JPS6040524A - Head position controller for rotary head type magnetic video recording and reproducing device - Google Patents

Abstract

PURPOSE:To avoid the transient disturbance of a reproduced picture when a standard speed reproduction is shifted to a variable speed reproduction, by inserting partially a reproduced video signal given from a variable head in a standard speed reproduction mode. CONSTITUTION:The reproduced pictures are extracted out of fixed heads 4 and 6 via switches 9 and 10 in a standard speed reproduction mode. In this case, the switches 9 and 10 are switched to the side (b) for a fixed period of time by the switching signal given from a switching signal generator 20. Therefore the reproduced video signals given from variable heads 3 and 5 are partially inserted to the reproduced video signals given from the heads 4 and 6. Based on the reproduced picture thus obtained, a tracking control signal is produced. As a result, the positions of the heads 3 and 5 are already controlled at the time of a standard speed reproduction mode so that the positions of the heads 3 and 5 are set under optimum tracking states. Thus it is possible to avoid the transient disturbance of a reproduced picture when a standard speed reproduction is shifted to a variable speed reproduction.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention provides variable speed playback (slow, still, and replay).

A rotating head type magnetic recording device that allows quick playback, etc.

A rotating head suitable for use in an image reproduction device.

The present invention relates to a position control device.

[Background of the Invention] 1 () In a rotating head type magnetic recording and recording device, ``As is well known, a magnetic tape runs at a predetermined speed.

is rotated and scanned diagonally by a rotating head.

The magnetic tape was tilted at a predetermined angle on the magnetic tape.

A recording track is formed. Then, during so-called standard speed playback, in which the recording track is played back at a tape running speed that matches the 15-tape running speed during recording, the rotary head traces the recording track correctly.
Rotation phase of rotating head.

Controls the running speed of the magnetic tape according to... ()
It is common to perform so-called tracking servo.

However, when the magnetic tape is running at a different speed than when recording,
Alternatively, during variable speed playback in which the playback is stopped and played back, it is not possible to accurately trace the slanted recording rack on the magnetic tape using only the tracking servo.

The reason for this is that if the running speed of the magnetic tape is different from that during recording, the rotational scanning trajectory by the rotating head.

The inclination angle of the trace matches the inclination angle of the recording track.

10 Conventionally, in order to eliminate such inconvenience,
IiI7: A fixed head for standard speed playback with a fixed +a attached to the rotating drum that constitutes the head.

Separately, a movable head is provided which can be displaced in a direction approximately perpendicular to the rotational scanning direction by a position control element, and when the 1'i variable speed is internal, the position of the movable head is varied and controlled to adjust the tilt on the magnetic tape. A rotary head type magnetic/magnetic recording/playback device has been proposed which allows recording tracks to be accurately traced. FIG. 1 shows the structure of the rotating head in the conventional example.
Between 0 degree angles.

Two fixed heads 4.6 for standard speed playback at intervals.

Mounted and fixed head 4. Two movable heads 3 and 5 for variable speed playback are installed at the middle position. The movable head rollers 5 each have five position control elements, bimorph plates 7 and 8 in the illustrated example.

It is mounted on a rotating drum 2-to.

Therefore, depending on the drive control signal supplied to the electrodes applied to both sides of the bimorph plate 7.8.

It is arranged so that it can be displaced in a direction substantially perpendicular to the rotational scanning direction. There is a magnet around the rotating drum 2.

The tape 1 is attached with a winding angle range of approximately 180 degrees, so that the fixed heads 4, 6 and the movable head 5
, 5 sequentially and alternately come into contact with the magnetic tape 1 as the rotary drum rotates at a predetermined speed, and rotate and scan its 15 recording surfaces in an oblique direction.

During standard speed playback, the fixed heads 4 and 6 are magnetic.

Sequentially correct the inclined recording tracks on tape 1.

Rotating scan l~ in the ranking state, the fixed head 4. .

A reproduced video signal is extracted from 6. 2゜, 5.

On the other hand, during variable speed reproduction, the movable head 6.5 is magnetically controlled by the position control by the bimorph plates 7 and 8.

Correctly tray the slanted recording track on tape 1.

Tracking is controlled so that the object moves.

The reproduced video signals from the radars 6 and 5 are taken out. Through these steps, the movable heads 3 and 5 correctly trace the inclined recording track on the magnetic tape 1 during variable speed reproduction.

In order to, the inclination angle of its rotational scanning trajectory is.

Along with matching the tilt angle of the recording track.

Tracking control is performed so that the position of the rotational scanning locus coincides with the 10th position of the inclined recording track.

must be FIG. 2 shows a block diagram for performing such dragging control, and in the same figure, 3 to 8 are the movable head, 15 fixed head, and bimorph head in the rotary head shown in FIG. 1, respectively. Compatible with the board. .

9.10 has standard speed playback mode and variable speed playback mode.

With the changeover switch, you can switch between standard speed and normal speed.

During playback, it is at the α position shown in the diagram, and during variable speed playback, it is at position B.

can be switched to the position. 11.12 is a reproduction amplifier, 16 is,
0,4.

Demodulator 14 is a video signal output terminal, selector switch 9
, 100. Depending on the switching position, the video signal for reproduction from the fixed head 4.6 or the movable heads 3, 5 is selectively sent to the demodulator 13 via the reproduction amplifier 11, 12.

The signal is supplied, demodulated, and output from the video signal output terminal 14.

15.16 is an automatic tracking circuit, and 17 is a slope signal.

The signal generation circuit, 18.19 is an adder, and these.

Transmission of movable heads 3 and 5 during variable speed reproduction.

King control is performed. That is, at the time of variable speed playback 10, the slope signal generation circuit 17 presets the slope signal according to the variable speed mode such as slow, still, quick, etc.

The tilt signal has a determined tilt angle and is repeated in phase synchronization with the rotational scanning of the movable head 6.5.

The slope signal is passed through an adder 18.19 to a buffer I5.
It is supplied to the drive electrodes of the immorph plates 7 and 8, and drives the bimorph plates 7 and 8 to displace them in the vertical direction. As a result, the movable heno is placed on the bimorph plates 7 and 8.

Doro, 5 is the rotational scanning direction for each rotational scanning period.

The magnetic tape 1 is displaced in a direction perpendicular to the magnetic tape 1 according to the inclination signal, so that the inclination angle of the rotational scanning locus 20 almost matches the inclination angle of the recording track on the magnetic tape 1. On the other hand, during variable speed playback, selector switches 9 and 10, playback amplifier 11
．． Reproduction N from the movable head 6.5 taken out through 12
The video signal is supplied to a demodulator 13 and is automatically tracked.

15,1 (also supplied to S, the automatic tracking circuit.

Paths 15 and 16 are the playback video from the movable door 6.5.

A feedback control signal whose amplitude is almost at its maximum.

The feedback control signal is input to the adder 18.19'' to generate the slope signal from the slope signal generation circuit 17.

It is added to the signal and drives and controls the bimorph plates 7 and 8.

Then, the variable f〃positions of the movable heads 3 and 5 are controlled. So.

As a result, the movable head has a scanning trajectory of 6.50 rotations.

magnetic teetop 1 including the scanning position as well as the inclination angle of
It perfectly matches the inclined recording track above.

Now, this kind of conventional rotating head type magnetic recording.

In the image generator, set the playback mode to standard speed.

The tracking system of the movable head 6.5 at the point in time 2) when switching from the speed playback mode to the variable speed playback mode.

Considering your condition, standard speed playback mode.

In this case, selector switches 9 and 10 are turned to position a.

Automatic tracking circuit 15.16
The input to is not the playback output from the movable heads 3 and 5,
This is the reproduction output from the fixed heads 4 and 6.

Therefore, a control loop for controlling the positions of the movable heads 3 and 5 is not configured, and in such a state, the movable heads 6 may change due to changes in the temperature and humidity of the bimorph plates 7 and 8, or changes over time. .5 Installation 10 Due to variations in the height position, etc., there is a considerable positional deviation between the movable head 3.50 rotation scanning locus and the inclined recording track on the magnetic tape 1. Therefore, even if the changeover switches 9 and 10 are switched from this state to the variable speed playback mode 15, the positional deviation of the movable head 6.5 is eliminated.

Accurate by automatic tracking circuit 15.16.

By the time tracking control is done, less.

It takes about the same amount of time to pick up sand, and during that time, there is noise.

The reproduced image was distorted by scratches, etc., and was very unsightly.

[Purpose of the invention]

The object of the present invention is to eliminate the drawbacks of the above-mentioned prior art.

From standard speed playback mode to variable speed playback mode.

During the transition, the variable speed playback head quickly tracks the slanted recording tracks on the magnetic tape in five precise directions.

It can rotate and scan under dragging control, making it movable.

It is possible to avoid transient disturbances in the reproduced image from the throat.

The head position of a rotating head type magnetic recording/playback device.

Provides control equipment. 10 [Summary of the Invention] In order to achieve this object, the present invention provides a system in which, during standard speed playback, the fixed head for standard speed playback performs playback from the fixed throat during a part of the rotation scanning period by the fixed head for standard speed playback. Reproduction is performed by rotating and scanning a movable head 15 for variable speed reproduction instead of using a video signal.

The reproduced video is made capable of outputting a video signal.

What is the amplitude of the signal? Move it to the above position so that it can withstand 1 hour.

Controls a position control element that controls the position of the throat.

As a result, the position of the movable head for variable 2° speed playback is always at the optimal position even when the standard speed is p1.

It is characterized by being able to be controlled. .

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

reactor.

FIG. 3 shows a head position control device according to the present invention.

FIG. 2 is a block diagram showing the basic configuration of an embodiment of the present invention.

FIG. 4 is an explanatory diagram of the operation. .

In FIG. 3, the subordinate shown in FIGS. 1 and 2.

Components that are the same as those in the previous example are designated by the same reference numerals, and their explanation will be omitted. 20 is a switching signal generation circuit for switching the changeover switches 9 and 10; 21 is a head switching signal from an input terminal 22; and a reproduction amplifier 11, which alternately switches the video signals outputted from the reproduction amplifiers 11 and 12; 1) This circuit is well known in itself. 25 is sampling.

Based on the output of the switching signal generation circuit 20 in the control circuit.

The video signal output for reproduction from the switching circuit 21 is switched.

Sample and hold the tracking control signal.

It is designed to output .　2゜ Next, the operation of the embodiment shown in FIG. 3 will be explained with reference to FIG. 4.

Magnetic recording and playback devices are now at standard speeds.

If in raw mode, fixed head 4. The Sono video signal reproduced by B is amplified by reproduction amplifiers 11 and 12 via switches 9 and 10, and input to the switching circuit 21.

As is well known, the rotational position of the fixed heads 4 and 6 is detected.

The head switch shown in FIG. 4(a) is formed by

A switching signal is input, and the switching signal is input.

According to the signal, the reproduced video signal No. 0 from the fixed heads 4 and 6 is alternately switched and inputted to the demodulator 13, and a demodulated video signal is obtained at its output terminal 14.

Ru. At this time, the switching signal generation circuit 20 operates as described above.

Fixed heno in synchronization with the head switching signal.

Immediately after the switching of the switching pins 4 and 6, a switching signal (see FIG. 4 (b)) is output for switching the switching pins 15 and 9 and 10 to the b side for a certain period of time. During the period of this switching signal, one of the movable heads 3 and 5 is magnetic.

Carefully record near the center of the track length on the tape.

Therefore, the fixed heads 4 and 6 reproduce m video signals at 2 degrees, as shown in FIG. 4(C).

Reproduction is performed by the movable heads 5, 5 during each switching period.

The reproduced m video signal from the above scanned point is switched.

It is inserted. This switching insertion position is for playback video.

It is desirable to set it at a position where the image signal does not appear on the television screen, for example within vertical blanking. Na.

Also, the synchronization signal in vertical blanking that disappears due to such switching insertion may be removed if necessary.

Created externally and reinserted into the playback video signal after demodulation.

can be entered. The reproduced y video signal is sampled through 10 reproduction amplifiers 11 and 12 and a switching circuit 21.

It is input to the ring control circuit 26 and a switching signal is generated.

The signal is sampled and held by sampling pulses based on the switching signal output from the circuit 20. .

That is, the movable head 153. in the reproduced m video signal.
y video signal level of the portion reproduced by 5.

is sampled and held sequentially for each movable head.

Ru. The sampling control circuit 23 controls the above sample.

Tiger for each movable head based on hold value.

The tracking system, which creates a tracking control signal.

・11・ The control signals are sent to the automatic tracking circuit 15. .

16, the automatic tracking circuits 15, 16° are respectively input to the movable head 6 through a bimorph plate 7.8.

The amplitude of the reproduced N video signal from 5 is almost the maximum.

The positions of the movable heads 3 and 5 are controlled so as to Na5o,
In this case, the output from the slope signal generation circuit 17.

has stopped. In this way, the movable head.

At position 3.5, the magnetic recording/playback device is before standard speed.

The above even though it is running in raw mode.

Due to the feedback control loop 10 using the tracking control signal, the amplitude of the reproduced y video signal is approximately maximized.

In other words, it is controlled to a position that provides approximately the best tracking state and position for the inclined recording and tracks on the magnetic tape.

When the magnetic recording/playback device is shifted from the standard playback mode to the variable 15-speed playback mode, a switching step is performed.

Switches 9 and 10 are supplied from the switching signal generation circuit 20.

It was switched and fixed to the b side regardless of the output.

From the movable head 6.5 for constant variable speed playback.

The reproduced y video signal is passed through reproduction amplifiers 11 and 12. .

・　12・ It is output from the switching circuit 21. The output is san.

It is input to the pulling control circuit 26 and played back at standard speed.

Samples are held and moved in the same way as when.

Tracking control signals for the heads 3, 5 are generated. The tracking control signals are supplied to an automatic tracking circuit 15, 16 for each movable head.

A feedback control loop is configured to control the position of 6.5.

However, the control by this feedback control loop is already performed in the standard speed playback mode, as described above.

Since the position of the movable head is controlled to a position that provides approximately the optimum tracking state, normal tracking position in variable speed playback mode can be quickly achieved.

A state of quantity control may be entered.

Further, with the transition to the variable speed playback mode, the tilt/signal generating circuit 17 generates the same tilt signal as in the conventional example, and the movable head scans 6.50 rotations.

The feedback control lever controls the inclination angle of the trajectory.

- The top of the movable head 6.5 in conjunction with the control by the tap.

``Control the racking condition to the optimum.

The basic structure of one embodiment of the present invention has been described above, and its specific structure and operation will be further explained with reference to FIGS. 5 and 6. FIG. 5 shows a cutout, which is the main component in FIG. 3.

The configurations of the switching signal generation circuit 2D and the sampling control circuit 23 are shown in a more concrete form 1-1, and the other five components are the same as those shown in FIG. .

In addition, in FIG. 5, it is connected by a rotating shaft 24 and rotates.

The drum motor 25 that rotationally drives the drum 2, and the rotational position of the drum motor 25 is detected as shown in FIG. 6(a).

A tack head 26.10 which outputs the tack pulse shown in FIG.
As shown, these are rotating spatulas.

This is a well-known type of magnetic recording/playback device.

Ru. 15 Now, in FIG. 5, the switching signal generation circuit 20 is
The monostable multivibrator 28 and 29 are constructed as follows.

A head switch output from the waveform shaping circuit 27.

Each edge of the rising signal outputs a pulse signal shown at 2° in FIG. ) is output. As explained in FIG. 3, this switching signal is used to switch the changeover switches 9 and 10, and to set the switch to a fixed state during standard speed playback.

A part of the m video signal reproduced from the fixed heads 4 and 6.

The reproduction m video signal from the movable head 6.5 is switched.

However, this switching insertion position.

is the pulse width of the pulse signal output 10 from the monostable multivibrator 28, that is, the width.

Switching signals from each edge of the switching signal.

For example, by setting the delay amount of the signal appropriately.

A drop of the m video signal reproduced from the fixed heads 4 and 6.

It can be located within the bounce line period, and can be made not to appear on the playback television screen. - The sampling control circuit 23 is a sampling pulse generation circuit 50
, sample and hold circuits 51-64,.

Consists of comparators 35, 36 and envelope detector 37.
has been done. The envelope detector 37 is fixed by 2°,
15.

The movable head 6 is attached to a part of the reproduced m video signal from the rads 4 and 6.
．． FIG. 6 (
The m video signals shown in (v) are subjected to envelope detection, and the outputs thereof are input to sample and hold circuits 31 to 64, respectively. The sampling pulse generator 60 generates sampling pulses in synchronization with the switching signal from the switching signal generation circuit 20, and the sampling pulses are used to control the head switching signal from the waveform shaping circuit 27. In particular, the output terminal 30. .about.304 and input to 10 sample hold circuits 31 to 34, respectively. Figures 6 and 6) show the sampling pulses input to each sample and hold circuit, and these sampling pulses cause the envelope detector 37 to
The outputs from the sample and hold circuits 3115 to 64 are sampled and held. That is, as is clear from Fig. 6, the sample hold circuit 31.32
is one of the movable heads 3.5 by means of alternating sampling pulses.

For example, if the playback output level from the movable head 3 is set to 20.1
6.

Sample and hold alternately during each rotation scanning period.

On the other hand, the sample and hold circuits 33 and 34 are crossed.

By mutual sampling pulse (nu), four, the other.

The reproduction output level from the movable head 5 is as above.

The sample is held in the same way. The outputs of 5 sample hold circuits 31 and 32 are compared.

input to the sample and hold circuit 35. .

The output of 34 is input to a comparator 36 and the movable head.

The playback output level from 3.5 is in order of magnitude.

A comparison is made every next rotation scan period. Then, the outputs of the ratio IO comparators 35 and 56 are automatically tracked.

input into the programming circuits 15 and 16. Automatic tracking.

The circuits 15 and 16 are connected to the re+5 signals outputted from the comparators 55 and 36 for each rotation scanning period of each movable head 3.5 based on the command signal from the sampling pulse generator '50.
Determine whether the raw output level increases or decreases and based on the results.

As shown in Figure 6 @') and (wa), the voltage is increased or decreased from a predetermined voltage value in steps of 1°, and the output is performed.

- the voltage is applied via adders 18.19 to bimorph plates 7, 8;
The tracking position of the movable head 6.5 is controlled by 2°. That is, for example, initially the output voltage from the automatic tracking circuit 15, 16 is 1 step.

When incremented, the sample from the movable head 3.5 was sampled and held in the next rotation scan period.

If the output level increases, the automatic tracking circuit 15
, 16 further increases its output voltage by one step, and such increases are sampled one after another.

Reproduction output from movable heads 3 and 5 that are held.

This continues until the level decreases. vice versa.

If the playback output level from the movable head 6.5 decreases by 10, then sample-and-hold playback occurs.

Automatic tracking times until the output level increases.

The output voltage from paths 15 and 16 is reduced. In this way, the automatic tracking circuit 15,16 performs the following operations.

In the equilibrium control state, the movable head 5's 15th position is held near the position where the reproduction output level is maximum, that is, near the optimum tracking position.

Ru. Such an automatic tracking circuit 15.16.

The position of the movable head 6.5 is controlled by the target.

Even in the semi-speed image reproduction mode, it is always controlled to almost the optimum position 2 (1) and is not significantly disturbed.In addition, in the standard speed reproduction mode, the tilt signal generation circuit 17 [stops generating the approximately tilt signal, Therefore, the output is Fig. 6 ψ)
, 2), the DC voltage is zero or constant. When switching from standard speed playback mode to variable speed playback mode.

As explained in FIG. 3, automatic tracking.

position side of the movable head 6.5 by means of the switching circuit 15.16.

control is performed in the same way as in standard speed playback mode.

At the same time, the slope signal generation circuit 17 outputs, for example, 10
Figure 6 (y), inclination angle of the triangular shape as shown in H.

A signal output is generated, which causes the movable head 6 to move.

The tilt color spacing of the rotation scanning locus of No. 5 is controlled. Up.

In the curve signal output waveform, the part shown by the broken line is the period when the movable head 6.5 is not in contact with the magnetic tape 1, and the waveform during that period may be arbitrary. Head 3. Corresponds to 50 rotations of the previous period, and therefore its inclination angle is: - The inclination angle of the rotational scanning locus of the movable head 6.5 is magnetic.

Matches the inclination angle of the recording track on table 1 20.1
9.

Slow, still, and slow so that it looks exactly like it did.

These are determined for each variable speed playback mode such as Tsuk.

It is. By controlling the position and tilt angle as described above, it is movable for variable speed playback.

The tracking state of the heads 5, 5 is always controlled to the optimum state, and the movable heads 3, 5 always provide a sufficient level of reproduction N, as shown in FIG.

A video signal can be obtained.

In addition, in variable speed playback mode, waveform shaping.

As shown in FIG. 6(c), the head switching signal lO obtained from the type circuit 27 is compared to the head switching signal in the standard speed playback mode [FIG. 6(b)].
It goes without saying that the mounting of the movable head 3.5 relative to the fixed head 4.6 should be done so that they are out of phase by the angular difference in position. 15 or higher, fixed head for standard speed playback and acceptable.

When there are two movable heads for variable speed playback.

The embodiments of these heads have been described.

The number does not necessarily have to be two, but is generally arbitrary.

The present invention is equally applicable to any number of heads (2+),
It is clear that a deviation of 20° is possible. Also variable speed playback.

Tracking control circuit for a movable head.

The configuration is not limited to the above embodiment, but the point is that the configuration of the reproduced video signal during standard speed reproduction.

Based on the output from the variable speed playback five movable heads that are inserted and played back in the standard speed playback section.

Movable head tracking for variable speed playback even at half o'clock.

Any device that can control the position of the

It's okay.

[Effects of the Invention] 10 As explained above, according to the present invention, even when the movable head for variable/speed playback is not used at the standard speed, a part of the playback period can be used. The position of the movable head for variable speed playback is detected and controlled so that the position is at the proper tracking position, so it can be varied from the standard speed playback mode.

For variable speed playback when transitioning to fast playback mode.

Quickly bring the movable head into optimal tracking state.

to avoid transient disturbances in the reproduced image.

Can be excellent, except for the drawbacks of the above prior art.

It is possible to provide a Hellard position control device for a rotary head type magnetic recording/reproducing device with functions as described above.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of a rotary head in a conventional rotary head type magnetic recording/playback device F4, and Fig. 2 is a block diagram showing a tracking control circuit of a conventional movable head for variable speed playback. FIG. 3 is a block diagram showing the basic configuration of an embodiment of the present invention. FIG. 4 is an explanation of its operation, a clear diagram, and FIG. Block 1□10 showing the configuration
The block diagram and FIG. 6 are explanatory diagrams of the operation. . 6.5...Movable head for variable speed playback, 4.6...Fixed head for standard speed playback, 7.8...
Position control element (bimorph plate). i5. i6... automatic tracking circuit, 1517.
...Slope signal generation circuit, 18...Switching signal generation circuit, 23.

Claims (1)

[Scope of Claims] n zero fixed heads fixedly mounted on a rotating drum, and "on position control elements for tracking control" at positions between each of these fixed heads. It has n movable heads attached to the drum, during standard speed playback.The fixed head rotates recording tracks on the magnetic tape by the movable heads during variable speed playback.Scans and reproduces video signals. In the head position control device of the Rad-type magnetic recording and reproducing apparatus, during standard speed reproduction, the reproduced video signal from the fixed head 15 is rotated during a part of the rotation scanning period by the fixed head. a switching means for switching and outputting a reproducing video signal from the head and a main video signal; and controlling the position control element so that the amplitude of the reproduced video signal from the movable head outputted from the switching means is approximately maximized; A head position control device for a Rad type magnetic recording/playback device, characterized in that the head position control device is configured to control the position of the movable head even during 2° standard speed playback.