JPS60115043A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain reproduced pictures of high quality by using a means to reproduce signals recorded previously on the track of a magnetic tape and another means for detecting and correcting a vertical shift of a traveling magnetic tape. CONSTITUTION:The signal of a fixed amplitude which is recorded on a control track 13 allocated to the lower part of a magnetic tape 4 wound around a drum 1 at a prescribed winding angle is reproduced by a magnetic head 8. A control post is provided to a tape drive system, and the tape 4 is wound around a rotary roll 20. If the traveling tape receives disturbance, the voltage is applied to a piezoelectric element 24 with the faulty output of the control signal. Then the element 24 is extended toward arrows P1 and P2 to correct the position shift of the tape 4. Thus it is possible to correct immediately the unstable drive of the tape 4 due to the disturbance, etc. by means of the element 24.

Description

[Detailed description of the invention] Technical field The present invention relates to a magnetic recording/reproducing device such as a VTR.

Prior Art In conventional magnetic recording and reproducing devices such as VTRs, a magnetic tape supplied from a reel is wound around a drum at a predetermined angle, and image signals are recorded or reproduced by a magnetic head provided on the drum. Here, since the running of the magnetic tape in the vicinity of the magnetic head is left to natural running, the running may be disturbed due to external disturbances, and the position of the magnetic tape may shift in the direction perpendicular to the running direction. Such positional deviation of the magnetic tape directly appears as a disturbance in the reproduced image.

FIG. 1 is an explanatory diagram of an envelope of a reproduced image signal. When the magnetic tape is running stably without any disturbance, the envelope of the reproduced output is stable as shown in FIG. 1(a). On the other hand, when the running of the magnetic tape becomes unstable due to a disturbance, the magnetic tape is displaced in a direction perpendicular to the running direction, and the envelope of the reproduced output is disturbed as shown in FIG. 1(b). Note that position A in the figure indicates a point in time when the running of the magnetic tape is unstable.

As mentioned above, if the running becomes unstable due to disturbances or the like, there is a drawback that the magnetic tape cannot properly reproduce the positional deviation area image signal, and therefore a good reproduced image cannot be obtained. However, conventionally, no particular measures have been taken to stabilize the running of the magnetic tape.

Purpose of the Invention The present invention has been made to overcome the above-mentioned drawbacks of the prior art. It is an object of the present invention to provide a magnetic recording and reproducing device that can obtain reproduced images.

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention reproduces a signal (for example, a control signal) of a constant amplitude recorded in advance on a predetermined track (for example, a control track) of a magnetic tape, and reproduces the reproduction output. To provide a magnetic recording and reproducing device which detects a deviation in a direction perpendicular to the running direction of a magnetic tape based on the magnitude of voltage, and corrects the position of the magnetic tape by a correction means operated based on the detection result. It is something.

Embodiments Hereinafter, some embodiments of the present invention will be described with reference to FIGS. 2 to 6 of the accompanying drawings. In addition, in the following description of the drawings, the same elements are indicated by the same reference numerals. FIG. 2 is a perspective view of a drum according to one embodiment. The drum 1 is composed of an upper drum 7 serving as a rotating drum and a lower drum 3 serving as a stationary drum. The magnetic tape 4 is wound around the drum 1 at a predetermined angle by posts 5 and 6, and a magnetic head 8 for reproducing control track signals is provided on the lower drum 3 at a position along the lead surface 7 of the magnetic tape 4. .

FIG. 3 is an explanatory diagram of the position of each track on the magnetic tape 4. As shown in FIG. An audio track 11 for recording audio signals is assigned to the top, a video track for recording video signals to the middle, and a control track 13 for recording control signals to the bottom.

FIG. 4 is an enlarged view of the vicinity of the magnetic head 8 in the perspective view of FIG. When the magnetic tape 4 is running stably, the magnetic head 8 is positioned along the lead surface 7 as shown in FIG. 4(a). Therefore, the magnetic head 8 stably reproduces a signal (for example, a control signal) having a constant amplitude recorded on the control track 13. On the other hand, if the running of the magnetic tape 4 is disturbed by a disturbance, the fourth
As shown in Figure (bl), the magnetic head 8 protrudes below the lead surface 7.

The reason why the magnetic spatula 8 protrudes downward in this way is because the magnetic tape 4 is restricted by the lead surface 7 and does not move downward (does not shift). This causes signal playback to become unstable (playback output decreases).

Figure 5 shows the transition from stable running as in Figure 4 (a) to Figure 4 (b).
7 is a graph showing changes in the reproduction output voltage (envelope) of the magnetic head 8 when running becomes unstable as shown in FIG. In FIG. 5, the reproduction output also maintains a constant value during stable running, but when disturbances are added and the vehicle becomes unstable from time t, the reproduction output sharply decreases.

FIG. 6 is a front view of a regulating post for correcting the position of the magnetic tape 4 based on changes in reproduction output voltage as shown in FIG. This regulating post is provided as close to the drum 1 as possible in the magnetic tape running system. The regulating post includes a rotating roller 20 with which the magnetic tape 4 comes into contact, a shaft 21 that serves as a rotation axis of the rotating roller 20 and a support for attaching the post to the main body of the apparatus, and a magnetic tape wound around the rotating roller 20. It is composed of a collar 22, 23 that regulates the tape from above and below, and a piezoelectric element 24 provided inside the collar 22. The piezoelectric element 24 extends in the direction of arrow P1 or contracts in the direction of arrow P by applying a voltage.

Next, the operation of the embodiment shown in FIGS. 1 to 6 will be explained. Assume that there is a disturbance while the magnetic tape is running stably, and the positional relationship between the magnetic head 8 and the control track 13 changes from the state shown in FIG. 4(a) to the state shown in FIG. 4(b). Then,
The reproduction output of the control signal by the magnetic head 8 is the fifth
The voltage decreases as shown in the figure, and a voltage is applied to the piezoelectric element 24 of the regulating post based on the change in the reproduced output voltage.

This voltage application causes the piezoelectric element 24 to extend in the direction of the arrow in FIG. 6, thereby correcting the positional deviation of the magnetic tape. When the magnetic tape returns to stable running, the reproduction output of the magnetic head 8 also stabilizes at a constant value, so the piezoelectric element 24 is returned to its original state.

The above embodiment is for a VTR in which a control signal is recorded in the control trunk (tracking is performed using control signal C2), but the distribution of control tracks is different from that of an 8mm VTR. Regardless of the content, the present invention can also be applied to VTRs that perform tracking using a four-frequency pilot system. In other words, in the 8mm JIVTR, we focused on the fact that any signal can be recorded on the control track without any problem.For example, when recording a video signal, a high frequency sine wave or square wave signal is recorded on the control track with a constant amplitude. to be recorded.

In this way, as in the embodiments shown in FIGS. 1 to 6, stable running of the magnetic tape can be maintained by driving the piezoelectric element of the regulating post based on changes in the envelope of the reproduction output voltage. .

Effects of the Invention As described above, according to the present invention, a signal with a constant amplitude recorded on a predetermined track of a magnetic tape is reproduced, and a positional deviation of the tape is detected based on a change in the reproduction output, and the running position is corrected. Therefore, when the running of the magnetic tape becomes unstable due to disturbance or the like, it is possible to immediately correct the instability, and to obtain a magnetic distribution reproducing apparatus which can obtain a good reproduced image.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an envelope of a reproduced image signal of a conventional device, and FIG. 2 is a perspective view of a drum according to an embodiment of the present invention.
Fig. 3 is an explanatory diagram of the position of each track on the magnetic tape, Fig. 4 is a partially enlarged view of the device shown in Fig. 2, and Fig. 5 is a graph illustrating changes in reproduction output voltage by the magnetic head of Fig. 4. , FIG. 6 is a front view of the regulating post for correcting the positional deviation of the magnetic tape. 1...Drum 2...Upper drum 3...Lower drum 4... ...Magnetic tape 5.6...
......Post 7...Lead surface 8...Magnetic head 11...
・・・・・・Audio track 12・・・・・・
・・・・・・Video track 13・・・・・・・・・・・・
Control track 20...Rotating roller 21...Shaft 22.
23...Brim 24...Piezoelectric element Fig. 1 (G) (b) A Fig. 2 Fig. 3 Fig. 4 (C1) (b)

Claims (2)

[Claims] (1) A magnetic tape is wound around a rotating drum over a predetermined angle, and a reimage signal is recorded on the magnetic tape by a magnetic head provided on the rotating drum. A magnetic recording and reproducing apparatus for reproducing the magnetic tape includes a reproducing means for reproducing a signal of a fixed size pre-recorded on a predetermined track of the magnetic tape, and a reproducing means for reproducing a signal of a constant magnitude recorded in advance on a predetermined track of the magnetic tape, and a signal of a certain magnitude perpendicular to the running direction of the magnetic tape based on the output of the reproducing means. A magnetic recording and reproducing apparatus comprising: a detection means for detecting a deviation; and a correction means for correcting the vertical deviation of the magnetic tape based on the output of the detection means. (2) The magnetic recording and reproducing apparatus according to claim 1, wherein the reproducing means is a magnetic head for position detection provided on the rotating drum.