JPS59191164A - Magnetic recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a magnetic recording/reproducing device, and particularly to a tracking method suitable for reproducing and scanning a magnetic tape on which digitized signals are recorded with high density using a multi-head. The present invention relates to a magnetic recording/reproducing device equipped with a control device.

[Background of the invention]

In recent years, as recording density has improved, research has progressed on digital magnetic recording and reproducing devices (hereinafter abbreviated as digital VTR) that have high image quality and excellent dubbing performance. For digital VTRs, it is several 10 Mbit/, i (home use) to several 1
It is necessary to record a digital signal of 00 Mbit/s (for broadcasting), and it is difficult to record one field of video signal with one rotary head as in current home analog VTRs.

For this reason, it is necessary to divide the digital data using a predetermined method and simultaneously perform helical scanning using two or more rotating multi-heads.

Figure 1 shows two sets of multi-heads 5.6f and rotating cylinder 4.
The entire structure installed is shown. Multi-head 5 shown in Figure 1
, 6 are four heads 5-, each having a stacked structure.
1 to 5-4. 9 from 6-1 to 6-4, rotating cylinder 4
are fixed 180 degrees apart from each other.

FIG. 2 is a diagram showing a tape pattern in which signals are recorded by scanning the entire magnetic tape 1 diagonally with these multiheads 5 and 6. In FIG. 2, A is the video track pattern recorded by the multi-head 5, and B is the video track pattern recorded by the multi-head 6. During recording, since the tape 1 is driven to run at a constant speed, these patterns A and B are recorded alternately.

On the other hand, during playback, the multiheads 5 and 6 record patterns A, B, etc. on the magnetic tape 1? : It is necessary to perform tracking control to scan accurately.

Conventionally, this tracking control involves associating a control signal 1 on the control track 10 at the lower end of the magnetic tape 1 with the positions of the recording patterns A and B of the video track.
1 is recorded by a fixed control head 15, and during playback, this control signal 11 is reproduced to detect all tracking errors and control the tape running phase, thereby performing tracking control.

However, the tracking control method using this control signal has the following drawbacks.

fil Since tracking errors can only be detected intermittently, sufficient tracking performance cannot be obtained when recording track patterns A and B have curvature. In particular, when performing high-density recording with the aim of recording for a long time, the track pitch becomes narrow (for example, the width of the pattern recorded by head 5-1 is several micrometers below the door plate), so accurate track and cross traces can be obtained. It becomes difficult.

(Since the positions of 2100 multi, 5 and 6, and control 15 are far apart, tracking may shift due to changes in tape length, etc., so the user needs to adjust tracking by looking at the playback image.) occurs, and a tracking adjustment mechanism is essential.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the conventional device described above and to provide a complete means for achieving automatic tracking control and higher performance in a high-density recording digital VTR using a multi-head.

[Summary of the invention]

In order to achieve the above object, the present invention provides a method for recording a tracking pilot signal on a magnetic tape by superimposing it on at least one of a video signal or an audio signal.
The rotating multi-head is configured to scan diagonally, and the tracking of the multi-head is controlled by a reproduced pilot signal.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 3 to 5.

FIG. 3 is a block diagram showing an embodiment of a rotating multi-head helical scan type magnetic recording/reproducing device according to the present invention, FIG. 4 is a table turn, and FIG. 5 is a trunking error detection device according to the present invention. FIG. 2 is a block diagram showing a specific example of the above.

In FIG. 6, the magnetic tape 1 is driven by a capstan 2 and runs in the direction of the solid arrow. This capstan 2 is rotationally driven by a capstan motor 6. On the other hand, two multi-heads 5 and 6 attached to the cylinder 4 180 degrees apart from each other are driven by a cylinder motor 7 and rotate in the direction of the dashed arrow.

This cylinder 4 is attached to a rotating shaft inclined with respect to the longitudinal direction of the tape 1, and is rotationally driven at a frequency (30 Bz) that is half the vertical synchronizing signal of the recorded video signal. Further, the tape 1 is wound around the cylinder 4 in a substantially semicircular manner. Therefore, the multi-head 5.6 alternately scans the tape 1 in diagonal directions from bottom to top, and records the video signal on each video track in units of one field of the video signal. This multi head 5
．． 6 is each four helads 5-1 to 5-4.6-1
~6-4, and as shown in FIG. They have different azimuth angles. Therefore, as shown in FIG. 4, high-density recording can be performed without providing a guard band.

FIG. 3 shows a complete block diagram of the reproducing system of the magnetic recording/reproducing apparatus, but the recording system is not shown.

First, the operation during recording will be briefly explained. At the time of recording, tape 1 is run at a predetermined speed while tape 1, ., 5.
6 is rotated in synchronization with the recorded video signal. After adding the digitized video signal in this state and the tracking control pilot signal generated by the pilot signal generation circuit 9, it is amplified by a recording amplifier and sent to the multiheads 5 and 6 via the rotary transformer 12. and record on the video track on tape 1.

As this pilot signal, four signals with different frequencies are used.
FIG. 4 shows an example of a video track pattern when different types of pilot signals are used.

In FIG. 4, A□ and A are tracks recorded with multi head 5, and Br and B2 are tracks recorded with multi head 6. Further, f, to f4 indicate the frequencies of pilot signals recorded on the respective video tracks.

In this way, four-frequency pyro 1. Four tracks, which are recording trajectories of a multi-head consisting of four heads, are used as unit video tracks, and recording signals are alternately recorded on each unit video track.

The frequencies f1 to f of these pilot signals are lower than the frequency band of the video signal, and the frequencies of the multihead 5. The low frequency is selected so that it will not be affected by the azimuth angle of the second one. Therefore, during playback, multi-head 5.6
When scanning over a recording video track, it is possible to detect not only the pilot signals of the video rack that is correctly tracking scanned, but also the pilot signals from the video tracks adjacent on both sides. Therefore, by detecting and comparing all the playback levels of the pilot signals from both adjacent tracks, it is possible to obtain an accurate tracking error signal that includes the direction and amount of tracking deviation.

Next, the normal operation during playback will be explained. In Figure 3,
The rotational phase of the multi-heads 5 and 6 is detected by the tack head 13, and this detection signal is sent to the phase adjustment circuit 14, which outputs the head phase detection signal 5F-q and the cylinder phase comparison circuit 16.

In the phase comparator circuit 16, this head phase detection signal J,
By comparing the phase with the reference signal REF at the terminal 8 and supplying the phase error signal to the cylinder motor 7 via the all-cylinder motor drive circuit 17, the multi-heads 5 and 6 are driven at a constant phase and speed determined by the reference signal REF. Rotate with . At this time, the frequency of the reference signal REF is set to 1/2 the frequency of the vertical synchronization signal of the recorded video signal, that is, the frequency of the vertical synchronization signal that was the reference signal at the time of recording.
If you choose approximately equal to z, go to multi, de 5. The rotational speed of B becomes almost the same as at the time of recording.

By controlling the running of the tape 1 using the tracking error signal while the multi-heads 5 and 6 are rotating at a predetermined speed, the multi-heads 5 and 6 can accurately scan the desired video track to the multi-head. Tracking control is performed so that Next, this tracking control operation will be explained.

From tape 1 to multihead 5. The signal reproduced by B is sent to the preamplifier 26 via the rotary transformer 12 and amplified. This amplified playback signal is sent to a switching circuit 27, and depending on the head phase detection signal y, a playback signal from the multihead 5 or 6 scanning the tape 1 is selected and output. After that, the video signal reproducing circuit 2
8, where signal processing such as Dμ conversion is performed, and a desired video signal is reproduced. On the other hand, the four-channel playback signal, which is the output of the switching circuit 27, is sent to the adder circuit 25 and added, and then sent to the low-nox filter 29, where the high-frequency video signal is removed, and the pyro-y) signal is PL is separated. From this reproduction signal PL, a trunking error signal TR is generated by the next stage tracking error detection circuit 60 by the method described in FIG. 5 below.

By supplying this L racking error signal TRY to the capstan motor 6 via the capstan motor drive circuit 23, the rotation of the capstan 2 is controlled. As a result, the running phase of the tape 1 is changed to the tracking error signal T
Tracking control is performed according to R so that the multi-heads 5 and 6 correctly scan the video track'.

Next, a specific example of forming the tracking error signal TR from the reproduced pilot signal PL will be explained using FIG.

Now, the frequencies of the four-frequency pilot signal shown in Fig. 4 are
fl=6.5fH9f2-Z5fH2fs ”10.5
7'H, f<=95fH (here, fx is the frequency of the horizontal synchronizing signal of the video signal), video track A1.
When scanning A, if the tracking shifts to the right, IJ'+ fz 1=Ifs f+ I=fy
If the component increases and shifts to the left, +L −f< +=+
fs-f2+=5hr component increases. Also, when scanning all of video tracks B, , B2, if the tracking shifts to the right, 1f2 fs I=Ifa fx l
=5hr component increases and shifts to the left, +:b −
f+ Nige 4 fs1=fi component increases.

Therefore, as shown in FIG. 5, a local pilot signal F2 having the same frequency as the pilot signal recorded on the main video track to be scanned is generated in the pilot signal generation circuit 9, and this local pilot signal F and the reproduced pilot The signal PL is sent to a mixer circuit 31 comprising, for example, a double-balanced modulator, and a signal having the difference frequency between the two signals, that is, a composite signal of the hr acid component and the 5fi component, is obtained at its output. Next, bandpass filters 52 and 33 filter fH acid components 6h and 6h from this composite signal.
The r component is separated and an envelope detection circuit 54.3
5, a voltage signal P having a value corresponding to each amplitude,
. This differential voltage signal T, T
represents the level difference of pilot signals detected from adjacent tracks on both sides of the main track to be scanned.

At this time, the direction of increase/decrease of the difference frequency signal with respect to the direction of tracking deviation is opposite to the case where the main track is A1 or A and the case where the main track is B1 or B, as described above.

Therefore, the differential amplifier 36 generates two differential voltage signals with different polarities, k (Pt - Pt) = τk (P, -P,) = T
, (k: constant), and supply the differential output signals T and T to the gate circuits 37 and 38, respectively,
The head phase detection signal y and a signal whose polarity is reversed by the inverter circuit 39 are used as gate signals, and by gating during the high level period of each gate signal, a differential voltage signal with a different polarity for each track is generated. Connect T and T to create a continuous correct tracking error signal T
Get R.

Next, another embodiment of the present invention will be described using FIGS. 6 and 7. FIG. 6 is a block diagram showing a tape pattern, and FIG. 7 is a block diagram showing a second embodiment of a tracking error detection device.

This second embodiment is characterized by the heads 5-1-5-4, which constitute the multi-heads 5, 6, as shown in FIG. ．． 6
-1 to 6-4 are different in frequency of the pilot signals recorded on the video tracks to be scanned. That is, the tracks to be scanned by the heads 5-1 and 6-1 receive a pilot signal of frequency f, the trunks to be scanned by the heads 5-2 and 6-2 receive a pilot signal of frequency f, and the heads 5-6 and 6-2 receive a pilot signal of frequency f. 6-6 should scan the tiger,
A pilot signal of frequency f is recorded on the tracks to be scanned by the heads 5-4 and 6-4, and a pilot signal of frequency f is recorded on the tracks to be scanned by the heads 5-4 and 6-4. In this way, four-frequency pilot signals f0 to f are alternately recorded on each unit video track, which is one track that is the recording locus of each head constituting the multi-head.

The tape 1 having the tape pattern shown in FIG.
A method for tracking scanning by the multiheads 5 and 6 during reproduction will be explained with reference to FIG. In FIG. 7, the circuit configuration until the output signal of the switching circuit 27 is formed is exactly the same as the embodiment shown in FIG. The four channels of reproduced signals output from the switching circuit 27 are sent to a low-pass filter 29', where high-frequency video signals are removed and the pyro- and g-signals PL1 to PL4 are separated.

A tracking error signal TR' is formed from the reproduced pilot signals PL1 to PL4 by a tracking error detection circuit 30' at the next stage.

Now, the frequency f of the four-frequency pilot signal shown in FIG.
I-f4k is set to the same value as in the case of FIG. In this case, each of the heads 5-1 to 5 making up the multi-heads 5 and 6
-4, pilot signals PL1 to PL4f reproduced by Oru-1 to 6-4, four mixer circuits 61-1 to 61
-Supply to each of the four.

And each of the above heads 5-1 to 5-4, or-1 to 6
Local pilot signals 11 to F4 k of the same frequencies f1 to f4 as the pilot signals recorded in the main video tolank to be scanned are simultaneously generated by the pilot signal generation circuit 9', and each mixer circuit port 1- 1
~31-4.

For example, a local pilot signal F1 having a frequency f1 is supplied to the mixer circuit 31-1 to which the pilot signal PL1 reproduced by the head 5-1 Suntakeru-1 is input.

These mixer circuits 31-1 to 31-4 output signals having a frequency that is the difference between the frequencies of the above-mentioned regenerated pilot signals PIA to PL4 and the local pilot signals F, -F, that is, the above-mentioned fi acid components and 3fH components. A composite signal is output. Next, fx components are sorted from the composite signal of this camera by bandpass filters 32-1 to 32-4,
3fH by bandpass filters 33-1 to 36-4
Separate the ingredients.

Then, envelope detection circuits 64-1 to 34-4 generate voltage signals P1-1 to P of values corresponding to the amplitude of the fg component,
−.

The envelope detection circuits 65-1 to 35-4 generate voltage signals 7', -, ~ according to the amplitude of the 3hr component.
P2-4k is formed. Then each differential amplifier 6
6-1 to 66-4, fi acid component voltage signals p, -
, ~P, -4 and 5fH component voltage signals P2-1~p2-
Find the difference between 4 and 4. Then, to,, 5-1 (S-1
) and the track to be scanned by head 5-3 (6-3) (the former is the track in which the pilot signal of frequency f1 is recorded, the latter is the track in which the pilot signal of frequency 13 is recorded), and the head 5-2 (6-2)
and the track to be scanned by 5-4 (6-4) (the track where the pilot signal of frequency f2 is not recorded for the former, and the frequency f for the latter), and the direction of increase/decrease of the difference frequency signal with respect to the direction of tracking deviation. is reversed, the differential amplifiers 66-1 and 36-3 have k(P+-+'
2:I)=T+,k(PI-s-p2-3)=13
k from the differential amplifiers 36-2 and 36-4.
(Pz-t'+-z)Tz, k (P2-4
? +-J)=14 is output. Thereafter, these differential output signals T, , T, , T3 . By adding T, with an adder 40, the multiheads 5 and 6
A continuous correct tracking error signal T#2 is obtained for completely accurate tracking scanning.

Next, FIG. 8 shows an example in which the tracking error detection circuit 30' shown in FIG. 7 is simplified. Figure 8 (
In α), the mixer circuits 61-1 to 61-4 that make up the entire tracking error detection circuit 30'' are completely the same as the circuit configuration shown in FIG.

The output signals of mixer circuits 31-1 and 31-6 are sent to bandpass filters 32-13 and 33-13, and the respective fy acid components and '5fH components are added and output. And envelope detection circuit 34 for fx and 3fx
-13.35-13, the voltage signal Pl-13s P2-13 is set to a value corresponding to the amplitude of the hr acid component 5fH component, and then the difference signal T+s =k is generated by the differential amplifier 36-15.
(Pr-1s, P2-13) is output. On the other hand, the output signals of mixer circuits 32-24 and 35-24 are
It is sent to band pass filters 34-24 and 35-24, and the respective fH acid components and 3fH components are added together and output. and fH and 3fH envelope detection circuits 54-24. 35-24, a voltage signal PI-14* P2-24 whose value corresponds to the amplitude of the fi acid component 5fx component.
After that, the differential amplifier 36-24 calculates the difference signal Tz-=
k (P 2-24'l-24) is output. These differential output signals 13. T24 k and the adder 41 add the signals to obtain a desired tracking error signal TR''.

Fig. 8 (Al is the band pass filter 32-13, 33-13 j32-24, 3 shown in Fig. 8 (α))
3-24 shows a specific example of the circuit. An input signal IN1. is sent from two mixer circuits. In
2 y2 Transistor T whose collector terminals are commonly connected
, , T.

The configuration is such that selective amplification is performed using an fg or 5fH parallel resonant circuit consisting of a coil L and a capacitor C connected to the common collector terminal. fx
The acid component or 5hr component is added and output. As described above, according to the embodiment shown in FIG. 8, by using the simple bandpass filter circuit shown in FIG.
Compared to the embodiment shown in FIG. 7, the number of tracking errors is reduced by half, and a simplified tracking error detection circuit can be obtained.

In the embodiments shown in FIGS. 4 and 5, the pilot signal generating circuit 9 generates a recording pyro signal depending on the polarity of the head phase detection signal y.

By determining the frequency of the pilot signal and the frequency of the local pilot signal during playback, the video track A,
``2K Multi Hera Rad 5 scans.

Piteotora, Ri B1. B2 can be specified as if it were to be multi-tracked, and the signal playback ability is particularly excellent during self-recording and playback. However, the multi-head 5.
6 is A.

It is also permissible to configure it so that scanning either A2 or B, , B is a factor. In addition, Fig. 6.

In the embodiment shown in FIGS. 7 and 8, it is not necessary to supply the head phase detection signal SW to the pilot signal generation circuit 9', and the video track scanned by the multi-heads 5 and 6 is the C track shown in FIG. and D track.

Furthermore, in the above embodiment, a case was described in which a video signal and a tracking pilot signal are recorded in a fully superimposed manner on a video track. The present invention is also effective when superimposing recording on a video track. Further, the present invention is effective regardless of whether recording is performed using a multi-head and reproduction is performed using a multi-head, or whether recording is performed using a single head and reproduction is performed using a multi-head.

In addition, in the above embodiment, a method of recording pilot signals of four types of frequencies alternately for each unit video track was explained, but in the case of a method of using pilot signals of three or five or more types of frequencies, For example, in the case of a method in which a pilot signal of a constant frequency is recorded with the phase changed for each unit piteo track, or instead of recording all pilot signals continuously on a video track, for example, one frequency signal is recorded intermittently at a predetermined period. The present invention is also effective in the case of a system in which the signal phase and recording timing are varied and the temporal and spatial arrangement is varied for each unit video track.

Furthermore, in the above embodiment, a case has been described in which a multi-head consisting of four heads is tracked on a recording tape pattern during reproduction, but a multi-head consisting of two, three, or five or more heads is used. The present invention can also be applied to both the tiger and king scans.

Further, in the above embodiment, a tracking control method was described in which the running phase of the tape is controlled using a pilot signal reproduced by a multi-head during playback, but the present invention is not limited to this, and the present invention is not limited to this. Using a piezoelectric element such as a bimorph plate or an electromagnetic drive means such as a solenoid, the position of the multi-head can be shifted in the width direction of the video track. By controlling the position of , it is possible to apply this to the case where the recording pattern on the tape is more accurately tracked and scanned.

〔Effect of the invention〕

As described above, according to the present invention, in a high-density recording VTR, m types (77L≧6
A rotating multi-head reproduces pilot signals with different frequencies, phases, or temporal and spatial locations (an integer of Multi-head tracking automatic control is achieved.

[Brief Description of the Drawings] Fig. 1 is a sectional view of a rotating cylinder attached to a multi-head, Fig. 2 is a diagram of a conventional tape pattern, and Fig. 3 shows an embodiment of a magnetic recording/reproducing device according to the present invention. 4 is a tape pattern diagram for correlating the tth embodiment of the present invention, FIG. 5 is a block diagram showing the first embodiment of the tiger/king error detection device, and FIG. 7 is a block diagram showing the second embodiment of the tracking error detection device, and FIG. 8 is a tape pattern diagram for explaining the second embodiment.
al is a block diagram showing a third embodiment of the tracking error detection device, and FIG. 8 (, 61 is a circuit diagram of a part thereof.
...Rotating cylinder 5-1 to 5-4.5...Multi head 6-1 to 6-4.6...Multi head 9...Pilot signal generation circuit 25...Addition circuit 26...Preamplifier 2
7...Switching circuit 29, 29'...Low pass filter 30, 30', 30"...Tracking error detection circuit 1st Figure 3'10"
Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. A magnetic tape on which a tracking pilot signal is recorded superimposed on at least one of a video signal or an audio signal, a rotating multi-head that scans the magnetic tape diagonally, and a reproducing pilot signal that drives the multi-head. What is claimed is: 1. A magnetic recording and reproducing device comprising: a device for performing tracking control;