JPS6117547Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a magnetic recording and reproducing device, which can form substantially one track by moving a non-rotating (fixed) head intermittently in the width direction on an endless tape, and Another object of the present invention is to provide a magnetic recording/reproducing device that can improve the utilization efficiency of a magnetic recording medium and can also perform good tracking.

VTRs that magnetically record and reproduce video signals or video signals and audio signals as information signals are currently available in 1 or 2 types.
For household use, the main type is a rotating head, but these devices inevitably require a complicated mechanical system, and even when using magnetic tape in a cartridge or cassette type, the tape loading mechanism and tape running mechanism are quite large. The process is complicated, resulting in poor productivity and inevitably high production costs, which is the biggest drawback in making it popular for household use.

Therefore, aiming at a low-cost VTR, the tape speed is increased to a desired value in an audio tape recorder format, and the linear velocity relative to the head is increased until a wideband video signal can be recorded and played back by a fixed head, and the audio can be heard. A so-called fixed head type that records and plays back video signals with a bandwidth more than 200 times that of the signal.
It is well known that VTR has been proposed.

FIG. 1 shows a schematic plan view of the main parts of a conventional fixed head type VTR. In the figure, 1 and 1' are reels on which the magnetic tape 2 is wound, and motors (not shown)
The magnetic tape 2 is configured to be rotatably driven in both clockwise and counterclockwise directions by the pinch rollers 4 and 3' relative to the capstans 3 and 3'.
By crimping 4', it is clamped and driven in the direction of arrow 5 at a predetermined high speed, and a non-rotating magnetic head 6 attached to the magnetic surface forms a magnetic track in its longitudinal direction, and a video signal, etc. information signals are formed. When forming magnetic tracks in the longitudinal direction of the tape, for example, reel 1' is used as a take-up reel, recording is started from the starting end of magnetic tape 2 wound around reel 1, and the first track is formed at the upper end of the tape. When the end of the tape is reached, the tape 2 is rewound at high speed with the reel to the recording end position, and when trying to record the second track in the same direction again, no signal is recorded during this rewinding period. , the recorded signal is lost. Therefore, in the conventional method, the head 6 is switched and transferred one track pitch from the position where the tape 2 reaches the recording end position on the tape, and at the same time, the capstan 3 is moved in order to reverse the tape running direction. , 3' and reels 1 and 1' at high speed, reel 1 is now a take-up reel, reel 1' is a supply reel, tape 2 is driven in a predetermined synchronous manner, and the return journey is performed in the longitudinal direction of the tape in the same manner as the outward journey. A track pattern is formed, and while the tape 2 is repeatedly reciprocated in the left and right direction a predetermined number of times, the head track position is sequentially moved intermittently or linearly at the start and end positions of the tape 2. However, conventional fixed heads form playback signals using similar operations.
This was a typical common example in VTRs.

However, in the conventional device described above, when switching the direction of tape reciprocating drive, there is always a signal dropout at the start and end positions of both ends of the tape, and the recording signal is interrupted for this direction switching time, making it impossible to record and reproduce signals continuously. It had a fatal flaw:

The present invention eliminates the above-mentioned drawbacks, and each embodiment thereof will be explained with reference to the drawings from FIG. 2 onwards.

FIGS. 2 and 3 each show a schematic diagram of the main parts of an endless tape drive mechanism applicable to the apparatus of the present invention. In each figure, the same parts are given the same reference numerals. Reference numeral 7 denotes a reel hub around which the magnetic tape 2 is wound in an endless loop, and is housed within the housing 11. The magnetic tape 2 is guided by a guide roller 8, held and driven by a capstan 9 and a pinch roller 10, and is made to run at a constant speed in the direction of the arrow. Reference numeral 12 denotes a fixed head (third magnetic head) fixedly disposed on the tape running path, and in the embodiment includes a tape full-width erasing head and a control head for tape speed control. Reference numeral 13 denotes a non-rotating magnetic head, which in the present invention is attached via a head moving mechanism for controlling the signal track during reproduction, as shown in FIG. 4, as will be described later. Pads 15 and 15' are pressed against the back surface of the tape 2 to maintain good contact between the heads 13 and 12 and the tape 2.

FIG. 4 shows a schematic configuration of an embodiment of a head driving machine that can be applied to the apparatus of the present invention. In the figure, 16 is a shaft with a screw screw 17 cut therein, and a part of the shaft has a gear part 18 having a gear on the outer peripheral edge.
is fixed through the shaft 16, and one end of the shaft 16 is rotatably supported by a bearing 19.
20 is a nut that fits with the screw 17, is cursor-fitted with the nut guide block 21, and is connected to the shaft 1.
The rotation of 6 allows smooth transfer in the vertical direction shown by arrow 27. The magnetic head 13 is fixed to the nut 20 via a bent bimorph (head control means) 14, and is moved in the same direction as the arrow 27 by rotation of the shaft 16.

Reference numeral 22 denotes an electromagnetic solenoid, which moves the shaft 24 forward when energized with driving power, releases the driving power of the shaft 24 when de-energized, and moves the shaft 24 backward with the spring force of a spring 25. . Therefore, the shaft 24 is reciprocated back and forth as shown by arrow 29. Shaft 2
4 has a driving pawl attached to its end that meshes with the gear part 18, so as it reciprocates in the direction of the arrow 29, rotational driving force is transmitted to the shaft 16 via the gear part 18, and this is transmitted to the shaft 16. Perform intermittent rotational motion. Here, by one reciprocating movement of the shaft 24 by the electromagnetic solenoid 22 and the spring 25, the nut 20 fitted to the screw 17 is moved in the vertical direction 27 to a predetermined bit by one step movement to the gear portion 18. The pitch relationship between the gear portion 18 and the drive pawl 23 is set. Furthermore, although omitted for convenience of explanation, the drive claw 23 is actually operated in combination with another electromagnetic mechanism to move the gear portion 18 in both clockwise and counterclockwise directions in conjunction with the reciprocating movement of the drive claw 23. The nut 20 is thereby driven intermittently in the vertical direction 27.

Furthermore, as is well known, the bending type bimorph 14 has a drive signal input terminal 28, which is provided with an electric terminal 28 for driving by gluing piezoelectric ceramics on both sides of a conductive flexible plate so that the bending polarity is in the opposite direction. It is used for acoustic conversion, and is configured to perform a bending operation according to the polarity and voltage value of the applied voltage by applying a DC voltage to the drive signal input terminal 28. In this embodiment, the bimorph 14 is configured to be displaced at high speed in a direction perpendicular to the track scanning direction by the head 13 by applying a voltage to the drive signal input terminal 28.

Next, track patterns recorded and reproduced by the apparatus of the present invention will be explained.

FIG. 5 shows a partially enlarged plan view of a track pattern of an embodiment of a magnetic tape recorded and reproduced by the apparatus of the present invention. In this embodiment, the head 13 is placed on a magnetic tape 2 that is continuously driven in an endless loop.
The track pattern is shown when the tape 22 is moved intermittently to a predetermined pitch every rotation period.
In the same figure, the tape width L (for example, 1/2 inch = 12.7
The magnetic tape 2 (mm) is driven in servo synchronization with, for example, a synchronization pulse of an input video signal. A drive motor (not shown) for the capstan 9 causes it to travel in the direction of an arrow 31 at a predetermined constant speed (for example, 5 m/s). The lower edge of the magnetic tape 2 has a width of 32 mm (0.6 mm) in the embodiment, for example, in order to record and reproduce control signals with the fixed head 12 shown in FIG. ) is recorded as a control track 34. Further, the width 33 is the blank area at the upper end of the magnetic tape 2, and is selected to be 0.1 mm in the embodiment, so that the effective tape width contributing to the video track 36 is 12 mm.

Now, during signal recording, no drive power is applied from the drive signal input terminal 28, and the head 13 fixed to the end of the bimorph 14, which can be regarded as a kind of rigid body, starts recording from the recording start point indicated by 35 in FIG. For example, at the same time as a video signal is recorded, a control track 34 is formed by a control head provided within the fixed head 12.
Corresponding to this recording start point 35, a start position indicating pulse is recorded by the fixed head 12 at a position indicated by 37 in FIG. This start position indicating pulse is inserted and recorded only at a predetermined time at some start positions on the control track 34 by the control head in the fixed head 12, but the normal control signal is, for example, a 15.75 KHz horizontal synchronizing pulse. On the other hand, a relatively high single frequency of, for example, about 300 KHz may be recorded as a reference signal so that reproduction can be distinguished from this. Next, at the end of one cycle of the endless loop tape 2, that is, at the end of recording the first track _t1 from the signal recording start position 35, the head 13 scans and records on track _t1 again. However, another fixed head 12 placed slightly ahead of this head 13 can be used as a reproducing mode, and the start position indicating pulse can be regenerated on this fixed head 12 immediately before the head 13 scans the position 35. be placed at a mechanical timing position such as
At the same time as the fixed head 12 detects the reproduction of the start position indication pulse, the control head stops recording the control signal, and the reproduction signal of the start position indication pulse from the fixed head 12 causes the capstan motor to read the first recorded control signal. By instantaneously switching the reference signal for servo driving in accordance with the reproduction signal, and further activating the solenoid 22 at this point, the head 13 is instantaneously and intermittently moved one track pitch below the tape. The second track in one period of the next tape without being superimposed on t _1.
t ₂ is recorded. Thereafter, in the same manner, 39 in FIG.
By stepping the head 13 by instantaneously operating the solenoid 22 at the position controlled by the head 13, the video track 36 becomes substantially one continuous track on the tape 2 up to the full predetermined width for a predetermined time. Continuous recording of video signals is performed.

On the other hand, during signal reproduction, by detecting a start position indicating pulse from an arbitrary position on the tape 2, the head 13 is automatically returned to the recording start position 35, and reproduction is performed by the same operation as during recording.

In this embodiment, it is desirable that the head stepping operation at position 39 be performed within the vertical blanking period of the recorded video signal so as not to affect the playback screen; It is difficult to strictly control the relationship between the total length and tape speed so that the relationship is always like this. However, this head stepping period at position 39 can be performed as high-speed stepping on the order of milliseconds in one field screen for several tens of seconds in one cycle of the tape, and is not accompanied by signal loss. Stepping motion does not pose a problem.

Further, a start pulse is magnetically recorded and reproduced as the start position indicating pulse for starting signal recording and reproduction on the endless tape and for controlling head stepping.

In addition, regarding the recording and reproduction of the tape speed control signal, this signal is recorded only during the first tape period of signal recording, and from the second period onwards, this recorded control signal is referred to from the time when the start position indication pulse is detected. Regeneration is performed to control the rotational speed of the capstan motor as a signal. Furthermore, as for the tape speed control signal in the present invention, it is not necessary to record a control signal each time a signal is written and recorded, but a predetermined control signal is permanently recorded magnetically on a predetermined portion of the tape 2 in advance. Therefore, it is more preferable to constantly refer to this control signal to control the speed of the capstan motor even when recording and reproducing main signals.

Next, a description will be given of a tracking control signal recording and reproducing means that can be used in conjunction with the apparatus of the present invention, and a schematic block system in this reproducing tracking.

Figures 6A and 6B show the first case where the tracking control signal is recorded on the tape together with the information signal, respectively.
FIG. 8 shows a partially enlarged plan view of a track pattern of the embodiment, a schematic structural diagram of a head, and a block system diagram of an example of a recording/reproducing system for a tracking control reference signal that can be applied to the apparatus of the present invention. In this embodiment, the recording density can be further improved by recording and reproducing the tracking reference signal using the recording and reproducing method previously proposed by the present applicant in Japanese Patent Application No. 51-38809.
Moreover, it is designed to be able to be regenerated stably.

That is, at the time of recording, for example, two or more information signals (for example, a video signal and an audio signal) modulated with different modulation bands in consideration of the recording capacity are supplied from the input terminal 58 to the recording amplifier 59, where the level is adjusted appropriately. After being amplified, the information (main) signal is guided to the information (main) signal recording/reproducing head (first magnetic head) 41 via the signal recording/regeneration changeover switch 60 which is closed on the contact R side, whereby the information signal is recorded on the magnetic tape 2. is recorded. On the other hand, the horizontal periodic pulse is separated from the video signal to be recorded, and as a result, a positive polarity switching pulse is generated only during the horizontal blanking period of the video signal to be recorded at a 2H period, for example, and the input terminals 53, 54 is applied to the oscillators 55 and 56. These oscillators 55, 56 have a single frequency p ₁
(for example, 300 KHz) and p ₂ (for example, 500 KHz), the switching pulse performs an oscillation operation during the positive polarity period, and the negative polarity period of the switching pulse is stopped. Thus, the oscillation signal p ₁ or p ₂ from the oscillator 55 or 56 is amplified by the recording amplifier 57 and then recorded by the reference signal recording magnetic head (second magnetic head) 40 as a reference signal for tracking control. .

Here, the heads 40 and 41 constitute a head 13 as shown in FIG. 6B, and a shield plate 42 is inserted between each head to prevent mutual interference during signal recording and reproduction. Gap spacing 43
are arranged at intervals of an integer multiple of one horizontal scanning period of the video signal recorded on the tape, and
The track center positions of each of the heads 40 and 41 are shifted in a predetermined direction with respect to the center line 44 in the track scanning direction of No. 3. The center positions of the tracks 40 and 40 are arranged to coincide with each other.

Therefore, a substantially continuous track pattern recorded by the head 41 is formed as shown in FIG.
The timings are as shown by _t1 , _t2 , _t3 , ..., and in the first guard band portion _g1 when _t1 is formed, only the signal _p1 from the oscillator 55, whose oscillation operation is controlled only during the period of _t1 formation, is recorded by the head 40 within the horizontal blanking interval of the video signal recorded by the head 41 and for every 2H period. Then, after one rotation period of the tape 2, the head 41 starts to form the next track _t2 , at which time the oscillator 55 is stopped by detecting the start position indication pulse, and switching control is performed so that only the oscillator 56 is in an operating state. At this time, since the tape speed is controlled by the reference pulse from the control signal as described above, the horizontal sync pulse recording positions of each video track _t1 , _t2 , _t3 , ... recorded on the tape are regularly aligned and recorded in the width direction of the tape, but the oscillator 56 in the guard band portion _g2
If the recording of the output signal _p2 of is conveniently made to oscillate and be recorded at a position shifted by 1H from _p1 , this signal _p2 will be inserted and recorded on _g2 as shown by the broken line in FIG. 6A.

Thereafter, signals p 1 and p ₂ are alternately sent to the guard band portion of the head ₄ in units of one rotation period of the tape 2 by detecting the start position display pulse in the same manner.
Recorded by 0.

Next, an outline of the processing of the tracking control reference signal during reproduction will be explained with reference to FIG. First, the tape 2 is returned to the start position at high speed with the playback operation of the apparatus, and the head 13 starts playback scanning from the recording start point 35. Also, the switch 60 is the contact point P.
Only the head 41 is connected in a closed manner to the side so that it can be reproduced. As a result, the head 41 moves to the track t ₁ ,
Not only the information signals of t ₂ , ... but also the guard band parts g ₁ ,
The reference signals p ₁ and p 2 inserted and recorded in g ₂ , . _{. .} are also reproduced at the same time. This reproduced signal passes through a preamplifier 61, is guided from an output terminal 62 to a demodulator (not shown), and is demodulated into predetermined video and audio signals, while a part of the output of the preamplifier 61 is
It is applied to band amplifiers 63 and 64 having steep frequency wave characteristics at p ₁ and p ₂ , where p 1 and p ₂ are respectively applied.
The reproduced signal component of p ₂ is separated.

The reproduced signals p ₁ and p ₂ are supplied to detectors 65 and 66 and converted into DC voltages according to their levels, and after level setting, are applied to a differential amplifier 67 and the levels of both signals are compared. The output signal of the differential amplifier 67 changes its polarity and level depending on the mistrack direction and magnitude on the tracks t ₁ , t ₂ of the head 41, and is supplied to a tracking servo amplifier 68 of well-known technology to provide control power. from the output terminal 69 to the drive signal input terminal 28 of the bimorph 14.
is applied, thereby performing stable and reliable tracking control in a closed loop. In this embodiment, the positions of p ₁ and p ₂ for each track correspond to each other in a relationship of opposite polarity, so it is necessary to reverse the polarity of the control every cycle of the tape 2. In the amplifier 68, a tape rotation period pulse, that is, a detection signal of the start position indicating pulse is applied from an input terminal 70, and the control polarity of the head 41 with respect to p ₁ and p ₂ is controlled by switching for each rotation period of the tape. It should be configured as follows.

Note that in the head 13 shown in FIG.
The placement relationship of the trailing ones is good, and the track width is also good.
T ₁ and T ₂ may be made to be slightly different, but as shown in A of the same figure, when the information signal is reproduced by the head 41,
It is desirable to select overlapping recording of p ₁ and p ₂ with respect to the main information track so that p ₁ and p ₂ are played back at the same time.

Figures 7A and 7B show the second case where the tracking control signal is recorded on the tape together with the information signal, respectively.
FIG. 2 shows an enlarged partial plan view of a track pattern and a schematic structure diagram of a head according to an embodiment. In Figure A and B, Figure 6 A,
The same parts as those in B are given the same reference numerals, and their explanations will be omitted. This example was originally filed by the applicant in the 1970s.
By recording and reproducing the tracking reference signal using the recording and reproducing method proposed in No. 134970, the same features as those shown in FIGS. 6A and 6B are obtained. That is, in this example,
The heads 13 are integrally formed and have different gap angles from each other and magnetic heads 45 and 4 for signal recording and reproduction.
6, and are arranged so that the center of the gap coincides with the center line 44. As a result, the signal recording and reproducing operations of the heads 45 and 46 are controlled by switching alternately every rotation period of the tape 2, and in connection with this, for example, only a single frequency p is sent as a tracking reference signal every 3H periods. By multiplexing and recording the signals, a so-called azimuth recorded track pattern is created in which reference signals are recorded at different 1H recording positions in adjacent tracks and there is no guard band portion, as shown by the solid line in FIG. 7A. It is formed.

During reproduction, the recorded information signal and the reference signal are simultaneously reproduced by the head 45 or 46, which has a gap angle in the same direction as during recording. The direction and amount of time shift can be detected, and tracking control of the head 13 can be performed based on this.

Note that two pilot signals having different frequencies for each track may be recorded as reference signals simultaneously with the information signal within the blanking period of each H unit signal, and processed in the same manner as in FIG. 8 above. In this case, by setting the reference signal to a recording wavelength on the order of KHz,
A reference signal recorded by one head during a mistrack can be reproduced by the other head.

According to this embodiment, the recording density can be improved more than in the embodiments shown in FIGS. 6A and 6B. For example, according to this embodiment, the total length of the magnetic tape 2 is 90 mm.
m, tape speed 5m/s, effective tape width 40μ
m, it is possible to record and play back video and audio signals for 90 minutes, and even in the embodiments shown in Figures 6A and B, the track pitch is 60 μm (track width 40 μm).
m, and the guard band portion is 20 μm), it is possible to record and reproduce signals for 60 minutes, and in both cases, the recording density can be improved compared to the conventional method in conjunction with tracking control.

In the apparatus of the present invention, when the reference signal is recorded on the tape 2 together with the main information signal, it is carried out in combination with the intermittent drive head drive device described in FIG. 5 above.

Furthermore, although the above embodiments have been described with reference to the case where video signals and audio signals are recorded and played back, the present invention is not limited to this. It can also be applied to quality magnetic recording and reproduction.

As mentioned above, the magnetic recording and reproducing apparatus of the present invention can record and reproduce information signals on substantially one track on a magnetic tape wound in an endless loop, without any loss of information, and therefore, it is possible to record and reproduce information signals on a magnetic tape wound in an endless loop without missing any data. In contrast to the fixed head type magnetic recording and reproducing device, which always caused recording signal dropouts at the beginning and end of the tape, we have developed a fixed head type magnetic recording and reproducing device that is essentially free of signal dropouts, has high quality, and is inexpensive. By using the tape reference position display signal as a timing reference signal during signal recording and reproduction, various devices can be operated reliably. Accordingly, a reference signal for tracking control is recorded along with the above information signal on the left and right sides of the information track, that is, an information track and/or a guard band, and a difference signal between the reference signals reproduced from the left and right sides of the information track is used. Since the first magnetic head is under tracking control, the guard band can be narrowed or eliminated, thereby improving recording density and compatibility between tape devices. By reproducing the speed control signal, the capstan motor can be servo-controlled, and the tape speed and phase can always be controlled stably, reliably, and with high precision.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of the main parts of a conventional fixed head VTR, FIGS. 2 and 3 are schematic diagrams of the main parts of an endless tape drive mechanism that can be applied to the device of the present invention, and FIG. FIG. 5 is a partially enlarged plan view of a track pattern of an embodiment of a magnetic tape recorded and reproduced by the device of the present invention; FIG. Figures A and B and Figures 7A and 7 are respectively enlarged partial plan views of the track patterns of the first and second embodiments when the tracking control signal is recorded on the tape together with the information signal, a schematic configuration diagram of the head, and Figure 8.
The figure is a block system diagram of an example of a tracking control reference signal recording and reproducing system that can be applied to the apparatus of the present invention. 2...Magnetic tape, 7...Reel hub, 12...
... fixed head (third magnetic head), 13 ... non-rotating magnetic head, 14 ... bending bimorph (head control means), 16, 24 ... shaft, 17
... Screw screw, 18 ... Gear part, 20 ...
Natsuto, 21... Natsuto guide block, 22...
...Electromagnetic solenoid, 23...Drive claw, 25...Spring, 40...Reference signal recording magnetic head (second magnetic head), 41...Information (main) signal recording/reproducing head (first magnetic head), 55, 56...
...Oscillator, 63, 64... Bandwidth amplifier, 65, 6
6...Detector, 67...Differential amplifier.

Claims (1)

[Scope of utility model registration request] a first magnetic head for recording and reproducing information signals that records and reproduces information signals on a longitudinal information track of a magnetic tape wound in an endless loop;
A second magnetic head for recording a reference signal, which is integrally formed with the first magnetic head and records a reference signal for tracking control on the information track and the guard band.
a third magnetic head for control and reference signal recording for recording a tape speed control signal and a tape reference position display signal at at least one location on a control track, and at least the first magnetic head. a head control means for controlling the tracking of the track formed by the first magnetic head during recording during regeneration; an intermittent head movement stage for intermittently moving the head control means in the upper width direction of the tape to a predetermined pitch every cycle; and a head control means for transmitting a signal representing the difference between reference signals sequentially reproduced from the left and right sides of the reproduction information track. A tracking servo amplifier that supplies a magnetic recording/reproducing device.