JPS6321973B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tracking method in a magnetic reproducing device, which stores the reproduced signal level of a track being scanned by a rotary head and the reproduced signal level of another track previously scanned by the rotary head. When correcting track deviation by displacing the rotary head in a direction perpendicular to the longitudinal direction of the recording track, based on the track deviation detection signal obtained by comparing the respective values, the amount of head displacement is limited and playback is performed. By predicting the track pattern according to the mode and changing the above memorized values in advance, the track pattern can be changed according to the playback mode without adversely affecting the playback screen or limiting the recording/playback signal frequency band. It is an object of the present invention to provide a tracking method that can accurately follow and scan a track in an instant.

In helical scan VTRs, the recording track has a unique curvature due to variations in the tape scanning system mechanism.
The best tracking condition cannot be obtained during compatible playback on a VTR. In addition, not only during compatible playback, but also in so-called self-recording and playback, in which the tape is played back on the same VTR that was used for recording, and during special playback, in which the tape is played back at a different speed from that at the time of recording, the rotary head is not able to track the recording track. Since the head draws a scanning locus different from that of the recording track, it is not possible to accurately scan the recording track, and noise may occur on the reproduced screen.

Conventionally, normal tracking was attempted by adjusting the tracking knob and delaying the playback control signal by the required time, but this was a control that moved the head scanning trajectory parallel to the longitudinal direction of one recording track. However, it was impossible to control the scanning so that it accurately followed the curve of a single track.

Therefore, in order to perform more accurate tracking control, it is necessary to correct the track deviation by displacing the rotary head using a head moving mechanism in a direction perpendicular to the longitudinal direction of the recording track (track axis direction). There is.

Conventionally, this method of detecting track deviation involves recording a total of four types of pilot signals with different frequencies superimposed on the main information signal, and reproducing two types of signals separately from the tracks on both sides of the track to be scanned during playback. There has been a method of detecting the track deviation direction and track deviation amount from the relative level difference of pilot signals, but this method is preferable because it causes beat disturbance and limits the band of the main information signal to be recorded and reproduced. Nakatsuta.

On the other hand, a dither (wobbling) method has conventionally existed as a method for detecting track deviation without recording a pilot signal on a recording track. This method uses a sine wave with a short frequency (for example, 420 Hz or 480 Hz) synchronized with the rotating drum to displace the rotating head upward in the track width direction, and creates a sine wave-like scanning trajectory on the rotating head for one recording track. was drawn, and track deviation was detected by detecting the difference in FM reproduction signal level between adjacent positive peak points and negative peak points in this scanning locus.

However, in this conventional dither method, in order to detect one track deviation, it is necessary to detect a point at which the rotary head shifts upward and a point at which it shifts downward. Since the peak point is the peak point of In addition, when a magnetic tape is recorded using the so-called azimuth recording method, when the rotating head is swung in the track width direction, time axis fluctuations occur in the reproduced signal, which appears as curvature or color unevenness on the reproduced screen. However, as mentioned above, since the conventional system swings the rotary head at a high frequency, it has the disadvantage that the reproduced screen is greatly curved and color uneven.

Furthermore, with the dither frequency in the conventional method described above, the number of track deviation detection points on one track is 16 at most, and one set of track deviation information above and below this detection point constitutes one piece of track deviation information, so there are at most 8 track deviations. Only shift information can be obtained, and as the dither frequency becomes higher, the amount of shift information increases, but there is a drawback that the time axis fluctuation further increases.

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to the drawings.

FIG. 1 shows a block system diagram of an embodiment of a tracking system in a magnetic reproducing apparatus according to the present invention. In this embodiment, for convenience of explanation, a case will be described in which the present invention is applied to a two-head helical scan type VTR in which recording and reproduction are performed using two rotary heads having gaps with different azimuth angles.
In FIG. 1, reference numerals 1 and 2 are rotary heads having gaps with different azimuth angles, and they are respectively installed at positions facing the rotating drum at 180 degrees. As shown in FIG. ₀ , _B0 ,
Tracks are recorded in the order indicated by A ₁ , B ₁ , A ₂ , B ₂ , A ₃ , B ₃ , . . . without guard bands. Here, A ₀ , A ₁ , A ₂ , A ₃ are tracks recorded by rotary head 1, B ₀ , B ₁ , B ₂ , B ₃ are tracks recorded by rotary head 2, and these It is assumed that at least a frequency-modulated video signal is recorded on each track at a rate of one field per track. In FIG. 2, the shaded area shows an example of the track scanning trajectory of the rotary heads 1 and 2 during conventional still motion reproduction.

First, to explain the operation during normal reproduction, the FM video signal alternately reproduced by the rotary heads 1 and 2 from the track on the magnetic tape 16, which is made to run in the same direction at the same speed as during recording, is The signal is supplied to a level detector 5 via an input terminal 3 shown in FIG. 1, and its level is detected. On the other hand, as is well known, the rotational speed and rotational phase of a drum motor (none of which is shown) that rotates the rotary drum to which the rotary heads 1 and 2 are attached are the same as the tracks recorded by the rotary heads 1 and 2. It is controlled by a drum servo system to scan the track, and the drum pulses used in this drum servo system are also supplied to the input terminal 4 in FIG. That is, a permanent magnet that rotates integrally with the rotating drum is provided around the rotating drum, and each time this permanent magnet passes a position facing away from the gap surface of the drum pick up head (not shown), the drum pick up A pulse is output from the head, and this is shaped by a well-known circuit to produce a fourth pulse.
As shown in FIG. Drum pulse a, which is a rectangular wave with a field period of 1/30 seconds), is simultaneously supplied to the drum servo system (not shown) via the input terminal 4 to the microprocessor 7 and countdown shown in FIG. circuit 9
are supplied respectively.

The countdown circuit 9 is reset by the reset pulse shown in FIG. 4B which is synchronized in phase with the rise and fall of the drum pulse a, respectively, and counts down the output signal of the oscillator 8 to 60×8 pps as shown in FIG. 4C, for example. A pulse c is outputted and applied to the microprocessor 7. On the other hand, the output level detection signal of the level detector 5 is applied to a control terminal of a voltage controlled oscillator (VCO) 6 to variably control its output oscillation frequency. Here, VCO6
When the input control voltage (level detection signal) of VCO6 increases, the output oscillation frequency of VCO6 also increases.
I am using VCO. The output oscillation frequency of this VCO6 (for example, within the range of 100kHz to 200kHz)
is applied to the microprocessor 7.

The microprocessor 7 has a configuration as shown in FIG. 3, and as described later, during the high level period of the output pulse c of the countdown circuit 9, the oscillation output from the VCO 6 and input via the input terminal 17 shown in FIG. The number of pulses is counted by a counter 18. Thereafter, the output count value of the counter 18 is stored in a predetermined location in the memory section 20, or is compared with the value read out from the memory section 20 in the accumulator (ACC) 19, and the comparison result is used. Accordingly, the stored value in the memory section 20 is changed or left unchanged, and the head swing data read out from the memory section 20 is sent to the output terminal 21 through the ACC 19.
Output to.

The output of the microprocessor 7 has two sets of 6-bit digital signals, which are respectively supplied to 6-bit DA converters 10 and 11 shown in FIG. 1 and converted into analog signals, and then amplified by amplifiers 12 and 13. A bimorph-like head moving mechanism 14,
15. Head moving mechanism 14,
Reference numeral 15 indicates the polarity of the signals from the amplifiers 12 and 13 independently of each other when rotating the rotating heads 1 and 2 in a direction perpendicular to their rotation surfaces, that is, in a direction perpendicular to the longitudinal direction of the track (in the track width direction). , displace it in the direction and amount of displacement according to the level.
In this embodiment, the period during which the rotary head 1 reproduces the first track is at a position approximately 1 μm higher than the normal height position during recording, and the period during which the rotary head 2 reproduces the second track. is also played back at a position approximately 1 μm higher than the normal height position, and then during the period when rotary head 1 plays the third track, it is played back at a position approximately 1 μm lower than the normal height position, and then During the period when No. 2 reproduces the fourth track, it is reproduced at a position approximately 1 μm lower than the normal height position, and the above-mentioned operation is repeated thereafter. In this way, the rotary head 1 is alternately oscillated up and down at each drum rotation period (the same applies to the rotary head 2).
Note that the track width of the recording track is, for example,
The track deviation of 1 μm due to the above-mentioned swing is extremely small compared to the track width, and there is no adverse effect on the playback screen. Also VTR
However, it is not possible to obtain both upper and lower scanning trajectories at the same time.
In the case of a two-head VTR, at least ten or more tracks played by heads of the same channel can be considered to be exactly the same. Therefore, as described above, the direction of track deviation can be detected by swinging the rotary heads 1 and 2 vertically in the track width direction in units of one frame and comparing the reproduced FM video signal levels at that time. Can be done.

Next, this embodiment will be explained in more detail, focusing on the operation of the microprocessor 7. As shown in FIG. 3, the memory section 20 of the microprocessor 7 is
There are 32 addresses shown as _M1-1 to _M1-16 and _M2-1 to _M2-16 , and _M2-1 to _M2-16 have track patterns according to the tape running mode (playback mode). A predicted value is stored in advance, and the value is changed when the tape running mode is switched, and is also changed sequentially during playback according to the track deviation situation.
Addresses M _1-1 to M _1-16 store track deviation information when the rotary heads 1 and 2 scan the track.

First, the operation during normal playback will be explained.
At this time, the address M _2-1 in the memory section 20 ~
In _M2-16 , a value (for example, "0" in FIG. 5) indicating that the rotary heads 1 and 2 are at the same height position as when recording is stored in advance. Therefore, during the first 1/8 field period during which the rotary head 1 reproduces the track indicated by _A0 in FIG.
Add a value that makes the height position of the rotary head 1 approximately 1 μm to the data at address _M2-1 in the memory section 20.
It is output from the microprocessor 7 via the ACC 19, and the rotary head 1 is set approximately 1 μm below the normal height position.
For example, the output oscillation frequency of the VCO 6 corresponding to the level of the reproduced FM video signal is determined by the counter 18 shown in FIG. 3 during the high level period p _1-1 of the pulse c shown in FIG. 4C. It is counted. The count value of this counter 18 is a value corresponding to the track deviation, and for example, the greater the track deviation, the lower the FM video signal level and the lower the output oscillation frequency of the VCO 6, so the value becomes smaller. The count value of counter 18 in the above high level period p _1-1 is
It is stored at address M _1-1 of the memory section 20 via the ACC 19 .

During the next 1/8 field period, a value that makes the height position of rotary head 1 approximately 1 μm is added to the data at address _M2-2 , and the data is sent to microprocessor 7 via ACC19.
The output oscillation frequency of the VCO 6 corresponding to the level of the FM video signal reproduced at this time is the pulse c shown in FIG. 4C. The counter 18 counts during the high level period p _1-2 , and the counted value is stored in the address M _1-2 via the ACC 19.
Thereafter, in the same manner as above, a value that makes the displacement of the rotary head 1 approximately 1 μm is added to the stored data at addresses M _2-3 to M _2-8 in the memory section 20 and outputted from the ACC 19, while the high pulse c Level period p _1-3 ~ _{p 1-8}
The counted values of the counter 18 are stored in addresses M _1-3 to M _1-8 in the memory section 20, respectively.
Therefore, the microprocessor 7 scans the track A ₀ with the rotary head 1 at a position approximately 1 μm higher than the normal height position, and extracts tracks sampled from 8 positions of one track A ₀ . The shift information data is stored at address M _1-1 in the memory section 20.
~M _1-8 respectively.

Next, the rotary head 2 moves to the track B ₀ shown in FIG.
However, in the same way as above, the microprocessor 7 adds a predetermined value to the data read from addresses _M2-9 to _M2-16 in the memory section 20, and moves the rotary head 2 to the normal height position. Scan track B ₀ at a position approximately 1 μm higher _than
Among them, p _1-9 to _{P 1-16} in FIG. 4 C of the pulse c
The track deviation information data sampled from eight positions corresponding to each high level period shown _{in FIG} .

Next, the rotary head 1 moves to the track A ₁ shown in FIG.
During one field period for reproducing the data, the microprocessor 7 subtracts a predetermined value from the data sequentially read from addresses _M2-1 to _M2-8 in the memory section 20 every 1/8 field period, and then outputs the data to the rotary head 1. The track A ₁ is scanned at a position approximately 1 μm lower than the normal height position, and in that one track A ₁ , the pulse c shown in _{FIG .} Each of the output track deviation information data of the counter 18 sampled from eight positions corresponding to each high level period shown and the address in the memory section 20
Compare each of the track deviation information storage data of track A ₀ of M _1-1 to _{M 1-8} in their corresponding sections, and if the value of M _1-1 to _{M 1-8} is larger, then ,
Since the height position of rotating head 1 is low, add "1" to the values of addresses _M2-1 to _M2-8 .
Restore each address separately to M _2-1 to M _2-8 and set address M _1-1.
If the value of ~M _1-8 is smaller, the value obtained by subtracting “1” from the value of address M _2-1 ~M _2-3 is used, contrary to the above.
Re-memorize each separately into M _2-1 ~ M _2-8 , M _1-1 ~ M _1-8
If it is equal to the value of , the values of M _2-1 to M _2-8 are left unchanged. The period during which the next rotary head 2 reproduces track _B1 shown in FIG. 2 is also track _A1 .
The memory section _M2-9 performs the same operation as the scanning period.
~M Change each value of _2-16 or leave it as is.

The above operation is repeated every two frames. As a result, as shown in FIG. 5, the height positions H 1,1 to H 1,3 of the rotary head 1 during the track scanning period of one field and the height positions H _1,1 to _{H 1,3} of the rotary head 2 during the track scanning period of the next one field are changed. Height position H ₁ , _91,9
~ _H1,16 is the height position of the pattern that is shifted by 1 μm in the positive direction from the state where the rotary head 1 or 2 is on the track, and also the height of the rotary head 1 during the track scanning period of the next field. position
H _2,1 to _{H 2,8} and the height position H _2,9 of the rotary head 2 during the track scanning period of the next one field.
H _2,16 indicates the height position of the pattern that is approximately 2 μm lower than that during the first frame scanning of the rotary heads 1 and 2, and the track on the tape is tracked in this state.

At this time, during one track scanning, the rotary head 1,
The height position H _1,i during the 1/8 field period of 2 is constant, but it is adjusted to prevent screen curvature and color unevenness.
The height position H _{1,i-1 is made not to change much more than the height position H 1,i-1} in the immediately preceding 1/8 field period. In this embodiment, H _1,i-1 −2≦H _1,i ≦H _1,i-1 +2. Note that if the address M1 _-i in the memory unit 20 and the count value of the counter 18 to be compared in the ACC 19 (track deviation information data at the same sampling point of the track one frame before) exceed the above range. Even if the result is as follows, the value of the head height position H _1,i is H _1,i-1
It is stopped at +2 or H _1,i-1 -2.

In addition, in FIG. 5, H _1,9 to _{H 1,16} are head height positions during track reproduction that are different from H _1,1 to _{H 1,8} , so H _1,8 and H _{1, 9} , the above restrictions do not apply.

Also, the values of addresses _M2-1 and _M2-9 in the first 1/8 field period of each track are, for example, “22”.
becomes larger and rotates heads 1 and 2 in the forward direction by about 2
When attempting to displace the head by more than a track pitch, set M _2-1 to a value such that the rotating heads 1 and 2 are displaced by about 2 track pitches in the negative direction.
Subtract it from the value of M _2-9 and store it again at addresses M _2-1 and M _2-9 . For example, address M _2-1 ,
If the value of M _2-9 becomes smaller than "-22" and you want to displace the rotary heads 1 and 2 by more than about 2 track pitches in the negative direction,
2 is displaced approximately 2 track pitches in the positive direction to the values at addresses M _2-1 and M _2-9 , and the values after the addition are stored again at addresses M _2-1 and M _2-9 . do. Each value from address M _2-2 to M _2-8 is subtracted in the same way when the stored data at address M _2-1 is subtracted, and added in the same way when added. Similarly, each value from address M _2-10 to _{M 2-16} is subtracted when the stored data at address M _2-9 is subtracted.
Add when added. As a result, the rotating heads 1 and 2 are displaced to adjacent tracks by two track pitches recorded at the same azimuth angle, so that
No reverse tracks are scanned.

Next, we will explain the case during still motion playback. At this time, the running of the magnetic tape is stopped, so if the rotary heads 1 and 2 are left as they are, they will not be able to scan across two tracks as shown by diagonal lines in FIG. It will draw a trajectory. However, during this playback, a high quality still motion playback image can be obtained by performing tracking control in the same manner as during normal playback.
If the height position of 2 is changed, it will take time to reach the best tracking state. Therefore, in this embodiment, at the same time as the tape stops running, the track pattern in a steady state during still motion playback is predicted, and each value of addresses M _2-1 to _{M 2-8} and addresses M _2-9 to _{M 2 are} Change the setting of each value of _-16 to a value that has a slope. In this case, the height positions of the rotary heads 1 and 2 are controlled according to the values of addresses M _2-1 to M _2-8 and the values of addresses M _2-9 to M _2-16 .
The scanning trajectories must be offset from each other by one track pitch. This is because each of the rotary heads 1 and 2 must reproduce tracks recorded by heads having the same azimuth angle gap as the rotary heads 1 and 2, and these tracks are offset from each other by one track pitch.

The data stored at addresses M _2-1 to _{M 2-16} are changed as shown in FIG. 6. In the figure, the values on the vertical axis indicate values obtained by converting the data stored in addresses M _2-1 to _{M 2-16} into the heights of the rotary heads 1 and 2. After changing this stored data, the height position H _1,i of the rotating heads 1 and 2 during a certain 1/8 field period will be
and the rotating head 1 of the immediately preceding 1/8 field period,
The relationship between the height position H _1,i-1 (excluding between H _1,8 and H _1,9 ) of H _1,i-1 ≦H _1,i ≦H _{1,i- 1} + 4, and as in the case of normal playback, during the first frame scan, addresses M _2-1 ~
Scan while adding a value that will displace the height position of rotating heads 1 and 2 by approximately +1 μm to the value of M _2-16 ,
After sequentially storing the reproduced FM video signal level data at addresses M _1-1 to M _1-16 , the next second
During frame scanning, a value that displaces the height position of rotary heads 1 and 2 by about -1 μm is subtracted from the values of addresses M _2-1 to M _2-16 while scanning, and the reproduced FM video signal at that time is Import the level data into ACC19 and play it and the first frame scan
Compare it with the FM video signal level data, and depending on the magnitude of the data, address M _2-1 ~
Change or leave each value of M _2-16 as is. As a result, a state is reached in which stable tracking control can be performed in a short time even during still motion reproduction.

Next, when switching from still motion playback to normal playback, the addresses M _2-1 to _{M 2-16} are again set to the value "0" that will result in the same height position as during recording, as described above.

In addition, not only during normal playback and still motion playback, but also during double speed playback and triple speed playback, the correct head scanning trajectory after changing the tape speed is predicted and a predetermined value is set at addresses _M2-1 to M2-1 in the same manner as above. By changing the setting to _2-16 , you can perform stable tracking in a short time.

By the way, during the period from immediately after the start of reproduction until the running of the magnetic tape becomes stable, there are cases where a reproduction signal is not obtained or the reproduction signal level is extremely low. Therefore, in such a case, change the data stored in addresses M _2-1 to _{M 2-16} to values that will cause the rotating heads 1 and 2 to displace a certain amount in a certain direction, and then try again with the changed values. Tracking is performed, and when the reproduction signal level reaches a certain value or more, the above-mentioned tracking is performed. This allows the track to be reproduced using a rotary head having the same azimuth angle gap as during recording.

It should be noted that the present invention is not limited to the above-mentioned embodiments in terms of the number of rotary heads, differences in azimuth angles, etc., and can also be applied to a reproduction-only device.

When the number of rotary heads is M, the head swing signal alternately swings each rotary head up and down every M track scans. however,
The number M of rotary heads is not the total number of rotary heads for reproduction attached to the rotary drum, but the total number of rotary heads used during reproduction, and therefore there are two rotary heads dedicated to the standard mode. If two 1/3 mode dedicated rotary heads are respectively attached to the same rotary drum, the above M will be 2.

As mentioned above, the tracking method in the magnetic reproducing apparatus of the present invention is synchronized with the rotation of the rotary head, and alternately moves up and down every M track scans (M is the total number of rotary heads used during reproduction). A swinging signal for swinging the rotary head is generated based on the data read from the memory and applied to the head moving mechanism, so that the swinging head can reproduce data from multiple sections of one track. The track deviation of each section is detected from the playback signal level detected, and the detected track deviation amount and each playback signal level from a plurality of sections of another track previously scanned by the rotary head are detected and stored. The memory is configured to compare the amount of track deviation of each section with respect to each corresponding section, and increase/decrease or maintain the level of the swinging signal to the head moving mechanism so that the two become substantially equal according to the comparison result. In addition to controlling the output data from the rotary head, it also maintains a constant difference between the amount of head displacement in one section that the rotary head is scanning among multiple sections in one track and the amount of head displacement in the section immediately before it. This is a tracking method in which the rotating head is tracked on the track by controlling the swing signal so as to limit the swing signal to a value below a certain value, and the data stored in the memory is used to control the track scanning locus of the rotating head in accordance with the magnetic tape running mode. Since the data has been changed and set in advance to the value that should give the predicted head displacement amount for each of the plurality of sections, tracking can be instantly stabilized during special playback, and the oscillation signal can be When displacing more than M track pitches in the positive or negative direction, the swing signal is set to a value that should give the displacement amount of M track pitches in the negative or positive direction.
It is possible to prevent the tracking from becoming deviated, and furthermore, when the reproduction signal level of the rotary head is zero or extremely small, a swinging signal for displacing the rotary head in a certain direction is supplied to the head moving mechanism to rotate the head. Since the head is tracked, even when the rotary head is not on the track to be scanned, such as at the start of playback, it can be quickly placed on the track, especially when recording using the azimuth recording method. It has many features such as being able to prevent the track from becoming unstable due to reverse track during playback of a magnetic tape.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the method of the present invention, FIG. 2 is a diagram showing an example of a track pattern tracked by the method of the present invention, and FIG. 3 is an example of the main part of FIG. 1. FIGS. 4A to 4C are time charts for explaining the operation of FIGS. 1 and 3, respectively. FIGS. 5 and 6 are head scanning trajectories during normal playback and still motion playback, respectively. It is a figure showing an example. 1, 2... Magnetic head, 3... Playback FM video signal input terminal, 4... Drum pulse input terminal, 5... Level detector, 7... Microprocessor, 14, 15...
Head moving mechanism, 18... Counter, 20...
Memory section, 21...output terminal.

Claims (1)

[Scope of Claims] 1. A head moving mechanism that displaces a rotary head in a direction perpendicular to the longitudinal direction of a recording track on a magnetic tape, which is synchronized with the rotation of the rotary head, A swinging signal is generated based on the data read from the memory and is applied to cause the rotating head to swing up and down alternately every time a track is scanned (total number of rotating heads used during playback). detecting a track shift in each section from the level of each reproduction signal that the rotary head reproduces from a plurality of sections in one track;
A section corresponding to the detected track deviation amount and the track deviation amount of each section detected and stored based on the reproduction signal level from each section of a plurality of sections in another track previously scanned by the rotary head. and controlling the output data from the memory so as to increase/decrease or maintain the level of the swinging signal to the head moving mechanism so that the two are substantially equal according to the comparison result, and one The oscillation is performed so as to limit the difference between the amount of head displacement in one section that the rotary head is scanning among the plurality of sections in the track and the amount of head displacement in the immediately preceding section to a certain value or less. This is a tracking method in which the rotary head is tracked on a track by controlling a motion signal, and the data stored in the memory is based on the predicted track scanning locus of the rotary head in accordance with the magnetic tape running mode. A tracking method in a magnetic reproducing device characterized in that the data is changed and set in advance to a value that should give the amount of head displacement at each time. 2. A head moving mechanism that displaces the rotary head in a direction perpendicular to the longitudinal direction of the recording track on the magnetic tape is provided with a head moving mechanism that is synchronized with the rotation of the rotary head and that has M (M is the number of rotary heads used during reproduction) A swinging signal for swinging the rotary head up and down alternately is generated and applied based on data read from the memory for each track scan (total number of tracks). The track deviation of each section is detected from the level of each playback signal reproduced from multiple sections of the track,
A section corresponding to the detected track deviation amount and the track deviation amount of each section detected and stored based on the reproduction signal level from each section of a plurality of sections in another track previously scanned by the rotary head. and controlling the output data from the memory so as to increase/decrease or maintain the level of the swinging signal to the head moving mechanism so that the two are substantially equal according to the comparison result, and one The oscillation is performed so as to limit the difference between the amount of head displacement in one section that the rotary head is scanning among the plurality of sections in the track and the amount of head displacement in the immediately preceding section to a certain value or less. This is a tracking method in which the rotating head is tracked on a track by controlling a moving signal, and when the swinging signal displaces the rotating head by more than M track pitches in the positive or negative direction, the swinging signal is set to negative. 1. A tracking system for a magnetic reproducing apparatus, characterized in that tracking of the rotary head is performed by supplying a displacement amount of M track pitches in the direction or the positive direction to the head moving mechanism as a value to be given. 3. A head moving mechanism that displaces the rotary head in a direction perpendicular to the longitudinal direction of the recording track on the magnetic tape is provided with a head moving mechanism that is synchronized with the rotation of the rotary head and that has M (M is the number of rotary heads used during reproduction) A swinging signal for swinging the rotary head up and down alternately is generated and applied based on data read from the memory for each track scan (total number of tracks). The track deviation of each section is detected from the level of each playback signal reproduced from multiple sections of the track,
A section corresponding to the detected track deviation amount and the track deviation amount of each section detected and stored based on the reproduction signal level from each section of a plurality of sections in another track previously scanned by the rotary head. and controlling the output data from the memory so as to increase/decrease or maintain the level of the swinging signal to the head moving mechanism so that the two are substantially equal according to the comparison result, and one control so as to limit the difference between the amount of head displacement in one section that the rotary head is scanning among the plurality of sections in the track and the amount of head displacement in the immediately preceding section to a certain value or less. In this tracking method, the rotary head is tracked on a track, and the data stored in the memory is changed to a value that displaces the rotary head in a certain direction when the reproduction signal level of the rotary head becomes zero or extremely small. A tracking system for a magnetic reproducing apparatus, characterized in that the swinging signal generated based on the change data is supplied to the head moving mechanism to track the rotating head. 4. The recording tracks on the magnetic tape are recorded by M recording rotary heads having gaps with different azimuth angles, and the M reproducing rotary heads each have the same azimuth as the recording rotary head. A tracking method in a magnetic reproducing device according to claim 3, characterized in that the magnetic reproducing device has an angular gap.