JPH0612744A - Method and device for reproduction - Google Patents

Abstract

PURPOSE:To execute special reproduction in a broad reproducing speed range by providing a suspension time reproducing no signal at a reproducing time and driving a movable post, to execute jump operation to a next target track position during the suspersion time. CONSTITUTION:A magnetic tape 50 is wound on a drum 10 in helical exceeding 180 degree a few, and the recording or the reproducing of a signal is executed by heads 11a, 11b attached to the drum 10 when the tape is moved from a feeding reel 40 to a take-up reel 42 by a capstan 28. In such a case, by a system that the jump operation to the next target track is executed during the suspension time after reproducing 1 track, other reproducing speeds (3 times, 4, 5 times or -1/2 times, -1 times, -2.5 times etc.), as well are applicable and a smooth special reproducing image is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for reproducing a signal recorded on a tape-shaped recording medium by a rotary head drum.

[0002]

2. Description of the Related Art As a reproducing apparatus of this kind, a VTR, a DAT and the like which use a magnetic tape have been conventionally known.
In such an apparatus, it is necessary to correctly trace the head attached to the rotary head drum (hereinafter referred to as drum) on the recording track of the magnetic tape. In order to achieve this, a. A method of controlling the rotation speed of the capstan based on the tracking error signal generated from the reproduction signal, b. Based on a tracking error signal generated from a reproduction signal, a method is used in which the head itself is moved by an actuator using a bimorph element, a voice coil, etc., and the position is controlled.

As a third method, a method of driving a tape wound around a drum in a traveling direction using a movable post based on a tracking error signal generated from a reproduction signal is prior to the applicant of the present application. Applications have been filed (Japanese Patent Application No. 63-1188553, Japanese Patent Application No. 63-127002, etc.). This third method can realize higher responsiveness, smaller device size, and lower cost than the previous two methods, and is particularly suitable for a narrow track digital VTR.

[0004]

However, in the above-mentioned third method, the most frequently used method is 2
When a reproducing operation is performed by the head constantly outputting a reproducing signal like a head helical scan type VTR, a good reproduced image cannot be obtained especially in special reproduction such as slow motion reproduction or search reproduction. There are cases.

For example, in the case of double speed reproduction, as shown in FIG.
As indicated by the solid line in (a), the tape must be run so as to reproduce every other track. Then, the difference from the locus of the average traveling speed indicated by the broken line in the figure is solved by moving the tape with the movable post. This operation command signal is formed by a sawtooth wave as shown in FIG. 5B. However, in actuality, there is a limit to the response of the movable post as shown by the broken line in the figure, so off-track As a result, a good reproduction signal cannot be obtained.

In view of the above problems, it is an object of the present invention to provide a reproducing method and apparatus in which the off-track generated while the tape moves to the next target position does not affect the reproduced signal.

[0007]

SUMMARY OF THE INVENTION In order to solve the conventional problems and achieve the above object, a reproducing method according to the present invention is a rotary drum having a head capable of reproducing information recorded on a recording medium. In a reproducing apparatus provided with a speed varying means for changing the traveling speed of a wound tape-shaped recording medium with respect to the average traveling speed, there is a reproducing operation pause period in which the head is separated from the recording medium, and during special reproduction. , Regardless of the average traveling speed during special reproduction, during the reproducing operation, the speed changing means allows the vehicle to travel at the standard reproducing speed, and during the reproducing operation pause period, the vehicle can travel at the standard reproducing speed from the next target track position. Thus, the traveling speed of the recording medium is changed by the speed changing means.

Further, in the reproducing apparatus according to the present invention, a tape-shaped recording medium is wound around a rotary drum having a head to form a recording medium running system, and a signal recorded on the wound tape-shaped recording medium is recorded. Is a reproducing device for reproducing the recording medium traveling system, the recording medium traveling system being located at an inlet side and an outlet side with respect to the rotary drum, respectively, abutting the tape-shaped recording medium to move the recording medium traveling system, and a traveling position of the recording medium. First to regulate
And a second post, first and second support means for movably supporting the first and second posts, and a driving force for driving the first and second support means. Drive means, the first and second posts are capable of changing the traveling speed of the tape-shaped recording medium wound around the rotating drum with respect to the average traveling speed, and the head is configured to change the traveling speed of the recording medium. The drive means has a reproduction operation pause period separated from each other, and during the special reproduction, the drive means performs the standard reproduction of the recording medium by the first and second posts during the reproduction operation regardless of the average traveling speed during the special reproduction. In order to allow the vehicle to travel at a speed, and to travel at a standard reproduction speed from the next target track position during the reproduction operation pause period,
And a second post configured to control the first and second support means to change the traveling speed of the recording medium.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of the present invention, and FIG. 2 is an operation explanatory view of this embodiment. In FIG. 1, 10
Is a drum, 12 is a tape cassette, 14 to 27 are guide posts, 28 is a capstan, 30 is a pinch roller, 32 is an erasing head, 34 to 36 are fixed heads, 40 is a supply reel, 42 is a take-up reel, Reference numeral 50 is a magnetic tape, and 65 and 75 are voice coil motors.

A magnetic tape (hereinafter referred to as a tape) 50 is helically wound around the drum 10 at a little more than 180 degrees, and when the capstan 28 travels from the supply reel 40 to the take-up reel 42, the drum 50 is rotated. Signals are recorded or reproduced by the heads 11a and 11b attached to the device 10. In this embodiment, the heads 11a, 1
1b is arranged close to one side of the drum 10.
Recording or reproduction is performed during about half a rotation in which the heads 11a and 11b are in sliding contact with the tape 50, and the rest state is maintained during the remaining half rotation. Also, the posts 18, 2
3 is erected on arms 60 and 70 which are swung by voice coil motors 65 and 75, respectively. And
By driving these two motors 65 and 75, it is possible to change only the portion wound around the drum 10 with respect to the average running speed V _C of the tape 50 run by the capstan 28.

With the configuration as described above, the amount of information that can be recorded or reproduced is the same as when two heads arranged opposite to each other at 180 degrees are used alternately, but two heads at the same time. In order to operate, the signal must be digitized and at least one track must be stored in memory. However, using a memory for one track or more in a digital VTR or the like for recording / reproducing a digital signal can be said to be an essential requirement for error correction processing and signal processing, so there is almost no problem. Rather, by centrally arranging the heads, unevenness of the track pitch due to tape vibration and drum bearing accuracy is reduced, and the track pitch accuracy is improved.
There is an effect that recording and reproduction of a narrower track can be realized.

Further, even in the case of analog recording, the digitization of the signal processing unit improves the accuracy, reduces the adjustment man-hours, and the LSI.
It is being promoted for the purpose of facilitating the improvement of the system, and only a small part such as a modulation / demodulation part is required for two systems, and it is hardly disadvantageous as in the case of digital recording, and rather the effect for narrowing the track is greater. .

Next, the special reproduction operation in this embodiment will be described with reference to FIG. FIG. 2A shows the movement of the tape 50 wound around the drum 10 (FIG. 1), with the tape running position on the vertical axis and the time on the horizontal axis. With respect to the straight line of double speed reproduction shown by the broken line,
That is, one track is played back at half the speed, the speed is increased during the next playback pause time, and the tape is moved to the next target track position during the next playback. Even at the double speed, the target track can be traced at the single speed during the reproducing operation. At this time,
The component that drives the posts 18 and 23 (FIG. 1) to move the tape is the difference from the average speed indicated by the broken line, and thus has a triangular waveform as shown in FIG. Since the waveform is continuous in this way, it is possible to trace faithfully. However, in reality, since the response band is limited, the area around the apex will be rounded and a phase delay will occur.
As indicated by the broken line in FIG. 2B, the drive waveform may be close to a sawtooth wave so that the track is completely traced during reproduction and the disturbance of the waveform is converged during the reproduction pause time. This operation waveform is subjected to a jump operation to the position of the next target track after the end of reproduction of one track, and damping is added according to the response characteristic of the drive system so that the disturbance is converged by the time the reproduction of the next track is started. That is what you get.

As described above, other reproduction speeds (3 ×, 4.5 × or −1 / 2 ×, −1) are obtained by the method of performing the jump operation to the next target track during the pause time after the reproduction of one track. 2 times, -2.5 times, etc.) and a smooth special reproduction image can be obtained.

Although the waveform of FIG. 2B has an offset (DC component) in the lower part, in practice, such a low frequency component is reduced by performing feedback control on the capstan 28. Can be made. In this embodiment, the tracking error signal is generated by the low frequency pilot method used in the 8 mm VTR.
The jump operation described above is performed by the voice coil motors 65, 7
This is performed by driving the posts 18 and 23 by a predetermined amount based on a signal from a rotation angle detector (not shown) incorporated in the device 5. When the reproducing operation starts, a tracking error signal is generated and fed back to the voice coil motors 65 and 75 to trace the target track, and the low frequency component of the drive waveform of the voice coil motors 65 and 75 at this time is capstaned. Please give feedback to 28.

By the way, according to the present invention, it is possible to follow the waviness and inclination of the track even in the tracking operation during the reproduction at the normal speed. This will be described below.

The track linearity is practically 4-8 μmp.
An error of about −p is unavoidable, and tracking that follows the waviness and inclination of the track is necessary to realize compatible reproduction on a narrow track of 10 μm or less. When reproducing a continuous envelope as in the prior art, since the heights of the track start end and track end do not match at the time of head switching, a discontinuity occurs in the method of moving the tape in the running direction. As a result, complete playback was not possible.

However, in this embodiment, since there is a reproduction pause time, no discontinuity occurs and complete tracking can be performed. That is, as described above, in this embodiment, the tracking error signal is generated by the pilot method, and the voice coil motors 65 and 75 may be driven by this. In this case, it is necessary to store the error signal in advance so as to move to the start position of the next track during the reproduction pause time. This is effective only at the track start position, but more effective when performed over all tracks. Further, not only the immediately preceding error signal but also a plurality of times of signals are averaged and used to perform so-called learning control, whereby stability and accuracy can be further improved.

In the above-mentioned embodiment, one screen is formed by two tracks and is reproduced simultaneously by the two heads 11a and 11b. However, one screen is formed by four tracks or one screen is formed by seven tracks. Even if the number of tracks is different from that in the embodiment, the present invention can be similarly implemented by performing the jump operation during the pause time after reproducing one screen. In that case, the larger the number of tracks, the longer the jump distance, and therefore the range of reproducible magnification becomes smaller.

The number of heads is not two but four and six.
Individuals are also acceptable. Alternatively, as shown in FIG. 3, the winding angle may be reduced. In this embodiment, the winding angle is approximately 90 degrees. Further, even in the same head arrangement as that shown in FIG. 4, the number of rotations of the drum 10 may be doubled so that the recording or reproducing operation is performed only once every two rotations. In any case, it is sufficient that the pause time during which the reproducing operation is not performed occurs after reproducing one screen.

When the signal is an interlaced image signal, only one field signal may be reproduced and output using the field memory, and the time of the opposite field may be used as the reproduction pause time. In that case, although the temporal or spatial resolution of the reproduced image is somewhat lowered, a sufficient reproduced image with no practical problems can be obtained.

Further, in the above embodiment, the device for moving the tape by using the voice coil motor is used, but other actuators using a piezoelectric element or pneumatic pressure or hydraulic pressure may be used. In short, it suffices if the position of the tape contacting the rotary head can be moved at high speed.

The tracking error signal may be generated by various methods other than the pilot method.

Further, in the above-described example, the fixed head 35 for recording / reproducing the control signal is provided outside the tape movable portion so as not to increase the load. However, the fixed head 35 may be installed inside the movable portion and used for tracking. You can also

[0026]

As is apparent from the above description, according to the present invention, the movable post is driven so as to perform the jump operation to the next target track position while providing the pause time during which the signal is not reproduced during the reproduction. This enables special reproduction in a wide reproduction speed range.

Further, there is an effect that the compatibility is improved in a narrow track of 10 μm or less.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the embodiment shown in FIG.

FIG. 3 is an explanatory diagram of a rotary head drum of another embodiment.

FIG. 4 is an explanatory view of a rotary head drum of still another embodiment.

FIG. 5 is an operation explanatory diagram of a conventional example.

[Explanation of reference numerals] 10 rotating head drum 11a head 11b head 12 cassette 17 guide post 18 guide post 19 guide post 22 guide post 23 guide post 24 guide post 28 capstan 50 magnetic tape 65 voice coil motor 75 voice coil motor

Claims (3)

[Claims] 1. A reproducing apparatus having speed varying means for changing a traveling speed of a tape-shaped recording medium wound on a rotary drum having a head capable of reproducing information recorded on a recording medium with respect to an average traveling speed. In the apparatus, the head has a reproduction operation pause period in which the head is separated from the recording medium, and during special reproduction, the speed changing means travels at a standard reproduction speed regardless of the average traveling speed during special reproduction. The reproducing method is characterized in that the traveling speed of the recording medium is changed by the speed changing means so that the vehicle can travel at a standard reproducing speed from the next target track position during the reproducing operation pause period. 2. A reproducing apparatus for winding a tape-shaped recording medium around a rotary drum having a head to form a recording medium running system, and reproducing a signal recorded on the wound tape-shaped recording medium. First and second positions of the recording medium running system that are located on the inlet side and the outlet side of the rotary drum, respectively, are brought into contact with the tape-shaped recording medium to move the recording medium, and regulate the running position of the recording medium. And a first post that movably supports the first and second posts.
And a second supporting means, and a driving means for generating a driving force for driving the first and second supporting means, wherein the first and second posts are wound around the rotary drum. The traveling speed of the tape-shaped recording medium is changed with respect to the average traveling speed, the head has a reproduction operation pause period in which the recording medium is separated from the recording medium, and the drive means during special reproduction, during special reproduction. Irrespective of the average traveling speed of the
The first and second posts allow the recording medium to run at the standard playback speed by the post of the first post, and to run at the standard playback speed from the next target track position during the playback operation pause period. A reproducing apparatus characterized in that the first and second supporting means are controlled to change a traveling speed of a medium. 3. A speed varying means for changing a running speed of a tape-shaped recording medium wound on a rotary drum having a head capable of reproducing information recorded on the recording medium with respect to an average running speed, and In a reproducing apparatus capable of reproducing a signal forming an image of one frame in two fields, during special reproduction, a signal obtained by performing a reproducing operation of one or a plurality of tracks having information of one field is stored in a field memory. During playback pauses that occur during storage and repeated display of this memorized signal,
A reproducing method characterized in that the recording medium is run to a next target track position.