JPH028384B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic tracking control device for a magnetic recording/reproducing device such as a VTR.

In conventional rotary head type VTRs, tracking control is performed to ensure that the video track recorded on the magnetic tape is scanned correctly by the rotary head during playback, based on control signals recorded on so-called control tracks at the ends of the magnetic tape. Generally, methods are used to control the rotational speed of a rotating head or the running speed of a magnetic tape.

However, in conventional devices that perform tracking control using this control signal, the relative positional relationship between the control head that records and reproduces the control signal and the rotary head must be constant for each device; If the relationship is different for each device, there is a problem that tracking will not be performed correctly, so when performing so-called compatible playback, tracking must be manually adjusted each time to obtain the best S/N. There was a problem.

In addition, not only in compatible playback but also in self-recording, if the control head is not properly mounted with respect to the tape, the control signal will not be recorded and played back correctly, and tracking control will become unstable. There was a problem with reliability.

In view of the above-mentioned drawbacks of the prior art, it is an object of the present invention to eliminate the control head that has conventionally been commonly used for tracking control, and to always achieve the best S/N not only in self-recording and playback but also in compatible playback. The object of the present invention is to provide a device that automatically controls tracking so as to obtain the desired results.

In order to achieve the above objects, the present invention firstly measures the running speed of a magnetic tape based on an index signal that is multiplexed with a video signal to be recorded instead of a conventional control signal and is reproduced. to perform tracking control, and second, detect a temporal change in the index signal before the tracking control locks in, and use the detected signal to determine the S/N of the reproduced video signal.
After setting the target value for the tracking control that gives the best value, the control operation is performed so that the system locks into the target value.

Hereinafter, the case where the present invention is applied to a rotary two-head type VTR will be explained in detail by way of an example.

FIG. 1 is a diagram showing an embodiment of a servo control device for recording an index signal according to the present invention, and FIG. 2 is a diagram showing waveforms of various parts thereof.
The magnetic tape 1 is driven to travel by a capstan motor 5, and the capstan motor 5 is driven to rotate at a constant speed by a capstan servo circuit 52. 2
Reference numerals 1 and 22 designate magnetic heads that alternately record video signals from the video signal recording circuit 61 on the magnetic tape 1 for each field.
22 are mounted on the disk 2 at an angle of 180 degrees to each other and are driven to rotate together with the disk 2 by the disk motor 4.

Although not shown, two magnets are attached to disk 2 at an angle of 180 degrees to each other.
By detecting this with the task head 3, a pulse (hereinafter referred to as a disk task pulse) synchronized with the rotation of the magnetic heads 21 and 22 is generated.
Abbreviated as DTP. ) is obtained from Task Head 3.
The DTP signal from the tack head 3 is phase-adjusted by a phase adjustment circuit 31 so that the magnetic heads 21, 22 and the magnetic tape 1 have a predetermined relative positional relationship, and then supplied to a pulse forming circuit 32. The pulse forming circuit 32 outputs a pulse S having a duty ratio of 50% in synchronization with the DTP signal as shown in FIG. 2a. 10 is a terminal to which a video signal to be recorded is supplied; the video signal from this terminal 10 is supplied to a vertical synchronization separation circuit 101, which separates a vertical synchronization signal VS and outputs it. This vertical synchronizing signal VS is down-done to 1/2 in frequency by the frequency down-down circuit 102,
A vertical synchronization signal VF with a frame period is output from the circuit 102. This vertical synchronization signal VF is phase-compared with the rising phase of the pulse S from the pulse forming circuit 32 in a phase comparison circuit 40, and a phase error signal corresponding to the phase difference between the two is outputted from the phase comparison circuit 40. This phase error signal is supplied to the disk motor 4 via the disk servo circuit 41,
As a result, the disk motor 4 is driven at a rotational speed equal to the frame frequency, and therefore the frequency of the pulses S is equal to the frame frequency.

Next, the pulse S from the pulse forming circuit 32 is
is supplied to a delay multi-circuit 33, which outputs a pulse P that is triggered by the rising edge of the pulse S and remains at a high level for a certain period of time _tx , as shown in FIG. 2b.

34 is an index signal forming circuit;
As shown in FIG. c, an index signal that is triggered by the falling edge of the pulse P from the delay multi-circuit 33 and remains at a high level for a certain period of time is formed. Therefore, this index signal is synchronized with the pulse S,
The pulse has a frame period delayed by a fixed time t _x from the rising phase of the pulse S. This index signal is multiplexed with the video signal from the terminal 10 by the index multiplexing circuit 60 during, for example, a vertical blanking period, and then recorded on the magnetic tape 1 via the video signal recording circuit 61 by the magnetic heads 21 and 22. be done.

Next, FIG. 3 is a diagram showing a part of the pattern of a video track recorded and formed on the magnetic tape 1 by the above-described servo control during recording. The operating principle of tracking control will be explained below.

In the figure, Ho is the scanning start point of the magnetic head on the magnetic tape, and thereafter the magnetic head scans the tape to form a video track To. C indicates the scanning center line at this time.

The relative relationship between this scanning start point Ho and the magnetic tape end A is determined by the relative positional relationship between the disk 2 and the magnetic tape 1 in FIG.
Ho is located on line H at a position on the tape a certain distance from end A of the magnetic tape. So is the point at which the rising phase of the pulse S corresponds to the position on the video track To, and the relative positional relationship between So and the magnetic tape end A is determined by the phase adjustment circuit 31 in FIG. This So is located on a line G at a position on the tape a certain distance from the end A of the magnetic tape.

Io is the video track of the index signal.
As is clear from the waveform diagram in FIG. 2, the recording position Io is on the pulse S
The point corresponds to a phase difference of a certain time t _x from the point So corresponding to the rising phase of , and is located on the line F at a position on the tape a certain distance away from the end A of the magnetic tape.

If we consider a case where a tracking shift occurs when reproducing the image track To thus formed and the image is reproduced along the scanning center line shown in FIG.
The rising phase of the pulse S is located at the point So' on the G line, and the time of the phase difference between the index signal reproduced as a result and the rising phase of the pulse S is t _x '. Appears with age. Therefore,
If the servo system during reproduction is controlled so that this time t _x ' becomes the target value t _x determined during recording, the magnetic head will scan on the regular scanning center line C of the video track To. Now you can track correctly.

The above is the basic operating principle of tracking control according to the present invention.

According to the tracking control method described above, when recording and playback are performed using the same device, tracking can always be performed correctly as long as the target value t _x of tracking control described above is specified for each device for recording and playback. be able to. However, if we consider the case where recording and playback are performed using separate devices, the above target value t _x
In general, it is difficult to perform tracking control correctly even if set to the same value in each device.

That is, in FIG. 1, the spatial positional relationship between the disk 2 and the tape 1 is not necessarily constant because there are slight mechanical differences between the devices. For this reason, as shown in FIG. 4, for example, when a track To (its magnetic head scanning starting point is Ho) recorded by a certain device is to be reproduced by a different device, the magnetic head scanning starting point
Ho'' does not necessarily coincide with the Ho point of the track To, and the head scans on the track To'' shown by the broken line in the figure.

Therefore, the phase track of the pulse S is
The point So'' on the track To'' no longer matches the So point on the track To that was determined during recording, and therefore the control target value for tracking during playback is as shown in the figure.
t _x '', which differs from the value t _x determined at the time of recording.

In addition, in FIG. 1, the mounting position of the magnet on the disk 2, the mounting position of the task head 3 that detects it, and the phase adjustment circuit 31 are also shown.
Since the amount of phase adjustment of the DTP signal etc. differs depending on each device, in Fig. 4,
Even if the head scanning start point Ho'' can coincide with the Ho point, the So'' point cannot necessarily coincide with the So point, and therefore, even in this case, the tracking control target value during playback is It will be different from t _x .

In view of the above, the present invention provides a method of performing tracking control so that the S/N ratio is always the best even in the above-mentioned compatible playback.

Next, the principle of operation will be explained.

Again in FIG. 4, it is assumed that the position on the tape of the rising phase of the pulse S during reproduction is located on a line G'' that is a certain distance away from the tape end A. Also, the running direction of the tape and the position of the head are The scanning direction is the direction shown by the arrow in the figure.

If the tape runs at a different speed during playback than during recording, the envelope of the signal played back from the head will have a waveform that alternately repeats the maximum level M and the minimum level N, as shown in FIG. 5a.

The maximum level M occurs when the phase of the pulse S is located at the point So'' on G'' in Figure 4, and the minimum level N occurs when the phase of the pulse S is located at the point So'' on G'' in Figure 4.
This is when it is located at So ₁ point or So ₂ point.

On the other hand, the time of the phase difference between the phase of the pulse S and the reproduced index signal is detected as the minimum value t ₁ when the pulse S is located at the So ₁ point, and when the pulse S is located at the So ₂ point. Since it is detected as the maximum value _t2 , the phase difference signal has a waveform as shown in Figure 5b when the tape speed during playback is faster than the specified tape speed during recording, and as shown in Figure 5b when it is slow. The waveform becomes as shown in c, and in any of these cases, only when the level of the reproduced signal a reaches the minimum N, does it change sharply with an amplitude equal to a certain time difference (t ₂ − _{t 1} ). A phase difference signal is obtained.

However, the reason why the level of the reproduced signal a reaches the maximum M is that when the tape speed is faster than the specified speed, the pulse S is delayed by a certain time difference (t ₂ - t ₁ )/2 from the phase corresponding to the So ₁ point. If the tape speed is slower than the specified speed, the pulse S is located at the So'' point of the phase, which is delayed by a fixed time difference (t ₂ - t ₁ )/2 from the phase corresponding to the So ₂ point. ” when it is located at the point.

The present invention sets this fixed time difference (t ₂ - t ₁ )/2 in advance as a tracking control target value, and then performs a control operation so that the system locks in to that target value. Therefore, the level of the reproduced signal a is always maximized, so that the S/N ratio is always the best. Referring again to FIG. 4, first a delay circuit is provided to delay the phase of the pulse S, and the delay time is preset to be equal to _t1 or _t2 at the timing when the phase difference signal described above changes sharply.

That is, considering the case where the tape speed is faster than the specified speed, the timing at which the phase difference signal changes sharply is when the pulse S is at a position corresponding to the So ₁ point, and after a time t ₁ from that phase. The head is Io ₁
Since this is the time when the pulse S passes through the point, the time _t1 of the phase difference between the pulse S at this time and the phase difference signal when the phase difference signal changes sharply is preset as the delay time of the delay circuit. Thereafter, the pulse S is delayed by the delay circuit by the time _t1 , so that the pulse _S1 output from the delay circuit is aligned with the line G'' where the pulse S is located, as shown at J in FIG. Therefore, it is located on line J, which is separated by a distance corresponding to the phase difference at time _t1 .

On the other hand, this line J and the scanning center line C of track To
The intersection point _S10 with the index signal recording position Io is located at a phase difference equal to a constant time difference ( _t2 - _t1 )/2. Therefore, the time of the phase difference between the pulse S ₁ and the reproduction index signal is a constant value (t ₂ −
If the control operation is performed so that t ₁ )/2, the pulse
S ₁ will always be located at the S ₁₀ point, so the head will correctly scan on the scanning center line C.

The same is true when the tape speed is slower than the specified speed, and the timing at which the phase difference signal changes sharply is when the pulse S is at the position corresponding to the So ₂ point, and after a time t ₂ from that phase. Head is Io ₂
Since this is the time when the phase difference passes through the point, the time _t2 of the phase difference at this time is preset as the delay time of the delay circuit. Therefore, in this case, the pulse _S2 output from the delay circuit is located on the line K, which is separated from the line G'' by a distance corresponding to the phase difference of time _t2 , and this pulse S2 If the control operation is performed so that the phase difference time between ₂ and the playback index signal becomes the same constant value (t ₂ - t ₁ )/2, then
Since the pulse S ₂ is located at the intersection S ₂₀ of the lines K and C, tracking is performed to obtain the best S/N ratio as described above.

According to the operating principle of the present invention described above, the target value of tracking control during playback is set to the value t _x determined during recording.
(or t _x ″), and set the target value to a constant value (t ₂ -t ₁ )/2, so tracking can always be performed correctly not only during self-recording and playback but also during compatible playback.
Furthermore, tracking can be automatically performed so as to always obtain the best S/N ratio.

An embodiment of the tracking control device of the present invention based on the above operating principle is shown in FIG. 6, and waveforms of various parts thereof are shown in FIGS. 7a to 7e. A part of the tracking control device shown in FIG. 6 can be shared with a part of the servo control device during recording shown in FIG. 1, so the common parts are given the same numbers. Since the functions and operations of the common parts are exactly the same as those described in FIG. 1, detailed explanation thereof will be omitted.

In FIG. 6, reference numeral 43 denotes a reference signal generating circuit which generates a reference signal having a frequency approximately equal to the frame frequency of the video signal.

The pulse S from the pulse forming circuit 32 is phase-compared with the reference signal from the reference signal generation circuit 43 in a phase comparison circuit 42, and a phase error signal corresponding to the phase difference between the two is outputted from the phase comparison circuit 42.

This phase error signal is transmitted to the disk servo circuit 41.
As a result, the pulse S is servo-controlled to be phase-synchronized with the reference signal, and therefore the magnetic heads 21 and 22
is rotated at a rotational speed equal to almost the same frame frequency as during recording.

The magnetic heads 21, 22 whose rotation is thus controlled
The video signal that is alternately reproduced field by field from the magnetic tape 1 is switched alternately field by field by the pulse S from the pulse forming circuit 32 in the video signal reproducing circuit 62, and becomes one continuous signal. After being subjected to appropriate signal processing, the reproduced video signal is output to the output terminal 20.

On the other hand, this reproduced video signal is supplied to an index signal separation circuit 63, and the index signal described in FIG. 1, which is multiplexed with the reproduced video signal, is separated in this circuit 63. This index signal is supplied to a phase comparator circuit 60.
SW1 and SW2 are both switches, and are controlled by a control signal W output from a control circuit 71, which will be described later.
When W is at a low level (hereinafter abbreviated as "L"), the switch SW1 is set to the terminal 1L side, and the switch SW2 is set to the terminal 1L side.
are respectively connected to the terminal 2L side, and when W is at a high level (hereinafter abbreviated as "H"), the switch SW1
is connected to the terminal 1H side, and switch SW2 is connected to the terminal 2H side. 80 is a clear pulse generating circuit, which is "L" during the period from when the capstan motor 5 is started until the video signal is reproduced from the tape 1, as shown in FIG. Then, a clear pulse R that becomes "H" is generated.

This clear pulse R is supplied to the control circuit 71. In this control circuit 71, the control signal W becomes "L" during the period when the clear pulse R is "L", and the clear pulse R becomes "H", as shown in FIG. 7b.
After the writing to the memory, which will be described later, is completed, the state is controlled and outputted so that it becomes "H".

Therefore, during the period after the tape 1 starts running until the video signal is played back, the control signal W of "L" is output from the control circuit 71, and therefore the switches SW1 and SW2 are connected to the terminals 1L and 2L, respectively. Connected.

Therefore, the pulse S from the pulse forming circuit 32 is supplied to the phase comparator circuit 60 via the switch SW1. In this phase comparison circuit 60, the pulse S and the index signal are phase-compared, and the seventh
A phase difference signal φ corresponding to the phase difference between the two as shown in FIG. c is output.

54 is a reference voltage generation circuit that generates a constant reference voltage. This reference voltage is supplied to the capstan servo circuit 53 via the switch SW2, and as a result, the capstan motor 5 is rotated at a constant speed, and the tape 1 is run at a constant speed.
For example, the reference voltage is set so that the tape running speed is slower than the specified recording speed.

Therefore, as described in FIG. 5 above, head 2
The envelope of the signal reproduced from 1 and 22 is
The waveform is as shown in FIG. 5a, and the phase difference signal φ output from the phase comparison circuit 60 has a sawtooth waveform as shown in FIG. 5c and also FIG. 7c. This phase difference signal φ is supplied to a pulse shaping circuit 72. This pulse shaping circuit 72 generates a pulse only when the amplitude of the phase difference signal φ changes sharply, as shown in FIG. 7d, and only when the control signal W from the control circuit 71 is "L". Output Q. This pulse Q is supplied to the control circuit 71. The control circuit 71 has a memory, and data D corresponding to the phase difference between the pulse S from the pulse forming circuit 32 (FIG. 7e) and the pulse Q is written into the memory.

Writing to the memory is performed using the above clear pulse R.
is blocked during the “L” period, and the clear pulse R
It is controlled so that writing is possible only during the "H" period.

Therefore, after the clear pulse R changes from "L" to "H", that is, after the video signal from the tape 1 is correctly reproduced, the phase difference signal φ as described above is output from the phase comparator circuit 60. After the pulses are detected correctly, data D corresponding to the phase difference between the first pulse Q and the pulse S is written into the memory.

After the writing is completed, the control signal W becomes "H" and is output from the control circuit 71.
After the control signal W becomes "H" after the writing to the memory is completed, it continues to be "H" unless the clear pulse R becomes "L".

This control signal W is supplied to the pulse shaping circuit 72, and since the pulse Q is not output during the period when the control signal W is "H", writing to the memory is performed only once, and the writing is performed only once. The data D is retained. The data D written in the memory is outputted from the control circuit 71 and supplied to the delay circuit 70.

Note that the memory may be an analog type memory that holds an analog value corresponding to the phase difference between the pulse S and the pulse Q (for example, a voltage amplitude value corresponding to the phase difference), or , a binary system that counts the time interval of the phase difference between pulse S and pulse Q using a predetermined clock, and then outputs a binary digital value that is held by stopping the counting operation. It may also be a digital memory composed of a counter.

After the above writing to the memory is completed, the control signal W becomes "H" as described above, and therefore the switches SW1 and SW2 are set to the terminal 1H side and the terminal 2H side, respectively.
connected to the side. On the other hand, the delay circuit 70 is supplied with the pulse S from the pulse forming circuit 32, and the delay circuit ₇₀ outputs a pulse S2 whose phase is delayed according to the value of the data D from the control circuit 71. is output. This delay time is the fourth
It goes without saying that it is equal to t ₂ as mentioned in the figure, and therefore this pulse S ₂ is located on line K in FIG.

This pulse _S2 is supplied to the phase comparator circuit 60 via the switch SW1. The phase comparison circuit 60 outputs a phase difference signal φ corresponding to the phase difference between this pulse S ₂ and the index signal. This phase difference signal φ is supplied to the capstan servo circuit 53 via the switch SW2, and as a result, the loop of the capstan servo system that controls the tape running speed is closed, and the pulse _S2 and the index signal are Negative feedback control is performed so that the phase difference time is always equal to the target value (t ₂ −t ₁ )/2 described in FIG. 4. This control target value is set by adjusting the tape running speed to be equal to a specified speed, for example, by adjusting the rotational speed of the capstan motor 5 in the capstan servo circuit 53. Alternatively, although not shown, a delay circuit for delaying the index signal is provided after the index signal separation circuit 63 and its output is supplied to the phase comparator circuit 60, and the delay time in the delay circuit is This is done by adjusting the

Since these adjustments related to the tape running speed are unique to each device, no inconvenience occurs during compatible playback.

In this way, tracking is controlled so that the time of the phase difference between the pulse S ₂ and the index signal is equal to the target value (t ₂ −t ₁ )/2, and as a result, a record is formed as described in FIG. 4 above. track
The head correctly scans on the scanning center line C of To, so that the best S/N ratio can always be obtained and image reproduction can be performed stably.

In the above example, the tape running speed before closing the tracking control loop is set to be slower than the specified speed, but even if the tape running speed is set in advance to be faster than the specified speed, the basic operation will still continue. In this case, as described _{in FIG .} )/2, it is possible to perform automatic tracking control exactly the same as above.

Furthermore, in the present invention, as described above, writing to the memory is performed after the video signal is correctly reproduced from the tape and the pulse Q is correctly and faithfully detected. Even if there is a period when no signal is recorded, the pulse Q will not be erroneously generated during that period, and the desired data will be reliably stored in the memory only during the period when the video signal is always recorded on the tape. written. Furthermore, in the present invention, even if the index signal is erroneously detected due to, for example, drop-out, tracking errors can be prevented by repeating writing to the memory.

That is, in the present invention, in FIG. 4, the pulse S is reproduced when the pulse S is located at the So ₂ point (or So ₁ point) and the head passes through the Io ₂ point (or Io ₁ point). The time t ₂ (or t ₁ ) of the phase difference between the index signal and the pulse S at that time
Since the data is written to the memory according to the
If the index signal is detected incorrectly due to an error or noise, correct data will not be obtained, which may cause the tracking control system to malfunction. In order to solve this problem, in the present invention, after the tracking control loop is closed after the writing to the memory is completed, it is detected whether the tracking control is being performed correctly, and if the tracking control is malfunctioning, the tracking control loop is closed. In this case, the above-mentioned writing to the memory is repeated again.

Specifically, in the embodiment shown in FIG. 6, the clear pulse generating circuit 80 detects whether the tracking control is correct or not, and if the tracking control is not correct, the state is controlled so that the clear pulse R is set to "L". In this way, as described above, the control signal W of "L" is output from the control circuit 71, and therefore the switches SW1,
SW2 is connected to the terminals 1L and 2L, respectively, and the tracking control loop is opened again, returning to the initial state. Thereafter, the same control operations as described above are performed, and after desired correct data is written into the memory, the tracking control loop is closed.

As a specific example of detecting whether the tracking control is correct or not, as shown by the broken line in FIG. There are ways to detect changes.

As described above, the embodiments shown in FIGS. 1 and 6 are cases in which the present invention is applied to a rotating two-head type magnetic recording/reproducing device, but the present invention is not limited to this.
For example, it can be applied to a magnetic recording/reproducing device having any number of heads, such as a 1-head type or a 4-head type, and the embodiment shown in FIG. However, the number is not limited to this, and the number can be arbitrary, such as multiplexing at the field cycle or recording at a cycle less than the frame cycle.
In any of these cases, the spirit of the present invention is not departed from.

As described above, according to the present invention, in a rotary head type magnetic recording/reproducing device, the best S is always possible, not only when recording and reproducing are performed using the same device, but also when recording and reproducing are performed using separate devices. Tracking control can be automatically performed to obtain /N, and the reliability of the device can be significantly improved.

Furthermore, since the control head that has conventionally been commonly used for tracking control can be eliminated, the apparatus can be made smaller and lighter, and tape running can be stabilized.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a servo control device for recording an index signal according to the present invention, FIGS. 2 a to c are waveform diagrams of each part thereof, and FIGS. 3 and 4 are video track diagrams. FIGS. 5a to 5c are timing diagrams showing the operating principle of the present invention. FIG. 6 is a block diagram showing an embodiment of the automatic tracking control device according to the present invention. FIG. a to e are waveform diagrams of each part thereof. 32... Pulse forming circuit, 63... Index signal separation circuit, 60... Phase comparison circuit, 54...
...Reference voltage generation circuit, 70...Delay circuit, 71...
...Control circuit, 72...Pulse shaping circuit, 80...
Clear pulse generation circuit.

Claims (1)

[Scope of Claims] 1. A magnetic recording and reproducing device in which an index signal generated in synchronization with the rotation of a rotating magnetic head is recorded or reproduced on a magnetic tape 1 by the rotating magnetic head, multiplexed with a video signal. The automatic tracking control device includes: an index signal separator 63 configured to separate the index signal multiplexed therefrom from the reproduced video signal reproduced from the magnetic tape 1; a pulse generator 32 configured to generate a synchronized first pulse signal S; and at least the first pulse signal S from the pulse generator 32 and the index signal from the index signal separator 63. is entered,
a phase comparator 60 configured to detect at least a phase difference signal φ corresponding to the phase difference between the first pulse signal S and the index signal; and at least the phase difference signal from the phase comparator 60. a pulse former 72 having a configuration in which φ is input and a second pulse signal Q is formed at a timing corresponding to an amplitude change of the phase difference signal φ; A pulse signal Q and the first pulse signal S from the pulse generator 32 are input, and data D corresponding to the phase difference between the second pulse signal Q and the first pulse signal S is at least Within a period in which the second pulse signal Q is output from the pulse generator 72, the memory 71 having a configuration to be written is inputted, and the first pulse signal S from the pulse generator 32 is inputted to the memory 71. a delay device 70 having a configuration in which the first pulse signal S is delayed according to the value of the data D written in the data D; a third pulse signal _S2 output from the delay device 70; A configuration for controlling the rotary magnetic head to normally scan the recording tracks formed on the magnetic tape 1 in response to a phase difference signal corresponding to the phase difference with the index signal from the index signal separator 63. An automatic tracking control device comprising: a control circuit; and an automatic tracking control device. 2. The memory 71 is controlled so that the writing of the data D is prevented during the period from when the magnetic tape 1 is running until the video signal is reproduced, or when the data D is written during that period. The automatic tracking control device according to claim 1, wherein the automatic tracking control device is configured to include a circuit that controls the data D so that it is not output. 3 The memory 71 stores the position of the second pulse signal Q from the pulse generator 72 and the first pulse signal S from the pulse generator 32 when a malfunction of the tracking control is detected. The automatic tracking control device according to claim 1, wherein the automatic tracking control device is configured to include a circuit for controlling so that data corresponding to the phase difference is written again. 4 The memory 71 counts the time interval of the phase difference between the second pulse signal Q from the pulse generator 72 and the first pulse signal S from the pulse generator 32 using a predetermined clock. Claim 1 includes a binary counter having a configuration and a configuration in which a binary digital value that is held when the counting operation is stopped is output. Automatic tracking control device as described. 5 The above-mentioned pulse former 72 has a structure in which the above-mentioned second pulse signal Q is outputted at a timing when the amplitude of the phase difference signal φ from the above-mentioned phase comparator 60 changes sharply. The automatic tracking control device according to item 1. 6 The memory 71 stores data D corresponding to the phase difference between the second pulse signal Q from the pulse generator 72 and the first pulse signal S from the pulse generator 32. 72 to the second pulse signal Q
The automatic tracking control device according to claim 1, wherein the automatic tracking control device is configured to be controlled so as to be written at the timing when the . 7 The phase comparator 60 receives the third pulse signal S ₂ output from the delay device 70 and the index signal from the index signal separator 63, and separates the third pulse signal S ₂ and the index signal from the index signal separator 63. The automatic tracking control device according to claim 1, further comprising a configuration for detecting a phase difference with the index signal. 8. The control circuit according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the control circuit includes a circuit 53 in which a control signal for controlling the running state of the magnetic tape 1 is generated. Automatic tracking control device as described. 9. In an automatic tracking control device for a magnetic recording and reproducing device, in which an index signal generated in synchronization with the rotation of a rotating magnetic head is recorded or reproduced on a magnetic tape 1 by being multiplexed with a video signal by the rotating magnetic head. , an index signal separator 63 configured to separate the index signal multiplexed therefrom from the reproduced video signal reproduced from the magnetic tape 1; and a first index signal separator 63 synchronized with the rotation of the rotating magnetic head. a pulse generator 32 configured to generate a pulse signal S; at least the first pulse signal S from the pulse generator 32 and the index signal from the index signal separator 63 are input;
At least a phase comparator 60 configured to detect a phase difference signal φ corresponding to the phase difference between the first pulse signal S and the index signal; and at least a phase difference signal φ from the phase comparator 60. is input, and a second pulse signal Q is formed at a timing corresponding to the amplitude change of the phase difference signal φ, and the running speed of the magnetic tape 1 is determined at the time of recording. A speed setting means 54 is set to a speed different from the specified speed, and at least the second pulse signal Q from the pulse generator 72 and the first pulse signal S from the pulse generator 32 are input. Then, data D corresponding to the phase difference between the second pulse signal Q and the first pulse signal S is transferred to the magnetic tape 1.
During a period in which the vehicle is running at the speed set by the speed setting means 54, the first pulse signal S from the pulse generator 32 is input to the memory 71 having a configuration to be written, and the first pulse signal S is input to the memory 71. a delay device 70 configured to delay the first pulse signal S according to the value of the written data D; a third pulse signal S ₂ output from the delay device 70 and the index signal; The rotary magnetic head is configured to control the rotating magnetic head to normally scan the recording track formed on the magnetic tape 1 in response to a phase difference signal corresponding to the phase difference with the index signal from the separator 63. , a control circuit, and an automatic tracking control device. 10 The memory 71 is controlled so that the writing of the data D is prevented during the period from when the magnetic tape 1 is running until the video signal is reproduced, or when the data D is written during that period. The automatic tracking control device according to claim 9, wherein the automatic tracking control device is configured to include a circuit for controlling the data D so as not to be output. 11 The memory 71 stores the position of the second pulse signal Q from the pulse generator 72 and the first pulse signal S from the pulse generator 32 when a malfunction of the tracking control is detected. The automatic tracking control device according to claim 9, wherein the automatic tracking control device is configured to include a circuit for controlling so that data corresponding to the phase difference is written again. 12 The memory 71 counts the time interval of the phase difference between the second pulse signal Q from the pulse generator 72 and the first pulse signal S from the pulse generator 32 using a predetermined clock. Claim 9 includes a binary counter having a configuration and a configuration in which a binary digital value held by stopping the counting operation is output. Automatic tracking control device as described. 13 Claims: The pulse former 72 is configured to output the second pulse signal Q at a timing when the amplitude of the phase difference signal φ from the phase comparator 60 changes sharply. The automatic tracking control device according to item 9. 14 The memory 71 stores data D corresponding to the phase difference between the second pulse signal Q from the pulse generator 72 and the first pulse signal S from the pulse generator 32. 72 to the second pulse signal Q
10. The automatic tracking control device according to claim 9, wherein the automatic tracking control device is configured to be controlled to be written at the timing when . 15 The phase comparator 60 receives the third pulse signal S ₂ output from the delay device 70 and the index signal from the index signal separator 63, and inputs the third pulse signal S ₂ and the index signal from the index signal separator 63. The automatic tracking control device according to claim 9, further comprising a configuration for detecting a phase difference with the index signal. 16. Claims 9, 10, 11, 12, 13, 14, wherein the control circuit includes a circuit 53 in which a control signal for controlling the running state of the magnetic tape 1 is generated.
Or the automatic tracking control device according to item 15.