 100,
At 4, 2 ′ and 4 ′, the recording signal amplifier 410 and the reproduction signal amplifier 420 are not turned on at the same time, and the loop path described above is not formed. Therefore, the reproduction signal amplifier 420 does not become the oscillation state and the correct verify operation is performed. There is an effect that can be done.

Further, according to the above method, at the timings 1, 3, 1'and 3'when the recording rotary magnetic heads 203A and 203B are tracing on the magnetic tape 100, the reproduction signal amplifier control circuit 437 performs the recording operation. Timing 2, 4 at which the reproducing rotary magnetic heads 203C and 203D are tracing on the magnetic tape 100 by controlling the reproducing signal amplifier 420 in the OFF state for a transient response time of the signal amplifier 410 or longer time.
In 2 ′ and 4 ′, since the reproduction signal amplifier 420 is controlled to be in the ON state, impulse noise generated when switching the operation control of the recording signal amplifier 410 is not transmitted to the tracking control circuit (not shown). There is no mistake in tracking control when recording.

Also, at the timings 2, 4, 2 ', and 4'when the reproducing rotary magnetic heads 203C and 203D are tracing the magnetic tape 100 during recording or after-recording, the reproducing signal amplifier control circuit 437 traces at this time. The reproduction signal amplifier 420 is controlled so that the amplification degree of the reproduction signal amplifier 420 is reduced by an increase in the recording track width to be traced during normal reproduction, so that the reproduction signal amplifier 420 is not saturated and a correct verify operation is performed. There is an effect that can be.

FIG. 7 is a block diagram of the apparatus in the above embodiment. The host computer (not shown) is SCSI401
(Small size computer system interface).

 First, the operation during recording will be described.

At the time of recording, the RAM controller 402 controlled by the system microcomputer 412 temporarily stores the data sent from the host in the RAM 403, reads the data again, and reads the signal processing circuit 404.
Generates an error correction code by the error correction circuit 405,
The data signal and the error correction code are stored in the RAM 406. here,
This error correction code is a doubled Reed-Solomon code, like the conventional DAT. Next, this data signal, the error correction code, and the subcode data generated by the subcode processing 411 are read according to the recording format,
The tracking control signal and the synchronization signal generated by the ATF signal generation circuit 408 are subjected to a predetermined modulation, and the multiplexer 40
Add with 9. The recording signal amplifier control circuit 436 turns on the recording signal amplifier 410 at the timing when the recording rotary magnetic heads 203A and 203B are tracing on the magnetic tape 100,
The reproduction signal amplifier control circuit 437 turns off the reproduction signal amplifier 420, sets the recording signal amplifier 410, and the rotary transformer 20.
Recording is performed on the magnetic tape 100 from the recording rotary magnetic heads 203A and 203B via 5, 204. The recording format is the conventional D
It complies with the AT recording format, data is recorded in the PCM signal area, block numbers, frame numbers, etc. are recorded in the subcode area.
The tracking control signal and the synchronization signal generated by the ATF signal generation circuit 408 are recorded in the F area.

The rotation speed of the rotating drum 202 is detected and the speed is controlled, and the phase of the tack pulse is controlled so that the tack pulse is synchronized with the internal reference signal. The drum control circuit 433 controls the rotation of the rotating drum to a constant speed. Circuit 4
Shapstan motor 434 controlled to rotate at a constant speed by 32
The data is recorded by the recording rotary magnetic heads 203A and 203B on the basis of the tack pulse as a reference.

At the time of recording, a so-called verify (read after write) operation is performed in which the recorded data is immediately reproduced to verify whether or not the data is correctly recorded.

That is, at the timing when the reproducing rotary magnetic heads 203C and 203D are tracing on the magnetic tape 100, the recording signal amplifier control circuit 436 turns off the recording signal amplifier 410,
The reproduction signal amplifier control circuit 437 turns on the reproduction signal amplifier 420, and the verify circuit 429 controls the data recorded by the recording rotary magnetic heads 203A and 203B and the four minutes of the drum by the reproducing rotary magnetic heads 203C and 203D. It is verified whether the data is correctly recorded by comparing it with the data reproduced with one rotation delay.

 Next, the operation during reproduction will be described.

During playback, the rotary magnetic heads for reproduction 203C and 203D feed back to the capstan motor 434 and perform capstan servo based on the tracking control signal in the ATF area recorded at the both ends of the data signal. Play the signal. Playback signal is a playback signal amplifier
After being amplified in 420, the waveform equivalent circuit 421 corrects the characteristic deterioration of the magnetic head and the magnetic tape in the high frequency region, and then is input to the data strobe circuit 422 to obtain data and a clock. From this signal, the sync signal detection circuit 42
3, the timing generation circuit 424 detects the synchronization signal,
A timing signal is generated and the demodulation circuit 425 demodulates the data. The signal processing circuit 426 includes an error correction circuit 427.
An error detection / correction operation is performed by, and the corrected data signal is stored in the RAM 403 and then sent to the host computer (not shown) via the SCS 1401. Next, the operation at the time of after-recording will be described.

The tracking control at the time of after-recording is the tracking control by the tracking control signal in the ATF area, like the playback.

Capturing servo is performed by feeding back to the capstan motor 434 based on the tracking control signal in the ATF area recorded by being arranged at both ends of the data signal by the reproducing rotary magnetic heads 203C and 203D. When the reproducing rotary magnetic head 203C is positioned at the center of the recording track 101B by the tracking control by the crosstalk amount of the tracking control signal in the ATF area reproduced from the recording tracks 101A and 101C on both sides of the recording track 101B to be traced. As described above, the recording rotary magnetic head 203B is traced next to the reproducing rotary magnetic head 203C.
Will trace the left end of the head gap in line with the left end of the recording track 101D.

In this state, the recording signal amplifier control circuit 436 activates the recording signal amplifier 410 at the timing when the recording rotary magnetic heads 203A and 203B are tracing on the magnetic tape 100,
The reproduction signal amplifier control circuit 437 puts the reproduction signal amplifier 420 into a stopped state, and the recording signal amplifier 410 and the rotary transformer 20
Recording is performed on the magnetic tape 100 from the recording rotary magnetic heads 203A and 203B via 5, 204. At this time, the recorded data exists only in the PCM signal area or subcode area, and the AT
It does not exist in the F area and does not rewrite the ATF area. As a result, data other than the tracking control signal can be rewritten, that is, the after-record operation has been performed.

Also, during after-recording, the verify operation is performed as in normal recording.

The rotary magnetic heads 203C and 203D for reproduction use the magnetic tape 100.
At the timing of tracing above, the recording signal amplifier control circuit 436 turns off the recording signal amplifier 410, the reproduction signal amplifier control circuit 437 turns on the reproduction signal amplifier 420, and the verify circuit 429 determines the recording rotary magnetic head 203A. , 203B
The data recorded by the rotary magnetic head for reproduction 203
C, 203D is compared with the data reproduced with a quarter rotation delay of the drum to verify whether or not it is recorded correctly.

〔The invention's effect〕

According to the present invention, when performing the so-called verify (read after write) operation of immediately reproducing the recorded data and verifying whether or not the data is correctly recorded,
At the first timing when the first pair of rotary magnetic heads are tracing on the magnetic tape, the recording circuit is controlled to the active state, and the second pair of rotary magnetic heads traces on the magnetic tape. Since the recording circuit is controlled to stop at the second timing, the recording circuit and the reproducing circuit are simultaneously activated at the second timing when the second pair of rotary magnetic heads traces on the magnetic tape. Since the loop path is not formed, the reproducing circuit does not enter the oscillation state and the correct verify operation can be performed.

Further, according to the above method, at the first timing when the first pair of rotary magnetic heads are tracing on the magnetic tape, the reproducing circuit is stopped for the transient response time of the recording circuit or longer. And the second pair of rotary magnetic heads are tracing the magnetic tape at the second timing, the reproducing circuit is controlled to the active state, so that the impulse noise generated when the operation control of the recording circuit is switched. Is not transmitted to the tracking control circuit, the tracking control will not be erroneous during after-recording.

At the second timing when the second pair of rotary magnetic heads are tracing on the magnetic tape, a value approximately equal to the increment of the recording track width traced at this time with respect to the recording track width traced during normal reproduction. Only because it controls to reduce the amplification of the playback circuit,
The reproduction circuit is not saturated, and the correct verify operation can be performed.

[Brief description of drawings]

FIG. 1 is an operation explanatory diagram at the time of verify operation, and FIG. 2 is
FIG. 3 is a side view showing the structure of the drum, FIG. 3 is a plan view showing a magnetic head mounted on a rotary drum, FIG. 4 is a side view of FIG. 3, and FIG. 5 is a recording track of each magnetic head. FIG. 6 is a diagram showing an embodiment around a recording / reproducing circuit, FIG. 7 is a system block diagram of the apparatus, FIG. 8 is a diagram showing a DAT track format, and FIG.
FIG. 10 is a diagram showing the first problem, FIG. 10 is a timing diagram showing the first problem, and FIG. 11 is a timing diagram showing the second problem. 100 …… magnetic tape, 101 …… recording track, 102 …… ATF area, 203 …… rotating magnetic head.

Claims (2)

(57) [Claims] 1. A first pair of rotary magnetic heads having different azimuth angles arranged on a rotary drum at an angular interval of 180 degrees, and angular intervals arranged substantially orthogonal to the first pair of rotary magnetic heads. The first on the rotating drum at 180 degrees
And a second pair of rotary magnetic heads having different azimuth angles arranged on different planes from the pair of rotary magnetic heads, and a magnetic tape is helically wound around the rotary drum at an angle of approximately 90 degrees. The first and second pair of rotary magnetic heads are respectively connected to a recording circuit and a reproducing circuit to record a signal on the magnetic tape and reproduce the recorded signal. The first pair of rotary magnetic heads has a recording gap width wider than the track pitch, and sequentially scans the magnetic tape obliquely to perform azimuth recording while partially overwriting without providing a guard band, and an inclined track. In the second pair of rotary magnetic heads, the center of the reproducing gap in the width direction is scanned so as to match the center of the recording track after overwriting. A recording track which is attached to the first pair of rotary magnetic heads while being shifted downward in the height direction of the rotary drum and recorded by the first pair of rotary magnetic heads when data is recorded. Above, the second
The pair of rotary magnetic heads scans to reproduce the signal recorded on the recording track, and the record data recorded by the first pair of rotary magnetic heads and the reproduction data reproduced by the second pair of rotary magnetic heads. In the helical scan type magnetic tape storage device having a verify (read after write) function of re-recording the recorded data when the recorded data and the reproduced data do not match each other, the recording circuit is activated. Recording circuit control means for switching between the ON state and the stopped state. When recording data, the recording circuit control means causes the first pair of rotary magnetic heads to scan the magnetic tape. At a first timing, the recording circuit is controlled to be in an active state, and the second pair of rotary magnetic heads scans a magnetic tape on a second timing. In the control method of the recording and reproducing circuit and controls said recording circuit in a stopped state. 2. A reproducing circuit control means for switching the reproducing circuit between an active state and a stopped state, wherein the reproducing circuit control means, at the first timing, has a transient response time of the recording circuit or 2. The reproducing circuit is controlled to a stopped state for a longer time, and the reproducing circuit is controlled to an active state at the second timing.
A method for controlling the recording / reproducing circuit described.