JPH11162049A - Magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording and reproducing device capable of making the accuracy of a tracking control operation higher. SOLUTION: In a helical scanning type magnetic recording and reproducing device by a multisegment system recording and reproducing a recording signal on which the pilot signal for tracking of an AFT system in which digital data and an f1 signal and an f2 signal are made so as to be successively and alternately recorded every recording track is superposed, a specified, one kind of a difference signal is selected by a signal selecting circuit 34 according to whether the relation of signal levels among the difference signal (f1-f2)=A, the difference signal (f2-f1)=-A obtained from the f1 signal and the f2 signal reproduced from heads Hp1, Hp2 and the difference signal (f1-f2)=B, the difference signal (f2-f1)=-B obtained from the f1 signal and the f2 signal reproduced from heads Hm1, Hm2 coresponds to four kinds of relations of signal levels which are preliminarily set. Then, a tracking control signal is made to be generated based the selected difference signal and the running phase of a magnetic tape is controlled by the control signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to one frame of digital data based on a main signal such as image information and audio information divided so as to correspond to a plurality of predetermined recording traces, and has a frequency of f.
A multi-segment system for recording / reproducing a recording signal obtained by superimposing a tracking pilot signal of the ATF system in which a pilot signal of frequency 1 and a pilot signal of frequency f2 are alternately recorded every other recording trace. And a helical scan type magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art A magnetic tape wound around a part of a peripheral surface of a drum composed of an upper drum and a lower drum is run at a predetermined running speed, and a recording / reproducing operation is performed using a rotating magnetic head. The helical scan type magnetic recording / reproducing apparatus thus configured has been widely used as a VTR. In the helical scan type magnetic recording / reproducing apparatus described above, as one means for achieving high-density recording, a pair of rotating magnetic heads having magnetic air gaps having opposite azimuth angles, that is, The azimuth angle of the magnetic gap is 9 clockwise with respect to the width direction of the recording trace.
A rotating magnetic head having a magnetic gap set at a predetermined angle of 0 ° or less, and an azimuth angle of the magnetic gap set at a predetermined angle of 90 ° or less counterclockwise with respect to the width direction of the recording trace; A pair of rotating magnetic heads comprising a rotating magnetic head having a magnetic air gap, by rotating an upper drum provided at a position symmetrical by 180 degrees at a predetermined number of rotations,
A magnetic tape that runs at a predetermined running speed in a state where the position of the reference edge of the magnetic tape that is obliquely wound around at least a part of the peripheral surface of the drum is regulated by a guide that is provided on the lower drum. Is sequentially and alternately helically scanned by the pair of rotating magnetic heads,
180 of each rotating magnetic head in a pair of rotating magnetic heads
Corresponding to the rotation every degree, sequential recording traces by a signal to be recorded are sequentially recorded and formed on the magnetic tape adjacent to each other, or recorded information in the recording traces is reproduced.

A digital VTR (VCR) for home use, in which a running magnetic tape is helically scanned by a rotating magnetic head and digital data can be recorded and reproduced on the magnetic tape in an azimuth manner, is widely used in many countries around the world. Manufacturers and laboratories participated in “HD
The DVC standards defined as a result of consultations at the Digital VCR Council include discrete cosine transform (DCT),
Performs high-efficiency compression of image information by various techniques such as adaptive quantization and variable-length coding, and converts the digital data of the highly efficient compressed image information and the digital data of acoustic information to
High efficiency compression mode to be applied when recording and reproducing on a magnetic tape as SD mode signal or HD mode signal,
The configuration of recording data, a predetermined tape pattern, physical characteristics of a magnetic tape, the configuration of a cassette, and the like are defined.

[0004] Data having a predetermined format is recorded on a magnetic tape as a sync block formed by adding a SYNC word, an ID code, and a parity word (inner parity) for error correction coding. Is done. One frame of image data consists of a total of 10 lines (in the case of an NTSC color video signal) or 12 lines.
It is divided and recorded into recording tracks (tracks) of a book (in the case of a PAL color video signal). Helical scan type magnetic recording, including a home digital VTR (VCR) for recording and reproducing the SD mode signal of the DVC standard and the HD mode signal of the DVC standard by a multi-segment recording / reproducing method. In the reproducing apparatus, the position of the rotation trajectory of the rotary magnetic head drawn in the space by the rotary magnetic head is always constant under the condition that the inclination angle of the rotation axis of the rotary magnetic head does not change.

In a helical scan type magnetic recording / reproducing apparatus, a pattern (track pattern) of a recording mark formed on a magnetic tape in accordance with a rotation locus of a rotary magnetic head.
Depends on various conditions such as the diameter of the drum, the number of rotations of the rotating magnetic head, the rotating direction of the rotating magnetic head, the running speed of the magnetic tape, the running direction of the magnetic tape, the track angle, the head track width, and the recording area width of the magnetic tape. Therefore, when the operation mode of the magnetic recording / reproducing device is changed, for example, when the conditions such as the running direction and the running speed of the magnetic tape change, the rotation locus of the rotating magnetic head drawn on the magnetic tape by the rotating magnetic head is changed. The pattern will change.

That is, in a helical scan type magnetic recording / reproducing apparatus, an operation mode other than a normal reproduction (normal reproduction) operation in which a reproduction operation of recorded information is performed at the same magnetic tape traveling speed as a recording operation, for example, a recording mode Magnetic head in which special reproduction (trick play) is performed in which a magnetic tape is run (including stoppage) at a running speed or running direction different from the running speed or running direction of the magnetic tape at the time, and a reproducing operation is performed. The rotation locus of the magnetic tape becomes different depending on the change in the running speed and running direction of the magnetic tape, and the rotating locus of the rotary magnetic head intersects with the recording trace on the recorded magnetic tape. Rotating magnetic head during trick play where the running speed of the magnetic tape is significantly different from the running speed of the magnetic tape during recording Al can not be accurately reproduce recording signals recorded in the recording marks.

In particular, in a helical scan type digital magnetic recording / reproducing apparatus, it is necessary to reproduce a signal having a signal level which can be corrected.
This poses a major obstacle to the configuration of the scan type digital magnetic recording / reproducing apparatus. Therefore, during a special playback operation in which the recorded magnetic tape is run at a running speed different from the running speed of the magnetic tape during the recording operation by the multi-segment recording / reproducing digital VTR, the recorded magnetic tape is used. It is necessary that reproduced signals from all recording tracks (tracks) recorded on the tape be reproduced as signals of a signal level at which error correction is possible.

For this purpose, in a digital VTR for business use, a rotating magnetic head is mounted on an electro-mechanical transducer used as an actuator (head actuator) in an open-loop control circuit or a closed-loop control circuit, and the electro-mechanical transducer is mounted. The rotary magnetic head is displaced to cause the rotary magnetic head to follow the recording mark of the magnetic tape. Also, in a consumer digital VTR which is required to be inexpensive with a pair of rotary magnetic heads, the rotary magnetic head is formed by an electro-mechanical conversion element like the above-mentioned digital VTR for business use. Because it is not possible to adopt a configuration that displaces and causes the rotating magnetic head to follow the recording trace of the magnetic tape, for example, by connecting a part of the slow reproduction image using a memory,
Special playback is realized.

In a conventional helical scan type magnetic recording / reproducing apparatus for home use, a control signal recorded for each rotation of an upper drum using a fixed head at the lower end of a magnetic tape is used for a tracking operation during a reproducing operation. The control track method (CTL method) used in the above was adopted as the reproduction tracking method. However, in the helical scan type magnetic recording / reproducing apparatus implementing the reproduction tracking method, extra space is required for installing a fixed head. This hinders downsizing of the device.

[0010] In recent years, a helical scan type digital magnetic recording / reproducing apparatus for home use which has been commercialized in recent years,
A rotating magnetic head attached to the upper drum records a recording signal in which a tracking pilot signal is superimposed on digital data based on main signals such as video and audio. An ATF (Automatic Tracking Finding) system is adopted in which the tracking operation of the rotating magnetic head is performed by comparing the crosstalk components of the pilot signal reproduced from the recording trace.

In the above-mentioned ATF system, a recording trace on which a pilot signal of frequency f1 is recorded and a pilot signal of frequency f2 are recorded on recording traces on both sides of a recording trace on which no pilot signal is recorded. And two types of pilot signals, a pilot signal having a frequency of f1 and a pilot signal having a frequency of f2, are alternately arranged every other recording trace. It is in the state where it is. Now, assuming that a pilot signal having a frequency of f0 is recorded in a recording trace where no pilot signal is recorded, an arrangement state of pilot signals recorded in sequential recording traces will be described. 4 recordings such as a signal → a pilot signal having a frequency f1 → a pilot signal having a frequency f0 → a pilot signal having a frequency f2 → a pilot signal having a frequency f0 → a pilot signal having a frequency f1 → a pilot signal having a frequency f0. The array is in a state of making a round for each trace [see (a) of FIG. 6].

The head track width of the reproducing rotary magnetic head is set to be wider than the recording track width of the recording track recorded on the magnetic tape, and the reproducing rotary magnetic head has a frequency f0. When tracking the recording trace where the pilot signal is recorded, the pilot signal of the frequency f1 recorded in the recording trace adjacent to both sides of the recording trace by the rotary magnetic head for reproduction, Since the crosstalk component with the pilot signal having the frequency f2 is reproduced, the tracking control operation is performed so that the signal levels of the crosstalk components of the reproduced two pilot signals become equal. Thus, it is possible to bring the reproducing rotary magnetic head into a state where it accurately tracks the recording trace recorded on the magnetic tape.

[0013]

However, the arrangement pattern of the pilot signals f0, f1, f2 is as shown in FIG.
As shown in the figure, in the case of an array pattern in a state of making a round every four recording traces, tracking for the rotating magnetic head for reproduction performed based on a pilot signal reproduced by one rotating magnetic head for reproduction. The control action is
In FIG. 6B, recording is performed only on one of the slopes marked with a circle or on one of the slopes without the circle or on both slopes. Could not perform tracking control operation. Therefore, there has been a demand for a means capable of performing a good tracking control operation for each successive recording trace.

[0014]

According to the present invention, a digital signal of a main signal such as image information and audio information of one frame divided so as to correspond to a plurality of predetermined recording traces includes a pilot signal having a frequency of f1. And a helical scan type multi-segment type recording and reproducing a recording signal obtained by superimposing an ATF tracking pilot signal in which a pilot signal having a frequency of f2 is sequentially and alternately recorded every other recording trace. In a magnetic recording / reproducing apparatus, a first rotating magnetic head and a second rotating magnetic head in which an azimuth angle of a magnetic gap is set at a predetermined angle of 90 degrees or less clockwise with respect to a width direction of a recording mark are used. And the azimuth angle of the magnetic air gap is set counterclockwise with respect to the width direction of the recording trace. The third rotary magnetic head which is set to a predetermined angle of 90 degrees or less and a fourth rotary magnetic head to Ri, the third rotary magnetic head described above is the one
The upper drum is disposed at a position symmetrical with respect to the center axis of the drum and is 180 degrees symmetrical, and is provided coaxially with the upper drum. A lower drum, means for performing a reproducing operation by running a recorded magnetic tape in a state of being wound on a part of the peripheral surface of the upper and lower drums, and the first (or third) rotating magnet The frequency extracted from the reproduced signal of the head is f1
Difference signal (f1-f2) = A, difference signal (f2-f1) =-A obtained with respect to the pilot signal f1 and the pilot signal f2 having the frequency f2, and the second (or fourth) rotation described above. Difference signal (f1-f2) obtained from pilot signal f1 having a frequency of f1 and pilot signal f2 having a frequency of f2 extracted from a reproduction signal of the magnetic head =
B, when the difference signal (f2-f1) =-B, the relationship between the signal levels of the four types of difference signals A, -A, B, and -B is determined by four predetermined signal levels. Means for selecting a specific type of difference signal according to which of the following conditions is satisfied, means for generating a tracking control signal based on the selected difference signal, and the tracking control A magnetic recording / reproducing apparatus including means for controlling tracking of a magnetic head by a signal, and a digital signal based on main signals such as image information and audio information of one frame divided so as to correspond to a plurality of predetermined recording tracks. An ATF tracking pilot signal in which a pilot signal having a frequency of f1 and a pilot signal having a frequency of f2 are sequentially and alternately recorded every other recording track is superimposed on the data. In a multi-segment helical scan type magnetic recording / reproducing apparatus for recording / reproducing a recording signal, the azimuth angle of a magnetic gap is set to a predetermined angle of 90 degrees or less clockwise with respect to the width direction of a recording mark. The first rotating magnetic head and the second rotating magnetic head which are
A third rotating magnetic head and a fourth rotating magnetic head which are disposed at symmetrical positions and the azimuth angle of the magnetic gap is set to a predetermined angle of 90 degrees or less counterclockwise with respect to the width direction of the recording trace. In a state where the third rotating magnetic head is located in the vicinity of the first rotating magnetic head and 180 degrees symmetric with respect to the center axis of the drum. An upper drum, a lower drum provided coaxially with the upper drum, and a recorded magnetic tape running around a part of the peripheral surface of the upper and lower drums. Means for controlling the change so that the rotation trajectory of the rotary magnetic head coincides with the direction parallel to the direction in which the recording trace extends, means for performing a reproducing operation by running the recorded magnetic tape, Or 3) Reproduction of the rotating magnetic head The difference signal (f1-f2) = A and the difference signal (f2-f1) =-A obtained from the pilot signal f1 having the frequency f1 extracted from the signal and the pilot signal f2 having the frequency f2 are described above. 2nd (or 4th)
Difference signal (f1−f2) = B obtained from a pilot signal f1 having a frequency f1 and a pilot signal f2 having a frequency f2 extracted from the reproduction signal of the rotating magnetic head of FIG.
When the difference signal (f2−f1) = − B, the aforementioned 4
One specific type of difference signal is generated according to which of the four types of signal level relationship the signal level relationship among the type difference signals A, -A, B, and -B corresponds to. A magnetic recording / reproducing apparatus comprising: means for selecting; means for generating a tracking control signal based on the selected difference signal; and means for controlling tracking of a magnetic head by the tracking control signal. It is.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific contents of a magnetic recording / reproducing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
1 and 2 are block diagrams showing a schematic configuration of a reproducing system in the magnetic recording / reproducing apparatus of the present invention. FIG. 3 is a diagram showing an example of an arrangement of a rotary magnetic head used for a recording and reproducing operation in the magnetic recording and reproducing apparatus of the present invention and an example of a configuration of the magnetic head. FIG. 3A shows the upper drum D
FIG. 4B is a plan view for explaining an example of the arrangement of the rotating magnetic head in u. FIG. 3B is a plan view of each of the upper drums Du arranged as shown in FIG. FIG. 3 is a development view showing a configuration mode and an arrangement relationship of the rotating magnetic head.

In FIG. 1, FIG. 2 and FIG.
Denotes a drum base. The drum base DB includes a drum structure D including an upper drum (rotary drum) Du and a lower drum Dd provided coaxially with the upper drum.
A is provided. Further, in the magnetic recording / reproducing apparatus shown in FIG.
Even if the running direction or running speed of the recorded magnetic tape T running while being wound on a part of the peripheral surface of the upper and lower drums is changed, the rotation drawn on the magnetic tape T by the rotating magnetic head H is changed. A drum tilt control circuit and a drum tilt control mechanism for performing a control operation of changing and controlling the tilt of the center axis of the drum so that the locus always matches a predetermined track angle with respect to a reference edge Te of the magnetic tape T. [The structural part shown by the block 8 and a specific structural example thereof will be described later with reference to FIGS. 4 and 5] is also provided.

FIGS. 3A and 3B show a plurality of magnetic heads H (Hp1, Hm) attached to the upper drum Du in the magnetic recording / reproducing apparatus shown in FIGS.
1, Hp2, Hm2). In FIG. 3A, Du is an upper drum (rotary drum),
Further, in each of FIGS. 3A and 3B, Hp1,
Hm1, Hp2 and Hm2 are rotary magnetic heads.

Each of the rotary magnetic heads Hp1, Hm
1, Hp2 and Hm2, the rotary magnetic heads Hp1 and Hp2 to which the subscript p is attached have an azimuth angle of the magnetic gap Mg of 90 degrees or less clockwise with respect to the width direction of the recording mark. Shows a rotating magnetic head configured with a magnetic air gap Mg set at a predetermined angle α. On the other hand, in the rotary magnetic heads Hm1 and Hm2 with the subscript m, the azimuth angle of the magnetic gap Mg is set to a predetermined angle α of 90 degrees or less counterclockwise with respect to the width direction of the recording trace. 2 shows a rotary magnetic head configured with a magnetic gap Mg. Each of the rotary magnetic heads Hp1, Hp2, Hm
When the recording signal to be recorded is, for example, a bit stream of digital data, the azimuth angle α of the magnetic gap Mg of each rotating magnetic head is defined as: For example, it may be selected at 20 degrees.

First, the four rotating magnetic heads Hp1, Hp2, Hm1, Hm shown in FIGS.
2, the first rotary magnetic head Hp1 and the second rotary magnetic head Hp2 are mounted on the rotary drum Du so as to have the same mounting height at 180-degree symmetric positions about the center axis of the drum as a symmetric center. ing. The third rotating magnetic head Hm1 and the fourth rotating magnetic head Hm2 are
It is mounted on the rotating drum Du at the same mounting height at 180 degrees symmetrical with respect to the center axis of the drum as the center of symmetry.

The third rotating magnetic head Hm1 disposed near the first rotating magnetic head Hp1 has a height corresponding to one track pitch with respect to the mounting height of the first rotating magnetic head Hp1. The fourth rotating magnetic head Hm2, which is provided on the rotating drum Du in a state having a difference in height, and disposed in the vicinity of the second rotating magnetic head Hp2, is a second rotating magnetic head Hp2. Is provided on the rotating drum Du in a state having a height difference corresponding to one track pitch with respect to the mounting height of the drum.

As described above, the first and third rotating magnetic heads Hp1 and Hm1 having the magnetic air gaps Mg having different azimuth angles are arranged such that the distance between the magnetic air gaps is only a predetermined minute interval. A first magnetic head pair (first pair head) H1 disposed apart from each other constitutes a first magnetic head pair (first pair head) H1, and the second rotating magnetic head Hp2 and the fourth rotating magnetic head Hm2 are mutually separated. The second magnetic head pair (second pair head) H2 is arranged such that the distance of the magnetic air gap is spaced apart by a predetermined minute interval. In FIG. 3A, reference numeral 12 denotes an upper drum Du.
And the center axis (12 in FIG. 5) of the drum structure DA including the lower drum Dd.

FIG. 4 shows the rotation locus drawn on the magnetic tape T by the rotary magnetic head by changing the running direction and running speed of the magnetic tape T as described above.
Configuration example of a drum tilt control circuit and a drum tilt control mechanism (a component shown by a block 8 in FIG. 1) that always perform a control operation to make the reference edge Te coincide with a predetermined track angle. Is shown. FIG. 5 is an exploded perspective view of a configuration example of the drum tilt control mechanism unit. First, referring to FIG. 4, the rotation locus drawn on the magnetic tape T by the rotating magnetic head is controlled so as to be at an arbitrary predetermined angle with respect to the reference edge Te of the magnetic tape T, and the position of the lead ring Lr is controlled. An outline of a configuration principle and an operation principle of a tilt correction mechanism portion for making the regulating surface G coincide with the movement locus of the traveling magnetic tape T will be described.

In FIG. 4, DB is a drum base, and a drum structure DA including an upper drum Du, a lower drum Dd, and a lead ring Lr is supported by the drum base DB. The upper drum Du is a drum structure D
A lower bearing Dd is fixed to the center axis of the drum assembly DA by a bearing (not shown) mounted on the center axis 12 of A in a rotatable manner with respect to the center axis of the drum assembly DA. Have been. The lead ring Lr functioning as a guide for the reference edge Te (for example, see FIG. 1) of the magnetic tape T is formed separately from the above-described lower drum Dd, and is provided on the outer peripheral portion 13 below the lower drum Dd. It is close to and coaxially fits (not shown) with the lower protrusion of the lower drum Dd by a knife edge E (see FIG. 5) provided on the inner periphery of the lead ring Lr.

As shown in FIG. 4 (an exploded perspective view of a specific structure is shown in FIG. 5), the drum tilt control circuit 8 is a tilt drive motor (DD in FIG. 4) which is a power source. Motor) 14, and reduction mechanisms 15, 16 including a plurality of gears,
It includes a rotary encoder 17, a position detector (preset sensor) 18, and the like. The tilt drive motor 14 indicated by a block 14 in FIG.
It also includes a motor drive control circuit. As the above-described position detector 18, for example, one having a configuration in which an arc-shaped light shielding plate is moved in an optical path in which a light emitting element and a light receiving element are arranged to face each other may be used. The position detector 18 is configured such that the signal output from the position detector 18 at the moment when the arc-shaped light shielding plate is removed from the optical path in which the light emitting element and the light receiving element are arranged to face each other is the drum described above. It is used as information indicating the reference position of the center axis 12 of the structure DA and the reference position of the lead ring Lr.

Also, by knowing the amount of rotation of the light shielding plate from the reference position in the position detector 18 by measuring the number of pulses output from the rotary encoder 17, the reference position of the center axis 12 of the drum structure DA is determined. Direction and the amount of deviation from the reference position of the lead ring Lr can be obtained. The running direction and running speed of the magnetic tape T are controlled by the main control unit 5 according to various operation modes set in the main control unit (system controller) 5 of the magnetic recording / reproducing apparatus. Drum tilt control circuit 8 given information
Are the upper drum Du and the lower drum D in the drum structure DA.
The screws 26 and 28 are advanced and retracted so that the central axis 12 of the drum structure DA including the d and the lead ring Lr is inclined by a predetermined amount in the direction of the arrow 12a (or 12b) in FIG. Control operation.

The lead ring Lr is also tilted by a predetermined amount in a predetermined direction under the control of the drum tilt control circuit 8 so that the running direction and the running speed of the magnetic tape are changed. The pattern of the rotation locus drawn on the magnetic tape T by the rotation locus of the rotating magnetic head is as follows:
A state where the track angle is determined, that is, a state where the inclination is corrected, and the reference edge Te of the magnetic tape are set.
The guide portion G (position regulating surface) of the lead ring coincides with the movement locus of the lead ring. First, in a state where the magnetic tape T is run in the forward direction (the direction of the arrow b in FIG. 1) at a predetermined running speed during a normal recording / reproducing operation, a predetermined specific rotation direction (the arrow in FIG. 3). The lower drum D in the case where recording is alternately and sequentially formed on the magnetic tape T by the rotating magnetic head which is driven and rotated at a predetermined number of rotations in the direction a).
d are four rotation fulcrums (the rotation fulcrums 20, 20, 21, and FIG. 5 in FIG. 5) whose bottoms protrude from the drum base DB.
21 (see FIG. 21).

The lead ring Lr is supported by four pivots (see pivots 22, 22, 23, 23 in FIG. 5) projecting from the lead ring Lr. To be. Between the above-mentioned lead ring Lr and the drum base DB and between the lower drum Dd and the drum base DB
And springs (springs 19 and 19 in FIGS. 4 and 5), respectively.
24, 25) are mounted so that the above-mentioned parts are connected to each other in a predetermined connection state. For example, when the magnetic recording / reproducing apparatus performs forward recording, the screw 27 is driven so as to push up the bottom surface of the lower drum Dd, and the screw 29 is driven in a direction away from the bottom surface of the lower drum Dd. Two rotation fulcrums (rotation fulcrums 20, 20) out of the four rotation fulcrums protruding from the base DB are in contact with the bottom surface of the lower drum Dd. The center axis of the upper drum Du and the lower drum Dd is shown in FIG.
It is made to rotate in the direction of the middle arrow 12a.

When recording and reproduction are performed with the running direction of the magnetic tape reversed, the screw 29 is connected to the lower drum Dd.
And the screw 27
Is driven in a direction away from the bottom surface of the lower drum Dd, and two of the four rotation supporting points protruding from the drum base DB.
Of the lower drum Dd
And the center axis of the upper drum Du and the lower drum Dd is rotated in the direction of the arrow 12b in FIG. 4 using the two rotation fulcrums as the rotation fulcrum. The above-described driving operation for the screws 27 and 29 is performed by the operation of the driving mechanism. The driving mechanism includes a motor 14 as a power source, a speed reduction mechanism including a plurality of gears, a position detector 18, a rotary encoder 17, and the like as shown in the exploded perspective view of FIG. ing.

In accordance with the running direction and running speed of the magnetic tape T set in the main control unit 5 provided in the magnetic recording / reproducing apparatus in accordance with various operation modes, the main direction is changed. The drum tilt control circuit 8 to which the control information is given from the control unit 5 controls the upper drum D in the drum structure DA.
u, the lower drum Dd (see FIG. 4), and the lead ring Lr, the center axis of the drum structure DA is indicated by an arrow 12a in FIG.
(Or 12b) by controlling the drive mechanism so as to incline by a predetermined amount in each direction.
Move 7,29 forward and backward. For example, when the magnetic tape is running in the direction of arrow b in FIG.
r, two rotation fulcrums (rotation fulcrums 22, 22) of the four rotation fulcrums come into contact with the bottom surface of the lower drum Dd, and rotate the two rotation fulcrums. As a fulcrum, the lead ring Lr is screwed into the lead ring Lr so that the center axis of the lead ring Lr is rotated by a predetermined amount in the direction of arrow 12a in FIG. The two screws 26 and 28 provided in contact with the bottom surfaces of the two are rotated in opposite directions.

Further, for example, when the magnetic tape is running in the direction of arrow b in FIG. 1, two of the four pivots projecting from the lead ring Lr are pivoted. The fulcrum (rotation fulcrum 23, 23) is in contact with the bottom surface of the lower drum Dd, and the lead ring L is set with the two rotation fulcrums as the rotation fulcrum.
r is screwed into the lead ring Lr such that the center axis of the r is rotated by a predetermined amount in the direction of the arrow 12b in FIG. 4, and the leading end portions respectively contact the bottom surface of the lower drum Dd. Two screws 2 provided as state
6, 28 are rotated in opposite directions.

The above-mentioned driving operation for the screws 26 and 28 is also performed by the operation of the above-mentioned driving mechanism operating under the control of the drum inclination control circuit.
The control information is supplied from the main control unit 5 according to the running direction and the running speed of the magnetic tape T set in the main control unit 5 provided in the VTR in accordance with various operation modes. The drum inclination control circuit 8 is connected to the lead ring L.
The drive mechanism is controlled so that r is inclined by a predetermined amount in the direction of the arrow 12a (or 12b) in FIG. 4, and the screws 26 and 28 are advanced and retracted. In the above description, in order to facilitate understanding of the operation, the tilting operation of the center axis of the drum assembly by the forward and backward operations of the screws 27 and 29 and the screws 26 and 28
It has been described that the tilting operation of the center axis of the lead ring Lr due to the forward / backward movement is performed independently of each other. However, each of the screws 26 to 29 described above is a screw 2
7 and the screw 26 are simultaneously driven and rotated by a common power transmission mechanism, and the screw 29 and the screw 28 are simultaneously driven and rotated by a common power transmission mechanism. The inclining operation of the center axis of the drum structure by the advancing and retreating operation and the inclining operation of the central axis of the lead ring Lr by the advancing and retreating operation of the screws 26 and 28 may be performed simultaneously.

In the magnetic recording / reproducing apparatus described with reference to FIGS. 4 and 5, the rotation trace surface of the rotary magnetic head coincides with the recording trace formed on the magnetic tape by a predetermined angle. The first tilt drive means for tilting the central axes of the upper and lower drums and the rotary magnetic head is provided separately from the upper and lower drums and at the lower portion of the lower drum. A position-regulating guide member (lead ring) Lr for the magnetic tape having a restricting surface G at the position of the reference edge of the magnetic tape, which is disposed close to the outer peripheral surface of the small diameter portion 13 (see FIG. 5); A second inclination driving means for inclining the position regulating guide member of the magnetic tape so as to coincide with the reference edge position of the magnetic tape,
By inclining the lower drum and the lead ring Lr having the position regulating surface G of the reference edge of the magnetic tape as required according to various operation modes, the recording formed on the magnetic tape is performed. The track of rotation of the rotary magnetic head is made to coincide with the trace, and the reference edge Te of the magnetic tape T can be guided well by the position regulating surface G of the lead ring Lr.

When the magnetic recording / reproducing apparatus performs the recording / reproducing operation, a predetermined control signal is supplied from the main control unit 5 to the drum inclination control circuit unit 8 so that the drum inclination control circuit 8 The angle between the rotation trajectory of the rotating magnetic head and the reference edge of the magnetic tape is always set to the reference value regardless of whether the magnetic tape is running in the forward direction or the magnetic tape is running in the reverse direction. Of the track angle.

Now, in order to avoid complicating the drawing, the description of the components of the recording system is omitted, and the reproducing system in the magnetic recording / reproducing apparatus of the present invention shows different embodiments respectively in FIGS. In the respective block diagrams, the components corresponding to each other are denoted by the same reference numerals. The recorded magnetic tape to be reproduced by the magnetic recording and reproducing apparatus of the present invention is a recorded magnetic tape obtained by recording a recording signal by a recording operation of a recording system (not shown) in the magnetic recording and reproducing apparatus of the present invention. Or a recorded magnetic tape obtained by recording a recording signal by a recording operation of another magnetic recording / reproducing device.

In the magnetic recording / reproducing apparatus shown in each of the drawings, reference numeral 1 denotes a reproduction signal output terminal of the magnetic recording / reproducing apparatus, and reference numeral 2 denotes a reproduction signal processing unit. Reference numeral 5 denotes a main control unit. The main control unit (system controller) 5 includes, for example, a microprocessor, a random access memory (RA).
M), a memory including a read only memory (ROM) and the like can be used. The main control unit 5 controls various components of the magnetic recording / reproducing apparatus, for example, a drum control unit (drum rotation control unit) 6, and controls the running speed and running phase of the magnetic tape in accordance with input information from an operation unit (not shown). System (capstan control system: capstan 3, pinch roller 4, capstan motor 9, signal generator 10, adder 30, sample hold circuit 33,
Signal selection switching circuit 34, level adjusters 51, 52, f1
A control signal is supplied to the signal detectors 47 and 49, the f2 signal detectors 48 and 50, the differential amplifiers 53 to 56, etc., the drum tilt control unit 8 and the like, and the above-mentioned components are provided. Controls the operation.

The drum rotation control unit 6 includes a signal generator 31 mounted on the rotation shaft of the drum motor 7.
The rotary magnetic head (upper drum) is rotated at a predetermined rotation speed and rotation phase by the drum rotation signal DFG generated by the drum frequency generator and the drum rotation phase signal DPG generated by the drum rotation phase signal generator. Control to make it. Further, the capstan control system operates so that the magnetic tape runs at a predetermined tape running speed in a predetermined running direction in accordance with the reproducing operation mode.

The above-described drum inclination control section (drum inclination control mechanism section) 8 to which a control signal is supplied from the main control section 5 is provided in the forward direction (for example, the direction of arrow b shown in FIG. 1) or In the opposite direction (for example, arrow-shown in FIG. 1)
b), the angle formed between the rotation locus of the rotary magnetic head H and the reference edge of the magnetic tape on the magnetic tape traveling at a predetermined magnetic tape traveling speed is based on the reference of the recording mark formed on the magnetic tape. The center angle of the drum is tilted by the operation of the drum tilt controller (drum tilt control mechanism) 8 so as to be the same as the track angle of the drum.

In the control system (capstan control system) for the traveling speed and the traveling phase of the magnetic tape, the main control unit is controlled in accordance with the reproduction mode information of the magnetic recording / reproducing apparatus inputted to the operation unit (not shown). 5 to the adder 30 and a frequency-voltage converter corresponding to the output signal of the frequency generator 10 attached to the rotating shaft of the capstan motor 9 for driving the capstan 3 to rotate. 11
Is supplied to the drive circuit 32 to control the magnetic tape to have a predetermined running speed. In addition, a tracking error signal supplied from a sample hold circuit 33, which will be described later, to the adder 30 is supplied to the drive circuit 32, so that the magnetic tape is controlled to have a predetermined running phase. As a result, the output signal from the drive circuit 32 is supplied to the capstan motor 9 so that the magnetic tape T sandwiched between the capstan 3 and the pinch roller 4 runs at a predetermined running speed and running phase. State.

Then, the main control unit 5 to which the instruction information of the reproduction operation in the desired reproduction mode is given from the operation unit, according to the input information from the operation unit, the drum control unit (drum rotation control unit) in the magnetic recording / reproducing apparatus. 6. The control signal is supplied to the control system of the running speed and running phase of the magnetic tape, the drum tilt control unit 8, and the like. Accordingly, the drum rotation control unit 6 controls the rotating magnetic head (upper drum) to rotate at a predetermined rotation speed and a predetermined rotation phase, and the capstan control system controls the reproduction operation in the desired reproduction mode. The automatic speed control operation is performed while the recorded magnetic tape T is running at a running speed corresponding to the above. Further, the drum tilt control unit (drum tilt control mechanism unit) 8 performs the reproduction in the desired reproduction mode. Even if the traveling speed corresponding to the operation is different from the traveling speed of the magnetic tape during the recording operation,
The rotating magnetic head H (Hp1, Hp2, Hm1, Hm) moves relative to the reference edge Te of the running recorded magnetic tape T.
2) The center axis of the drum is inclined so that the angle formed by the rotation trajectory is the same as the reference track angle of the recording mark recorded on the magnetic tape, and the rotation trajectory of the rotary magnetic head is recorded on the magnetic tape. The reproducing operation is performed in a state parallel to the extension direction of the recording trace of the head.

During the reproducing operation, the rotating magnetic head H (rotating magnetic heads Hp1, Hm) is read from the recorded magnetic tape running at the running speed corresponding to the selected predetermined reproducing mode.
1, Hp2, Hm2) are amplified by the corresponding one of the preamplifiers 35 to 38, and then amplified by the changeover switch 3
The signals are supplied to waveform equalization circuits 41 and 42 via the components 9 and 40. That is, in the magnetic recording / reproducing apparatus shown in FIGS. 1 and 2, after the bit stream from the first rotating magnetic head Hp1 is amplified by the preamplifier 36, it is connected to the fixed constant contact a of the changeover switch 40. Is supplied to the waveform equalizing circuit 41 when the movable contact v is switched to the fixed contact a, and the bit stream from the second rotating magnetic head Hp2 is supplied to the preamplifier 38. After being amplified by the switch, the signal is applied to the fixed contact b of the changeover switch 40 and supplied to the waveform equalizing circuit 41 when the movable contact v is switched to the fixed contact b.

Further, after the bit stream from the third rotating magnetic head Hm1 is amplified by the preamplifier 35, the bit stream is given to the fixed contact a of the changeover switch 39, and the movable contact v is moved to the fixed contact a side. Is supplied to the waveform equalizing circuit 42 when the state is switched to
After the bit stream from the fourth rotating magnetic head Hm2 is amplified by the preamplifier 37, the bit stream is applied to the fixed contact b of the changeover switch 39, and the movable contact v is switched to the fixed contact b. Is supplied to the waveform equalizing circuit 42 at the time of

Therefore, the bit stream supplied to the waveform equalizer 41 is composed of two rotating magnetic heads H
The bit stream reproduced by p1 and Hp2 is one selected by the switching operation of the changeover switch 40. The bit stream supplied to the waveform equalizer 42 is One of the bit streams reproduced by the two rotating magnetic heads Hm1 and Hm2 is selected by the changeover operation of the changeover switch 39.

The waveform equalizers 41 and 42 perform waveform equalization of the supplied bit stream. The bit stream output from the waveform equalization circuit 41 is output to a code detection circuit 45 and a phase locked loop (PLL) 4.
3 and the bit stream output from the waveform equalization circuit 42 is supplied to a code detection circuit 46 and a phase locked loop (PLL) 44.

The code detection circuits 45 and 46 perform a code detection operation on the bit stream, supply the output digital data to the reproduction signal processing unit 2, and supply the digital data from the code detection circuit 45 to the f1 signal. It is also supplied to the detection circuit 49 and the f2 signal detection circuit 50,
The digital data from the code detection circuit 46 is also supplied to the f1 signal detection circuit 47 and the f2 signal detection circuit 48.

The digital data supplied to the reproduction signal processing unit 2 to which the digital data has been supplied from the code detection circuits 45 and 46 are subjected to error correction by an error correction circuit in the reproduction signal processing unit 2. The variable length decoding unit decodes the variable length code, then performs an inverse DCT process in an inverse DCT circuit and stores the result in a frame memory.
The digital data read from the frame memory is sent to the output terminal 1 after D / A conversion.

In the f1 signal detection circuit 49 to which digital data is supplied from the code detection circuit 45, the f1 signal f1
And supplies it to the non-inverting input terminal of the differential amplifier 55 and the inverting input terminal of the differential amplifier 56. Further, the f2 signal detection circuit 50 to which the digital data is supplied from the code detection circuit 45 detects the f2 signal f2 and sends it to the inverting input terminal of the differential amplifier 55 and the non-inverting input terminal of the differential amplifier 56. Supply.

Further, the f1 signal detected by the f1 signal detection circuit 47 to which digital data is supplied from the code detection circuit 46 is detected.
The signal f1 is supplied to the level adjuster 51, and the f2 signal f2 detected by the f2 signal detection circuit 48 to which digital data is supplied from the code detection circuit 46 is supplied to the level adjuster 52. The f1 signal f1 adjusted to a predetermined signal level by the level adjuster 51 is supplied to the non-inverting input terminal of the differential amplifier 53 and the inverting input terminal of the differential amplifier 54. The f2 signal f2 adjusted to a predetermined signal level by the level adjuster 52 is supplied to the inverting input terminal of the differential amplifier 53 and the non-inverting input terminal of the differential amplifier 54.

By the way, as shown in FIG. 6A, a recording trace where a pilot signal of frequency f1 (f1 signal f1) is recorded, and a pilot signal of frequency f2 (f2 signal f2). In the state where the two types of pilot signals are alternately arranged every other recording trace, one rotating magnetic head traverses the sequential recording trace on the recorded magnetic tape T on which the sequential recording trace is recorded and formed. In this state, the tracking error signal obtained as the difference between the magnitudes of the two pilot signals (f1 signal, f2 signal) f1 and f2 reproduced from the one rotating magnetic head is changed. , As illustrated in FIG. 6 (b).

That is, the head track width of the reproducing rotary magnetic head is set to be wider than the recording track width of the recording track recorded on the magnetic tape, and the reproducing rotary magnetic head has a frequency f0. When the recording trace where the pilot signal is recorded is accurately tracked, the f1 signal f1 recorded in the recording trace adjacent to both sides of the recording trace by the above-mentioned rotary magnetic head for reproduction is used. , F2 signal f
2 is reproduced with the same magnitude, so that the f1 signal f1 obtained from the rotating magnetic head tracking the recording trace (f0) where no pilot signal is recorded as described above, The tracking error signal obtained as the difference between the f2 signal f2 becomes zero as shown in FIG.

Also, when the rotating magnetic head for reproduction tracks a recording trace where a pilot signal of frequency f0 is recorded, the rotating magnetic head for reproduction causes the rotating magnetic head for reproduction to move on both sides of the recording trace. In a tracking state in which the crosstalk component between the pilot signal of frequency f1 recorded in the recording trace adjacent to and the pilot signal of frequency f2 is different, the recording trace where no pilot signal is recorded ( f0) a tracking error signal obtained as the difference between the f1 signal f1 and the f2 signal f2 obtained from the rotating magnetic head tracking the f0), that is, (the magnitude of the pilot signal whose reproduced frequency is f1 ... the magnitude of the f1 signal) Tracking) obtained as a result of an operation such as-(the magnitude of the pilot signal whose reproduced frequency is f2 ... the magnitude of the f2 signal). Error signal (f1-f2) has a size corresponding to the size of the tracking deviation.

Regarding the magnitude of the two pilot signals f1 and f2 reproduced by one rotating magnetic head, the magnitude of the magnitude of the pilot signal having the reproduced frequency f2... When the calculated result is a tracking error signal (f2−f1) such as the magnitude of the pilot signal having the frequency f1..., The magnitude of the f1 signal), the tracking error signal (f2−f1) is obtained. It goes without saying that the signal has a polarity opposite to the polarity of f1-f2).

As is apparent from FIG. 6B, when the rotating magnetic head accurately follows the recording trace f0 where no pilot signal is recorded, the recording trace f0.
Since the two ends of the magnetic air gap in the rotating magnetic head following the recording track protrude by an equal size in the recording traces on both sides of the recording trace f0, the pilot signal is output from the rotating magnetic head. The frequency recorded in the recording traces on both sides of the unrecorded recording trace f0 is f1
And the pilot signal of frequency f2 is equal to the pilot signal of frequency f2. Therefore, when the rotating magnetic head accurately follows the recording trace f0 where no pilot signal is recorded, the tracking error signal becomes 0, but the position of the rotating magnetic head is shifted from the above state in the width direction of the recording trace. , A tracking error signal is generated in which the polarity and the magnitude are changed according to the direction and magnitude of the deviation.

That is, as described above, the change of the tracking error signal generated based on the pilot signal f1 having the frequency f1 and the pilot signal f2 having the frequency f2 extracted from the reproduction signal of one rotating magnetic head. The state corresponds to the displacement of the rotating magnetic head in a specific direction,
As shown in FIG. 6B, the tracking error signal is represented by a triangular wave having a period of four recording traces and a tracking error signal of "-polarity" when the rotating magnetic head is displaced in a specific direction. As shown in FIG. 6B, when the tracking error signal becomes 0 when a change is made as shown by a straight line rising to the right like “→→ 0 →“ + polarity ”, the state shown in FIG. (B) appears every four recording traces as indicated by a circle in the figure. Further, when the rotating magnetic head is displaced in a specific direction, the tracking error signal is represented by a straight line falling rightward in FIG. 6B, such as “+ polarity” → 0 → “−polarity”. During the change as shown, a state where the tracking error signal becomes 0 also appears every four recording traces.

As described above, the running phase of the magnetic tape is determined by the tracking error signal generated based on the pilot signal having the frequency f1 and the pilot signal having the frequency f2 extracted from the reproduction signal of one rotating magnetic head. When the tracking control operation is performed by changing
The problem is that the retraction time is long. Therefore, in the present invention, two rotating magnetic heads [the two rotating magnetic heads Hp1 and Hm1 forming the first pair head (or the second pair head forming the second pair head) are disposed adjacent to each other. Two rotating magnetic heads Hp2, Hm2)]
From the two reproduced signals simultaneously reproduced by
Each of the extracted pilot signals f1 having a frequency f1
And the tracking control operation is performed by changing the running phase of the magnetic tape by the tracking error signal generated based on the pilot signal f2 having the frequency f2. Made it possible.

Now, the two differential amplifiers 55, 5 already described
6, the f1 and f2 signals supplied from the f1 and f2 signal detectors f1 and f2 correspond to the rotating magnetic heads Hp1 and Hp.
2, the signals f1 and f2 reproduced individually.
F1, supplied to the two differential amplifiers 53 and 54 from the level adjusters 51 and 52.
The f2 signal is generated by the rotating magnetic heads Hm1 and Hm2.
These are the signals f1 and f2 reproduced individually.
The differential amplifier 55 outputs a difference signal (f1-f2) = A of f1 and f2, which is reproduced separately by the rotary magnetic heads Hp1 and Hp2. And from the differential amplifier 56, the rotary magnetic heads Hp1, Hp
According to p2, the f1 signal and f
A difference signal (f2−f1) = − A from the two signals is output,
The signal is supplied to a signal selection circuit (tracking error signal selection circuit) 34.

From the differential amplifier 53, the difference signals (f1-f2) of f1 and f2 reproduced individually by the rotary magnetic heads Hm1 and Hm2, respectively.
= B is output and given to the signal selection circuit 34, and the differential amplifier 54 outputs the rotary magnetic heads Hp1,
The difference signal (f2−f1) = − B between the individually reproduced f1 signal and f2 signal is output by Hp2 and supplied to the signal selection circuit 34.

In the above-described signal selection switching circuit 34, when the relationship between the signal levels among the four difference signals A, -A, B, and -B inputted thereto is (1) -B <A <B, Selects the difference signal A, (2) selects the difference signal B when A <B <−A, and further selects (3) the difference signal B when B <−A <−B Then, (4) when −A <−B <A, the difference signal −B is selected, and the one selected difference signal is supplied to the sample hold circuit 33. The sample-and-hold circuit 33 uses the sampling pulse supplied from the main control unit 5 to operate the signal selection switching circuit 34.
Sample the difference signal provided from the above and hold it. The time position of the sampling pulse in the case where the rotation trajectory of the rotating magnetic head and the extension direction of the recording trace of the recorded magnetic tape are parallel to each other corresponds to any part in the longitudinal direction of the recording trace. However, the time position of the sampling pulse when the rotation trajectory of the rotary magnetic head and the extension direction of the recording trace of the recorded magnetic tape are in a non-parallel state may be determined in the longitudinal direction of the recording trace. It may be set to correspond to the central part.

FIG. 7B is a diagram schematically showing the manner of change of the four types of difference signals A, -A, B, and -B. The difference signal A and the difference signal -A are shown. Of course has a phase difference of 180 degrees and the difference signal A
And the difference signal B have a phase difference of 90 degrees. Naturally, the difference signal B and the difference signal -B have a phase difference of 180 degrees. The change state of the tracking error signal illustrated in FIG. 7B constitutes the two rotating magnetic heads Hp1 and Hm1 forming the first pair head and the second pair head. Two rotating magnetic heads Hp
2 and Hm2, as illustrated in FIG. 7A, constitute the first pair head under the same reproduction condition that the recording trace is correctly tracked. Signals f1 and f2 reproduced by one rotating magnetic head in each of the rotating magnetic heads Hp1 and Hm1
1 and f2, and the f1 and f2 signals f1 and f2 reproduced by the respective rotating magnetic heads of the two rotating magnetic heads Hp2 and Hm2 forming the second pair head. The change mode of the signal level of f2 is shown as being the same. Under the above-described conditions, the rotating magnetic heads are given Hp1, Hm1, Hp2, and Hp2.
In order to make the signal levels of the f1 and f2 signals f1 and f2 reproduced by m2 the same, the signals of the f1 and f2 signals individually reproduced by the rotating magnetic heads Hm1 and Hm2 are used. This can be realized by adjusting the level by the above-described level adjusters 51 and 52 which may be configured using, for example, an attenuator.

FIG. 7A shows a recording trace (f1) in which a pilot signal having a frequency f1 is recorded on both sides of a recording trace (f0) where no pilot signal is recorded.
And a recording trace (f2) in which a pilot signal of frequency f2 is recorded, a recording trace (f1) in which a pilot signal of frequency f1 is recorded, and a pilot trace of frequency f2. A recorded magnetic tape T having a recording trace pattern in which recording traces (f2) are alternately arranged every other recording trace is running at the same running speed as the magnetic tape during the recording operation. In the state,
During the half rotation of the upper drum Du, the first pair head H1
The rotating magnetic heads Hp1 and Hm1 of the above-described embodiment correctly scan in the direction parallel to the recording mark of the recorded magnetic tape T, and during the next half rotation of the upper drum Du,
Magnetic head Hp constituting the pair head H2 of FIG.
FIG. 2 is a diagram used to explain a state where Hm2 is correctly scanning in a direction parallel to a recording mark of a recorded magnetic tape T.

In FIG. 7A, for convenience of illustration, the second pair head H1 is located immediately after the rotary magnetic head Hm1 in the first pair head H1.
2 as if there is a rotating magnetic head Hp2 in the second paired head H2, and at a position immediately after the rotating magnetic head Hm2 in the second paired head H2. Is adopted. .. # 10 described above (a) of FIG. 7A are used to distinguish ten consecutive recording traces in which one frame of image information is divided and recorded. Sign.

A state in which the recorded magnetic tape T is run at the same running speed as the running speed of the magnetic tape at the time of the recording operation with respect to the operation unit (not shown) of the magnetic recording / reproducing apparatus shown in FIG. If done,
The main control unit 5 to which the instruction information of the reproduction operation in the 1 × speed reproduction mode is given from the operation unit, according to the input information from the operation unit, the drum control unit (drum rotation control unit) 6 in the magnetic recording / reproducing apparatus, the magnetic tape A control signal is supplied to the control system for controlling the running speed and the running phase of the vehicle, the drum inclination control unit 8 and the like, so that each of the above-mentioned components can perform the playback operation in the 1 × speed playback mode. Controls the operating state of each component by the control signal.

Thus, two rotating magnetic heads Hp1 and Hm1 forming the first pair head and two rotating magnetic heads Hp2 and Hp2 forming the second pair head are formed.
With Hm2, a 1 × speed reproduction operation can be performed in a state in which sequential recording traces are correctly tracked as shown in FIG. 7A. At this time, a capstan control system in which a control signal for performing the 1 × speed reproduction operation is supplied from the control unit 5 to the adder 30 is used for the capstan control system.
Of the magnetic tape at the same running speed as the running speed of the magnetic tape during the recording operation.

Then, each rotating magnetic head Hp1, Hm
When the rotating magnetic heads Hp1, Hm2, Hp2, and Hm2 are tracing successive recording traces on the recorded magnetic tape T so as to be in the state shown in FIG.
switching modes for the reproduction signals reproduced from m1, Hp2, and Hm2 by the changeover switches 39 and 40; the reproduction signal selected by the changeover switch 39;
The f1 detectors 47 and 49 and the f2 detectors 48 and 50 are selected from the reproduced signals selected by the changeover switch 40.
Are selected by the signal selection switching circuit 34 from among the four types of tracking error signals A, -A, B, and -B generated by the differential amplifiers 53 to 56 based on the f1 and f2 signals detected as described above. The one error signal is sampled and held by the operation of the sample and hold circuit to which the sampling pulse at the predetermined time position described above is supplied from the main control unit 5.

The tracking error signal output from the sample and hold circuit is supplied to the adder 30 so that the capstan control system changes the running phase of the recorded magnetic tape, and H
p1, Hm1, Hp2, and Hm2 perform a reproducing operation in a correct tracking state. Since the above-described tracking control operation is performed at intervals of one recording trace (one track pitch), as shown in FIG. 7C, the tracking control operation in the conventional device is performed as shown in FIG. The tracking control operation can be performed with higher accuracy as compared with the case where the recording control operation is performed every four recording trace intervals as shown in FIG. The tracking control may be performed by displacing the rotary magnetic head by an actuator (bimorph type, Boss coil type, electromagnetic type, or the like) driven by the tracking error signal.

Next, the magnetic recording / reproducing apparatus shown in FIG. 2 has a configuration in which the drum tilt control circuit 8 provided in the magnetic recording / reproducing apparatus described above with reference to FIG. 1 is removed. The magnetic recording / reproducing apparatus shown in FIG.
The running speed of the recorded magnetic tape during the playback operation is
When the running speed of the magnetic tape during the recording operation is the same as the running speed of the recorded magnetic tape during the reproducing operation, and
If the speed is close to the running speed of the magnetic tape during the recording operation, the time position of the sampling pulse supplied to the sample and hold circuit 33 is set so as to correspond to the central portion of the recording trace in the longitudinal direction. The operation similar to that of the magnetic recording / reproducing apparatus described above can be performed well, and the tracking control operation can be performed with higher precision than the conventional magnetic recording / reproducing apparatus.

[0066]

As apparent from the above description, according to the present invention, the magnetic recording / reproducing apparatus is provided with one frame of image information and audio information etc. divided so as to correspond to a plurality of predetermined recording traces. ATF tracking pilot signal in which a pilot signal having a frequency of f1 and a pilot signal having a frequency of f2 are sequentially and alternately recorded at every other recording trace on the digital data of the main signal. In a multi-segment helical scan type magnetic recording / reproducing apparatus for recording / reproducing a recording signal, an azimuth angle of a magnetic gap is set to a predetermined angle of 90 ° or less clockwise with respect to a width direction of a recording trace. A first rotating magnetic head and a second rotating magnetic head,
The azimuth angle of the magnetic air gap is set at a predetermined angle of 90 degrees or less counterclockwise with respect to the width direction of the recording trace. When the third rotating magnetic head and the fourth rotating magnetic head are located near the first rotating magnetic head, the center axis of the drum is symmetrical. An upper drum disposed at a position symmetrical with respect to the center by 180 degrees; a lower drum provided coaxially with the upper drum; and a part wound around a part of a peripheral surface of the upper and lower drums. When the reproducing operation is performed by running the recorded magnetic tape in the state in which the magnetic tape has been read, the frequency extracted from the reproduction signal of the first (or third) rotating magnetic head is f1.
Difference signal (f1-f2) = A, difference signal (f2-f1) =-A obtained with respect to the pilot signal f1 and the pilot signal f2 having the frequency f2, and the second (or fourth) rotation described above. Difference signal (f1-f2) obtained from pilot signal f1 having a frequency of f1 and pilot signal f2 having a frequency of f2 extracted from a reproduction signal of the magnetic head =
B, when the difference signal (f2−f1) = − B, the relationship between the signal levels among the four types of difference signals A, −A, B, and −B is determined by four predetermined signal levels. A specific one type of difference signal is selected in accordance with which of the relations, and a tracking control signal is generated based on the selected difference signal. Since the running phase of the tape is controlled, the tracking control operation which has been conventionally performed in units of recording trace sections is performed for each recording trace section, so that the tracking control operation is performed with high accuracy. In addition, the inclination of the center axis of the drum is controlled to be changed so that the rotation trajectory of the rotary magnetic head can be made to coincide with the direction parallel to the extension direction of the recording mark of the recorded magnetic tape. Case, in order to be more time to sample the tracking error signal in one scanning period of the rotary magnetic head can be easily configured the stable control system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a reproducing system of a magnetic recording / reproducing apparatus of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a reproducing system of the magnetic recording / reproducing apparatus of the present invention.

FIG. 3 is a plan view showing an arrangement example of a rotating magnetic head.

FIG. 4 is a side view showing a schematic configuration of a drum tilt control mechanism.

FIG. 5 is an exploded perspective view of a part of a drum tilt control mechanism.

FIG. 6 is an explanatory diagram of a recording trace, a pilot signal arrangement, and a tracking error signal.

FIG. 7 is a diagram for explaining tracking control.

[Explanation of symbols]

DB: drum base, Dd: lower drum, Du: upper drum, DA: drum assembly, T: magnetic tape, Te: reference edge of magnetic tape T, Lr: lead ring, G: guide provided on lead ring Lr Hp1, Hp2, Hm1, Hm2 ... rotating magnetic head, H1, H2 ... pair head, 1 ... output terminal, 2 parts (position regulation surface of the reference edge of the magnetic tape formed on the guide member for regulating the position of the magnetic tape) …
Reproduction signal processing unit, 3: capstan, 4: pinch roller, 5: main control unit, 6: drum control unit, 7: drum motor, 8: drum tilt mechanism unit, 9 capstan motor, 1
0, 31 ... signal generator, 11 ... frequency-voltage converter, 1
2 ... Center axis, 30 ... Adder, 32 ... Drive circuit, 33 ... Sample hold circuit, 53-56 ... Differential amplifier, 47,
49 ... f1 signal detector, 48, 50 ... f2 signal detector,
35-38 ... preamplifier, 39, 40 ... changeover switch,
41, 42... Waveform equalization circuit, 43, 44.
5, 46 ... code detection circuit,

Claims (3)

[Claims] A digital signal based on a main signal such as image information and audio information of one frame divided so as to correspond to a plurality of predetermined recording traces includes a pilot signal having a frequency of f1 and a pilot signal having a frequency of f2. In a multi-segment helical scan type magnetic recording / reproducing apparatus for recording / reproducing a recording signal obtained by superimposing an ATF type tracking pilot signal which is sequentially and alternately recorded every other recording track, The first rotating magnetic head and the second rotating magnetic head in which the azimuth angle of the gap is set to a predetermined angle of 90 degrees or less clockwise with respect to the width direction of the recording trace are symmetrical with respect to the center axis of the drum. It is disposed at a position 180 degrees symmetrical with respect to the center, and the azimuth angle of the magnetic gap is 90 degrees or less counterclockwise with respect to the width direction of the recording trace. The third rotating magnetic head and the fourth rotating magnetic head set at an angle are placed on the drum while the third rotating magnetic head is located near the first rotating magnetic head. An upper drum arranged at a position symmetrical with respect to the center axis of the upper drum at 180 degrees, a lower drum provided coaxially with the upper drum, and one of the peripheral surfaces of the upper and lower drums. Means for performing a reproducing operation by running a recorded magnetic tape in a state of being wound around a portion, and a pilot signal having a frequency f1 extracted from a reproduced signal of the first (or third) rotating magnetic head. f1
(F1-f2) = A, difference signal (f2-f1) =-obtained with respect to pilot signal f2 having frequency f2.
A and a difference signal (f1-f2) obtained from a pilot signal f1 having a frequency f1 and a pilot signal f2 having a frequency f2 extracted from the reproduced signal of the second (or fourth) rotating magnetic head. ) = B, the difference signal (f2-f)
1) When = −B, the four types of difference signals A,
Means for selecting one specific type of difference signal according to which of the four types of predetermined signal level relationships the signal level relationship among -A, B, and -B corresponds to; A magnetic recording / reproducing apparatus comprising: means for generating a tracking control signal based on the selected difference signal; and means for controlling tracking of a magnetic head by the tracking control signal. 2. A digital signal based on a main signal such as image information and audio information of one frame divided so as to correspond to a plurality of predetermined recording traces includes a pilot signal having a frequency f1 and a pilot signal having a frequency f2. In a multi-segment helical scan type magnetic recording / reproducing apparatus for recording / reproducing a recording signal obtained by superimposing an ATF type tracking pilot signal which is sequentially and alternately recorded every other recording track, The first rotating magnetic head and the second rotating magnetic head in which the azimuth angle of the gap is set to a predetermined angle of 90 degrees or less clockwise with respect to the width direction of the recording trace are symmetrical with respect to the center axis of the drum. It is disposed at a position 180 degrees symmetrical with respect to the center, and the azimuth angle of the magnetic gap is 90 degrees or less counterclockwise with respect to the width direction of the recording trace. The third rotating magnetic head and the fourth rotating magnetic head set at an angle are placed on the drum while the third rotating magnetic head is located near the first rotating magnetic head. An upper drum arranged at a position symmetrical with respect to the center axis of the upper drum at 180 degrees, a lower drum provided coaxially with the upper drum, and one of the peripheral surfaces of the upper and lower drums. Means for controlling the rotational trajectory of the rotary magnetic head to match the direction parallel to the extension direction of the recording trace of the recorded magnetic tape running in a state wound around the part, and the recorded magnetic tape. Means for performing a reproducing operation by running, and obtaining a pilot signal f1 having a frequency f1 and a pilot signal f2 having a frequency f2 extracted from the reproduced signal of the first (or third) rotating magnetic head. Difference signal ( 1-f2) =
A, the difference signal (f2-f1) =-A, the pilot signal f1 having the frequency f1 extracted from the reproduction signal of the second (or fourth) rotating magnetic head, and the frequency f2.
Difference signal (f1-f) obtained with respect to the pilot signal f2 of
2) = B and the difference signal (f2−f1) = − B,
One specific type of signal is determined according to which of the predetermined four types of signal level relationships the signal level relationships among the four types of difference signals A, -A, B, and -B have. A magnetic recording system comprising: means for selecting a difference signal; means for generating a tracking control signal based on the selected difference signal; and means for controlling tracking of a magnetic head by the tracking control signal. Playback device. 3. A magnetic recording apparatus according to claim 2, wherein a means for changing and controlling the center axis of the drum is used to make the rotation locus of the rotary magnetic head coincide with the direction parallel to the extension direction of the recording mark of the recorded magnetic tape. Playback device.