JPS60264175A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a TV picture with normal arrangement in reproducing a tape at a tape speed earlier than that at recording by providing a magnetic head moving means moving a magnetic head in the track width direction and returning it to the initial state, and reproducing a split track sequentially in order of 1-field forming. CONSTITUTION:Video tracks T1, T2- are recorded on a magnetic tape 23 by dividing alternately one field into three with heads 28, 29 different in azimuth, and vertical synchronizing signals V1, V2- are recorded at each 3-track. Further, control signals P1, P2- in synchronizing with a period two times that of the vertical synchronizing signal are recorded to the lower part of the magnetic tape 23. In reproducing the recorded signal as above at a tape feeding speed being twice that at recording, since the arrangement of TV pictures is changed as a conventional system if the magnetic heads are fixed similarly as at recording, the magnetic heads scanning the part whose arrangement is changed are adhered together and moved to a track having the normal arrangement by piezoelectric elements 26, 27, then the signal is reproduced, in order to correct the arrangement change.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic head provided on a rotating drum.
The present invention relates to a magnetic recording and reproducing apparatus that records and reproduces video signals by dividing fields in a diagonal direction on a magnetic tape.

Conventional configurations and their problems In recent years, magnetic recording and reproducing devices (hereinafter referred to as VTRs) have been moving toward higher recording signal density and higher image quality, and recording and reproducing using digital signals is being considered. In order to perform recording, a method is used in which the rotational speed of a cylinder is increased and one field is divided into a plurality of tracks for recording and reproduction.

A method for recording and reproducing signals on a magnetic tape in a conventional field division recording type VTR will be described below.

FIG. 1 is a plan view showing part of a tape running system of a conventional field division recording type VTR. (1) is a magnetic tape, which runs in the direction of the arrow. (2) is a rotating drum equipped with video heads (3) and (4) located at 180 degrees and having opposite azimuth angles, and rotates in the direction of arrow a at 5400 rpm+a in the case of three-part recording. (
5) and (6) are guide posts that guide the magnetic tape (1) to the rotating drum (2). (7) is a fixed head, which records and reproduces audio signals on the upper part of the magnetic tape (1) and control signals on the lower part.

Figure 2 shows the pattern of each signal recorded by the device in Figure 1, and (8) (8') CP ) (8') is the video track recorded by the magnetic head (3) in Figure 1. This azimuth direction is defined as the A channel, and the magnetic head scans in the direction of the arrow. (9) (9') (9')
is a video track recorded by the magnetic head (4) in FIG. 1, this azimuth direction is taken as the B channel, and the magnetic head scans in the direction indicated by the arrow. After that A
Channel and B channel tracks are recorded alternately, and in this example, one field of the TV signal is divided into three tracks and recorded, so a vertical synchronizing signal (10) ( 10')(
10') is recorded. Also, on the top of the magnetic tape, an audio track (11) is created using the fixed head (7) shown in Figure 1.
However, a control signal (12) is recorded at the bottom, and the control signal (12) is synchronized with the vertical synchronization signal (10). Also magnetic tape (1)
travels in the direction of arrow C.

Conventional field division recording method V configured in this way
The operation of the TR will be explained below. When a video track recorded as shown in Fig. 2 by the magnetic heads (3) and (4) in Fig. 1 is played back at twice the tape feed speed at the recording time, the magnetic head (3) (A channel) plays the video track as shown in Fig. 2. The trajectory is second
The solid lines (13) (13') in the figure represent the magnetic head (
4) The playback trajectory of (B channel) is a solid line (14), and the playback signal waveform of each head is (15) (15') for magnetic head (3) (A channel) as shown in Figure 3.
Therefore, the magnetic head (4) (B channel) is (16
). Next, the relationship between this reproduced signal and the TV screen will be explained based on FIG. 4. First, during recording, Figure 4 (a)
) The image having the shape shown in (17), (18), and (19) is divided into three tracks, each assigned to the three tracks shown in Fig. 2, and recorded by the A channel head and the B channel head.This signal is recorded as described above. When playing at twice the tape speed, the magnetic head (3) (A channel) first tracks the first A channel track (8) and B channel where the vertical synchronizing signal (10) is recorded, as shown by the solid line (13). When played back across track (9), the played signal is on the A channel side shown in (15) in Figure 3, forming the upper image (20) shown in Figure 4(b).Next, The magnetic head (4) (B channel) is indicated by the solid line (
When playing back across both channel tracks as shown in (14), the reproduced signal is the B channel side signal shown in (16) in Fig. 3, and the central part image (21) shown in Fig. 4 (b) is reproduced. ) to form. And magnetic head (3) (
When the A channel) is played back across both channel tracks as shown by the solid line (13'), the reproduced signal is the A channel side signal shown at (15') in Figure 3, and the signal played back is the signal on the A channel side shown in Figure 4 (b). ) is formed. In the signal reproduced at double speed in this way, the arrangement of images at the division positions changes, making it impossible to obtain a normal image. Also,
This phenomenon occurs similarly even at other high playback speeds, and also when the field is divided into three or more. As described above, the conventional VTR with a field division recording system of three or more divisions has had the problem that a normally arranged TV image cannot be obtained during high-speed reproduction.

Purpose of the Invention The present invention solves the above-mentioned conventional problems, and provides a TV image with a normal arrangement even when a signal recorded by dividing the field into three or more fields is reproduced at a tape speed faster than the recording speed. The purpose of the present invention is to provide a magnetic recording/reproducing device that can perform the following functions.

Composition of the Invention The magnetic recording and reproducing apparatus of the present invention comprises a drum that guides a magnetic tape in a spiral manner, and a drum that moves in the track width direction and that divides one field into n parts (n≧3, an integer) and records and reproduces different azimuths. a control signal consisting of at least two magnetic heads having the same polarity, one in the 2P field (P is an integer) when n is an odd number, and one in the P field when n is an even number; and a fixed head for recording and reproducing information, and when reproducing at a tape speed m times (m is an integer) the recording speed, the magnetic head moves one of the divided tracks.
The magnetic head is moved in the track width direction so as to reproduce the field into the divided layers.

A magnetic head moving means is provided which returns the movement of the magnetic head to the initial state every m pulse periods of the control signal using the control signal, and the divided tracks are sequentially reproduced in the order in which one field is formed. Even when playing back at a faster tape speed, it is possible to obtain TV images with a normal arrangement.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Fifth
The figure shows a sectional view of a drum device equipped with a magnetic head in the magnetic recording/reproducing apparatus of the present invention.

In Figure 5, (23) is a magnetic tape, (24) is a fixed drum, (25) is a rotating drum, (26) (27)
is a laminated piezoelectric element, each having a magnetic head (28) (A channel) with a different azimuth at one end and (
29) (B channel), and the other end is equipped with a rotating drum (
25) are attached to blocks (30) (31) fixed to the block (30) (31). Further, the laminated piezoelectric element (26) (2
7) has electrode terminals (32) and (33), (34) and (
35), and by applying a predetermined voltage, the piezoelectric elements (26) and (27) are deflected, causing the magnetic heads (28) and (29) to move in the direction of the arrow d.
, move them in the e direction.

When the voltage is removed, it returns to its original position. (36) is a rotating shaft, which is rotatably supported by the fixed drum (24) via a ball bearing (37), and is integrated with the rotating drum (25) and a motor (not shown). When one field is divided into three, it is approximately 540 Orpm, and 4
When divided, it rotates at approximately 7200 rpm+. Here, the tape running direction and head scanning direction are the same as in the conventional example.

The operation of the magnetic recording/reproducing apparatus of this embodiment configured in this manner will be described below. Here, the first odd-numbered division into three will be explained. First, during recording, a video signal is transferred to the magnetic tape in one field for three times with both heads fixed without applying voltage to the piezoelectric elements (26) and (27).
At the same time, a sawtooth wave with a 2-field period as shown in FIG. 6 is applied to a fixed head similar to that in FIG. 1 to record a positive pulse control signal with a 2-field period. A pattern shown in FIG. 7 is formed. Video tracks are recorded on the magnetic tape (23) by alternately dividing one field into three by heads (28) and (29) with different azimuths, and each field is divided into three by T1. T2...
・Indicated by Here, the odd-numbered tracks have the A channel in the azimuth direction, and the even-numbered tracks have the B channel, and the vertical synchronization signal V1. V, . . . are recorded. Further, at the bottom of the magnetic tape (23), two of the vertical synchronizing signals are provided.
Control signal p1. synchronized with twice the period. p2...
is recorded. When reproducing the signals recorded in the above manner at twice the tape feed speed of recording, if the magnetic head is fixed in the same manner as during recording, the magnetic head (28) (A channel ) is shown by the dashed line E.
The playback locus of the magnetic head (29) (B channel) becomes the dashed line F1°F2..., and the arrangement of the TV image changes as in the past, so to correct this, the arrangement of the TV image changes. The magnetic head that scans the changing portion is moved to the track where the laminated piezoelectric elements (26) and (27) have a normal arrangement for reproduction.

The details will be explained below. In FIG. 8, the horizontal axis shows repeated head scans of both heads, S,,S,.

S2... is a head switching point. The vertical axis indicates the amount of movement in the track width direction, and the amount of movement is one track pitch per graduation. Further, voltages are applied to the electrode terminals (32) and (33), (34) and (35) of the piezoelectric elements (26) and (27), respectively, so that the magnetic heads (28) and (29) move as shown in FIG. shall be taken as a thing. In the figure, solid lines indicate signal reproduction periods, and broken lines indicate signal reproduction periods.

First, the A channel head (28) is
When scanning El across tracks 1 and T2, the track to be reproduced is the first track T1 of the three divisions, and since T1 has the same axis, the arrangement of the TV screen is normal even with the reproduction signal as it is. However, the output decreases at the end of the scan.

Therefore, in order to scan the entire area on the T1 track, it is sufficient to continuously move the head downward (arrow d) in FIG. 5 by one track pitch.

Next, when the B channel head (29) scans Fl across the T3 and T4 tracks, the track to be reproduced is the second track in the three divisions, and the second track of the same axis is T2 or TI1. , move the scanning start point downward by one track pitch in the case of T2 or upward by five track pitches in the case of T8 from the F1 scanning position, and move the scanning start point downward by one track pitch in the case of T2, or upward by five track pitches in the case of T8. It suffices to scan while continuously moving downward by a certain amount. Here, T2 and Tll are selected as T2, which has a small amount of movement, and is moved to the starting point in advance while the A channel side is reproducing the signal, as shown in FIG. Next, when the A channel head scans F2, it is the third track in the three divisions that should be reproduced, and since the third track of the same system is either T3 or T9, it is set to T3, which has the smallest amount of movement. Here, the head may be moved continuously to the starting point of T3 after the end of T1. Next, when the B channel head scans F2,
What should be played is the first track in the three divisions, and the same track is T4 or To. It is. Here T 41 T 1
[The movement distance of the starting point for both + and 3 track pitches is equivalent to 3 track pitches, but considering the movement of 1 pitch to obtain a uniform output as mentioned above, T4 is the movement amount of 4 track pitches, so this position The scanning at is Tlo.

Similarly, the E3 position is T11 and the F□ position is T.
□2, and since the height positions of both channels return to the E1 starting point at the end of F3, the operations from El to F can be repeated from the subsequent E9 position T□3. Here, each head switching point S. , Sl... and control signal P
1. Looking at the relationship with P2..., it can be seen that SG at the end of one period of head movement matches F3 of the control signal, and the 5o-S period is equal to 2 pitches of the control signal. Therefore, in the case of double-speed playback, the head movement pattern for both channels is configured as shown in FIG. 8, in which one cycle is the two-pulse pitch period of the control signal, and the divided tracks are played back in the order in which they are formed by repeatedly moving the head. Can be done. Also, since the control position is the first track of the same channel head,
The control signal is operated for two pitches based on the control signal, and the control signal after the pitch is set to ``S'' in FIG. 8, which is the starting point. If you restore it to , the tape speed will be 2.
Even if it deviates slightly from double, it can be corrected every two pulse pitches.

The same applies thereafter.

The above is the explanation for double speed playback, but the same explanation will be given for triple and quadruple speed playback. First, when the head is not moved during triple speed playback, the A channel head scans G1102... and the B channel head scans H1, F2... as shown in Figure 7(b), and the TV is set as in the case of double speed playback. Although the arrangement of images changes, it is sufficient to move the head as shown in FIG. One period of head movement at this time is S. -8
, and the control signal during this period has a three-pulse pitch. Also, during 4x speed playback, as shown in Figure 7(c), the A channel head scans J,, J,..., the B channel head scans □, 2..., and the TV image arrangement is similarly changed. The head may be moved as shown in FIG. 10, although it may vary. One cycle of the head movement at this time is S from FIG. -86, but since the points that match the control signal position in Fig. 7(c) are □ at S6 and F5, S
. ~S6 is applied for one period, and the control signal becomes a 4-pulse pitch.

As described above, a head movement pattern is set for each speed, with one period consisting of two pulse pitch periods of the control signal at double speed, three pulse pitch periods at triple speed, and four pulse pitch periods at quadruple speed. The selection can be made in conjunction with the switching operation.

Although the case of three divisions (odd number division) has been described above, the case of first four divisions (even number division) will be explained. 11th
The figure shows a pattern recorded by dividing one field into four, and the magnetic tape (23) has two heads (2
8) Video tracks are recorded by dividing one field into four alternately in (29), and each is recorded as T1',
It is shown as T2'... Here, the odd-numbered tracks are A channels in the azimuth direction, and the even-numbered tracks are B channels, and vertical synchronization signals V,', V2/... are recorded every four tracks. Further, at the bottom of the magnetic tape (23), sawtooth wave control signals p, ', p2t, . . . are recorded with the synchronization shown in FIG. When reproducing a signal recorded as described above at twice the tape speed of recording, if the magnetic head is fixed and scanned in the same way as during recording, the magnetic head (
28) The scanning locus of (A channel) is the dashed-dotted line E1'
.

E2'..., magnetic head (29) (B channel)
The trajectory becomes F,',F,'..., and when the signal is reproduced at this position, both TV image arrays change as in the conventional case. Therefore, as shown in FIG. 12, T1' is alternately applied to both heads.

If the images are reproduced in the order of T2', T7'tT,', one field can be obtained as an image with a normal arrangement. In this case, one period of head movement is S. ' to S4', which correspond to the two-pulse pitch of the control signal. In addition, when playing at 3x speed, 01' shown in Figure 11(b)
, 02'... and H1'lH2'... are the scanning trajectories when the head is fixed, and as shown in FIG. 13, T1', Ts
If the images are reproduced alternately in the order of ', T7', and T1□', images with a normal arrangement can be obtained. Head movement 1 in this case
Although the period is 80' to 82', the position coincides with the control signal position at 84', which corresponds to the 3-pulse pitch of the control signal. Similarly, in the case of 4x speed, J1'lJ2''',21',2', etc. shown in Fig. 11(c) are the scanning trajectories when the head is fixed, and as shown in Fig. 14, One cycle at this time is 86' to 84', which corresponds to 4 pulse pitches of the control signal.In this way, the control pulse included in one cycle of the head movement pattern when playing at m times the speed. The number T becomes T=m, and this relationship means that if the number of divisions n is an odd number, one control signal is sent to the 2P field (P is an integer), and if n is an even number, one control signal is sent to the P field. This is true if the signal is recorded, and the same holds true even if n and m have values other than those in this embodiment.

In addition, in the above configuration, the head movement amount 2 during one track scanning period at m times the speed is Z = (m-1), and as m increases, the movement amount also increases, and the track pitch is increased to obtain high image quality. A VTR or a VT that records the luminance signal and color signal separately on separate tracks.
In R, the amount of movement is particularly large, which causes problems such as having to apply a large voltage to the piezoelectric element and the head and touch changing, making it impossible to obtain good output, so it is better to have a smaller amount of movement. preferable. FIG. 15 shows a head movement locus in a second embodiment of the present invention that reduces the amount of head movement. FIG. 15 explains the case where the three-division recording pattern shown in FIG. 7 is reproduced at four times the speed.
Video tracks are recorded on the magnetic tape (23) by alternately dividing one field into three by heads with different azimuths, each of which is indicated by T1', T2', . . . .

Here, the odd-numbered tracks have the A channel in the azimuth direction, and the even-numbered tracks have the B channel, and vertical synchronizing signals Viy, V, ', . . . are recorded every three tracks. Further, in the lower part of the magnetic tape (23), one control signal is recorded for every two fields recorded in a sawtooth waveform with a two-field period as shown in FIG.

The scanning locus when reproducing the above signal with a fixed head at 4x speed is Ji'tJ2#... and Kl'tK2
''..., and in order to make the image arrangement normal, the head is moved so as to play back the tracks indicated by the thick solid lines.By doing this, the maximum playback output is uniform during one track period. However, when the purpose is to distinguish between images, it is not necessary that the entire area be extremely clear. Even when scanning in a straddling state, there is no change in the signal arrangement and a distinguishable image can be obtained.The amount of head movement at this time is one track pitch less in the vertical direction than in Fig. 10, as shown in Fig. 16. Therefore, Z=(m-2) for one head.

Effects of the Invention The magnetic recording and reproducing apparatus of the present invention has a drum that guides the magnetic tape in a spiral manner, and a drum that moves in the track width direction and divides one field into n parts (n≧3, an integer) for recording and reproducing, which are different from each other. A control consisting of at least two magnetic heads with azimuth and one same polarity pulse in the 2P field (P is an integer) when n is an odd number and one in the P field when n is an even number. a fixed head for recording and reproducing signals, and the magnetic head is configured to reproduce one field of the divided track into divided classes when reproducing at a tape speed m times (m is an integer) the recording speed. By moving the magnetic head in the track width direction and returning the movement of the magnetic head to the initial state every m pulse periods of the control signal using the control signal, playback can be performed at m times the speed of recording. It is possible to obtain TV images with a normal arrangement even when the method is used, and double-speed playback in the field division recording method is possible, and its practical effects are extremely large.

Further, the magnetic head moving means is constituted by a bonded piezoelectric element, and a scanning track is selected such that the absolute value of the voltage applied to the bonded piezoelectric element is minimum during m pulse periods of a control signal from a plurality of fields during m-times speed reproduction. In addition, by setting the amount of movement of the magnetic head moving means during one track scanning period to (m-2) times the track pitch during m-times speed reproduction, it is possible to reduce the voltage of the driving power source for the piezoelectric element, etc. , is effective in reducing size and weight. Furthermore, by reducing the amount of movement of the head, the touch between the head and the tape becomes stable and good output can be obtained. Further, in a large track pitch VTR, there is an effect that the actual amount of movement can be increased.

[Brief explanation of drawings]

Fig. 1 is a plan view showing part of the tape running system of a conventional magnetic recording/reproducing device, Fig. 2 is a plan view showing a tape pattern recorded by conventional field division, and Fig. 3 is a plan view showing a tape pattern recorded by conventional field division. FIG. 4 is a waveform diagram showing the head output during double speed playback of a recording system VTR; FIG. 4 is an explanatory diagram illustrating the arrangement of TV images; FIG. The figure is a waveform diagram showing the voltage applied to the control head, Figure 7 is a tape pattern diagram explaining head scanning when recording and reproducing one field divided into three parts, and Figure 8 is a tape pattern diagram explaining the head scanning when one field is divided into three parts and recorded at double speed. An explanatory diagram showing the head movement state when playing back, FIG. 9 is an explanatory diagram showing the head movement state when reproducing 3-divided recording at 3x speed, and FIG.
An explanatory diagram showing the head movement state when reproducing divided recording at 4x speed. Fig. 11 is a tape pattern diagram illustrating head scanning when recording and reproducing one field divided into four parts. Fig. 12 is a tape pattern diagram showing the head movement state when reproducing divided recording at 4 times speed. FIG. 13 is an explanatory diagram showing the head movement state when reproducing a signal at double speed. FIG.
Fig. 4 is an explanatory diagram showing the head movement state when reproducing 4-division recording at 4x speed, Fig. 15 is a pattern diagram showing the head scanning locus in another embodiment of the present invention, and Fig. 16 is another embodiment. FIG. 3 is an explanatory diagram showing a head movement state. (7)...fixed head, (23)...magnetic tape,
(26) (27)...Laminated piezoelectric element, (28)
(29)...Magnetic head agent Yoshihiro Morimoto181FiguretSZFigure3Ii4 (ffl) (b) No.! j Figure 186 Figure 7 (a) (Tono H' -111 Figure 1 Heeeeeeeeeeeee-sq Figure 11 □-/ IIIA-111 4th θ section low I Figure 1f (d) t Tonol River Figure 12 1ii/Figure 4

Claims (1)

[Claims] 1. A drum that spirally guides the magnetic tape, and a drum that moves in the track width direction and divides one field into n (n≧3. integer)
At least two magnetic heads having different azimuths for recording and reproducing data, one for the 2P field (P is an integer) when n is an odd number, and one for the P field when n is an even number. a fixed head for recording and reproducing a control signal consisting of pulses of the same polarity, and when reproducing at a tape speed m times the recording speed (m is an integer), the magnetic head divides one field of the divided track into a divided type. A magnetic recording device comprising a magnetic head moving means for moving the magnetic head in the track width direction so as to reproduce data, and returning the movement of the magnetic head to an initial state every m pulse period of the control signal using the control signal. playback device. 2. The magnetic head moving means is composed of a bonded piezoelectric element,
m of control signals from multiple fields during double-speed playback
2. The magnetic recording and reproducing apparatus according to claim 1, wherein a scanning track is selected in which the absolute value of the voltage applied to the bonded piezoelectric element is minimum during the pulse period. 3. The amount of movement in one track scanning period by the magnetic head moving means is determined by the track pitch (m-2) during m-times speed playback.
) The magnetic recording and reproducing apparatus according to claim 1, wherein the magnetic recording and reproducing apparatus is set to double.