JPH04319512A - Tracking control system for reproducing head - Google Patents

Abstract

PURPOSE:To satisfactorily conduct a tracking control of a segment in the rear by fixing an actuator voltage of the segment in the rear after fixed an actuator voltage of a segment in the front without being affected by the segment in the front. CONSTITUTION:A control circuit 16 is divided a reproducing track into plural (for example, three pieces) segments and the first segment s1 is conducted a tracking control by varying an actuator voltage in order to perform a hill climbing control. On the other second and third segments s2, s3, the same actuator voltage as the segment s1 is applied. Hence the actuator voltage V1 to make minimize a tracking shift against the segment s1 is fixed. Next the tracking control for the segments s2, s3 as well as the segment s1 are performed, and the actuators V2, V3 to make minimize the tracking shift are decided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking control method for a playback head in a device such as a video tape recorder.

0002

[Prior Art] In a video tape recorder, FIG.
Structurally, as shown in FIG.
while attaching the actuator 6 to the end portion of the actuator 6, for example, so that the playback head 8 can track and control the playback track of the magnetic tape 14 from the slit 12 between the rotary drum side 4 and the fixed drum side 10 of the rotary head drum 2. A playback head 8 is attached to the playback head 8, and the magnitude of the voltage applied to the actuator 6 (actuator voltage) is controlled by a control circuit 16 based on the playback output of the playback head 8 to mechanically displace the end of the actuator 6. In some cases, the reproducing head 8 can also be displaced within the slit 12 of the rotary head drum 2 in the width direction of the reproducing track.

By the way, in the control circuit 16, as shown in FIG.
As shown in FIG. 1, the reproduction track 18 of the magnetic tape 14 is divided into a plurality of segments s1, s2, ..., sn, and the reproduction output of each segment is divided into the same corresponding segments s1, s1, s1, s1, s1, s2, . s2,...,sn
Compare the size with the playback output of each segment s1, s2,
..., sn, the playback head 8 is moved to the slit 12 of the rotating head drum 2 so that the playback output of the playback head 8 is maximum, that is, the tracking deviation of the playback head 8 from the playback track 18 is the minimum for each segment. Tracking control for displacing in the width direction of the playback track has been considered [see pages 131-132 of the 1990 Annual Conference of the Institute of Television Engineers (ITEC'90). ].

[0004] In such tracking control,
For example, a reproduction output corresponding to the current actuator voltage for the actuator 6 at segment s1 in an arbitrary reproduction track is taken into the control circuit 16 and stored in memory. Next, the reproduction output when the actuator voltage is increased in the corresponding segment s1 of the next reproduction track, that is, the tracking deviation of the reproduction head 8, is memorized. As a result of comparing the tracking deviation in both memories, segment s1 is better when the actuator voltage is increased.
If the tracking deviation of the reproducing head with respect to the tracking deviation becomes smaller, the actuator voltage is further increased, and if it becomes larger, the actuator voltage is decreased. By repeating such increases and decreases in the actuator voltage, at the actuator voltage when the reproduction output is maximum, that is, when the tracking deviation is minimum, the segment s
1, that is, the displacement position of the reproducing head 8 in the reproducing track width direction at segment s1 is determined.

[0005] Such tracking control is called "mountain climbing control", and conventionally this tracking control is applied to all segments s1, s2,..., sn.
Both were done simultaneously and independently of each other.

[0006]

[Problems to be Solved by the Invention] Conventionally, tracking control was performed simultaneously and independently for each segment s1, s2, ..., sn in this way. If the hunting of the vibration of the actuator 6 does not settle within the required time, for example, the actuator voltage may be increased or decreased for the segment (front segment) that is tracked earlier in time by the playback head 8 within the same playback track. When the actuator is displaced and the actuator displacement overshoots and causes hunting, the effect of the hunting also extends to the segment (backward segment) that is tracked later in time by the playback head. As a result, there is a problem in that it becomes difficult to perform tracking control in the rear segment favorably.

Therefore, in the present invention, the playback track of the magnetic tape is divided into a plurality of segments, and the playback output of each segment of the previous playback track is compared with the corresponding playback output of each segment of the next playback track. When performing tracking control on the segment based on the size comparison with the respective playback outputs, it is possible to perform good tracking control on the rear segment without being affected by the tracking control on the previous segment on the same playback track. The aim is to make it possible to do so.

[0008]

[Means for Solving the Problems] In order to achieve the above object, a tracking control method for a playback head according to the present invention is applied to a device having a playback head, an actuator, and a control circuit. The playback head tracks the playback track of the tape, the actuator moves the playback head in the width direction of the tape playback track in response to an actuator voltage, and the control circuit tracks the playback track of the tape. The actuator voltage is output-controlled so that the input playback output is maximized and the tracking deviation of the playback head with respect to the playback track is minimized. Divide into multiple segments, compare the magnitude of the playback output between corresponding segments of each playback track, determine the actuator voltage for each segment that will minimize the tracking deviation in that segment, and make sure that the actuator voltage is the same for each segment. The present invention is characterized in that after the actuator voltage in the front segment of the reproduction track is determined, the actuator voltage in the rear segment is determined.

[0009]

[Operation] When determining the actuator voltage that minimizes the tracking deviation for each segment of the playback track, the control circuit determines the actuator voltage for the segment that is tracked first by the playback head (front segment) in terms of time. Since the actuator voltage for the next segment (rear segment) is determined after this, there is no overshoot in the actuator displacement during tracking deviation control that minimizes the tracking deviation of the reproducing head with respect to the front segment. the result,
Tracking control that minimizes tracking deviation in the rear segment has no effect on the front segment.

0010

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. A video tape recorder to which the playback head tracking control according to the embodiment of the present invention is applied includes a rotary head drum 2, an actuator 6, a playback head 8, and a control circuit 16, similar to the one shown in FIG. The configuration of each of them is as described above, so a description thereof will be omitted.

The control circuit 16 specifically includes a head amplifier 20 that amplifies the reproduction output from the reproduction head 8, and an A/D converter 22 that converts the output of the head amplifier 20 from analog to digital.
, a microcomputer 24 that outputs a control output that maximizes the reproduction output based on the output of the A/D converter 22, a D/A converter 28 that converts the output of the microcomputer 24 from D/A, and a low-pass filter that cuts noise. 28 and
The driver 30 outputs an actuator voltage corresponding to the control output from the microcomputer 24.

The control circuit 16 also inputs the playback output from the playback head 8 as in the conventional case, and controls the actuator so that the input playback output is maximized and the tracking deviation of the playback head 8 with respect to the playback track is minimized. Although the voltage output is controlled, the difference from the conventional example is as follows.

That is, as shown in FIG. 1, the control circuit 16 divides the reproduction track into a plurality of segments, for example three (for convenience of explanation of the embodiment, three is used, but normally, the number of segments is greater than that). First, tracking control is performed by changing the actuator voltage for performing the "hill climbing control" for the first segment s1. At this time, other second and third segments s2,
The same actuator voltage as the first segment s1 is applied to s3 as well. In this way, when the actuator voltage at which the reproduction output for the first segment s1 is maximum, that is, the tracking deviation is minimum, is v1, the actuator voltage is determined to be v1 as shown in FIG. 1(a).

Next, the same tracking control as that for the first segment s1 is performed on the second segment s2, and if the actuator voltage when the tracking deviation becomes the minimum is v2, then (b) in FIG. Its v2 as shown
confirmed. Similarly, for the third segment s3, v3 is determined as shown in FIG. 1(c).

[0015] Thus, in the embodiment, the case where the reproduced track is divided into three segments has been explained, but even when the reproduced track is divided into n segments, the tracking control can be performed in the same way. Tracks the entire playback track.

Therefore, in this embodiment, tracking control is performed to determine the actuator voltage in the segment that is tracked earlier in time (front segment) by the reproducing head, and the actuator voltage for the next segment (rear segment) is determined. Since tracking control is performed for confirmation, tracking control can be performed on the rear segment without being affected by tracking control on the front segment, and good tracking control is possible for the entire playback track. Become.

Although the tracking control method of this embodiment is applied to a video tape recorder, it can be similarly applied not only to such a video tape recorder but also to other magnetic recording/reproducing devices or playback-only devices. be able to. Further, although the reproducing head in a video tape recorder is a magnetic head, the reproducing head can be applied not only to a magnetic head but also to an optical type or other type of head. Furthermore, since this embodiment has been described as being applied to a video tape recorder, the tape is a magnetic tape, but the present invention can be applied not only to magnetic tape but also to optical or other types of tape.

[0018]

[Effect of the invention] As is clear from the above explanation,
According to the present invention, when determining the actuator voltage at which the tracking deviation is minimum for each segment of the playback track, the actuator voltage at the segment that is temporally tracked first by the playback head (front segment) is determined. Since the actuator voltage for the next segment (backward segment) is determined, the actuator displacement during tracking deviation control to minimize the tracking deviation of the playback head with respect to the front segment will overshoot and cause hunting. Tracking control of the rear segment is no longer affected, and tracking control of the rear segment can be performed satisfactorily.

[Brief explanation of drawings]

FIG. 1 is a diagram showing changes in actuator voltage for tracking control for each segment, which is used to explain a tracking control method for a reproducing head according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a video tape recorder.

FIG. 3 is a diagram showing a playback track divided into a plurality of segments.

[Explanation of symbols]

2 Rotating head drum 4 Rotating drum side 6 Actuator 8 Play head 10 Fixed drum side 12 Slit 14 Magnetic tape 16 Control circuit

Claims (1)

[Claims] 1. Applicable to a device having a playback head (8), an actuator (6), and a control circuit (16), wherein the playback head (8) is connected to a tape (14).
The actuator (6) moves the playback head (8) in the width direction of the playback track of the tape (14) in response to the actuator voltage, and the control circuit (16) tracks the playback track of the tape (14). , inputs the playback output from the playback head (8), and controls the output of the actuator voltage so that the input playback output is maximized and the tracking deviation of the playback head (8) with respect to the playback track is minimized. If yes, each playback track is divided into multiple segments, and the magnitude of the playback output between the corresponding segments of each playback track is compared, and the actuator voltage that minimizes the tracking deviation in the segment is determined for each segment. A tracking control method for a playback head, characterized in that the actuator voltage in the rear segment of the same playback track is determined after the actuator voltage in the front segment in the same reproduction track is determined.