JPH08306025A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE: To obtain high picture quality related to level drop much due to a cause excepting positional shift by providing a discrimination control means controlling so as to perform no head drive by a magnetic head drive device. CONSTITUTION: An output signal of a magnetic head 5 is amplified 14, and its envelope is detected by a detection signal 15. Its analog signal is converted to a digital signal by an A/D converter 16 at every a sampling time ΔT to be sent to an error storage 21. The device 21 detects the scan positional shift amount 1 (k.ΔT) (where, k: the number of times of the sampling time) of the magnetic head for a recording track at every a track of a tape 3, and cumulatively stores it at every trial (the equation I). A head drive waveform Xd (k.ΔT) suitable to a running mode generated in a waveform generation device 17 and the value of the equation I stored in the error storage 21 are inputted to a waveform operation device 22, and the drive waveform Xcj (k.ΔT) is operated to a head of j-th times shown by the equation II to be outputted to a D/A converter 19. The D/A converter 19 converts the digital signal to an analog signal by the waveform operation device 22 to output it to a head driver 20, and the magnetic head 5 is driven.

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 system. Is.

[0002]

2. Description of the Related Art FIG. 8 shows, for example, JP-A-53-45509.
FIG. 6 is a diagram showing a head control system of a conventional magnetic recording / reproducing apparatus disclosed in Japanese Patent Publication No. In the figure, 1 is a fixed drum,
A rotary drum 2 is mounted so that the tape 3 can run obliquely along the tape guide guide groove provided on the fixed drum 1 over about 190 °. The magnetic head actuators 4a and 4b are attached to the rotary drum 2 by 180 °.
It is attached at an angle of. 14 is a head amplifier that amplifies the output signal of the magnetic head 5, and 15 is its FM.
An envelope detection circuit that detects an envelope signal and detects an envelope, and 16 is an A / D converter that converts an analog signal into a digital signal. Reference numeral 17 is a waveform generator that generates a basic waveform for driving the magnetic head so as to accurately follow the trajectory on the tape during speed search or the like, and 18 is a signal from the waveform generator 17 and a signal from the A / D converter 16. Is an automatic follow-up control device for generating an output that traces the track on the tape, 19 is a D / A converter for converting a digital signal into an analog signal, and 20 is a head driver for driving a head actuator.

Here, the magnetic head actuator 4a,
Reference numeral 4b is for moving the magnetic head along the drum axis, and has a structure as shown in FIG. 9, for example. Ninth
In the figure, 5 is a magnetic head, 6 is a coil bobbin, and 6
a is a cylindrical bobbin, and 6b is a coil. 7a is the first
Gimbal spring, 7b is a second gimbal spring, and 8a is a first mounting member for firmly fixing one end of the coil bobbin 6 and the gimbal spring 7a. A second mounting member 8b firmly fixes the other end of the coil bobbin 6 and the gimbal spring 7b. Reference numeral 9 denotes a cylindrical outer peripheral yoke 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 fixed to both ends of the cylindrical outer peripheral member 9. 11a and 11b are cylindrical permanent magnets. A center pole 12 has permanent magnets 11 on both ends.
The magnetic circuit is formed by coaxially arranging a and 11b inside the cylindrical yoke 9 and fixing them with an adhesive. A coil bobbin 6 is inserted through the center pole 12 and is held by gimbal springs 7a and 7b so as to be displaceable in the axial direction. A leaf spring 13 is a head mounting member. One end is fixed to the coil bobbin 6, and the magnetic head 5 is fixed to the free end side.

Next, the operation will be described. Magnetic head 5
The output signal of 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 at every sampling time ΔT and input to the automatic tracking control device 18. On the other hand, the waveform generator 17 generates a head drive waveform suitable for the traveling mode such as speed search, and supplies it to the automatic tracking controller 18. The automatic tracking control device 18 detects the scanning error from the FM envelope envelope obtained from the head signal, superimposes the correction signal in the direction for correcting the error on the target trajectory generated by the waveform generator, and sampling time ΔT A head drive signal is output to the D / A converter 19 for each. D / A converter 19
Converts the digital signal from the automatic tracking control device 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 trace the track on the tape. When one magnetic head 5a finishes scanning the tape, the other magnetic head 5b starts scanning. While 5b is scanning the track on the tape, 5a is returned to, for example, a straight line so as to return to the initial point. As described above, for example, in special reproduction, the head drive waveform has a triangular waveform as shown in FIG.

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

Further, in the head control method in the conventional magnetic recording / reproducing apparatus, as shown in FIG. 10, the positions of the tracks on the tape should be aligned when scanning the tracks and when the magnetic head is moved back on its back side. Since there is a sharp change in the speed and acceleration at the change point of the operation, there is a problem that the image quality is deteriorated due to the vibration of the magnetic head.

Further, the head control method in the conventional magnetic recording / reproducing apparatus detects the track deviation amount of the head based on the level of the reproduced FM envelope signal. But,
The level of the FM envelope signal decreases not only due to the track deviation but also due to a defective head contact,
There is a problem that an accurate track deviation amount cannot be obtained and the track deviation amount cannot be completely corrected.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and has the characteristics of a magnetic recording / reproducing apparatus which repeatedly scans a locus drawn at a constant interval on a tape. An object of the present invention is to provide a head control system in which the head accurately follows the trajectory on the tape every time the scanning is repeated, and to obtain 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 magnetic recording / reproducing apparatus having a high image quality without vibration or the like at the changing point.

The present invention has been made in order to solve the above problems, and can distinguish the difference in the level reduction of the FM envelope signal due to the positional deviation and the head contact failure, and the high quality magnetic recording / reproducing. The purpose is to obtain the device.

[0011]

A magnetic recording / reproducing apparatus according to the present invention is a magnetic head drive for displacing a magnetic head mounted on a rotary drum and attached to a driven portion in a direction perpendicular to a scanning direction thereof. In a magnetic recording / reproducing apparatus having an apparatus and a relative position deviation amount detecting means for detecting an amount of scanning position deviation of a magnetic head with respect to a recording track from a reproduction signal of the magnetic head, a level drop of an envelope due to a position deviation, a head hitting defect, etc. It is provided with a discriminating control means for discriminating that the level of the envelope is lowered due to the above, and controlling the head not to be driven by the magnetic head driving device with respect to the amount of level reduction due to other than the positional deviation.

[0012]

In the magnetic recording / reproducing apparatus according to the present invention,
With the above configuration, the magnetic head can be controlled based on the accurate track position deviation amount in the magnetic recording / reproducing apparatus capable of reducing the error and obtaining the high image quality as the trial is repeated.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 . Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a head controller of a magnetic recording / reproducing apparatus according to a first embodiment of the present invention. In the figure, the same reference numerals as in FIG. 8 are the same or corresponding parts. Reference numeral 21 is an error accumulating storage device for accumulating and storing the relative positional deviation amount of the head for each sampling, and 22 is a waveform calculating device for determining the next head drive waveform based on the information.

Next, the operation of this embodiment will be described. Similar to the conventional example, the output signal of the magnetic head 5 is amplified by the head amplifier 14, and the envelope thereof 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 sent to the error storage device 21. In the error accumulation storage device 21, the scanning position shift amount e (k ·
ΔT) (where k represents the number of sampling times) is detected and is cumulatively stored for each trial as shown in the equation (1).

[0015]

[Equation 1]

In the waveform calculation device 22, the head drive waveform Xd (k · ΔT) generated by the waveform generation device 17 and suitable for the traveling mode such as speed search and the accumulated error stored in the error storage device 21 are stored. ADERR _j (k · ΔT) is input, the drive waveform Xc _j (k · ΔT) is calculated in the next (j-th) head shown in equation (2), and the D / A converter 19
Is output to

Xc _j (k · ΔT) = Xd (k · ΔT) + γADERR _j-1 (k · ΔT) (2) Here, γ represents the gain of learning control.

The D / A converter 19 converts the digital signal from the waveform calculator 22 into an analog signal and outputs it to the head driver 20. The head driver 20 drives the magnetic head 5 by passing a current according to the head drive waveform through the coil of the magnetic head actuator 4. The trace of the j-th trial is completed as the magnetic head moves. The magnetic head output 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 error generator 17, the error accumulating storage device 21, and the waveform calculation device 22 are composed of separate elements, but it goes without saying that they are composed of one element such as a microcomputer. Of course, it can be replaced with one capable of performing the same processing as. Further, the present invention is not limited to the above-described embodiments, and can take various other configurations without departing from the gist of the present invention.

Embodiment 2 . 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,
The error decreases as the trial is repeated, 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 in which the above-mentioned problems of the first embodiment are solved, error convergence is fast, and higher image quality can be realized. 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 the envelope envelope waveform at every sampling time ΔT, 24 is the phase of the waveform advanced by a certain sampling time, Is a phase advancing device that enables to take out.

Next, the operation of this embodiment will be described. Similar to the first embodiment, 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 sent to the waveform storage device 23. In the phase advance device 24, the envelope envelope waveform of that time (for example, the (j−1) th trial) stored in the waveform storage device 23 is set to a preset phase advance time (K _tan · ΔT).
Only, and sends it to the error accumulation storage device 21. Therefore, in the error accumulation storage device 21, not (3)
The previous error as indicated by the equation is cumulatively stored.

[0023]

[Equation 2]

In the present algorithm, the error information is lost by the amount advanced at the terminal portion, but the error is set to zero or a constant value for that amount.

After that, the head drive waveform Xg · (k · ΔT) is calculated and D / A is calculated as in the first embodiment.
The magnetic head 5 via the converter 19 and the head driver 20.
Is driven. Then, similar to the above embodiment, the above process is sequentially repeated.

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

In the second embodiment, the waveform generator 17, the error accumulation storage device 21, the waveform calculation device 22,
Although the waveform storage device 23 and the phase advance device 24 are composed of separate elements, it goes without saying that one element such as a microcomputer can be replaced with one capable of performing equivalent processing.

Third Embodiment The head control method in the second embodiment is used by assuming a certain error because there is no advance information at the end for the advance time. Therefore, there is a problem in that the accuracy is not improved so much in the terminal portion.

FIG. 3 shows a third embodiment of the present invention which solves the above-mentioned problems of the second embodiment, has a fast 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 designate the same or corresponding parts, 25 is an error detecting head amplifier capable of taking out all the reproduced signals for tape winding, and 26 is an error detecting envelope detection for detecting the envelope thereof. Circuit.

Next, the operation of this embodiment will be described. The basic operation is similar to that of the second embodiment. The difference from the second embodiment is that the tape 3 is wound around the drums 1 and 2 by 190 ° in the conventional magnetic memory reproducing apparatus, but the head amplifier 14 can be used for each channel 180 °. At 180 °, only 180 ° is cut out and ch1 and ch2 are 16.7 as shown in Fig. 4 (b).
Since the connected envelope waveform was created every ms, the previous information could not be used at the terminal end, but in the present embodiment, a head amplifier for error detection and an envelope detection circuit are provided and drawn on the tape. The point is that all information can be retrieved. As a result, the information is input to the terminal part when the accumulated error of the equation (3) is stored.

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

In the third embodiment described above, since it is sufficient to reproduce video on each channel of 180 °, a new error detection head amplifier and envelope detection circuit are provided for all tapes wound. However, this can be configured so that one head amplifier and envelope detection circuit can perform two functions.

Fourth Embodiment 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 controller according to the fourth embodiment. In the figure, the same reference numerals as those in FIG.
Is a non-reproduction side pattern correction device for correcting 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 similar to that of 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 via the non-reproduction side pattern correction device 27. To be sent to 19. 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 these initial and end points are obtained using numerical differentiation. Next, a waveform of 16.7 ms that satisfies the positions of the initial point and the end point, the velocity, and the acceleration is, 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 at every sampling time ΔT.

Although the non-reproduction side pattern correction device is separately provided in the above description, it may be configured to be performed in the waveform calculation device.

In the fourth embodiment, the initial point,
The non-reproduction side pattern was determined so that the conditions of the position, velocity, and acceleration at the end point were made to coincide, and the initial point and end point were made to coincide smoothly. It is possible to apply various things to the definition of smoothness such as matching.

Although the fourth embodiment has been described as an extension of the first embodiment, it goes without saying that the non-reproduction side pattern correction is applied to the second and third embodiments. It is also possible to add and apply a device.

Fifth Embodiment Next, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a block diagram of the head controller showing the present embodiment. In the figure, the same reference numerals as those in FIG.
Is an envelope pattern database that stores various envelope patterns other than track deviations, and 29 compares the current envelope pattern sent from the waveform storage device 23 with the patterns in the envelope pattern database 28 to detect the envelopes due to track position deviations. This is a track error detecting device that distinguishes between a level drop and a level drop below an envelope and detects an accurate track error.

Next, the operation of this embodiment will be described. The basic operation is similar to that of the first embodiment of the present invention. The difference from the first embodiment is that the A / D converter 16
That is, the signal converted in step (3) is not directly sent to the error cumulative storage device 21, but is 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 for each T, and the envelope waveform at that time is stored. The stored waveform is sent to the track error detector 29. The track error detecting device 29 detects a track error according to the flow shown in FIG. 7 and sends it to the error accumulation storage device 21. Next, the flow of FIG. 7 will be described in detail. First, in step 30, N indicating whether or not the patterns are the same is set to 1, or the embedding pattern database 28 or the like is initialized. Next step 31
Then, the target envelope pattern is input from the waveform input device 23. Subsequently, in step 32, the model embedding pattern whose level is lowered except for the track deviation is input from the embedding pattern database 28. In step 33, it is determined whether 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 are not searched, the model embedding pattern is updated to another one in step 35, and step 3
In 2, the model envelope pattern is input again, and the similar determination is repeated. If all the databases are searched, it is considered that the level of the target envelope pattern has not deteriorated except for the track shift. Therefore, in step 38, the track error of the target envelope waveform is obtained, and in step 39, the error accumulation storage device 21. Output to. The following is Step 40
This is the same as the operation so far, as shown in. If the target embedding pattern is similar to the model embedding pattern in step 33, first, in step 36, it is determined whether this is the first embedding pattern. In the case of the first time, the target embedding pattern is similar to the model pattern, but it is not possible to determine whether the embedding level decrease is due to a track deviation or other reasons, so in step 37 that pattern is taken as the previous pattern. After storing and incrementing N by 1, the operations of steps 38, 39 and 40 are executed. If it is not the first time in step 36, the level reduction other than the track deviation of the model pattern determined to be similar to it in the target envelope pattern in step 41 (the level reduction part other than the track deviation is known in the model pattern is known in advance). It is determined whether the same part has changed from the previous pattern. If it is changing, the level decrease is due to the track deviation. Therefore, N is returned to 1 in step 42, and the operations of steps 38, 39 and 40 are executed. If there is no change in the level-lowering part other than the track deviation in step 41, it is considered that this part is not the track deviation and the level is decreasing due to other causes. Therefore, in step 43, the error of this part is set to the reference value. Then, the track error of other portions is obtained in the same manner as in step 38, and is output to the error cumulative storage device 21 in step 39. After that, the process up to this point is repeatedly executed.

As described above, the present embodiment is provided with the database storing various envelope patterns other than the track deviation, and compares the pattern stored in this database with the current pattern to detect the track position deviation and other cases. It is possible to distinguish the difference in level drop caused by the error and output the reference signal for the level drop caused by other than the position shift.Therefore, it is not possible to correct the track shift amount by the wrong error signal, and high image quality can be obtained. To be

In the fifth embodiment, a database of various envelope patterns in the case where the envelope level is lowered due to other than the track shift is made into a database, and the difference between the track position shift and the level drop due to other cases is distinguished based on the database. Although it is configured so as to be possible, it is natural that any configuration may be used as long as it is possible to distinguish the difference between the track position deviation and the level decrease due to other than that.

Also, in the fifth embodiment, the first
However, it is of course possible to apply the present invention to the above-mentioned second, third, and fourth embodiments, and further applicable to the device shown in the conventional example. is there.

[0044]

As described above, according to the magnetic recording / reproducing apparatus of the present invention, the magnetic head mounted on the rotary drum and attached to the driven portion is displaced in the direction perpendicular to the scanning direction. In a magnetic recording / reproducing apparatus having a magnetic head driving device and relative positional deviation amount detecting means for detecting an amount of scanning positional deviation of the magnetic head with respect to a recording track from a reproduction signal of the magnetic head, a decrease in envelope level due to positional deviation and a head As the level reduction of the envelope due to a hitting failure or the like is discriminated and the level reduction due to other than the positional deviation is controlled so as not to drive the head by the magnetic head drive device, an error occurs as the trial is repeated. Accurate track position in a magnetic recording / reproducing device that can obtain high image quality by reducing Is amount can be controlled in the magnetic head based on an effect that can obtain high-quality.

[Brief description of drawings]

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

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

FIG. 3 is a block diagram showing a head controller of a magnetic recording / reproducing apparatus 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 controller of a magnetic recording / reproducing apparatus according to a fourth embodiment of the present invention.

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

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

FIG. 8 is a block diagram showing a head controller of a conventional magnetic recording / reproducing apparatus.

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,
20 head driver, 21 error cumulative 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 (1)

[Claims] 1. A magnetic head driving device mounted on a rotary drum for displacing a magnetic head mounted on a driven part in a direction perpendicular to a scanning direction thereof, and a magnetic signal for a recording track from a reproduction signal of the magnetic head. In a magnetic recording / reproducing apparatus having a relative positional deviation amount detecting means for detecting a scanning positional deviation amount of a head, it is possible to discriminate an envelope level decrease due to a positional deviation and an envelope level decrease due to a head hitting defect,
A magnetic recording / reproducing apparatus provided with a discrimination control means for controlling so that the head is not driven by a magnetic head driving device with respect to a level decrease due to a cause other than a positional deviation.