JP2825465B2 - Magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical scan type magnetic recording / reproducing apparatus capable of displacing a magnetic head in a direction perpendicular to a scanning direction, and more particularly to a magnetic recording / reproducing apparatus having an improved head control method. It is.

[0002]

2. Description of the Related Art FIG. 8 shows, for example, JP-A-53-45509.
FIG. 1 is a diagram showing a head control method of a conventional magnetic recording / reproducing apparatus disclosed in Japanese Patent Application Laid-Open Publication No. H10-26095. In the figure, 1 is a fixed drum,
Reference numeral 2 denotes a rotary drum, which is mounted so that the tape 3 can be driven obliquely along a tape guide groove provided on the fixed drum 1 over about 190 °. The magnetic drum actuators 4a and 4b are 180 ° on the rotating drum 2.
It is attached at an angle. 14 is a head amplifier for amplifying the output signal of the magnetic head 5, and 15 is its FM.
An envelope detection circuit 16 detects an envelope signal and detects an envelope, and an A / D converter 16 converts an analog signal into a digital signal. Reference numeral 17 denotes a waveform generator for generating a basic waveform for driving the magnetic head so as to accurately follow the locus on the tape at the time of speed search, etc., and 18 denotes a signal of the waveform generator 17 and a signal of the A / D converter 16. , An automatic tracking control device that generates an output that traces the locus on the tape, 19 is a D / A converter that changes a digital signal into an analog signal, and 20 is a head driver that drives a head actuator.

Here, the magnetic head actuator 4a,
Numeral 4b moves the magnetic head along the drum axis, and has a configuration as shown in FIG. 9, for example. Ninth
In the figure, 5 is a magnetic head, 6 is a coil bobbin, 6
a is a cylindrical bobbin and 6b is a coil. 7a is the first
7b is a second gimbal spring, 8a is a first mounting member, and firmly fixes one end of the coil bobbin 6 to the gimbal spring 7a. 8b is a second mounting member for firmly fixing the other end of the coil bobbin 6 to the gimbal spring 7b. Reference numeral 9 denotes a cylindrical outer yoke, which is made of a material having an inner diameter larger than the diameter of the coil bobbin 6 and having a high magnetic permeability. Reference numerals 10a and 10b denote disk-shaped outer peripheral yokes, which are made of a material having high magnetic permeability and are fixed to both ends of the cylindrical outer peripheral member 9. 11a and 11b are columnar permanent magnets. Reference numeral 12 denotes a center pole, and permanent magnets 11 are provided at both ends.
The magnetic circuits are arranged coaxially in the cylindrical yoke 9 with a and 11b arranged and fixed with an adhesive. The coil bobbin 6 is inserted into the center pole 12, and is held by gimbal springs 7a and 7b so as to be displaceable in the axial direction. Reference numeral 13 denotes a leaf spring serving as a head mounting member, one end of which is fixed to the coil bobbin 6, and the magnetic head 5 is fixed to a free end thereof.

Next, the operation will be described. Magnetic head 5
Is amplified by the head amplifier 14 and its envelope is detected by the envelope detection circuit 15. The analog signal is converted into a digital signal by the A / D converter 16 every sampling time ΔT, and is input to the automatic tracking controller 18. On the other hand, the waveform generator 17 generates a head drive waveform suitable for the running mode such as speed search and the like, and supplies it to the automatic following controller 18. The automatic tracking control device 18 detects the scanning error from the FM envelope obtained from the head signal, superimposes a correction signal in the direction to correct the error on the target trajectory generated by the waveform generating device, and performs sampling time ΔT The head drive signal is output to the D / A converter 19 every time. D / A converter 19
Converts the digital signal from the automatic tracking controller 18 into an analog signal, and drives the magnetic head actuators 4a and 4b through the head driver 20. As a result, the magnetic head 5 is controlled so as to follow the locus on the tape. When one magnetic head 5a finishes scanning on the tape, the other magnetic head 5b starts scanning. While 5b is scanning a track on the tape, 5a is returned to its initial point, for example, on a straight line. As described above, for example, in the special reproduction, the head drive waveform becomes a triangular waveform as shown in FIG.

Since the head control device of the conventional magnetic recording / reproducing apparatus is configured as described above, there is a problem that the head cannot be controlled with an accuracy higher than the correction signal.

In a conventional head control system in a magnetic recording / reproducing apparatus, as shown in FIG. 10, the positions of the movements when scanning a track on a tape and returning the position of a magnetic head on the back side of the track must be aligned. However, there is a problem that the image quality is deteriorated due to the vibration of the magnetic head and the like, because the speed and acceleration change suddenly at the change point of the operation because the focus is only on the main point.

Further, in the head control method in the conventional magnetic recording / reproducing device, the track deviation amount of the head is detected based on the level of the reproduced FM envelope signal. But,
Since the level of the FM envelope signal decreases not only due to track deviation but also due to a head hitting defect, etc.,
There is a problem that an accurate track shift amount cannot be obtained and the track shift amount cannot be completely corrected.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and has been made in view of the characteristics of a magnetic recording / reproducing apparatus which repeatedly scans a locus drawn at regular intervals on a tape. It is an object of the present invention to provide a head control system in which a head accurately follows a locus on a tape every time scanning is repeated, thereby obtaining a high-quality magnetic recording / reproducing apparatus.

Another object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to obtain a high-quality magnetic recording / reproducing apparatus having no vibration or the like at a change point.

The present invention has been made in order to solve the above-described problems, and it is possible to distinguish a difference between a level shift of an FM envelope signal due to a position shift and a head contact defect, and to provide a high-quality magnetic recording / reproducing. The aim is to obtain a device.

[0011]

Means for Solving the Problems According to claim 1 of the present invention.
The magnetic recording / reproducing device is mounted on a rotating drum,
The magnetic head attached to
A magnetic head driving device that displaces
From the read signal of the magnetic head to the recording track.
Relative displacement detection means for detecting the scanning displacement of the scanning
In the magnetic recording / reproducing apparatus having:
Waveform storage device that stores the envelope pattern of the playback signal
And the envelope pattern stored in the waveform storage device.
Whether the level drop of the pattern has changed from the previous pattern
A track error detection device for determining
Even if the magnetic head is moved with the
When the value of the drop level of the
Control not to drive the head by the drive device
It is characterized by comprising a discrimination control means. Ma
The magnetic recording / reproducing apparatus according to claim 2 of the present invention is characterized in that
2. The magnetic recording / reproducing apparatus according to claim 1,
It stores various envelope patterns other than
Equipped with an embedded pattern database,
Envelopes stored in this database by the difference detection device
Current pattern stored in the waveform storage device
Track by comparing with envelope pattern
Level drop due to misalignment of
Bell drop can be distinguished from the track position
For the level decrease due to reasons other than misalignment,
Control so that the head drive by the head drive device is not performed.
A discrimination control means.

[0012]

According to the magnetic recording / reproducing apparatus of the first aspect,
Stores the envelope pattern of the magnetic head playback signal
Waveform storage device, and an edge stored in the waveform storage device.
The level drop of the envelope pattern changes from the previous pattern.
And a track error detecting device for determining whether
Even if the magnetic head is moved by the error detection device,
If the value of the lower part of the envelope pattern does not fluctuate,
Head drive by magnetic head drive is not performed
Control means for controlling the
Move the head if the envelope is lowered due to
Moving the track will change the track position,
The degree of reduction of the envelope also changes, while the head contact
If the envelope decreases due to
Utilizing that the lowered state does not change even if you move
And the level of the envelope decreases due to the track misalignment.
Or no track position due to defective head contact
The envelope level has dropped for other reasons than
Can be determined. Further, the magnetic device according to claim 2 is provided.
According to the recording / reproducing apparatus, various kinds of information other than the track position deviation are used.
Envelope pattern data that stores the envelope pattern
A base is provided and this data is
Envelope pattern stored in the database and the above waveform
The current envelope pattern stored in the storage device
By comparing, the level due to track misalignment
Distinguish between drop and level drop for other reasons
Allow for track misalignment for reasons other than
The head drop by the magnetic head drive
Equipped with discrimination control means for controlling not to drive
Of the envelope due to poor head contact etc.
With bell drop, the level drops extremely at the beginning of the envelope signal
Using the characteristic envelope waveform such as
Envelope level is low due to misalignment
Or track misalignment due to head contact failure, etc.
Determine if envelope level is low for other reasons
be able to.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a head control device of a magnetic recording / reproducing apparatus according to a first embodiment of the present invention. In FIG. 1, the same reference numerals as those in FIG. 8 denote the same or corresponding parts. Reference numeral 21 denotes an error accumulation storage device that accumulates and stores the relative positional deviation amount of the head for each sampling. Reference numeral 22 denotes a waveform calculation device that determines the next head drive waveform based on the information.

Next, the operation of this embodiment will be described. As in the conventional example, the output signal of the magnetic head 5 is amplified by the head amplifier 14, and its envelope is detected by the envelope detection circuit 15. The analog signal is converted into a digital signal by the A / D converter 16 every sampling time ΔT, and is sent to the error accumulation storage device 21. In the error accumulation storage device 21, the scanning position deviation amount e of the magnetic head with respect to the recording track of each trial (one track of the tape).
(K · ΔT) (where k indicates the number of sampling times) is detected and accumulated for each trial as shown in equation (1).

[0015]

(Equation 1)

The waveform calculating device 22 generates a head driving waveform Xd (k · ΔT) generated by the waveform generating device 17 and suitable for a running mode such as a speed search, and the accumulation stored in the error accumulation storage device 21 described above. Error ADERR _j (k · Δ
T) is input and the next (j-th) head shown in equation (2)
The drive waveform Xc _j (k · ΔT) is calculated and output to the D / A converter 19.

Xc _j (k · ΔT) = Xd (k · ΔT) + γ ADERR _j−1 (k · ΔT) (2) where γ represents the gain of the learning control.

The D / A converter 19 converts the digital signal from the waveform calculator 22 into an analog signal and outputs the analog signal to the head driver 20. The head driver 20 drives a magnetic head 5 by passing a current according to a head drive waveform to a coil of the magnetic head actuator 4. With the movement of the magnetic head, the trace of the j-th trial is completed. The output of the magnetic head at this time is again amplified by the head amplifier 14 and taken out. The above process is sequentially repeated.

In the first embodiment, the waveform generator 17, the error accumulator 21 and the waveform calculator 22 are composed of separate elements. Needless to say, it can be replaced with one that can perform the same processing as. In addition, the present invention is not limited to the above-described embodiment, and can take various other configurations without departing from the gist of the present invention.

Embodiment 2 FIG. Since the head control method in the first embodiment is configured to determine the head drive waveform using only the position error up to the previous time,
As the trial is repeated, the error decreases, but the error reduction rate is small and the accuracy is limited.

FIG. 2 is a diagram showing a second embodiment of the present invention which can solve the above-mentioned problems of the first embodiment, realize a faster error convergence, and realize higher image quality. It is. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, 23 is a waveform storage device for storing an envelope envelope waveform for each sampling time ΔT, 24 is a phase advance for the waveform by a certain sampling time, and Is a phase advancing device that enables to take out.

Next, the operation of this embodiment will be described. Similarly to the first embodiment, the output signal of the magnetic head 5 is amplified by the head amplifier 14, and the envelope detection circuit 15 detects the envelope. The analog signal is converted into a digital signal by the A / D converter 16 every sampling time ΔT, and is sent to the waveform storage device 23. In the phase advance unit 24, the envelope envelope waveform of that time (for example, the (j-1) -th trial) stored in the waveform storage unit 23 is set to a preset phase advance time (K _tan · ΔT).
And forward it to the error accumulation storage device 21. Accordingly, in the error accumulation storage device 21, instead of the expression (1), the expression (3) is used.
The previous error as shown by the equation is accumulated and stored.

[0023]

(Equation 2)

In the present algorithm, the error information is lost by the amount advanced in the terminal part, but the error is set to zero or a constant value.

Thereafter, as in the first embodiment, the head drive waveform Xc · (k · ΔT) is calculated, and the D / A
The magnetic head 5 via the transducer 19 and the head driver 20
Is driven. Then, similar to the above embodiment, the above processes are sequentially repeated.

As described above, in the present embodiment, the waveform storage device and the phase advance device are provided, and the head drive waveform is calculated based on the preceding error by a certain time of the previous trial pattern. Error convergence is quick, and higher image quality can be obtained.

In the second embodiment, the waveform generator 17, the error accumulator 21, the waveform calculator 22,
Although the waveform storage device 23 and the phase advance device 24 are constituted by separate elements, it is needless to say that one element such as a microcomputer which can perform the same processing as this can be used.

Embodiment 3 FIG. In the head control method according to the second embodiment, since there is no preceding information for the advance time at the end, a certain error is assumed and used. For this reason, there is a problem that the accuracy is not so much improved in the terminal portion.

FIG. 3 shows a third embodiment of the present invention which can solve the above-mentioned problems of the second embodiment, can realize faster error convergence at the terminal end, and can realize higher image quality. FIG. In the figure, the same reference numerals as those in FIG. 2 denote the same or corresponding parts, 25 is an error detection head amplifier capable of extracting all reproduction signals for the tape winding, and 26 is an error detection envelope detection for detecting the envelope. Circuit.

Next, the operation of this embodiment will be described. The basic operation is the same as that of the second embodiment. The difference from the second embodiment is that in the conventional magnetic storage / reproducing apparatus, the tape 3 is wound around the drums 1 and 2 by 190 °, but the head amplifier 14 is used for only 180 ° for each channel. , Only 180 ° is cut out, and ch1 and ch2 as shown in FIG.
Since the connected envelope waveform was generated every ms, the preceding information could not be used at the end portion. The point is that all information can be extracted. As a result, information is also stored in the terminal part when storing the accumulated error of the equation (3).

As described above, in this embodiment, in addition to the configuration of the second embodiment, a head amplifier and an envelope detection circuit for error detection are separately provided, and all the information of the wound tape is stored. Because it is configured so that it can be used, since the true tip error can be used even at the end part,
The accuracy of the end portion is improved, and higher image quality can be obtained.

In the third embodiment, since the image can be reproduced only at 180 ° for each channel, a new head amplifier for error detection and an envelope detection circuit are provided to all of the tape wound around. However, this can be configured so that one head amplifier and an envelope detection circuit can fulfill two functions.

Embodiment 4 FIG. Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a block diagram of a head control device according to the fourth embodiment. In the figure, the same reference numerals as those in FIG.
Is a non-reproduction-side pattern correction device that corrects the non-reproduction-side (drum back side) head drive pattern so as to be smoothly connected to the reproduction-side head drive pattern at the initial point and the end point.

Next, the operation of this embodiment will be described. The basic operation is the same as in the first embodiment. The difference from the first embodiment is that the head drive waveform obtained by the waveform calculation device 22 is not directly sent to the D / A converter 19, but the D / A converter is supplied via the non-reproduction-side pattern correction device 27. 19 to be sent. The non-reproduction-side pattern correction device 27 extracts the reproduction-side pattern from the head drive waveform sent from the waveform calculation device 22,
The positions, velocities, and accelerations of the initial point and the end point are obtained using numerical differentiation and the like. Next, a waveform of 16.7 ms that satisfies the position, velocity, and acceleration of the initial point and the end point is represented by, for example, 6
Obtained as an interpolated waveform such as a dimensional equation. Finally, the non-reproduction-side pattern obtained as described above is connected to the reproduction-side pattern and output to the D / A converter 19 every sampling time ΔT.

In the above description, the non-reproduction-side pattern correction device is separately provided, but it is also possible to adopt a configuration in which the correction is performed in the waveform calculation device.

In the fourth embodiment, the initial point,
The non-playback side pattern was determined to match the conditions of the position, speed, and acceleration at the end point, and the initial point and the end point were smoothly matched. However, only the position and speed or higher-order changes than the acceleration were considered. Various definitions can be applied to the definition of smoothness such as matching.

Although the fourth embodiment has been described as an extension of the first embodiment, it is needless to say that the non-reproduction-side pattern correction is added to the second and third embodiments. It is also possible to apply additional devices.

Embodiment 5 FIG. Next, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a block diagram of a head control device according to the present embodiment. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, 28 is an envelope pattern database storing various envelope patterns other than track deviation, and 29 is the current envelope pattern sent from the waveform storage device 23. And Embe Pattern Database 2
8 is a track error detecting device that compares the pattern No. 8 with a pattern position discrimination to discriminate a decrease in the level of an envelope due to a track position deviation from a decrease in the level of other envelopes, and detects an accurate track error.

Next, the operation of this embodiment will be described. The basic operation is the same as that of the first embodiment of the present invention. The difference from the first embodiment is that the A / D converter 16
Is not sent directly to the error accumulation storage device 21 but sent via the waveform storage device 23 and the track error detection device 29.

In the waveform storage device 23, the sampling time Δ
A signal is sent from the A / D converter 16 every T, and the envelope waveform at that time is stored. The stored waveform is sent to the track error detecting device 29. The track error detector 29 detects a track error according to the flow shown in FIG. Next, the flow of FIG. 7 will be described in detail. First, in step 30, N indicating whether or not the pattern is the same is set to 1, or the envelope pattern database 28 and the like are initialized. Then step 31
, The target envelope pattern is input from the waveform input device 23. Subsequently, at step 32, a model embedding pattern whose level has been lowered due to other than track deviation is inputted from the embedding pattern database 28. In step 33, it is determined whether or not the target envelope pattern and the model envelope pattern are similar. If they are not similar, the database is searched in step 34. If all databases have not been searched, the model embedding pattern is updated to another one in step 35, and step 3
In step 2, the model embedding pattern is input again, and the similarity determination is repeated. If all the databases are searched, it is considered that the level of the target envelope pattern is not reduced except for the track deviation. Therefore, the track error of the target envelope waveform is determined in step 38, and the error accumulation storage device 21 is determined in step 39. Output to The following is step 40
As shown in FIG. If the target envelope pattern is similar to the model envelope pattern in step 33, it is first determined in step 36 whether this is the first time. In the first case, the target envelope pattern is similar to the model pattern, but it cannot be determined whether the decrease in the envelope level is due to a track deviation or other causes. After storing and increasing N by 1, the operations of steps 38, 39 and 40 are executed. If it is not the first time in step 36, a level decrease other than the track deviation of the model pattern determined to be similar to the target embedding pattern in the target envelope pattern in step 41 (the level decrease portion other than the track deviation in the model pattern is known in advance). It is determined whether the same part has changed from the previous pattern. If it has changed, the level decrease is due to the track deviation, so N is returned to 1 in step 42, and the operations of steps 38, 39 and 40 are executed. If the level lowering portion other than the track deviation has not changed in step 41, it is considered that this level is not track deviation and the level is lowered for other reasons. The track errors of the other parts are obtained in the same manner as in step 38, and are output to the error accumulation storage device 21 in step 39. After that, the process up to this point is repeatedly executed.

As described above, in the present embodiment, the database storing various envelope patterns other than the track deviation is provided, and by comparing the pattern stored in the database with the current pattern, the track position deviation and the other positions are determined. The difference in level drop caused by the difference can be distinguished, and the reference signal is output for the level drop caused by other than the position shift. Can be

In the fifth embodiment, various envelope patterns in the case where the envelope level decreases due to factors other than track deviation are compiled into a database, and based on the database, the difference between the track position deviation and the level decrease due to other factors is discriminated. Although it is configured so that it can be used, it is natural that any configuration may be used as long as the difference between the track position deviation and the other level decrease can be distinguished.

Also, in the fifth embodiment, the first
Although the embodiment has been described as an extension, it is needless to say that the present invention is applicable to the second, third, and fourth embodiments, and is also applicable to the device shown in the conventional example. is there.

[0044]

As described above, according to the first and second aspects of the present invention,
According to the magnetic recording / reproducing apparatus of the second aspect, the discrimination system
Envelope due to track misalignment by means
Level is low, or there is a head
Envelope level for other reasons other than rack misalignment
Bell drop can be determined, which allows
How to reduce errors as you repeat to get high image quality
And correct the track position deviation amount by the wrong error signal
Without the need for
The head can be controlled and the image quality is even higher
There is an effect that can be obtained .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a head control device of a magnetic recording / reproducing device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a head control device of a magnetic recording / reproducing device according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a head control device of a magnetic recording / reproducing device according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a typical FM envelope waveform.

FIG. 5 is a block diagram showing a head control device of a magnetic recording / reproducing device according to a fourth embodiment of the present invention.

FIG. 6 is a block diagram showing a head control device of a magnetic recording / reproducing device according to a fifth embodiment of the present invention.

FIG. 7 is a flowchart showing processing performed by the track error detection device.

FIG. 8 is a block diagram showing a head control device of a conventional magnetic recording / reproducing device.

FIG. 9 is a sectional view of a magnetic head actuator.

FIG. 10 is a typical head drive pattern diagram.

[Explanation of symbols]

2 rotating drum, 4 magnetic head actuator, 5
Magnetic head, 14 head amplifier, 15 envelope detection circuit, 16 A / D converter, 19 D / A converter,
Reference Signs List 20 head driver, 21 error accumulation storage device, 22
Waveform calculation device, 23 Waveform storage device, 24 Phase advance device, 25 Error detection head amplifier, 26 Error detection envelope detection circuit, 27 Non-reproduction side pattern correction device, 28 Envelope pattern database, 29 Track error detection device.

Claims (2)

(57) [Claims] 1. A magnetic head drive device mounted on a rotating drum and displacing a magnetic head attached to a driven portion in a direction perpendicular to a scanning direction thereof, and a magnetic head for a recording track based on a reproduction signal of the magnetic head. A magnetic recording / reproducing apparatus having a relative positional deviation amount detecting means for detecting a head positional deviation amount, wherein an envelope pattern of the magnetic head reproduced signal is stored.
Waveform storage device, and an edge stored in the waveform storage device.
The level drop of the envelope pattern changes from the previous pattern.
And a track error detecting device for determining whether
Even if the magnetic head is moved by the error detection device,
If the value of the lower part of the envelope pattern does not fluctuate,
Further comprising a determination control means for controlling so as not to perform head driving by the magnetic head driving device to focus the magnetic recording reproducing apparatus according to claim. 2. The magnetic recording / reproducing apparatus according to claim 1,
There are a variety of envelope patterns other than track misregistration
With the stored envelope pattern database,
The error stored in this database by the
The envelope pattern and the current stored in the waveform storage
By comparing with the current envelope pattern,
Level drop due to rack misalignment and other reasons
Level difference due to
Level decrease due to reasons other than misalignment
Do not drive the head by the magnetic head drive
Characterized by comprising a discrimination control means for controlling
Recording and playback device.