JPS60182510A - Position controller for rotary magnetic head - Google Patents

Abstract

PURPOSE:To control the relative position between an erasion head and a mobile head by reproducing the signals recorded by displacing a preceding rotary mobile head with a displacement signal by a rotary erasion head and holding the level of the displacement signal when the output of said reproduction is set at a prescribed level. CONSTITUTION:A signal of f3 is supplied to a BM head 11B preceding an FE head 60 from a signal generator 62 via an amplifier 61. The output of the head 60 is supplied to an amplifier 51. The timing signals are supplied to amplifiers 61 and 51 from a timing signal generator 63. Then a bimorph control signal (c) is supplied to a drive amplifier 41 via contacts 64a and 64c of a switch 64. The data of a CPU70 is supplied to a D/A converter 75. A signal (b) of f3 which is keyed in a field cycle (V) is supplied to the head 11B. The head 11B is controlled so that the tape traveling locus of the head 11B is superposed on that of the head 60 since the signal (c) is supplied to the amplifier 41. Then the signal of f3 is recorded so as to have the cross to a normal recording track. In this way, the superposition or over-erasion of recording is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a helical scanning videotape recorder (Vl”
The present invention relates to a position control device for a rotating magnetic head which is commonly used and suitable for R).

BACKGROUND ART AND PROBLEMS In a helical scanning VTR, a rotating magnetic head is attached to an electro-mechanical converter such as a bimorph, and a required drive voltage is supplied to the bimorph, and the head is moved almost perpendicular to its scanning direction. It is well known to provide a device which allows the head to accurately scan a diagonal track on a tape from start to finish by displacing the head in the same direction. , D'I this
” F (Dynamic Track Followi
n) is sometimes called a device.

In order to operate the DTP device correctly, it is naturally necessary to be able to detect the position of the head aligned with the Chibuto tilt rack. Regarding this head position detection, many methods have been proposed in the past.

- On the other hand, even at constant speed l11 of V ``I'' R - in raw mode - the capstan phase servo ensures that the head accurately scans the playback trunk on the tape. In the case of this tracking servo as well, it is necessary to be able to detect the position of the head with respect to the track.゛For this reason, a control signal is recorded on a control track provided at the edge of the tape,
This control signal was widely used to apply tracking servo to the capstan.

However, with such a controlled trunk method, only trunking information near the starting point of the recording trunk can be obtained, and it is difficult to maintain the required tracking accuracy over the entire length of the trunk.

Therefore, as an alternative to the control trunk method, a method has been proposed in which a plurality of different pilot signals are sequentially and cyclically recorded on each trunk on the tape, and tracking servo is performed by referring to the pilot signals during playback.

First, this PI-Japan-Soviet 1-signal system will be explained with reference to FIGS. 1 and 2.

In the pilot signal system, as shown in FIG. 1, frequencies fi, f2 . Four types of pilot signals, f3 and I4, are set. For example, the frequencies f1 to f4 of each pyro throat signal are as follows.

f 1 = 102.54kl! z r 2 = 118.95 ktlz f 3 = 165.21 kllz f 4 = 148.69 kHz Also, as can be seen from this, the following relationship holds between the frequencies of each pyro throat signal.

1 [1-I21=l f=-I41=EL=1
6kl121[2-I31””IF5 fI I=fH
=46kllz When recording, the above-mentioned bi-I color signals f1 to I4 are frequency-multiplexed with the general transmission luminance signal YFM and the low-frequency conversion chromaticity signal CL, and are sequentially applied to each track on the tape. iIl! f is recorded cyclically.

An example of the configuration of a 1-Ra knocking service using the pilot signal system is shown in Figure 2.

In FIG. 2, the Pyro Note number η is recorded as described above, and each trunk t1.12, I3, I4...' of the tape VT traveling in the direction of the arrow is connected to a rotating head (
11), the recorded signal is sequentially scanned and reproduced. The reproduction signal from the head (11) is transmitted to the reproduction amplifier (12).
), and among the outputs of the amplifier (I2), the carrier luminance signal Y FM and the low-pass converted chromaticity signal CL are supplied to the reproduction processing circuit (13) and undergo signal processing such as fjt fled.

(20) controls the head position sensing device as a whole, and the pilot signal component from the amplifier (12) is extracted by a low pass filter (21) and supplied to a multiplier (22). In the multiplier 22), a rotary head (11) is attached to the track 1. at the edge of the tape. The frequencies El and I4' from the signal generator (24) are transmitted through the 111 child rotary switch (23) synchronized with sequential scanning of ~t4...
, fx, I2 are cyclically supplied in this frequency order.

In addition to the original pilot signal recorded for each trunk, the reproduced bicot 1 signal component includes crosstalk components from the previous 1] and each subsequent adjacent trunk.

Therefore, the multiplier (22) smells ``ζ'', and the reproduction pi date so 1-
Multiplication of the signal component by the reference pilot signal results in a difference signal component as shown in the table below.

These difference signal components H and fL are passed through bandpass filters (25) and (26), respectively, to a peak detector (27).
) and (28). Detector (27) and (2
The outputs of 8) are respectively supplied to one and the other input terminals of a differential amplifier (29).

The error signal output of the differential amplifier (29) is supplied to the capstan servo circuit (30), and the output of the servo circuit (30) is supplied to the capstan motor (32) via the drive amplifier (31). Control.

As is clear from the table above, in the multiplier (22), the C frequency fHO difference signal is obtained due to the crosstalk from the preceding track, whereas the difference signal of the frequency fL is obtained due to the crosstalk from the following track. I get a signal.

Therefore, by comparing the levels of the difference signals r, . Therefore, in order to track a given trunk, the capstan motor (32) should be controlled so that both difference signals are at the same level and the error signal output of the differential amplifier (29) is at zero level. .

ATF (Automatic Track F
This ATF type head position detection technology can be directly applied to head position detection in a DTP device.

An example of the configuration of a DTP device using an ATF type error signal is shown in FIG. In FIG. 3, parts corresponding to those in FIG. 2 are designated by the same reference numerals, and redundant explanation will be omitted.

In FIG. 3, the bimorph (40) is connected to the drive amplifier (40).
1), an error signal output is supplied from the differential amplifier (29) of the head position detection device (20), and this error 11
The position of the rotary magnetic head (11) attached to the bimorph (40) is controlled by the signal output so that it accurately scans a predetermined track from the beginning to the end even during variable speed reproduction.

By the way, the rotating magnetic head attached to the bimorph
When performing ζ recording using multiple 3M heads (hereinafter referred to as BM heads), the crystallinity of each 3M head is adjusted (i.e., the level difference between them is eliminated to obtain a uniform recording pattern). However, due to the hysteresis characteristic of the pimol itself, simply returning the drive voltage to zero does not restore the initial state, and there is a risk that the I/rack pitch may be disturbed.

So, a specific frequency [5Cfx
A method has been proposed in which the pilot of BM head (different from f4) is intermittently recorded, and the amount of displacement of the BM head is controlled so that the cross of the signal of f5 from the preceding adjacent trunk is at a constant level. Publication No. 54-115113)
.

In this crosstalk playback method, ・In order to prevent the f5 pilot signal from affecting the playback screen, the fourth
As shown in the figure, the frequency f5 is 223 during one horizontal scanning period (IH) within the vertical retrace period at the beginning of writing of each trunk.
Record the kHz signal.

Then, during the next IH, the recording current is cut off and the recurrent (PB
) mode. Note that the recording period of the f5 signal of the preceding adjacent track and the reproduction mode period of the succeeding track are aligned on the tape in the width direction of the trunk. In this way, each 3M head reproduces the crosstalk of the f5 signal recorded one trunk ago in a burst, so each 3M head By controlling the amount of displacement, that is, the width, the quotient of each 3M head is equal, and the track pinch can be made uniform.

An example of the configuration of a BM head control circuit using the crosstalk reproduction method is shown in FIG.

In FIG. 5, two 8M heads (IIA) and (
IIB) is, as is well known, arranged at an angle of 180° within the head drum (not shown in FIG. 4).

Also, the magnetic tape has a length of 180” along the circumference of the head drum.
(or 221°) winding runs diagonally around the corner, so that each track on the tape is scanned alternately by both heads (118) and (IIB). In the case of a track pattern as shown in FIG. 4, tracks t1 and t3 are scanned by the head (118), tracks t2 and t4
is scanned by the head (IIB). Therefore, an output is taken out from each head (118) or (IIB) for each frame.

During recording, the switch S is closed and the recording current is supplied from the recording signal input terminal (50) to the two 8M heads (II
A) and (IIB) are capacitors C^ and CB, respectively.
The signal is alternately supplied to each track via the . When in regeneration mode, switch S is opened by a control pulse and 8
The M head (IIA) or (IIB) regenerates the crosstalk of the f5 signal from the preceding adjacent trunk. The meat BM head (IIA
) and (ll[l) are alternately supplied to the reproducing amplifier (51) for each track. Only during the PB mode period shown in FIG. 4, a control pulse is supplied from the control terminal (52), and the amplifier (51) enters the operating state. The output of the amplifier (51) is passed through a bandpass filter (53) to an envelope detector (5
4). The output of the detector (54) is commonly supplied to sample and hold circuits (hereinafter referred to as S/H circuits) (55A) and (55B).

Both S/H circuits (55/j) and (55B) perform S/H operations alternately during the reproduction mode period of each trunk by sampling signals supplied to their respective control terminals (56Δ) and (56B). be exposed. Both S/H circuits (55A)
The output signals of (55B) and (55B) represent the amplitude of the crosstalk of the f5 signal between the scans of two adjacent trunks.

These output signals are supplied to a differential amplifier (57), and the output thereof is taken out from an output terminal (58) as a position control signal for the 8M head.

The above-mentioned DTP technology using the ATF method and head control technology using crosstalk playback have already been proposed to the industry and have been adopted in a new method of compact VTRs (8 mm video, hereinafter referred to as the 8■ method) for which the standard has been unified. ing.

The 8V system will now be briefly explained with reference to FIGS. 6 to 8.

As is clear from the frequency spectrum in Figure 6, 8V
In this method, the FM audio signal AFM is the carrier luminance signal Y.
A frequency domain is set between the FM and the low frequency converted chromaticity signal CL, and frequency multiplexed recording is performed with the °6 video signal. Additionally, optionally, as shown in the format of FIG.
A two-channel commercial audio signal can be recorded in advance of the video signal, and only the audio signal can be recorded later (after-recording). When recording and playing back PCM audio signals,
The winding angle of the tape around the head drum is set at 221°, and the winding angle (recording area) of the PCM audio signal and video signal on the tape is set at 26.3° and 1°, respectively.
It is 80°. Between each recording area of the PCM audio signal and video signal, there is provided an area for recording and reproducing a pilot signal using the above-mentioned crosstalk reproducing method. Therefore, if we pay attention to the f5 signal of the 8■ system, its track pattern will be as shown in FIG. As can be seen from FIG. 7, there are some blank spaces at the beginning of each track.

As mentioned above, in the 8v system, the audio signal is either converted to FM and frequency multiplexed with the video signal, or converted to PCM and recorded by dividing the area into areas on the extended track preceding the video signal recording area. Therefore, the audio head used in conventional VTRs becomes unnecessary in any case. Also,
Since the ATF based on the pilot signal is used, there is no need for a control signal, and therefore an erase head for audio and control is also no longer necessary.

Therefore, if a video erasing head is mounted on a rotating disk in the same way as a video head, electronic editing will become possible and practical, and tape running accuracy will be improved. In addition, in the case of a rotating erase head (hereinafter referred to as a FL head), it is only necessary to erase several trunks at a time, so the erase power required is significantly lower than that of a conventional fixed erase head that erases the full width of the tape. Reduced. As the erasure signal, in order to avoid interference with the recording signal, the carrier luminance signal YFM itself or the carrier luminance signal at a frequency tl lower than the upper limit frequency of the carrier luminance signal is used.
A single frequency signal is used.

When using both the FE head and the BM head, as conceptually shown in Fig. 9, the head drum (rotating drum) HD
Two (8M heads (118) and (IIB) hymorphs (40A) are arranged at an angle of 180° within the
) and (40B) are attached (not shown), the FE head (6o) is attached at an angle of 90"0) to the meat BM head (118) and (JIB). In this case, the erasure width of the FE head (60) is set to approximately one or two times the trunk width.

When recording using such a rotating head system, the difference in level between the two BM heads (118) and (IIB) is eliminated by the aforementioned crosstalk reproduction method, and a recording pattern with a uniform trunk pitch can be obtained. . However, at this point, even if the relative heights between the 8M head (11Δ) and (IIB) can satisfy the predetermined relationship, the 8M head (118).

(IIB') and the FE head (60)) cannot be adjusted to a proper relationship, and depending on the relative height of each head, the newly recorded trunk may be deleted immediately after ζ There is a risk that the newly recorded first track may overlap with the old recording trunk during after-recording (insert) or splicing, or there may be an over-erased portion at the end.

OBJECTS OF THE INVENTION In view of the above, an object of the present invention is to provide a position control device for a rotating magnetic head that can control the relative position of a rotating J-motion head with respect to a rotating erasing head to an appropriate ratio. .

SUMMARY OF THE INVENTION The present invention provides that the first trunk of each adjacent trunk on a record carrier
a plurality of rotating movable magnetic heads for recording a pilot signal in a predetermined section of each track and reproducing a pilot signal recorded in a first predetermined section of an adjacent preceding track in a second predetermined section of each track; Shake 1 to detect the amplitude of the reproduced pilot signal by the rotary movable magnetic head
11a detector, and obtains a control signal for controlling the amount of displacement of the nods to a plurality of rotating movable magnetic heads from the amplitude detector. A rotary erasing magnetic head is attached to a rotating body on which a displacement signal and a displacement detection E are sent to one of a plurality of rotating movable magnetic heads preceding the rotating erasing head. 9. A housing unit, an A/D converter, and this A/D
a data comparing means for comparing the output data of the amplitude detector which has been A/D converted by the converter with a predetermined value; a time setting means responsive to the data comparing means; and a time setting means controlled by the time setting means. , by A/D converter -ζA/D
One rotary movable magnetic head is provided with a data holding means to which the converted output data of the first signal generator is supplied, and a D/A converter for D/A converting the output data of the data holding means. A displacement signal is supplied from a first signal generator to cause a displacement, and a displacement detection signal is supplied from a second signal generator to be recorded on a recording medium, and the displacement detection signal recorded on the recording medium is The rotating erasing magnetic head performs reproduction, the signal output for detecting the reproduction displacement of the rotating erasing magnetic head is supplied to the amplitude detector, the time setting means sets the time, and the set time causes the first signal to be transmitted to the data holding means. This is a control device for a rotary magnetic head which holds displacement signal data of a generator.

According to the present invention, the relative position of the rotary movable head with respect to the rotary erasing head can be properly adjusted in a short time, and there is no possibility of overlapping records or overerasing during +111 photography.

Example I will explain about °ζ.

The same reference numerals are used to denote the same parts, and redundant explanation will be omitted.

In FIG. 10, the 8M preceding the FB head (60)
A signal f3 is supplied to the head (IIB) from a signal generator (62) via a recording amplifier (61).

The timing signals ■ and ■ are supplied, and the bimorph control signal @ is transmitted through one fixed contact (64a) and movable contact (64c) of the first switch (64) 70) to the input/output interface (71), central processing unit CC
PU) (72) and memory (73), the microcomputer is composed of a second switch (65)
The envelope detector (54) is
) is supplied. The output data of the computer (70) is supplied to the D/A converter (75), and the output of the D'/A converter (75) is taken out to the other fixed contact (64b) of the first switch (64). Ru. Note that the other fixed contact (65b) of the second switch (65) is connected to one fixed contact (64a) of the first switch (64), and both switches (64) and (65) are interlocked. Can be switched.

The operation of this embodiment is as follows. In the standby mode prior to recording, the switches (64) and (65) are initially in the connected state. The recording amplifier (61) is supplied with a timing signal (1) as shown in FIG. 11A from the signal generator (63), and as shown in FIG. The signal (2) of f3 keyed with (V) is supplied to the 8M head (IIB). At this time, the bimorph control signal (displacement signal) ■ shown in ff1ll1c is sent to the drive amplifier (41).
Therefore, the position (height) of the 8M head (IIB) is controlled so that its tape scanning locus overlaps with that of the FE head (60) and reaches from the upper limit to the lower limit of the displacement range. Therefore, the f3 signal is tape V.
It is recorded on T so as to intersect with the regular recording track.

The r3 signal thus recorded is reproduced by the FE head (60) with a delay of % field. The regenerative amplifier (51) operates only during a single timing pulse (2) delayed by % field from the timing signal (2) shown in Figure 11.

The output of the regenerative amplifier (51) is detected by the envelope detector (54) via the bandpass filter (53), but the 10i of the 8M head (11B) is lowered (away from the FE head).
Accordingly, the output of the FE head (60), and therefore the output (2) of the detector (54), decreases as shown in FIG. 11E.

The analog output of the detector (54) is the A/D converter (74).
) is converted into ζ digital data and manually inputted to the computer (70).

The functional block diagram and flowchart of the microcomputer (70) are shown in FIGS. 12 and 13.

In FIG. 12, detection from the first input terminal (81)!
The output data VE(t) of (54) is
2) and is compared with a predetermined value of a comparison data terminal (83). As shown in FIG. 11E, when data VB and K become equal after one hour has elapsed since the rise (data input start) of the output (2) of the detector (54), the time setting means (timer (84) ) is set for this hour.

At this point, both switches (64) and (65) in FIG.
) is switched to a connection state opposite to that shown in the figure, and after a short field period has elapsed, a displacement signal @ as shown in FIG. 11C is sent to the °C computer (70
) is input.

Returning again to FIG. 12, the data V c of the displacement signal O is input to the second input terminal (85).When τ time has elapsed since the manual force of 11, the timer (84) operates and the data V at that moment is inputted to the second input terminal (85).
c (τ) is held by the data holding means (86) and taken out from the output terminal (87).

This data Vs(τ) is transferred to the D/A converter (75
) is converted into a constant level analog voltage VC,
It is supplied to the drive amplifier (41) via the first switch (64). This situation is shown in Figure 11 F and G. Therefore, the bimorph (40B) is deflected by a certain amount, and the 8M head (IIB) is adjusted to an appropriate level difference with the FB head (60). As can be seen from Figure 11, the required time is l/2
It is within 0 seconds (=3V). Before or after this level difference alignment, the 8M head (I) following the FE head (60)
Since the relative orientations of IA) and the preceding 8M head (IIB) are matched by the above-mentioned crosstalk reproduction method,
The 8M heads (II8) and (IIB) can maintain a proper height difference with respect to the rotating erase head (60).

In the above embodiment, the f3 pilot signal was used to set the height of the preceding 8M head (11B), but for example, the low frequency conversion color side IM transmission wave (743kllz) may be used.

Effects of the Invention As detailed above, according to the present invention, the signal recorded while the preceding rotary movable head is displaced by a displacement signal is reproduced by the rotary erasing head, and when the output of the rotary erasing head reaches a predetermined level. Since the instantaneous value of the displacement signal is held, it is possible to obtain a position control device for a rotating magnetic head that can control the relative position of the rotary movable head with respect to the rotary erasing head to an appropriate ratio in a short time, thereby preventing erroneous erasing, Or, there is a possibility that the recording may be distorted or over-erased during splicing.

[Brief explanation of the drawing]

Figures 1 and 2 are frequency spectra and block diagrams for explaining the conventional ATF system, and Figure 3 is a diagram of the conventional ATF system.
A block diagram showing a configuration example of a DTP device 6 based on TF technology; FIGS. 4 and 5 are track patterns and block diagrams illustrating a position control device for a rotating magnetic head using a conventional crosstalk reproducing method; Figures 6 to 8 are 8■
9 is a plan view of a rotating magnetic head used to explain the present invention, and FIG. 10 shows an embodiment of a position control device for a rotating magnetic head according to the present invention. The block diagrams shown in FIGS. 11 to 13 are a time chart, a functional block diagram, and a flow chart of the embodiment of FIG. 10. (11), (1, 18) and (IIB) are rotating movable magnetic heads, (20) is a head position detection device, (,40)
. (408) and (40B) are bimorphs, (54) is an amplitude detector, (60) is a rotating erase head, (62) is a displacement detection signal generator, (63) is a timing signal generator, (70 ) is a microcomputer. Hidemori Matsukuma, II, lj'; consort 1 (1,', ', l'1.', 1'a;9 Figure 1 Figure 6

Claims (1)

[Claims] A pilot signal is recorded in a first predetermined section of each adjacent track on the record carrier, and the pilot signal is recorded in the first predetermined section of an adjacent preceding trunk in a second predetermined section of each trunk. It has a plurality of rotary movable magnetic heads that reproduce signals, and an amplitude detector that detects the amplitude of the reproduced pilot signal by the plurality of rotary movable magnetic heads, and the amplitude detector detects the amplitude of the reproduced pilot signal from the plurality of rotary movable magnetic navel I.・The control signal that controls the amount of displacement of
In a position control device for a rotating magnetic head that
ζ, displacement signals and signals are sent to one of the rotary erasing magnetic head attached to the rotary body to which the plurality of rotary movable magnetic heads are attached, and one of the plurality of rotary nJ dynamic magnetic heads preceding the rotary erase magnetic head. first and second signal generators supplying displacement detection No. 4, an A/D converter, and the A/D converter;
a data comparison device that compares the output data of the amplitude detector that has been A/D converted by the /D converter and a predetermined value;
a time setting means responsive to the data comparison means; and data controlled by the time setting means and supplied with output data of the first signal generator that has been A/D converted by the A/D converter. and a D/A converter for D/A converting the output data of the data holding means, and supplies a displacement signal from the first signal generator to the one rotary movable magnetic head to cause displacement. At the same time, a displacement detection signal is supplied from the second signal generator to be recorded on the recording medium, the displacement detection signal recorded on the recording medium is reproduced by the rotary erasing magnetic head, and the following rotation is performed. The reproduction displacement detection signal output of the erasing magnetic head is supplied to the amplitude detector to set the time by the time setting means, and the displacement signal of the first signal generator is sent to the data holding means according to the set time. A position control device for a rotating magnetic head, characterized in that it retains data.