JPH02230509A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain noiseless special reproduction and ordinary reproduction having excellent C/N by executing automatic tracking while a set of movable heads are brought into contact with the surface of a magnetic tape so that the level of a reproducing FM signal is made the greatest. CONSTITUTION:Since the automatic tracking control is executed while the movable heads 3 and 4 attached to a rotating drum 7 are brought into contact with the surface of the magnetic tape so as to make the level of the reproducing FM signal the greatest at the time of reproducing operation, the special reproduction such as high speed search can be made noiseless and the C/N of the ordinary reproduction can be improved. Besides, since the movements of the movable heads can be precisely controlled by reading out an excellent driving signal waveform at the time of reproducing operation when recording operation is executed, the precise recording based on the format of a standard tape can be executed. Therefore, the special reproduction and the ordinary recording and reproducing are made possible only by the movable heads 3 and 4 and the occurrence of jitter accompanied with a tape tapping phenomenon caused by the reduction of head number is suppressed. Simultaneously, the cost of a device is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing device such as a video table recorder (hereinafter referred to as VTR).

[Prior Art] Conventionally, automatic scan tracking (
Dynamic Track Following (hereinafter referred to as AST) and Dynamic Track Following (hereinafter referred to as DTP), which automatically perform tracking while moving the head in the width direction of the tape track during playback. A system configured as follows has already been developed.

FIG. 7 is a perspective view showing the drum structure of a rotary head device in a conventional magnetic recording/reproducing device.
1). (2) is a regular fixed head for recording and playback; (3)
)． (4) is a movable head dedicated to special playback that operates during AST and DTP; (5) . (6) is a bimorph type piezoelectric element, and the above-mentioned special reproduction movable heads (3) and (4) are attached thereto. (7) is a rotating tram, which includes the above-mentioned fixed recording/reproducing head (1). (21 and bimorph type piezoelectric element (5). Attach (6) with the number 1800
Rotate at rpm.

Figure 8 is an enlarged view of the actuator structure of the special playback movable heads (3) and (4) in a DTF type VTR. In the figure, (8) is a fixed drum, and (9) is a magnetic tape It is.

Moreover, FIG. 9 shows the conventionally used high-morph type piezoelectric element (5). (6) shows the operating principle of this bimorph type piezoelectric element (5). (6) is two piezoelectric elements (5a), (5b) (8a)
, (6b) sandwiched between three electrodes (5C) and (6C) in the shape of a sandwich.The special regeneration movable head (3) is attached to the free end of this bimorph plate. 4) is attached.

This special playback movable head (3). (4) is the piezoelectric element (5a), (5b) (6a), (6
As shown in FIG. 8, the structure is such that it can move up and down in the axial direction (a-b) of the drum by the expansion and contraction action of b).

Next, with reference to FIG. 10, the principle of operation of the above-mentioned configuration will be explained, for example, when a high-speed reproduction operation (noiseless speed surge) is performed.

In FIG. 10, A I, B 1, A 2, B 2.
A 3B3 . . . indicates a video track recorded on the magnetic tape (9), C is a control track, and D is a control track.
is skipping the audio track. Here AI A2
A3 . . . and B 1 , B 2 , B 3 are video tracks recorded with heads having different azimuth angles.

Now, as an example of speed search, assume that playback is performed at 5x speed. When the piezoelectric element (5) for the special playback movable head (3) is not driven, the scanning locus of the special playback movable head (3) becomes as shown by the broken line L in Figure 10, and the special playback movable head (3) If the azimuth angle of (3) is the same as the azimuth angle of track A, the reproduced signal will be from track A1. Only the part that scans A2 and A3 is shown, and noise bars appear on the playback screen. here,
Even if the tape is running at 5x speed during playback, in order to completely play back track A1, a special playback dedicated movable head (3
) is in contact with the magnetic tape (9) for one field period, the head (3) is moved in the track axis direction (to the left in the figure) by 41
・You only need to move the rack pitch. In the next field, another movable head (4) exclusively for special reproduction is moved by four track pitches.

In this way, tracks A I, B 3, A 8 . . . are completely scanned, and a noiseless reproduced signal is obtained. That is, by the above-mentioned operation, by moving the special playback dedicated movable heads (3) and (4) in the track width direction according to the tape speed during playback, noiseless playback can be realized not only at normal playback but also at any speed.

FIG. 11 shows a block circuit diagram of a conventional automatic tracking device. In the figure, (10) is a rotary transformer, (11) is a head amplifier for normal playback, and fixed heads (1) for recording and playback. (2) Amplify the reproduced FM signal at a minute level that has been boosted up by the timing generator (36), and manually input it to the reproduced signal processing circuit (13) via the switch (12) which is switched by the output signal of the timing generator (36). ■It is demodulated to

Reference numeral (14) denotes a surge head amplifier, which amplifies the minute level reproduced FM signal that is surprised up by the movable heads (3) and (4) when performing, for example, 5x speed reproduction. (15) is an envelope detection circuit that detects the envelope of this reproduced FM signal, and (16) is a bimorph type piezoelectric element (5) at the time of search. (6) Drive voltage signal (
A microcomputer (l7) outputs a cab stun FG signal (hereinafter referred to as a search correction signal) (hereinafter referred to as a search correction signal).
(18) is a comparator, (19) is a floating counter, (20) is a speed counter, (21a) is a comparator, (19) is a floating counter, (21a is a )
, (2lb) is the output counter, (22a) (22b)
is an adder, (23a) . (23b) is a low-pass filter (hereinafter referred to as LPF), (24a), (2
4b) is a high-voltage amplifier that drives the piezoelectric element (s) and (6), and (25) is a vertical synchronous separation circuit (hereinafter referred to as ① synchronous separation circuit).

The conventional automatic tracking device shown in FIG.
A bimorph type piezoelectric element (5) is generated by manually inputting an L signal, a CP-FG signal, and a head switch signal (hereinafter referred to as an HSW signal). (6) is configured to determine the signal waveform of the drive voltage e. That is, C.P.
- FG whose FG signal is reset by CTL signal
It is counted by a counter (17) and supplied to a comparator (18). The threshold value of this converter (18) is determined by the speed counter (20). This threshold value is reset in the floating counter (19) by the output of the comparator (18). The output signal of this floating counter (19) is output to the output counter (21a),
(21b) is supplied as the preset value. This output counter (21a) (2lb) outputs the reset value manually inputted from the floating counter (19) to the HS.
This is a counter that is reset at the rise or fall of the W signal, and the microcomputer uses the envelope detection signal input from the envelope detection circuit (15) as a reference for the output signals of these output counters (21a) and (2lb). Adders (22a) and (22b) add search correction signals that perform corrections necessary for 5x speed playback in (l6), and add ripple components of these output signals to L.
P F is removed by (23a) and (23b) and applied to high voltage amplifiers (24a) and (24b) to drive bimorph piezoelectric elements (5) and ([i), thereby performing automatic tracking operation. .

[Problems to be Solved by the Invention] Since the conventional magnetic recording/reproducing device equipped with a movable head is configured as described above, it is difficult to perform the eighth
As shown in the figure, even if the tips of the movable heads (3) and (4) contact the magnetic tape (9) obliquely, almost satisfactory reproduction performance can be obtained. However, the movable head (3) in normal playback and recording operations. (
4) and the magnetic tape (9) directly affects the C/N, so if the tips of the movable heads (3) and (4) move in diagonal contact with the magnetic tape (9), the C/N will increase. N
becomes significantly worse, and satisfactory playback performance cannot be obtained.

Also, during normal playback operation, the movable heads (3), (4)
) can be operated so that the level of the reproduced FM signal is maximized, the reproduction performance can be improved somewhat, but during normal recording operation, the movable heads (3), (4)
) There are no standards that define the behavior of

For example, even if an attempt is made to perform a correct recording operation in accordance with the tape format of a VHS VTR, a signal that serves as a reference for behavior control cannot be detected from the magnetic tape.

For the above reasons, it is difficult to correctly perform normal recording and reproducing operations using a movable head. Therefore, in conventional magnetic recording and reproducing devices, the movable head is used exclusively as a special reproduction head, and therefore However, since the number of heads increases, there is a corresponding increase in the tape-beating phenomenon, which tends to cause jitter, and also increases costs.

This invention was made to solve the above-mentioned problems.With only one pair of movable heads, it is possible not only to eliminate noise during special playback such as speed search, but also to improve C/N during normal playback and improve normal playback. It is an object of the present invention to provide a magnetic recording/reproducing device that enables accurate behavior control in accordance with a standard format during recording and is effective in terms of performance and cost.

[Means for Solving the Problems] A magnetic recording and reproducing device according to the present invention has a magnetic recording and reproducing device that is mounted movably in the axial direction of a rotating drum during a reproducing operation.
The drive signal waveforms applied to the pair of movable heads are stored in a storage circuit, and during recording operation, the drive signal waveforms stored in the storage circuit are read out to drive the movable heads. do.

[Function] According to the present invention, the pair of movable heads are brought into surface contact with the magnetic tape so that the level of the reproduced FM signal is maximized in both special playback such as speed search and normal playback. By automatically tracking the signal while it is held, noiseless special playback and normal playback with good C/N can be performed. Also, during recording operation, the tape recording format for good playback operation as described above is read out,
By controlling the behavior of the movable head using this as a reference, correct recording can be performed by the movable head. In this way, all special playback and normal recording and playback operations can be performed with only one pair of movable heads, so the number of heads on the rotating tram can be reduced and the occurrence of jitter caused by the tape tapping phenomenon can be suppressed. At the same time, it is possible to reduce costs.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal sectional view showing the drum structure of a rotating magnetic head device in a magnetic recording and reproducing apparatus according to an embodiment of the present invention. In the same figure, (7) is a rotating drum, (8) is a fixed drum, ( 1o) is an electrode brush for applying current to the coil in the movable head unit, which will be described later; (11)
is a rotating slip ring, (12) is a drum motor,
(l3) is a rotary transformer.

(100) is a movable head unit, and at least the upper part of this head unit (100) and the rotary transformer (13) are fixed to the rotary drum (7), and the tram motor (12) rotates the movable head unit (100).
Rotates at a constant speed of 0 rpm.

FIG. 2(a) is a perspective sectional view showing the configuration of the movable head unit (+00), and FIG. 2(b) is a longitudinal sectional view thereof. In the same figure, (101) and (102) are circular springs. A movable head H) is attached to one end of one of the circular springs (101). (4) is fixed. At the center of these circular springs (101) and (102) are air-centered hobbins (
103) is fixed. Also, this air core bobbin (1
A winding coil (+04) made of a thin copper wire of about 0.1 mm is wound around the outer circumference of the wire 03).

FIG. 2(a) is a perspective sectional view showing the structure of the movable head unit (100), and FIG. 2(b) is a longitudinal sectional view thereof. In the same figure, (101) and (102) are circular springs. A movable head (3) is attached to one end of one of the circular springs (101). (4) is fixed. An air-core bobbin (103) is fixed to the center of the circular springs (101) and (102). Also, this air-core bobbin (
A winding coil (104) made of a thin copper wire of about 0.1 mm is wound around the outer circumference of the wire (103).

(105) is a permanent magnet made of rare earth cobalt, etc.
106) is a ball bead made of soft iron, (107) (
Reference numeral 108) denotes a yoke made of soft iron, and the permanent magnet (105) is arranged in the air-core pobbin (+03), and this permanent magnet (105) is fixed to the yoke (108). Due to these, the movable head (3), (
4) constitutes the drive mechanism. (109) is a cap, and (110) is a printed circuit board to which the lead wire of the winding coil (1.04) is connected.

Figure 3(a). (b) is the above circular spring (+01)
, (102) is an enlarged plan view showing the configuration of. This 2
The circular springs (101) and (102) are 0.08
Copper alloy plate (IOIA) with a thickness of mm, (10
As shown in FIGS. 3(a) and 3(b), 2A) is provided with soft and uniform elasticity by forming a large number of slits (IOIb) and (102a). In the center are small molded products (101B), (1
02B), and an air-core hobbin with coil (10
3) is fixed. Further, as shown in FIG. 3(a), a long protrusion (101a) with a notch is taken out from a part of the outer periphery of the circular spring (101), and a movable head (3) is attached to the tip of the protrusion (101a). , (4) are attached.

Now, as shown in Figure 4, S of the permanent magnet (+05),
N poles are provided above and below, and when a current flows through the winding coil (+04), a force acts in the eight directions of the arrow according to the left-hand rule of framing, and the air-core hobbin (103) moves downward. At this time, the outer peripheries of the circular springs (101) and (102) are fixed to the yoke (107), but since they have soft and uniform elasticity, the air-core bobbin (103)
moves downward in proportion to the magnitude of the current.

Along with such movement of the bobbin (103), the movable heads (3) and (4) attached to the long protrusion (101a) of the circular spring (101) directly move in parallel in the downward direction A1. Moreover, if the current flowing through the winding coil (104) is reversed to the above case, the air core bobbin (103) will move in parallel upward as shown by arrow B, contrary to the above, and the movable head ( 3). (4) is upward direction B
Move parallel to 1.

As you can see from the above explanation, the movable heads (3) and (4)
is a drum (7). The tape and the movable head (3) for vertical translation along the axis of (8). (
4) The sliding surface is always in full contact with the FM of the tape magnetic surface.
The signal can be increased to the maximum extent possible, and the tape will not be damaged by the edges of the outer circumferential surface of the head.

FIG. 5 is a block diagram of an electric circuit showing the configuration of the tracking device of the present invention. In the figure, the same reference numerals as in the conventional example of FIG. 11 indicate the same or corresponding parts. Incidentally, here is a conventional fixed head for recording and reproduction (1). (2) has been removed, and accordingly, the number of windings of the rotary transformer (10) has been reduced from four to two, and the normal reproduction head amplifier (11) has been removed. Further, (14) is a head amplifier during special playback and normal playback, and serves as an amplifier equipped with a recording amplifier during recording.

In FIG. 5, (31) is an A/D conversion circuit that converts the enherobe detection output voltage into a digital signal, and (32) is a digital data signal for controlling the drive head by the respective timing manual signals and mote output signals. A microcomputer that outputs two movable heads (3). (4) The winding coil (104
For a) and (10b), scanning signal basic waveform generation R O M (32a), (32e) and tilt angle correction R O M (32b), (32f), respectively.
and optimal track movement R OM (32C), (32g) that corrects the phase of the scanning signal with respect to the magnetic tape.
and climbing correction R OM (32d). (32h
) and a swing-back signal waveform generating R OM (32i) for swinging back the movable heads (3), (4) during the period when they are not in contact with the magnetic tape. (
33a) (33b) , (33c) (33d
) is a D/A conversion circuit that converts the output signal corresponding to each output port of the microcomputer (32) into an analog signal, and (34a) and (34b) are each D/A conversion circuit.
A conversion circuit (33a) (33b), (33c)
(33d) is an adder that adds the two analog signals output from the circuit, (35) is a sequence control circuit for performing sequence control in various playback modes, and includes a delay circuit (35a) and a control circuit (35b).
and has.

(36a). (36b) is a D/A conversion circuit that converts digital signals read from two erasable ROMs (39a) and (39b), which will be described later, into analog signals, and (37) is a D/A conversion circuit that converts digital signals read from two erasable ROMs (39a) and (39b), which will be described later.
9a). (39b) a microcomputer driving (38a) . (38b) are analog switches that are interlocked with each other, for special and normal playback positions PLAY, and for recording positions REC. exists. (39a). (39b) is a non-volatile memory consisting of a rewritable erasable ROM. (40) is a recording signal processing circuit.

At this point, the operation of the above configuration will be explained with reference to the signal waveforms of each part shown in FIG.

The sequence control circuit (35) shown in FIG. 6(a)
The fixed head switching flip-flop signal FF shown in FIG. Ru.

Now, assuming that 5x forward surge playback is to be performed as shown in FIG. (32i
), the scan signal basic waveform generation R O specifies the ideal value of the scan pattern of the 5x speed movable heads (3) and (4).
The ROM contents of M (32a) are sent. The waveform signals sent out from this scanning signal basic waveform generation R OM (32a) are (33a), (34a) . (38a)
, (23a) and (24a) to the movable head drive winding coil (104a), and is applied to the basic position where the movable head (3) scans on the track Al, that is, the first
It is determined to follow the trajectory L2 in Figure 0.

This operation corresponds to the operation shown by the broken line in part A in FIG. 6(C).

At this time, the signal of track A1 reproduced by the movable head (3) is envelope-detected by the envelope detection circuit (15), and the signal S converted to a digital signal by the A/D conversion circuit (31) is serially sent out. It is added to the microcomputer (32). Accordingly, this microcomputer (32) sequentially compares and calculates the envelope detection signal S and the basic waveform of the selected scanning signal for each step, and calculates the slope correction R for which various correction values are prepared.
The scanning signal obtained by selecting the optimal tilt correction value from among O M (32b) (about 30 types are required) and adding this tilt correction signal with an adder (34a) is sent to the winding coil (104).
a) is applied. As a result, the inclination angle of the scanning trajectory of the movable head (3) is corrected as shown by the arrow A in FIG. This corresponds to correction of the amount of movement.

With the operations up to this point, the inclination angle of the recording track A1 and the scanning locus of the movable head (3) during special playback coincide as shown in part A in FIG. 6(C).

Next, an optimum track movement signal for selecting a pre-selected track to obtain an optimum result during a 5x speed forward search is read from the optimum track movement ROM (32c), and a drive signal to which this movement signal is added is is the winding coil (
104a) to move the movable head (
3) scans. In this case as well, the envelope detection signal S is applied to the microcomputer (32), and the optimum track is selected from this level.

With the above operation, the head (3) can move almost on the optimal track.
Furthermore, in order to track the best position within the optimal track, that is, the position where the level of the envelope signal S is at its maximum value, a so-called mountain climbing operation is performed in which the movable head (3) is displaced parallel to the scanning trajectory. Apply correction.

This operation is demodulated by the reproduction signal processing circuit (13), and the vertical synchronization signal V-SY is separated by the synchronization separation circuit (25).
Using the NC as a reference, the hill climbing correction ROM (32d) in the microcomputer (32) is used to offset the serial envelope detection signal S so that it reaches its maximum value.

This operation corresponds to the operation shown by the broken line at the beginning of FIG. 6(d), and in FIG. 10, it is necessary to accurately follow the X point and scan the center line of the recording track during one field period. This corresponds to making fine adjustments perpendicular to the video track.

The above operation explanation was about the movable head (3), but
The same is true for the movable head (4); in this case, scanning signal basic waveform generation R O M (32e), tilt angle correction R O M (32f), and optimal track movement R O
M (32g), mountain climbing correction R O M (32h)
, D/A conversion circuit (33c), (33d)
, adder (34b) . Analog switch (38b)
, LPF (23b), drive amplifier (24b)
The movable head (4) is driven by the operation of the movable head (4), and the amount of movement thereof is as shown by the arrow b in FIG.

Next, when the movable head (3) finishes scanning the magnetic tape surface, and then the movable head (4) is scanning the magnetic tape surface, this movable head (3) does not come into contact with the tape surface and is in the air. The rotation is moving. The behavior of the movable head (3) during this field period, that is, the field period during which the movable head (4) is scanning the magnetic tape surface, is based on the waveform of the rewind signal assumed in advance by the envelope signal waveform of the previous field period. Generation ROM (321
) (approximately 5 types are required), select the best one, and D/
The signal is sent to the A converter (33a). The waveform of this return signal is shown in part 8 of FIG. 6(C). If an inappropriate swing-back signal waveform is selected as shown by the broken line in the eighth section, a large step will occur at the switching point of the MVFF signal, causing a large displacement of the movable head (3) and generation of noise.

In this way, the reversal signal waveform generated in advance is generated R O
When the movable head is driven when the drum is half rotated according to the swing-back signal waveform of M (32i), the result shown in Fig. 6(C) is
As shown by the solid line in (d), continuous and smooth driving is performed, and a stable 5x search signal without noise is obtained.

As shown in FIG. 6, if the number of steps of the microcomputer (32) within one field period is 256, as shown in FIG. ~116 steps (1/30HZ x 118/256 - approx. 15
msec), the movable head is driven back according to the selected fixed pattern, and during the remaining steps 117 to 256, comparison calculations are made with the envelope detection signal in the microcomputer (32), and the movable head is moved on the next recording track. Tilt angle correction and hill climbing correction are performed to ensure that the head travels accurately. The waveform of the swingback signal for the next approximately 15 msec is selected based on the envelope detection signal data at this time, and the movable head is moved so that the reproduction signals of the movable heads (3) and (4) are connected almost continuously. Driven.

A specific example of the microcomputer (32) is M50747 (8 bit 8k).

Next, the operation during normal playback will be explained.

The normal playback operation is basically the same as the speed search playback operation described above, but since the tape speed at this time is 1 times the speed, the movable head (3). (4) to 5
There is no need to move as much as when performing double speed search playback. Head movement amount (a), (b) in Fig. 10
) is almost flat. Therefore, the movable head (3),
The drive signal waveform in (4) is as shown in FIGS. 6(e) and 6(f). At this time as well, the movable head (3
) and (4) are completely tracked, sufficient playback output is obtained, there is little crosstalk between adjacent tracks, and high-quality playback is possible.

Next, the operation during recording will be explained.

During the recording operation, there is no reference signal on the tape, so there is no output from the envelope detection circuit (15).

Therefore, a standard recording tape, for example, a reference tape that accurately complies with the VHS format, is used to ensure that video track width, tilt angle, linearity, etc. are correctly controlled, and is the VHS standard used by tape manufacturers in their production processes. Insert the tape and start playing. The operation at this time is exactly the same as the reproducing operation described above, and each R OM (32a), (32b
) , (32c) , (32d) , (32i)
<7) Erasable output signal ROM (39a)
to be memorized. In addition, each R O M (32e) (32
f) , (32g) , (32h) , (32i
) Erase the output signal of R O M H9b)
Let me record a thousand thoughts. That is, erasable R O M
(39a) and (39b) The movable head (3) during playback operation using the above-mentioned VHS standard tape
．． The ideal drive signal waveform of (4) is stored in advance.

Then, during the actual recording operation, the digital drive signal waveforms stored in these erasable ROMs (39a) and (39b) are read out and converted into analog signals by the D/A conversion circuits (36a) and (36b). Convert and analog switch (38a), (38b)
REC. After position L P F (23a)
, (23b) and high voltage amplifier (24a), (2
4b) to the winding coils (104a), (1
Apply a drive signal to 04b).

In addition, the above erasable R OM (39a),
Writing (39b) only needs to be done once during production, but if the inside of the VTR drifts after long-term use,
By rewriting R OM (39a) and (39b) again, recording tape can be recorded in the ideal format. From this point of view, it is ideal for dubbing machines that create soft tapes.

In addition, in order to conform to the standard format, the mounting accuracy of the fixed head mounted on the drum needed to be 1 μm, but according to this invention, the erasable ROM
Since the data written in (39a) and (39b) are corrected, high precision is not required and a rough installation is sufficient, so the ease of assembly can be significantly improved.

Further, since various internal configurations of the microcomputer (32) can be considered, the configuration does not necessarily have to be that of the above embodiment.

In addition, in the above embodiment, the case of 5x search playback was explained with the configurations shown in FIGS. 1 to 6.
Slow, stall, and reverse playback can also be supported by increasing the ROM in the microcomputer. Furthermore, although the movable heads (3) and (4) are configured to be moved using wire-wound coils, the movable heads (3) and (4) are moved by approximately ±300μ in the direction of the rotational axis of the drum.
It is sufficient if it is configured so that it can be moved by m + i.

In addition, the basic waveform generation R O in the microcomputer
If the number of types of M (32a), H2e), and (32i) is increased so that they can be selected more precisely according to the envelope detection signal waveform, the amount of slope correction will be small, convergence will occur in a short period of time, and accuracy will improve, so noise can be quickly removed. This provides a tracking device that can eliminate noise and reproduce completely noiseless images.

Note that as an example of a storage circuit that stores the drive signal waveform,
In the above embodiment, erasable R, which is a non-volatile memory,
Although O M (39a) and (39b) are shown, they can also be constructed using general parts for memory elements.

Further, the two microcomputers (32) and (37) shown in the above embodiment may be configured with one microcomputer.

Furthermore, although the explanation has been made with a rotating drum equipped with a pair of movable heads, even if three or more movable heads are installed,
The same effects as in the above embodiment are achieved.

[Effects of the Invention] As described above, according to the present invention, the movable head attached to the rotating drum is automatically configured to maximize the level of the reproduced FM signal while keeping the movable head in surface contact with the magnetic tape during the reproduction operation. Tracking control makes it possible to achieve noiseless performance during special playback such as subito search and improvement of C/N during normal playback. Furthermore, during the recording operation, the behavior of the movable head can be accurately controlled by reading out the drive signal waveform during the good reproduction operation, so that accurate recording can be performed in accordance with the standard tape format.

Therefore, special playback and normal recording and playback are possible using only the movable head, and by reducing the number of heads, it is possible to suppress the occurrence of jitter due to the tape beating phenomenon, and it is also possible to reduce costs. Furthermore, even if the head installation accuracy is rough, it can be corrected by electrical control, so assembly workability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the drum structure of a rotating magnetic head device in a magnetic recording/reproducing apparatus according to an embodiment of the present invention, and FIGS. 2(a) and 2(b) are perspective sectional views showing the structure of the head unit. Longitudinal cross-sectional view, Figure 3(a). (
b) is an enlarged cross-sectional view showing the configuration of the circular spring; FIG. 4 is a schematic vertical cross-sectional view of the main parts explaining the operating principle of the head unit; FIG. 5 is a block diagram of the electric circuit showing the configuration of the tracking device; FIG. 6 is a signal waveform diagram for explaining the tracking operation, FIG. 7 is a perspective view showing the drum structure of a rotary head device in a conventional magnetic recording/reproducing device, and FIG. 8 is an enlarged structural diagram of the actuator portion of the movable head. , Fig. 9 is an explanatory diagram of the operating principle of the bimorph type piezoelectric element, Fig. 10 is an explanatory diagram of the movement of the movable head on the tape pattern during 5x speed search operation, and Fig. 11 is an explanatory diagram of the movement of the movable head on the tape pattern during 5x speed search operation. FIG. 2 is a block diagram of a specific electric circuit of the tracking device. (3), (4)...Movable head, (7)...Rotating head, (15)...Envelope detection circuit, (
24a), (24b)...-driving amplifier, (3
2), (37)...Microcomputer, (32a
), (32e) - base tree waveform generation ROM, (32b)
．． (32f) ...Tilt correction ROM, (32c)
, (32g) - Optimal track movement ROM, (32d
), (32h)...Mountain climbing correction ROM, (32i
)...Reverse basic waveform generation ROM, (33a),
(33b) -D/A conversion circuit, (34a)
, (34b) -Adder, (35)...Sequence control circuit, (36a), (36b) --
- D/A conversion circuit, (39a), (39b
)...Erasable ROM, (100)...Movable head unit, (104a)... (+04b) ...Wound coil. Note that the same reference numerals in the figures indicate the same or corresponding parts. brother ward

Claims (1)

[Claims] (1) A rotating drum, a pair of movable heads attached to the rotating drum so as to be movable in the axial direction, a drive mechanism that moves the movable heads in the axial direction of the rotating drum, and a drive mechanism that operates the drive mechanism. and a storage circuit that stores the drive signal waveform of the movable head. A magnetic recording and reproducing apparatus, characterized in that the magnetic recording and reproducing apparatus is configured to store the following information in the storage circuit, and to drive the movable head by reading out the drive signal waveform stored in the storage circuit during a recording operation.