JPH04195814A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To control a wide head in an optimum position capable of proving enough its effect as a wide magnetic head by changing the wide magnetic head as of a reproducing head in the widthwise direction of a recording track, detecting both ends of such a changing range that a reproduction detecting output is max. while a change of the reproduction detecting output is zero and controlling the reproducing head to the center between both ends. CONSTITUTION:Reproducing signals reproduced by the wide magnetic heads 1 and 2 are supplied through head amplifiers 7 and 8 to detector circuits 11 and 12. Signals detected by the circuits 11 and 12 are A/D-converted by A/D converters 15 and 16. and are supplied to a microcomputer 19. Now, the position of an electromechanical transducer element 5 is changed in order to make the detecting outputs from the detecting means 11 and 12 max., and when the max. detecting output has a range, those detecting outputs before and after a positional change of the element 5 are compared with each other to detect both ends of a range for making a detecting output change zero. Then, the element 5 is controlled to change the position in the center between both ends. By this method, the element 5 mounted with the wide magnetic heads 1 and 2 is controlled to come in an optimum point, and hence the effect of the wide magnetic head can be proved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording/reproducing device (hereinafter referred to as a VTR), and particularly to a device for controlling tracking during reproduction in a movable head.

BACKGROUND OF THE INVENTION In recent years, in order to realize long-time recording in VTRs, a method has been adopted to increase the recording density by slowing down the tape speed and recording each feel over multiple tracks. , the width of recording tracks is becoming narrower. For example, the track radiation in long mode for 8 gem video is 10 μm. In order for the reproducing magnetic head to accurately scan such narrow recording tracks, tracking control is required to control the position of the reproducing magnetic head with respect to the recording track using a movable head.

Hereinafter, conventional tracking control using a movable head having the same head width as the nl-rack will be described.

Conventionally, when the position of the movable head is changed, the level reproduced from the reproducing magnetic head is detected, the detected level is compared before and after the position of the movable head is changed, and the movable head is moved to obtain the maximum value. It was a method of driving Sodo. That is, as shown in the flowchart of FIG.
The re-biopsy wave output MA captured in I is compared with the previous re-biopsy wave output MB. If (MA-MB)>O, then
In step A3, the head drive voltage data DΔ is increased by 1, and if (M, l-MB)>0 is not satisfied, the head drive voltage data DA is decreased by 1 in step A4.

Furthermore, in step A5, the re-biopsy wave output MA and the previous re-biopsy wave output MB are compared, and if they are equal, it is determined that the re-biopsy wave output is the maximum value, and if they are not equal, step 86
At this point, the re-biopsy wave output MA is stored in the previous re-biopsy wave output MB, and the process returns to step A1. After that, the above operation is repeated.

Therefore, by changing the movable head, if the re-biopsy wave output is in a mountain shape and has one maximum point, the re-biopsy wave output is controlled to be focused at the maximum point.

Problems to be Solved by the Invention However, when the reproducing head is a wide head, the way the re-biopsy wave output changes is different as explained below, and therefore the reproducing head cannot be controlled to an optimal position.

Hereinafter, a case will be described in which playback is performed using a playback head that is wider than the recording trunk. FIG. 8 is a diagram showing the relative positional relationship between the recording track and the wide head, where 101 and 102 are wide heads with different azimuth angles, 103 is a tape,
104 indicates a recording track. Further, FIG. 9 is a diagram showing the positional relationship between the wide head 1 and the recording track 104. FIG. 10 is a diagram showing the relationship between each head position in FIG. 9 and the re-biopsy wave output, where the horizontal axis represents the head position and the vertical axis represents the re-biopsy wave output. Figure 11 shows the head position and electricity.
It is a diagram showing the relationship with the head drive voltage that drives the mechanical transducer element, where the horizontal axis shows the head position and the vertical axis shows the head drive voltage. Regarding the head positions, each head position (A), (B), (C) in Fig. 9 is the head position (A), (B), (C) in Fig. 1O and the head position in Fig. 11. They correspond to (A), (B), and (C), respectively.

The wide head 101 is moved to the ninth direction in the width direction of the recording track 104.
When changed as shown in the figure, the re-biopsy wave output is
The result will be as shown in Figure 0. The head position is (A) in Figure 9,
That is, the re-biopsy wave output increases in accordance with the movement of the wide head 101 until the right end of the wide head 101 comes to a position where it overlaps the right end of the recording track 104.

Until the head position reaches the position from (A) in FIG. 9 to (C) in FIG. 9, that is, the left end of the wide belly button 1" is at the left end of the recording track 104, playback is performed regardless of the position of the wide head 1. The detection output becomes a constant value E.Furthermore, after the head position is from (C) in FIG. 9, the re-biopsy wave output decreases in accordance with the movement of the wide head!01.

Therefore, in such a conventional method, that is, a method in which the movable head is driven so as to obtain the maximum value by comparing the detection level before and after the position of change of the movable head, the head position is either (A) or ( If it converges at C), the reproducing head will no longer be controlled to the center of the recording track, and there will be no sufficient margin for the linearity of the recording track, which is the effect of a wide head.

Furthermore, as shown in FIG. 12, the head arrangement is optimal when the left end of the wide magnetic head 102 and the left end of the recording track IO'4 are aligned, and the right end of the wide magnetic head 102 and the right end of the recording track +04 are aligned. In case of location,
There was a problem in that both the wide magnetic heads 101 and +02 could not be controlled to the optimum point only by the re-biopsy wave output of the wide magnetic head 101.

The present invention solves the above-mentioned conventional problems, and enables the wide head to be controlled to the optimum position where the effect of the wide magnetic head can be fully exhibited. The purpose of the present invention is to provide a VTR which can control the head to the optimum point even when the optimum head position is when the right edge of the other wide magnetic head and the right edge of the recording track are aligned, and which enables automatic tracking. It is something to do.

Means for Solving the Problems In order to solve the above problems, the magnetic recording/reproducing device of the present invention has two magnetic heads having different azimuth angles and a width wider than the recording track, and which is attached to an electro-mechanical transducer. A detection means for detecting the envelope of the video signal reproduced by one of the magnetic heads, and a position of the electro-mechanical conversion element is changed so that the detection output from the detection means is maximized, and the range of the maximum detection output is changed. When the electro-mechanical conversion element has a position change, the detection output before and after the change in position of the electro-mechanical conversion element is compared to detect both ends of a range where the change in the detection output becomes zero, and the electro-mechanical conversion element is placed in the center position between the two ends. and a drive control means for controlling to change.

In addition, the control means of the magnetic recording/reproducing apparatus of the present invention includes two magnetic heads having different azimuth angles and a width wider than the recording track, which are attached to the electro-mechanical conversion element, and the control means controls the envelope of the video signal reproduced by the two magnetic heads. When the position of the electro-mechanical conversion element is changed so that the summation detection output obtained by adding the detection outputs from the detection means and the detection means respectively detecting the waves is maximized, and the maximum summation detection output has a range, Comparing the addition detection output before and after the change in the position of the electro-mechanical conversion element, detecting both ends of a range in which the change in the addition detection output becomes zero, and changing the electro-mechanical conversion element to a central position between the two ends. It is also equipped with a drive control means that controls the movement of the motor.

Operation With the above configuration, the wide magnetic head, which is the reproducing head, is changed in the width direction of the recording trunk, and the re-biopsy wave output from the detection means is compared before and after the change, and the re-biopsy wave output is maximum and the change in the re-biopsy wave output is zero. Both ends of the range are detected, and tracking is performed by controlling the playback head to the center of both ends. In addition, the range where the sum of the re-biopsy wave outputs from the two magnetic heads is the maximum is detected, and both ends of the range where the re-biopsy wave output is maximum and the change in the re-biopsy wave output is zero are detected. Tracking is performed by controlling the playback head in the center. Therefore, even if the two magnetic heads on the electro-mechanical transducer are wide magnetic heads, or even if the optimum head positions of the respective magnetic heads are different, the electric Since the mechanical transducer is controlled, good reproduction is possible while maintaining a margin for the linearity of the recording track.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a VTR showing an embodiment of the present invention. In FIG. 1, reference numeral 1.2 is a wide magnetic head with different azimuth angles, which is mounted on the electro-mechanical transducer element 5. 3.4 is also a wide magnetic head yF with a different azimuth angle as in wide magnetic head 1.2,
It is mounted on the electro-mechanical conversion element 6. 7.8
．． 9 and 10 are head amplifiers corresponding to wide magnetic heads 1.2.3 and 4, respectively; II, 12.13 and 14 are head amplifiers 7.8.9 and 14 from wide magnetic heads l, 2.3 and 4, respectively. This is a detection circuit that detects the reproduced signal that has passed through 10. 15.16.17 and 18 are A/D
The signal detected by the converter is digitized and supplied to the microcomputer 19. 20.21 is a D//Δ converter, which converts the data processed by the microcomputer 19 into analogs and supplies them to five electro-mechanical conversion elements 1822.23. The electro-mechanical conversion element drive circuits 22 and 23 are circuits that drive the electro-mechanical conversion elements 5 and 6 in accordance with data processed by the microcomputer 19.

The operation will be explained below based on the configuration described in item 1. First, the reproduced signal reproduced by the wide magnetic heads l and 2 passes through the respective head amplifiers 7 and 8, and is sent to each detection circuit If.
12. The signals detected by the detection circuits 11 and 12 are sent to the respective A/D converters 15 and 16.
It is converted and supplied to the microcomputer 19. Next, the microcomputer 19 performs various calculations and
/A converter 20 is supplied with data. D/A converter 20
The D/A converted signal is supplied to the electro-mechanical conversion element drive circuit 22.
This drives the electro-mechanical conversion element 5. Furthermore, the wide magnetic head 3.4, which is mounted approximately 180 degrees opposite the wide magnetic heads 1 and 2, operates in exactly the same way as the wide magnetic heads 1 and 2.

Here, the arithmetic processing performed by the microcomputer 19 will be explained in detail.

FIG. 2 is a flowchart showing a process for tracking a wide magnetic head to an optimal point using the re-biopsy wave output. First, in step old, the re-biopsy wave output value EV is loaded into the memory MΔ, and in step B2, the memory MB in which the previous re-biopsy wave output is stored is compared with the memory MΔ. If (MA-MB)>0, the process moves to step BIO, and since the edge detection flag EF has not yet been set, the head drive voltage data DA is increased by 1 in step B3, and the re-biopsy wave output value E that has been fetched this time is obtained in step B4.
The value of the memory MA in which V is stored is moved to the memory MB, and the process returns to the old step. Also, in step B2, if (MA-MB)=0, the process moves to step B5,
When the counter G that counts when (MA-MB)=0 is 0, that is, when (MA-MB)=0, the process advances to step B6, and thereafter to step B7. In step B6, the head drive voltage data DA is stored in the memory MC.
Store in. In step B8, an edge detection flag indicating one end of the range in which the change in re-biopsy wave output becomes 0 is set, and further, in step B7, a counter G is incremented. In step B9, it is checked whether the head drive data DA increased last time, and in this case, the head drive data DA increases.
is increasing, the process moves to the next step B3, and then returns to the step B1 via the next step B4. Further, in step B2, if (MA-MB)<O, the process moves to step 811, and in this case, since the edge flag EF is set, the process moves to the next step 12. In step 12, the head drive voltage data D is stored in the memory MD. Furthermore, in step old 3, the average of memory MC and memory MD is calculated and stored in memory ME. The processing of the microcomputer 19 is completed by supplying the data in the memory ME to the D/A converter 20 or 21.

Therefore, until the head position reaches (A) in FIG. 9, the processes of step old, step B2, step 810, step B3, and step B4 are repeated, and when the head position reaches (A) in FIG. 9, the process of step B6 is repeated. is processed, head drive voltage data DA corresponding to head drive voltage VA is stored, and step B8 is processed. The head positions from (A) to (C) in Figure 9 are step old, step B2, step B5, step B7, and step B.
9. Repeat steps B3 and B4, and when the head position reaches (C) in FIG. Head drive voltage data D corresponding to the head drive voltage vc in FIG. 11 is stored. Further, head drive voltage data corresponding to the head drive voltage Vll in FIG. 11 is calculated in step 813. As a result, the wide magnetic head l is controlled to the head position shown in FIG. 9(B).

The above describes the case where the wide head l is moved to the right when the head position is (A) in order to obtain the optimal head position (B), as shown in FIG. (C) and the wide head is moved to the left, the optimum head position (B) can be obtained by the same operation. In other words, the head position is as shown in Fig. 9 (
Up to C), step B1, step B2, step B
Steps 814 and 815 are repeated, and when the head position reaches (C) in FIG. 9, step B6 is processed, head drive voltage data DA corresponding to head drive voltage VΔ is stored, and step B8 is performed. is processed.

The head positions from (C) to (A) in Fig. 9 are step old, step B2, step B5, step B7, step B9, step old 4, and step old 5.
Repeat the process, and if the edge detection flag EF is set in step old O when the head position reaches (A) in FIG. 9, step 812 is processed, and step old 2 corresponds to the head drive voltage VA. Head drive voltage data DA
or be remembered. Furthermore, the head drive voltage V in FIG.
The head drive voltage data corresponding to the head drive voltage data will be calculated in step old 3.

As a result, the wide magnetic head 1 is controlled to the optimum head position shown in FIG. 9(B).

Further, as shown in FIG. 3(E), the head positions are as follows: the left end of the wide magnetic head l, the left end of the recording track 24,
A case will be described in which the optimum head position is when the right end of the wide magnetic head 2 and the right end of the recording track 25 are aligned. Fig. 4 is a diagram showing the relationship between each head position and re-biopsy wave output in Fig. 3, where the horizontal axis is the head position, the vertical axis is the re-biopsy wave output, and the solid line is the re-biopsy wave output of the wide magnetic l\rad. - The dotted line indicates the re-biopsy wave output of the wide magnetic head 2. FIG. 5 shows the average value of the re-biopsy wave output of the wide magnetic head 1 (solid line in FIG. 4) and the re-biopsy wave output of the wide magnetic head 2 (dotted dotted line in FIG. 4) for each head position in FIG. It is a diagram showing the relationship, where the horizontal axis shows the head position and the vertical axis shows the average re-biopsy wave output. FIG. 6 is a diagram showing the relationship between each head position in FIG. 3 and the head drive voltage that drives the electro-mechanical conversion element. There is.

When the wide magnetic head 1.2 is changed in the width direction of the recording track 24, 25 by the electro-mechanical transducer 5 as shown in FIG. 3, the re-biopsy wave output becomes as shown in FIG. First, regarding the re-biopsy wave output (solid line in FIG. 4) of the wide magnetic head 1, until the head position reaches (D) in FIG. The re-biopsy wave output increases in accordance with the movement of the magnetic head 1. Until the head position reaches from (D) in FIG. 3 to (E) in FIG. 3, that is, until the left end of the wide head 1 reaches the left end of the recording track 24, the re-biopsy wave output will be constant regardless of the position of the wide head 1. It becomes a constant value E. Furthermore, if the head position is from (E) in Figure 3 onward, the wide head l
The re-biopsy wave output decreases according to the movement of. Next, regarding the re-biopsy wave output of the wide magnetic head 2 (one-dot broken line in FIG. 4), the head position is at (E) in FIG. In this case, the re-biopsy wave output increases in accordance with the movement of the wide magnetic head 2. The head position changes from (E) in Figure 3 to (F) in Figure 3.
), that is, until the left end of the wide head 2 reaches the position where it overlaps the left end of the recording l/rack 25, the re-biopsy wave output remains a constant value E regardless of the position of the wide head 2. Furthermore, after the head position is from (F) in FIG. 3, the re-biopsy wave output decreases in accordance with the movement of the wide head 2.

Therefore, even if only the wide magnetic l\rad is controlled to the optimum point by the tracking control method described above, the wide magnetic head 2 will not be at the optimum point.

Therefore, when controlling the head arrangement to the optimum head arrangement shown in FIG. It is effective to process it as the re-biopsy wave output. That is, when the average of the re-biopsy wave output of the wide magnetic head 1 and the re-biopsy wave top of the wide magnetic head 2 is taken, the relationship between the head position and the re-biopsy wave output is as shown in FIG. 5, and the tracking control method described above is obtained. Accordingly, the head position can be controlled to the optimum position as shown in FIG. 3(E).

In this way, if the position of the electro-mechanical transducer is changed so that the average re-biopsy wave output is maximized, and if the maximum average re-biopsy wave output has a range, the maximum average Both ends of the range in which the change in the re-biopsy wave output becomes 0 are detected, and the electro-mechanical transducer is controlled to be changed to the central position.

Furthermore, as is clear from Fig. 5, if the maximum average re-biopsy wave output does not have a range, it is possible to control the head position to the optimum position by performing the same operation as flowchart 1 in Fig. 7. I can do it. In other words, the head position is as shown in Figure 3 (
Steps A1, A2, A3, A5, and Step 86 in FIG. 7 are repeated until E), and when the head position reaches from (ε) in FIG. 3 to (F) in FIG. Repeat step AI, step A2, step A4, step A5, and step 86 in the figure.
The head position converges to (E) in FIG. Therefore, the microcomputer 19 supplies data corresponding to the head drive voltage V shown in FIG. By controlling the head positions of the wide magnetic heads 1 and 2 to the optimum point (E
) The head position can be controlled as shown in ( ).

Effects of the Invention As described above, according to the present invention, an electro-mechanical conversion element "-
Even if the magnetic head is a wide magnetic head, the electro-mechanical conversion element mounted on the wide magnetic head can be controlled to the optimum point, and the effect of the wide magnetic spatula I can be fully demonstrated. , there is also a margin for linearity of the recording trunk. In addition, when the head arrangement of two magnetic heads with different azimuth angles is performed, the optimum head is obtained when the left end of one wide magnetic head and the left end of the recording track are aligned, and the right end of the other wide magnetic head and the right end of the recording track are aligned. Even when the position of the magnetic head is changed, the electro-mechanical transducer on which the wide magnetic head is mounted can be controlled to the optimum position.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a VTR showing an embodiment of the present invention.
Figure 2 shows the process of racking the wide magnetic head to the optimum point using the re-biopsy wave output of the same VTR. Figure 3 shows the positional relationship between the two wide magnetic heads and the recording track. Figure 4 is a diagram showing the relationship between each head position in Figure 3 and the re-biopsy wave output of two wide magnetic heads, and Figure 5 is a diagram showing the relationship between each head position in Figure 3 and the two wide magnetic heads. FIG. 6 is a diagram showing the relationship between each head position in FIG. 3 and the head drive voltage that drives the electro-mechanical conversion element, and FIG. A flowchart showing the process of tracking the magnetic head to the optimum point using the re-biopsy wave output in a VTR. Fig. 8 is a diagram showing the relative positions of the recording track and two wide magnetic heads. Fig. 9 is a diagram showing the wide magnetic head and recording. Diagram showing each positional relationship with the truck, 1st
Figure O is a diagram showing the relationship between each head position in Figure 9 and the re-biopsy wave output, and Figure 11 is a diagram showing the relationship between each head position in Figure 9 and the head drive voltage that drives the electro-mechanical conversion element. , FIG. 12 shows two recording tracks where the optimal head position is when the left end of one wide magnetic head and the left end of the recording track, and the right end of the other wide magnetic head and the right end of the recording rack are aligned. FIG. 3 is a diagram showing the relative positions of wide magnetic heads of FIG. l, 2.3.4.101... wide magnetic head, 5.6
...Electro-mechanical conversion element, IL 12.13.14.
...Detection circuit, 15.1G, 17.18...A/D converter, 19...Microcomputer, 2o, 21.
...D/A converter, 22.23...Electro-mechanical conversion element drive circuit, 24.25, +04 recording track.

Claims (1)

[Claims] 1. Detection in which two magnetic heads with different azimuth angles and a width wider than a recording track are attached to an electro-mechanical conversion element and the envelope of a video signal reproduced by one of the magnetic heads is detected. and changing the position of the electro-mechanical conversion element so that the detection output from the detection means becomes maximum, and when the maximum detection output has a range, before and after the position change of the electro-mechanical conversion element. a drive control means that compares the detected outputs, detects both ends of a range where the change in the detected outputs becomes zero, and controls the electro-mechanical conversion element to change to a central position between the both ends. playback device. 2. Detection means for attaching two magnetic heads having different azimuth angles and a width wider than the recording track to an electro-mechanical transducer and detecting the envelopes of the video signals reproduced by the two magnetic heads, respectively; When the position of the electro-mechanical conversion element is changed so that the summation detection output obtained by adding the detection outputs is maximized, and the maximum summation detection output has a range, the a magnetic drive control means for comparing the summation detection outputs, detecting both ends of a range in which the change in the summation detection output becomes zero, and controlling the electro-mechanical conversion element to change to a central position between the two ends; Recording and playback device.