JPS58122638A - Magnetic recorder and reproducer - Google Patents

Abstract

PURPOSE:To eliminate the need for mechanical position adjustment of a control head and to decrease the adjusting time, by electrically adjusting the recording and reproduction phase of a control signal in response to the position shift of the control head. CONSTITUTION:A vertical synchronizing signal VF obtained from a video signal applied to a terminal 11 is given to a phase comparator 19 via a delay circuit 32 and a switch S1 and the phase is compared with a head phase detecting signal SW. This phase error signal is applied to a cylinder motor 12 via a drive circuit 20. The vertical synchronizing signal VF is recorded on a tape 1 as the control signal with the control head 10 via a delay circuit 27. At the reproduction, so that the rotating phase of video heads 8, 9 and the phase of a reproduced control signal are made to a prescribed phase relation by interposing the phase of a reference signal REF the rotation of the video heads 8, 9 and a capstan 2 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tracking control device for a magnetic recording/reproducing device, and in particular, the present invention relates to a tracking control device for a magnetic recording/reproducing device. This also relates to a magnetic recording and reproducing device that adjusts the recording phase and reproduction phase of the control signal 0.

Figure 111 shows a typical Nahelical Scan II video tape recorder (hereinafter referred to as V
(abbreviated as TR) shows the tape running mechanism. In FIG. 1, a magnetic tape 1 is transferred to a cassette half 4 by a rotating capstan 2 and a pinch roller 3 pressed against the capstan.
After being unwound from the supply IJ- 5 and driven to run in the direction of the arrow, it is deposited on a take-up reel 6 by a reel drive mechanism (not shown). During this tape pass, the tape
is wrapped over 180 degrees around the cylinder 7, which has a central axis inclined with respect to the longitudinal direction. And this O cylinder 70 @ rotating part, that is, rotating cylinder (7-1
) The tape 1 is alternately scanned obliquely by two rotating video radars 8 and 9 having different azimuth angles, and video signals are recorded and reproduced on the video tracks.

In this VTR, when the video head 8.9 records the video signal on the diagonal video track of tape 1,
A control signal for tracking control formed from the vertical synchronization signal of the video signal is recorded by the control head 10 on the control track at the lower end of the tape 14D. When the video signal recorded on the tape 1 is to be played back, the control head 10 plays back the control signal from the tape 1, and using this playback control signal, the video heads 8 and 9 control each tape 1. Tracking control is performed to accurately scan the video track.

As described above, in W-side layer VTRs, a tracking control method using the above control signal as a tracking control signal is generally used.

In this method, the video signal to be recorded and played back and the control signal are synchronized so that good tracking can be obtained even when tapes are played back interchangeably between devices, that is, when a tape recorded on one VTR is played back on another VTR. It is necessary to determine the relative phase relationship. For this reason, the video head 8
, 9 and the control head 10, and it was necessary to arrange them so that they would have a predetermined positional relationship.

Conventionally, the tape length adjustment method used is a method in which the control head 1OVa is moved in its fixed position in the longitudinal direction of the tape 10. However, with regard to this control head 10, In addition to horizontal position adjustment, height adjustment, tilt III!
It requires 1t azimuth adjustment, etc., and because they influence each other and make independent adjustment difficult, the adjustment becomes *m, and adjustment work during the manufacturing process and repair requires highly skilled and time-consuming work. .

The purpose of the present invention is to solve the above-mentioned drawbacks of the conventional technology, and to provide a magnetic recording system that facilitates adjustment work to ensure tape compatibility between devices, shortens adjustment time, and thereby enables cost reduction. Our purpose is to provide a playback device for achieving the above-mentioned goal of sound control.
By electrically adjusting the recording phase and the reproduction phase, t and b tape compatibility with respect to tracking is ensured, and conventional mechanical position adjustment of the control head is not required.

That is, the first control signal that delays the reproduced control signal
and a second delay circuit that delays the control signal to be recorded, so that the playback output of the video signal is approximately maximized while playing back a standard tape recorded with a standard tape making machine. , adjusts the delay time TP of the reproduction control signal by the delay circuit jIl. Then, the delay time TR of the second delay circuit is calculated from the period To of the control signal to be recorded to the delay time T.
By setting the value to be a value obtained by subtracting P, the relative positional relationship between the video signal and the control signal recorded on the tape is made to match that of a standard tape.

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

FIG. 2 is a block diagram showing one embodiment of the present invention, FIG. 3 is a schematic BA diagram showing a standard recording pattern on a magnetic tape, and FIGS. 4 and 5 are respectively examples of the present invention. The timing chart of each signal during playback and recording is shown in FIG.

First, the operation during recording will be explained using FIGS. 2 and 5. During recording, the switch S1 in FIG. S2°83 are all switched to the R111 point side.

In FIG. 2, reference numerals 8 and 9 indicate video heads which are applied to the input terminal 11 and record video signals onto the magnetic tape 1 alternately field by field. These two video heads 8.9 are
They are attached to a rotating cylinder (7-1) at an angle of 180 degrees to each other and are rotationally driven by a cylinder motor 12 that is directly connected to the shaft. Also, although not shown, a rotating cylinder (7-1
) Alternatively, two magnets with opposite polarities are attached to the coaxial rotating part at an angle of 180 degrees to each other, and by detecting this with the tack head 13, the rotation of the video head 8.9 is synchronized. The tack pulse TA shown in FIG. The phase is adjusted so that the tack pulse T is then sent to the waveform adjustment path 16.
A head phase detection signal SW [FIG. 5 (6)] with a duty ratio of 50% is formed in synchronization with A.

The video signal applied to the terminal 11 is supplied to a vertical synchronizing signal separation circuit 17, and this circuit 17 separates and outputs a field period vertical synchronizing signal S (FIG. 5(1)). This vertical synchronizing signal vS is down-done to 1/2 frequency by a frequency divider 18, and a frame-period vertical synchronizing signal VF is obtained.
5(2)] is output from this circuit 18. This vertical synchronizing signal VF is sent to the fourth delay circuit 32 and delayed by a predetermined time, resulting in a signal VF' [: FIG. 4)]
is sent to the phase comparator 19 via switch s1,
The phase is compared with the head phase detection signal SW described above. As a method of this phase comparison, for example, as shown in FIG.
A method is used in which a trapezoidal wave signal DT shown in FIG. 5 (5) is formed from w, and the sloped portion thereof is sampled and held with the signal VF'.

A phase error signal corresponding to the phase difference between the two is output from the phase comparator 19, and this phase error signal is supplied to the cylinder motor 12 via the drive circuit 20. As a result, the cylinder motor 12 is driven at a rotational speed higher than the frame frequency, and therefore the rotational frequency of the video heads 8 and 90 is also equal to this frame frequency. The fourth delay circuit 32 adjusts the rotational phase of the video heads 8 and 9 so that the video heads 8 and 9 write a vertical synchronization signal at a predetermined position on the tape 10 by adjusting the delay time of the signal VF'. It has the ability to adjust.

On the other hand, the capstan 2 is a capstan motor 2 that is directly connected to the shaft.
1 and rotates, thereby causing the tape 1 to travel in the direction of the arrow shown in FIG. During recording, the capstan 2 is controlled to rotate at a constant rotational speed determined by the reference signal REF [FIG. 5(8)] generated by the reference signal generating circuit 22. For this purpose, the rotation speed of the capstan 720 is detected by the speed detector 23, and this detection signal CF (FIG. 6 (11)) is frequency-divided by the frequency divider 24. figure(
10)) is sent to the phase comparator 25 via the switch S3, and the phase is compared with the reference signal RBF. As a phase comparison method, for example, as shown in FIG. 5, a method is used in which a trapezoidal wave signal CT shown in FIG. . The phase error signal output from this circuit 25 is supplied to a drive circuit 26 to control the rotation of the capstan motor 210.

Note that during this recording, the vertical synchronization signal VF of the frame period is delayed by a predetermined delay time TR, which will be described later, in the second delay circuit 27, and becomes the signal R shown in FIG. 5(3).
C, the signal is sent to the control signal recording circuit 28, and then sent to the control head 1 via the switch 82.
0 is recorded on the control track provided at the bottom end of the tape 1 as a control signal.

Next, using FIGS. 2 and 4, select the switch al in FIG.
The operation during reproduction in which all t 82 + s3 are switched to the P contact side will be described. During playback, the phase relationship between the vertical synchronization signal played back from tape 1 by video heads 8 and 9 and the control signal played back by control head 1° is made to be the same as during recording.
By controlling the rotational phase of the rotating cylinder (7-1) and the capstan 20, tracking control is performed so that the video heads 8 and 9 faithfully scan their respective video tracks.

For this reason, in FIG. 2, the 8°90 rotation phase of the video head and the phase of the playback control signal are different from the reference signal R.
Using the phase of FiF as an intermediary, the video heads 8 and 9 and the cab stuff 20 rotations are controlled so that they have a predetermined phase relationship. During playback, the video head 8 and 90 rotation phases are tacked in the same way as during recording. It is detected by the head 13 and this head phase detection signal SWC (FIG. 4 (7)) is sent to the phase comparator 19. On the other hand, the reference signal R'E F (4th riA (4)) generated by the reference signal generation circuit 22 is delayed by the third delay circuit 29 as shown in FIG.
After setting it to R, it is sent to the phase comparison @19 via the switch 81. The phase difference between the head phase detection signal SWo and the signal TR obtained by delaying the reference signal REF is determined by the phase comparator 19, and this phase error signal is applied to the drive circuit 20 to control the rotation of the cylinder motor 12. Controls the rotational phase of helads 8 and 9. The frequency of this reference signal BBF is selected to be almost the same frequency as the vertical synchronizing signal vS of the frame period in the recorded video signal. They are driven to rotate at the same number of rotations. The 30th delay circuit 29 is a circuit that delays the signal BEF, which is a reference for the cylinder system during reproduction, as described above, and tracking adjustment is performed by adjusting this delay time.

Further, the control signal reproduced from the tape 1 by the control head IO is sent to the control signal reproduction circuit 30 via the switch S2, and after becoming the signal PC shown in FIG. 31 in the same figure (
As shown in 2), the signal PC' is delayed by the TP waiting time and is then sent to the phase comparator 25 via the input signal 'fS3'. The phase comparator 25 outputs a zero phase difference between the reference signal REli' and the delayed reproduction control signal PC'. By applying this phase error signal to the drive circuit 26 and controlling the rotation of the capstan motor 210, the rotation phase of the capstan 20 is controlled and the running of the tape 10 is controlled.

Note that FIG. 4(9) represents the vertical synchronizing signal VD reproduced from the tape 1 by the video head 8.9.

In this way, the rotational phase of the video head 8.9 detected by the tuck head 13, that is, the phase of the reproduction vertical synchronization signal O, and the phase of the reproduction control signal detected by the control head 10 are determined by using the same reference signal RBF as an intermediary, Accurate tracking control is achieved by controlling the rotation of the video head 8,901m and the running of the tape 10, respectively, so that a predetermined phase relationship is achieved corresponding to the phase relationship between the vertical synchronization signal and the control signal during recording. I can do it.

Next, VTRo@4! A new method for adjusting compatibility so that excellent tracking can be obtained when tape 1 is played back interchangeably between the two will be described.

[3IA is standard tape 1 recorded with a standard tape making machine.
' is an explanatory diagram showing the recording pattern of 0. To ensure tape compatibility between TR devices, the normal
The tape pattern recorded with TR is recorded on this standard tape 1'
It is only necessary to match the recorded pattern.

In FIG. 3, video track T'st f Ta2
t'rss is a track recorded by a video head having the same azimuth angle as Video Rad8,
vS81゜■8I2. (2) 883 is the recording position of the vertical synchronization signal.

Further, the video track T'et*19m is a track recorded by a video head having the same azimuth angle as the video head 9, and VSe2*V8sz is the recording position of the vertical synchronization signal. Furthermore, RCQ-RC
I is the recording position of the control signal. In order to draw a pattern that matches this standard recording pattern, the normal tape 1 is run at a specified speed Vi, the video heads 8 and 9 are rotated and scanned at a specified speed, and the video head 8 is At the moment when the vertical synchronization signal VS is recorded at a predetermined position v881 on the track T81, the control head 10 records the vertical synchronization signal VS at a predetermined position on the control track, for example, RCl, RC2, R, C, etc.
It is necessary to record the control signal RC in It. For this purpose, in the past, the positions of the control head 10 were adjusted so that the control head 10 was placed at the standard position, as described above. In contrast, the present invention deals with this by adjusting the control signal RC (D recording timing) in accordance with the deviation of the fixed position.

C) The amount of wear at the fixed position of the control head IO is:
This can be determined by reproducing the 1111 quasi-Dave 1' and performing tracking adjustment so that the reproduced output of the video signal is maximized. Now, a VTR in which the video head 8 and the control head 10 are in the positional relationship shown in FIG.
Assume that the standard tape 1 shown in the figure is played back. In this case, the control head 10 is the standard RC tape.
The control head 10 is fixed at a distance LP closer to the video head 8 from the position RC2 than when the control head 10 is fixed at the standard position RC2.
The control signal RC is reproduced by reproducing the control signal Re recorded at the position RC2 on the t-plane 1' at a distance LP.

In this case, in the servo device shown in FIG. 2, with the delay time of the third delay circuit 29 fixed at the standard setting value at the center of the variable range, the phase of the reproduction control signal PC is
l[1c1 When tracking adjustment is performed by delaying the ms signal in the delay circuit 31, the best tracking state in which the reproduced output of the ms signal is maximized is as shown in FIG. This is when Tsuta time becomes TP.

FIG. 4 shows a timing chart in this most racking state, and as shown in e) of the figure, the playback vertical synchronization signal VD is detected 12 hours after the playback control signal PC is detected. be done.

By reproducing the standard tape 1' in this way and determining the playback control signal 0 maximum delay amount TP that provides the best tracking, it is possible to know the amount of positional deviation LP of the control head 100. can. Therefore, using this optimal delay time TP during playback, the control signal R during recording is
For example, if the control head 10 is fixed at a distance LP from the standard RC2o position in FIGS. Video track T
A vertical synchronizing signal v8 is recorded at a predetermined V8110 position on $l, and a signal RC obtained by delaying the direct synchronizing signal VF of five frame cycles is recorded on the dip l as a control signal. Here, Lo is the period of the control signal to be recorded at 5, as shown in the short period between the recorded Puntrol signals as shown in 3rd wJ, and is a constant value.

In this way, the control signal 'R- is used to record for a time corresponding to the amount of positional deviation of the control head 10.
By recording C with a delay by the 20th pendulum circuit 27 shown in the second WA, the control signal RC is recorded at the recording position of the vertical synchronizing signal V8 on the video track, for example, at the RC1o position which has a predetermined positional relationship with vs81. It becomes possible to record. As a result, even if the control head too is out of position, a recording tape is obtained in which the recording traces of the video signal and control signal match those of the standard tape 1', ensuring compatibility.

In FIG. 3, reference numeral 10' indicates a control head fixed at the RC1o position. When placed at the position RCl in this way, the delay time TP of the playback control signal PC' that provides the best tracking condition when the standard tape 1' is played back is almost zero or almost To
becomes. Therefore, the delay time 'rR (-To-'I'□) of the recording control signal RC during recording becomes approximately To or approximately zero. TR
''=, 0, the recording position of the control signal RC corresponding to the recording position V881 of the vertical synchronizing signal v8 becomes RCo or RCl, but there is no particular problem in performance no matter which one is selected.

The recording position of the control signal C corresponding to the vertical synchronization signal v8 recorded on the video track differs depending on the fixed position of the control head 100, but since it is recorded continuously in the longitudinal direction of the tape IC, it is standard. Pattern 11, which corresponds to tape 1', was obtained, and there were no particular problems.

However, if a composite head is used in which an audio head for recording audio signals is integrated with a control head on an audio track (not shown) normally provided at the upper end of the tape 1, the time lag between video and audio In order to prevent this, it is necessary to suppress at least the variation in the fixed position of this composite head within an allowable limit. However, since the permissible variation range of the zero fixed position of the audio head is wider than the permissible range of control variations without the present invention, the present invention is also applicable to the case where the above-mentioned composite head is used. Of course, if a method is adopted in which this audio signal is superimposed on the @儂儒 signal or recorded in the overlapping part of the video track using the video head 8.9, only the control head 10 needs to be installed. The tolerance range for variations in the fixing position of the control head 10 is greatly expanded.

Next, FIG. 6 is a front view of the cylinder to show other attachment points of the control head according to the present invention.

In FIG. 6, reference numeral 32 denotes a control wheel, which is fixed by cutting out a part of a fixed cylinder (7-2) that guides the running of the tape 10. This control head 32
are attached from between the outer peripheries of the fixed cylinder (7-2) so as to be slightly gathered together, and come into contact with the control track at the lower end of the tape 1. Control head 3 like this
2 into the fll cylinder 7-2), there is no need for an independent head such as the control head 1O shown in FIG. A power saving effect can also be obtained by reducing the load.

In this case, video heads 8, 9 and control head 3
Since the tape length between 2 and 2 changes due to variations in the fixing position of the control head 32 in the tape longitudinal direction and its width direction, it is necessary to adjust the 0 position in the same way as in the example shown in Fig. 1. However, the control head 32
In this case, adjusting the position of the control head becomes even more difficult because it incorporates the height reference plane and it is difficult to set the height reference plane.In this case, by applying the electrical adjustment means according to this case, the mechanical Since there is no need to adjust the position, use a control spatula (as shown in Figure 6)"321Dlil.
There is also an advantage that the filling of the constant cylinder (7-2) is easy.

As described above, according to the present invention, the recording phase and reproduction phase of the control signal are electrically adjusted according to the positional deviation of the control head O, thereby guaranteeing tape compatibility with respect to tracking. Therefore, the conventional mechanical position adjustment of the control head O is not required, and the adjustment time and cost can be reduced accordingly.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing a tape running mechanism of a general household VTR, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3Fj! J is an explanatory diagram showing a standard recording pattern on a magnetic tape, Figures 4 and 5 are timing charts of each signal during playback and recording, respectively, in an embodiment of the present invention, and Figure 6 is a diagram showing a standard recording pattern according to the present invention. Another mounting of the control head involved is a front view of the cylinder to show location. Description of symbols: magnetic tape, 1', song, standard magnetic tape, 2... capstan, (7-1), rotary cylinder, 8, 9... ...video head, 10,
10', 32...Control head, 27.
- Interval second delay circuit, 31...t! c1 delay circuit agent patent attorney Akio Namiki

Claims (1)

[Claims] 1) A rotating video head that diagonally scans a magnetic recording medium to record and reproduce a video signal on the video track, and a vertical synchronization signal of the Eirin signal on a control track of the magnetic recording medium when recording the video signal. means for recording the formed control signal; means for reproducing the control signal sound when reproducing the video signal; and means for correctly scanning the video head on the video track of the magnetic recording medium using the reproduction control signal. A magnetic recording and reproducing apparatus having a servo device that performs tracking control, a $10 delay circuit that delays an o'p4 raw control signal from the track signal reproducing means, and a $10 delay circuit that delays the control signal input to the control signal recording means. First, a standard magnetic recording medium having a standard relative positional relationship between the recording position of the video signal O in the video track and the recording position of the control signal in the control track is loaded and reproduced. Signal 0 playback output is y
The delay time TP in the l-th delay circuit is set so as to be the maximum, and then the delay time TR in the second delay circuit is set from the period To of the control signal to be recorded to the delay time TP. After subtracting the value, load the magnetic recording medium again, record the Eirin signal t on the video track on the medium, and the control signal on the control track, and check the relative positional relationship between the recorded video signal and the control signal. 411. A magnetic recording and reproducing device characterized in that the magnetic recording medium is made to match that of the standard recording medium.