JPS6113296B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for recording a video signal by forming a predetermined track on a magnetic medium that is transported at a constant speed using a magnetic head attached to a rotating body. A video signal is obtained by reproducing a video signal recorded by scanning a predetermined track by a magnetic head attached to a rotating body while transporting the magnetic medium at a constant speed to obtain a reproduced video signal. The present invention relates to a tracking control system for a video signal reproducing apparatus in which the relative relationship between a magnetic head and a magnetic medium is controlled so that the scanning of a predetermined track of a magnetic head in the reproducing apparatus does not deviate from the predetermined track.

In the tracking control system of this type of video signal reproducing device, a magnetic It is necessary to obtain a track deviation detection signal that can detect deviations that take into account the direction of scanning of a predetermined track of the head from this predetermined track. A magnetic medium for recording a video signal on which a control signal having a certain period is recorded in advance on a track different from a track on which the video signal is recorded is used as the magnetic medium for recording the video signal. A video signal is reproduced from a magnetic medium on which a video signal is recorded, and a reproduced video signal is obtained, and a control signal is reproduced using a magnetic head different from the magnetic head for obtaining the reproduced video signal. A track deviation detection signal is obtained based on the control signal.

However, by obtaining a track deviation detection signal in this way, the relative relationship between the magnetic head and the magnetic medium can be controlled so that the scanning of a predetermined track by the magnetic head does not deviate from the predetermined track. In the conventional method, in order to obtain a track deviation detection signal, the magnetic medium on which the video signal is recorded must be a magnetic medium on which the control signal is recorded on a track different from the track for the video signal. First, it is necessary to increase the size of the magnetic medium on which the video signal is recorded by the track on which the control signal is recorded, or the density of the video signal that can be recorded in a certain area becomes smaller, and the density of the video signal that can be recorded in a certain area becomes smaller. This had drawbacks such as requiring a separate magnetic head.

Therefore, the present invention aims to propose a new tracking control method for a video signal reproducing device of this kind that can eliminate the above-mentioned conventional drawbacks, and will be clear from the following detailed description of embodiments of the present invention with reference to the drawings. It will be.

FIG. 1 shows an example of the present invention, which includes a rotating magnetic head device 2 capable of recording and reproducing video signals on a magnetic tape 1 as a magnetic medium.

This rotating magnetic head device 2 has a magnetic tape 1 which is obliquely guided in an Ω shape on a guide cylinder (not shown) and transported at a constant speed, and is arranged concentrically with the guide cylinder at the position of the guide cylinder. /
Rotates at s, that is, one frame period of the video signal
The image is scanned by magnetic heads 4A and 4B, which are mounted on the rotating body 3, which rotates once every 2 Tv, with an interval of approximately 180 degrees from each other, and therefore, the information to be recorded on the magnetic heads 4A and 4B is scanned. When a video signal is supplied, it is recorded on the magnetic tape 1 in such a manner that each field is formed with each track 5 inclined in the longitudinal direction of the magnetic tape 1, as shown in FIG. A video signal recorded on a magnetic tape 1 is reproduced by scanning a track 5 of the magnetic tape 1 with magnetic heads 4A and 4B.

Since such a rotating magnetic head device 2 is similar to a rotating magnetic head device in a known so-called helical-route two-head Ω type magnetic recording and reproducing device, further detailed explanation of the structure of this rotating magnetic head device 2 will be omitted. In addition, when the present invention obtains a reproduced video signal by scanning the track 5 of the magnetic tape 1 on which a video signal is recorded with the magnetic heads 4A and 4B and reproducing the recorded video signal, that is, during reproduction, the magnetic Since the object is to ensure that the scanning of the track 5 of the heads 4A and 4B does not deviate from this track 5, a detailed explanation of the system for recording video signals on the magnetic tape 1 will be omitted. The rotating shaft 6 of the rotating body 3 of the magnetic head device 2 is driven by the output of the servo amplifier 7,
connected to a main motor 8 which rotates with a period of 30 c/s or 2 Tv, while associated with the rotary shaft 6 a pulse generator 9, known per se, is provided, from which a pulse generator of 30 c/s or 2 Tv is provided.
A pulse train P1 having a period of 2 Tv is obtained, which is supplied to a phase comparator 11 via an amplifier 10, while during reproduction, for example, a pulse train P1 of 60 C/V from a commercial power supply 12 is supplied.
The high current signal AC of s is passed through the frequency down pulse shaping circuit 1.
3, from which a pulse P2 having a period of 30 c/s or 2 Tv is obtained, which is then supplied to these phase comparators 11, from which a phase comparison output of pulse trains P1 and P2 is obtained. , this is supplied to the servo amplifier 7 as a control signal,
Therefore, the main motor 8 is configured to rotate in phase synchronization with the alternating current signal AC during reproduction.

The magnetic tape 1, which is obliquely guided in an Ω shape on the guide cylinder of the rotating magnetic head device 2 and is transported at a constant speed, is transferred to the main motor 8 through a pulley 14, a belt 15 having elasticity, and a pulley 16. It is configured to be driven by a capstan 17 connected to the capstan 17 and a pinch roller 18 rotatably connected to the capstan 17.
However, the auxiliary motor 1 is installed in the middle of extending the capstan 17.
9 is inserted, and this auxiliary motor 19 is inserted during playback.
The rotational speed of the capstan 17 is controlled by supplying a track deviation detection signal to be described later. Furthermore, Capstan 17
When the rotational speed of the capstan 17 is controlled by the track deviation detection signal, the change in the rotational speed from the previous rotational speed of the capstan 17 which is not controlled based on the control is absorbed by the belt 15.

Furthermore, during reproduction, the reproduced video signals (referred to as SA and SB, respectively) obtained from the magnetic heads 4A and 4B attached to the rotating body 3 of the rotating magnetic head device 2 are now transferred from the magnetic head 4A onto the magnetic tape 1. Assuming that a reproduced video signal for the first field of the recorded video signal can be obtained, as shown in FIG. 3A for the reproduced video signal SA, the magnetic tape 1
It is obtained as a signal consisting of the first field, the third field, etc. of the video signal recorded above, and the second field, the fourth field, etc. of the video signal for the reproduced video signal SB. ..., and the reproduced video signals SA and SB obtained from the magnetic heads 4A and 4B, respectively, are sent to the synthesis circuit 2 via amplifiers 20A and 20B, respectively, as necessary.
1, and when a video signal is recorded on the magnetic tape 1 by this synthesis circuit 21, that is, at the time of recording, a series of reproduced video signals (this will be referred to as SC) similar to the video signal is composed. It is designed so that you can get it. In this case, the video signal recorded on the magnetic tape 1 is in the form of a modulated wave that is frequency modulated as usual, and therefore the reproduced video signal
It is assumed that SA, SB, and SC are also in the same modulated wave mode. As described above, the reproduced video signal SC obtained from the synthesis circuit 21 is supplied through the amplitude limiter 22 to the demodulation system 23, which is known per se, and from which a reproduced video signal that can reproduce an image in a television picture tube device is produced. SE is obtained and supplied to the picture tube device 24, so that a reproduced image of the video signal SE can be obtained on the display surface of the picture tube device 24.

As described above, a predetermined track 5 is formed by the magnetic heads 4A and 4B attached to the rotating body 3 on the magnetic tape 1 which can be transferred at a constant speed, and the video signal is recorded. While transporting the magnetic tape 1 at a constant speed, magnetic heads 4A and 4B attached to the rotary body 3 scan the track 5 to reproduce the recorded video signals SC to SE. An example of a video signal reproducing device, which is the premise of the present invention, has been clarified, and in the case of such a video signal reproducing device, as will be described later based on the present invention, a small number of magnetic heads 4A and 4B can be used. If one of the magnetic heads 4A and 4B is not vibrated, the scanning of the track 5 of the magnetic heads 4A and 4B is
If there is a relative relationship between track 5 and the magnetic heads 4A and 4B as shown in Figure AO, and there is no deviation from this track 5, the playback video signal SC shows that it has a scheduled shift as shown in Figure 3 DO. Width V _M0
However, when the magnetic heads 4A and 4B scan the track 5, the magnetic tape is scanned from the track 5 by having the relative relationship between the track 5 and the magnetic heads 4A and 4B as shown in FIG. 4A1. 1, for example, in the running direction, the reproduced video signal SC is obtained with an amplitude V _M1 smaller than the planned amplitude V _M0 as shown in FIG. 3 D1, and the magnetic heads 4A and 4B are The scanning of track 5 is shown in Fig. 4 A2.
A track 5 and magnetic heads 4A and 4B as shown in FIG.
If the track 5 is deviated from the track 5 in the opposite direction to the running direction of the magnetic tape 1, the reproduced video signal SC will be shifted from the planned amplitude V _M0 as shown in FIG. 3 D2. Therefore, the reproduced video signal SE cannot be obtained as a good S/ signal, and the interval between adjacent tracks 5 on the magnetic tape 1 is smaller than the width of the track 5 _. In this case, track 5 of magnetic heads 4A and 4B
If the deviation of the scanning from the track 5 becomes large, a problem arises in that each of the magnetic heads 4A and 4B scans two adjacent tracks 5 at the same time.

For this reason, an example of the present invention is based on the example of the video signal reproducing device described above, and one of the magnetic heads 4A and 4B in the rotating magnetic head device 2 described above, for example, the magnetic head 4A, is arranged in the length direction of the gap. The magnetic head 4A is made to vibrate with a predetermined amplitude that is sufficiently smaller than the width of the track 5, and the above-mentioned reproduced video signal SA is obtained from the magnetic head 4A, and the above-mentioned reproduced video signal SC is obtained from the synthesis circuit 21. Then, from the reproduced video signal SC obtained in this case, for example, a track deviation detection signal is obtained which can detect the deviation of the scanning of the track 5 of the magnetic heads 4A and 4B taking into account the direction from this track 5, and this track deviation detection signal is used. In order to correct the deviation of the scanning of the track 5 of the magnetic heads 4A and 4B from this track 5, the magnetic heads 4A and 4B and the magnetic tape 1
This will become clear from the embodiments described in detail below.

First, we will discuss the configuration for vibrating the magnetic head 4A in the rotating magnetic head device 2 in the length direction of the gap.The magnetic head 4A is attached to the rotating body 3 via a piezoelectric element 30, and The piezoelectric element 30 of the lever is made to vibrate with a vibration voltage. That is, the piezoelectric element 30 is
As can be seen with reference to FIGS. 5 and 6,
Two piezoelectric plates 33 and 34, each having conductive layers 31 and 32 on both sides, are bonded together with the conductive layers 32 applied thereto, and the plate 3
The outer conductive layers 31 of 3 and 34 are connected to the leads 3, respectively.
5 and 36, the inner conductive layer 32 is connected to each other to form a common lead 3 for leads 35 and 36.
7, respectively, and if voltages of opposite polarity are applied to leads 35 and 36 with respect to the voltage applied to lead 37, the plates 33 and 3
4 are both bent in the same direction, and therefore, when one end of the piezoelectric element 30 is fixed to the fixed part, the other end is bent from the reference position to the fixed part.
4, and one end of the piezoelectric element 30 is attached to a substrate 38 (attachment means not shown) attached to the rotating body 3. ) The plate surfaces of plates 33 and 34 are on the substrate 3.
For example, the magnetic head 4A is fixed to the free end of the plate 33 of the element 30 so as to be parallel to the plate 33, and the length direction of the gap (not shown) is parallel to the plate 33. It is installed perpendicular to the surface.

In this case, a plate portion 40 having plate pieces 39a and 39b attached to the free end thereof facing opposite side surfaces of the piezoelectric element 30, respectively, is extended forward from the front lower part of the substrate 38 integrally therewith. plate pieces 39a and 3
A damper material 4 is provided between each of the piezoelectric elements 9b and the piezoelectric element 30.
1a and 41b, and as described above, the piezoelectric element 30 connects its free end to the fixed part (in this case, the substrate 3
8) The free damping vibration damper members 41a and 41b can absorb the vibration that tends to occur when the vibration is bent to cause a sudden deviation.

On the other hand, the rotating body 6 of the above-mentioned rotating magnetic head device 2
The pulse example P1 obtained from the pulse generator 9 associated with The pulse train P1 is supplied to the monostable circuit 52, which generates a rectangular wave having a width of Tv/2 for each pulse of the pulse train P1 as shown in FIG. 3F1. A rectangular wave train R1 is obtained,
This is supplied to a combining circuit 53, while a pulse generator 54 similar to the pulse generator 9 is provided in conjunction with the rotary body 6 of the rotary magnetic head device 2, and from this a pulse generator 54 as shown in FIG. 3E2 is provided. Pulse train P1
A pulse train P2 having a phase difference of Tv is obtained, which is supplied to the monostable circuit 55, which generates a rectangular wave having a width of Tv/2 for each pulse of the pulse train P1 as shown in FIG. 3 F2. A certain rectangular wave train R2 is obtained, which is supplied to the synthesis circuit 53,
Therefore, from this circuit 53, Tv as shown in FIG.
A rectangular wave train R3 having a period of is obtained. The rectangular wave train R3 thus obtained from the synthesis circuit 53 is supplied to a waveform conversion circuit 56 having a resonance circuit or having a resistance filter circuit configuration,
As a result, a sinusoidal alternating current voltage V0 having a period of Tv as shown in FIG. AC voltage V
1 and an AC voltage V2 having an opposite phase as shown in FIG. Leads 35 of element 30
and 37, and between 36 and 37, so that the piezoelectric element 30 receives the vibration voltage VM.
Therefore, the magnetic head 4A vibrates in the length direction of the gap with a period of Tv.

The configuration for vibrating the magnetic head 4A in the rotating magnetic head device 2 in the length direction of the gap has been clarified above, and according to this configuration, the reproduced video signal SA obtained from the magnetic head 4A can be but,
When the magnetic head 4A does not vibrate, if the magnetic heads 4A and 4B and the track 5 on the magnetic tape 1 have the relative relationship shown in FIG. Then, as shown in FIG. 3 JO, the vibration in the first half and the second half of each field is the amplitude when the magnetic head 4A does not vibrate (this is called V _M0 '
shall be. Note that this amplitude V _M0 ' is obtained as a waveform corresponding to the waveform of the vibration voltage VM, which is smaller than the amplitude V _M0 of the reproduced video signal SC described above in FIG. If the magnetic heads 4A and 4B and the track 5 have the relative relationship shown in FIG. 4 A1 when the head 4A is not vibrating, and the magnetic heads 4A and 4B are deviated from the track 5. , as shown in FIG. 3 J1, the amplitude in the first half of each field is the amplitude when the magnetic head 4A does not vibrate (this is called V _M1 '
shall be. Note that this amplitude V _M1 ' corresponds to the amplitude V _M1 of the reproduced video signal SC described above in FIG. When the magnetic head 4A is not vibrating, the magnetic heads 4A and 4B and the track 5 have the relative relationship shown in FIG. Assuming that the heads 4A and 4B are offset from the track 5, the amplitude in the first half of each field is the amplitude when the magnetic head 4A is not vibrating (this is set to _M2 '. Note that this amplitude V _M2 ' becomes larger with a waveform corresponding to the waveform of the vibration voltage VM (corresponding to the amplitude V _M2 of the reproduced video signal SC described above in FIG. 3 D2). However, the amplitude in the latter half becomes smaller, and the reproduced video signal SB obtained from the magnetic head 4B
However, if the magnetic heads 4A and 4B and the track 5 have the relative relationship shown in FIG. 4A0, and the magnetic heads 4A and 4B are not deviated from the track 5, each field is The magnetic heads 4A and 4B and the track 5 are arranged as shown in FIG _. 4 A1 (or A2).
The magnetic heads 4A and 4B have the relative relationship shown in
It is clear that if deviates from track 5, a uniform amplitude V _M1 ' (or V _M2 ') can be obtained for each field, as shown in FIG. 3 K1 (or K2). Therefore, the reproduced video signal SC obtained from the combining circuit 21 is transmitted to the magnetic heads 4A and 4B and the track 5.
If the magnetic heads 4A and 4B have the relative relationship shown in FIG. 4 A0 and the magnetic heads 4A and 4B are not deviated from the track 5, then the magnetic heads 4A and 4B have the swing width shown in FIG. 3 L0 and the magnetic heads 4A and 4B If the magnetic heads 4A and 4B have the relative relationship shown in FIG. 4 A1 (or A2) with the track 5, and the magnetic heads 4A and 4B are deviated from the track 5, the swing width mode shown in FIG. 3 L1 (or L2) will be obtained. Therefore, it is clear that each can be obtained.

The above has clarified the configuration for vibrating the magnetic head 4A in the rotating magnetic head device 2 in the length direction of the gap, and the mode of the reproduced video signal SC obtained from the synthesis circuit 21 by the configuration. Then, from the reproduced video signal SC, the magnetic head 4
This track 5 of the scan of track 5 of A and 4B
To describe the configuration for obtaining a track deviation detection signal that can detect deviations that take into account the direction of the track shift, the reproduced video signal SC is supplied to an envelope detection circuit 61, and the detection output is supplied to a clamp circuit 62. The rectangular wave train R2 from the monostable circuit 55 mentioned above is supplied to the clamp circuit 62,
Therefore, from this clamp circuit 62, the reproduced video signal
When SC is obtained in the amplitude mode shown in FIG. 3 L0, the amplitude is both at the reference level (zero level) in the sections for the first half and the second half of each odd field of the signal SC, as shown in FIG. 3 M0. The waveform becomes smaller in the negative direction according to the waveform of the vibration voltage VM, and when the signal SC is obtained with the amplitude shown in FIG. 3 L1, each odd field of the signal SC becomes smaller as shown in FIG. 3 M1. In the sections corresponding to the first half and the second half, the amplitude becomes smaller than the reference level with a waveform corresponding to the waveform of the voltage VM for negative direction and positive direction vibration, and furthermore, the signal SC has an amplitude shown in FIG. 3 L2. As shown in FIG. 3 M2, in the sections corresponding to the first and second half of each odd field of the signal SC, the amplitude of the oscillating voltage VM increases in the positive and negative directions from the reference level, respectively. The output Q1 is designed to be small depending on the waveform.

Further, the output Q1 obtained in this way is supplied to the polarity inverting circuit 63, and when the output Q1 is obtained from this as the output shown in FIG. But the output Q1
is obtained with the output shown in FIG. 3 M1 (or M2), the output Q1 in this case and the output 1 having the opposite polarity are obtained as shown in FIG. 3 N1 (or N2), and so on. The output 1 thus obtained is supplied to one input of the switch circuit 64, while the output Q1 obtained from the clamp circuit 62 is directly supplied to the other input of the switch circuit 64. . On the other hand, switch circuit 6
4 is controlled by the rectangular wave train R1 obtained from the monostable circuit 52 mentioned above, and therefore this switch circuit 6
4, an output Q2 is obtained in which the polarity of the section corresponding to the first half of each odd field of the reproduced video signal SC of the output 1 is inverted,
Therefore, when output Q2 is obtained as output 1 as shown in FIG. 3 N0, as shown in FIG. 3 as O0, as shown in FIG. 3, as shown in FIG. This is achieved as shown in Figure O1 (or O2).

Furthermore, the output Q2 thus obtained is supplied to the smoothing circuit 65, and from this, the output Q2 becomes as shown in FIG.
When the output Q2 is obtained as shown in FIG. 3, it has a zero level when averaged as shown in P0 in FIG. 3, and when the output Q2 is obtained as shown in O1 (or O2) in FIG. (or P2), when averaged, a smoothed output G having a negative (or positive) level is obtained. However, Figure 3 P
As is clear from the above, when the magnetic head 4A is not vibrating, the smoothed output G is obtained when the output shown as 0 is obtained.As shown in FIG. Figure 4 A0
This is the output obtained based on the reproduced video signal SC obtained from the combining circuit 21 when the magnetic heads 4A and 4B have the relative relationship shown in FIG. P2)
The smoothed output G obtained with the output shown in FIG. 3 is L1 when the magnetic head 4A is not vibrating.
(or L2) as shown in magnetic heads 4A and 4B.
This is the output obtained based on the reproduced video signal SC obtained when the magnetic heads 4A and 4B are shifted from the track 5 and the magnetic heads 4A and 4B have the relative relationship shown in FIG. 4 A1 (or A2). , the smoothed output G is output from the magnetic head 4A from the reproduced video signal SC.
This can be said to be a track deviation detection signal that can detect deviations in the direction from this track 5 of the scanning of the track 5 of 4B.

From the reproduced video signal SC obtained from the synthesis circuit 21 in the above manner, the track 5 of the magnetic heads 4A and 4B is
The configuration for obtaining a track deviation detection signal consisting of the above-mentioned smoothed output G that detects the deviation taking into account the direction from this track 5 of scanning has been clarified. Based on the track deviation detection signal G mentioned above, the magnetic heads 4A and 4
To describe the configuration for controlling the relative relationship between the magnetic heads 4A and 4B and the magnetic tape 1 in order to correct the deviation from this track 5 in the scanning of the B track 5, the configuration for driving the magnetic tape 1 as described above will be described. An auxiliary motor 19 is placed on the way to the capstan 17.
is provided, and the above-mentioned track deviation detection signal G is supplied to the auxiliary motor 19 via an amplifier 66 as required.

The above is an embodiment of the present invention. According to this configuration, when there is no deviation in the scanning of the track 5 of the magnetic heads 4A and 4B from this track 5 (as shown in FIG. 4 A0), the track 5 is Since the deviation detection signal G has a zero level when averaged as shown in FIG. The speed is not changed in any way, so that the scanning of the track 5 of the magnetic heads 4A and 4B continues without deviation from this track 5. However, if the scanning of the track 5 of the magnetic heads 4A and 4B deviates from this track 5 as shown in FIG. 4 A1 (or FIG. 4 A2) due to such a state, the track deviation detection signal G When averaged as shown in Figure P1 (or Figure 3 P2), a negative (or positive) level is obtained, so the auxiliary motor 19 is activated and the rotational speed of the capstan 17 and the magnetic tape 1 are The transfer speed will be changed. Therefore, if the relationship between the polarity of the track deviation detection signal G and the changing direction of the rotational speed of the capstan 17 is appropriately selected in advance, the deviation of the scanning of the track 5 of the magnetic heads 4A and 4B from this track 5 can be corrected. As a result, the scanning of the track 5 of the magnetic heads 4A and 4B will not deviate from this track 5. Therefore, the synthesis circuit 21
The reproduced video signal SC is obtained as the signal described above in FIG. 3 L0. The amplitude of the thus obtained reproduced video signal SC fluctuates in each odd field, but if the amplitude of the above-mentioned vibration of the magnetic head 4A is relatively small, the amount of the fluctuation is , the amplitude of the reproduced video signal SC on the input side of the demodulation system 23 can be easily removed by the amplitude limiting circuit 22 without becoming unnecessarily small.

As described above, according to the embodiment of the present invention, the relative relationship between the magnetic head and the magnetic tape can be controlled so that the scanning of a predetermined track of the magnetic head does not deviate from the predetermined track. In this case, in order to obtain a track deviation detection signal that can detect the deviation of the scan of a predetermined track of the magnetic head taking into account the direction from this predetermined track, a magnetic head on which a video signal is recorded as in the past is used. There is no need to use a magnetic tape on which control signals are pre-recorded on a track separate from the track on which the video signal is recorded, and it is also possible to use a magnetic tape separate from the magnetic head for obtaining the reproduced video signal. Since there is no need to reproduce control signals from the magnetic tape, it has a great feature that can eliminate the drawbacks mentioned at the beginning.

In the above description, the track deviation detection signal is used to control the relative relationship between the magnetic head and the magnetic tape by supplying the track deviation detection signal to the auxiliary motor 19 which can be inserted into the capstan 17 which is driven in the main mode 8. In the case described above, the capstan 17 is driven by another motor instead of the main motor 8, and the drive system of the motor is controlled by the track deviation detection signal. It is also possible to obtain the same effect by using it.

In addition, in the above description, the present invention is applied to a video signal reproducing device when a rotating magnetic head device similar to the rotating magnetic head device in a so-called helical two-head Ω type magnetic recording and reproducing device is applied to reproduce a video signal. This is an embodiment in which the invention is applied, and a video signal is reproduced by applying a rotating magnetic head device similar to a rotating magnetic head device in a so-called helical one-head α type magnetic recording and reproducing device. The present invention can also be applied to a video signal reproducing device in such a case.

Furthermore, since a magnetic tape is used to record video signals by forming a magnetization trajectory diagonal in the longitudinal direction, it can be used not only for reproducing video signals, but also for forming a magnetization trajectory parallel to the transport direction or the longitudinal direction sequentially in the longitudinal direction. The present invention can also be applied to an apparatus for reproducing video signals from a magnetic sheet on which video signals are repeatedly recorded, and many other modifications and changes may be made without departing from the spirit of the present invention.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an example of a tracking control method for a video signal reproducing device according to the present invention, FIG. 2 is a diagram showing tracks on a magnetic tape for explaining the method, and FIG. 3 is for explaining the present invention. Signal waveform diagram,
FIG. 4 is a diagram showing the relative relationship between the tracks on the magnetic tape and the magnetic head, and FIGS. 5 and 6 are a schematic plan view and a side view, respectively, showing a configuration for vibrating the magnetic head. In the figure, 1 is a magnetic tape, 2 is a rotating magnetic head device, 3 is a rotating body, 4A and 4B are magnetic heads, and 7
is a servo amplifier, 8 is a main motor, 9 is a pulse generator, 17 is a capstan, 19 is an auxiliary motor,
21 is a synthesis circuit, 22 is an amplitude limiter, 23 is a demodulation system, 24 is a picture tube device, 30 is a piezoelectric element, 53 is a synthesis circuit, 54 is a pulse generator, 61 is an envelope detection circuit, 62 is a clamp circuit, 64 represents a switching circuit, and 65 represents a smoothing circuit.

Claims (1)

[Claims] 1. In a video signal reproducing device configured to sequentially reproduce video signals from a plurality of tracks using a magnetic head from a magnetic recording medium in which video signals are recorded on a plurality of tracks, a vibration imparting means comprising a piezoelectric element mounted on a rotating body so that the head can vibrate in the width direction of the recording track at predetermined intervals; and a circuit for detecting a vibration width envelope value of the reproduced output from the magnetic head. a circuit for inverting the detected envelope value output; a circuit for alternately extracting the envelope value output via the inverting circuit and the envelope value output not via the inverting circuit every 1/2 cycle of the predetermined cycle; track deviation amount detection means comprising a circuit for smoothing the output taken out; recording medium transport means comprising a pinch roller, a capstan, and a capstan motor for transporting the recording medium; and the transport means based on the output of the detection means. and a speed control means for controlling the magnetic head and the recording medium transport means via the speed control means based on the output of the detection means to maintain the relative positions of the magnetic head and the recording medium in a predetermined relationship. A tracking control method for a video signal reproducing device characterized by: