JPS62249590A - Magnetic recording and reproducing method - Google Patents

Abstract

PURPOSE:To vary the recording/reproducing time for one same tape in two or more kinds by mounting four pieces of magnetic heads in specific position on a rotary cylinder so that a track on which each track travels is not overwritten by another track. CONSTITUTION:A brightness signal and a time-base-compressed chrominance signal are inputted to terminals 1 and 2 respectively and converted by a switch SW 3 into a signal in which they switch each other at every horizontal synchronization cycle. The outputs of the SW 3 are inputted respectively to an FM modulator 4 and, via a delay circuit 5, an FM modulator 6, where FM modulated respectively, then recorded in a magnetic tape by magnetic heads 7 and 9 and those 8 and 10 respectively. The heads 7 and 8, and 10 are mounted in positions apart from each other by an angle of theta on the rotary cylinder 11, and hence, by delaying the output of the SW 3 for a relative time difference corresponding to the angle theta by the dealy circuit 5, a brightness signal is recorded neighboring another brightness signal and a chrominance signal is recorded neighboring another chrominance signal on the tape. suppressing the interference from the neighboring track low. The data from the magnetic heads are demodulated 12, 13, delayed 14, and reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus such as a video tape recorder that records and reproduces video signals and audio signals using magnetic tape.

Conventional technology Conventional commercial and broadcast video tape recorders (VTRs)
In the field of (hereinafter abbreviated as ), a method has been developed for recording and reproducing a color video signal by decomposing it into two-channel component signals, a luminance signal and a color signal. For example, it is a VTR called M format or β-CAM,
The recording method described in Broadcasting Technology Magazine, October issue, 1980, pages 872-890, and the recording method called MII format and described in the Technical Report VR70-2゜pages 7-12 of the Television Society. It is a recording method. These two-channel component type VTRs have a chrominance signal track adjacent to the luminance signal track in the recording track recorded on the magnetic tape, so the chrominance signal track is located between the luminance signal recording nozzle and the chrominance signal recording head. Even if an azimuth angle is set, if overwritten recording is performed using solid writing without a guard band, unnecessary signal components will appear as interference during playback, resulting in a significant deterioration of the playback image quality. Yes, overwriting recording without guard bands is not currently performed. That is, a two-channel component type VTR requires a guard band, which has the problem of poor recording efficiency.

Furthermore, the tape feed amount is fixed for each method,
For example, there is a problem in that it is not possible to use different recording and playback times for the same tape, such as standard mode and long-time mode in the VH3 system, which is a system for home VTRs.

An example of the conventional two-channel component type VTR mentioned above will be described below with reference to the drawings. Third
The figure is a block diagram of main parts of a conventional two-channel component VTR. In FIG. 3, a luminance signal as shown in FIG. 2A, for example, is input to the input terminal 18.

Further, to the input terminal 19, for example, a time-base compression multiplexed color signal as shown in No. 218 is input. Here, as an example of the conventional technique, a two-channel component signal is formed by a luminance signal and a time-base compression multiplexed color signal.

The luminance signal input from the input terminal 18 is sent to the FM modulator 20.
The magnetic heads 22 and 2 are frequency modulated (FM).
The reproduced luminance signal recorded on the magnetic tape at 4 and reproduced by the magnetic healds 22 and 24 during reproduction is demodulated by the FM demodulator 27 and output from the output terminal 29. On the other hand, the time-base compression multiplexed color signal input from the input terminal 19 reaches the FM modulator 21 where it is FMed and recorded on the magnetic tape by the magnetic heads 23 and 25, and when reproduced by the magnetic helides 23 and 25. The reproduced time-base compressed multiplex signal is demodulated by the FM demodulator 28 and outputted from the output terminal 30. In the conventional example, for example, FIG. 2A.

The recording patterns of the luminance signal and the time axis compressed color signal indicated by B on the magnetic tape 29 are 401, 403.405 and 402.404, 4 in FIG. 4, respectively.
It will look like 06.

Problems to be Solved by the Invention In conventional two-channel component VTRs, a guard band 34 exists to suppress crosstalk interference between adjacent tracks, and the problem is that the recording density is lower than in solid writing recording or overwriting recording. There is. Furthermore, there is a major problem in that it is not possible to use the recording and playback time for the same tape differently, such as the standard mode and long-time mode mentioned above. SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a two-channel component VTR in which the recording density of the two-channel component VTR is newly improved and the recording/playback time for the same tape can be set to two or more types.

Means for Solving the Problems In order to solve the above problems, in the present invention, the center line or one end line of the running track of each of the four specific magnetic heads on the rotating cylinder of the two-channel component VTR is It consists of a magnetic head attached to a specific position on a rotating cylinder whose relative positional relationship changes similarly to the feeding speed of multiple magnetic tapes, and a drive system with multiple tape feeding speeds. It is something that

Operation The present invention achieves high-density recording without guard bands even though it is a 2-channel component VTR, and has two or more types of recording and playback time for the same tape, such as a standard mode and a long mode. This makes it possible to realize a VTR.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of main parts in one embodiment of the present invention. In FIG. 1, for example, a luminance signal as shown in FIG. 2A is input to input terminal 1, and a time-axis compressed color signal as shown in FIG. 2B is input to input terminal 2. .

Then, the two human input signals enter the switcher 3 and are switched every horizontal synchronization period, so that the luminance signal and the time-axis compressed color signal shown in FIG. 2C and D are switched alternately every horizontal synchronization period. is converted into a signal in the form of Figure 2C
The signal is frequency-modulated by an FM modulator 4 and recorded on a magnetic tape by magnetic disks 7 and 9. The signals in the second diagram are delayed by the delay circuit 5 by a relative time difference T1 on the magnetic tape, which is determined by the positional relationship between the magnetic heads 7 and 9 and the magnetic healds 8 and 10.
The signal is recorded on the magnetic tape by the magnetic heads 8 and 9 after being defeated by the M modulator 6. A recording track pattern of signals recorded on the magnetic tape 31 is shown in FIG. Is the arrow 32 a magnetic head in Fig. 5? , 8, 9. The arrow 33 indicates the direction in which the magnetic tape 31 runs. Recording tracks 501 and 505 are the recording tracks recorded by the magnetic helad 7, recording tracks 502 and 506 are the recording tracks recorded by the magnetic helad 8, and recording track 503 is the recording track recorded by the magnetic head 9. A recording track 504 is a trunk, and a recording track 504 is a magnetic head 10.
This is a recording track recorded by. Since the magnetic heads 7 and 8, and 9 and 10 are mounted at positions different from each other by an angle θ on the rotating cylinder, the relative time difference T1 of the magnetic head scanning on the magnetic tape with the position angle difference θ is second. If the intended signal is delayed, a recording track pattern as shown in FIG. 5 can be obtained. In FIG. 5, the luminance signal Y is located adjacent to the luminance signal Y, and the chrominance signal C is located adjacent to the chrominance signal C. For this reason, I am writing again! Even if 3 (solid writing) is performed, interference from adjacent trunks can be suppressed to a low level due to the correlation of images, so high-density recording without guard bands due to overwriting recording is possible. Furthermore, as shown in FIG. 5, it goes without saying that azimuth recording between tracks is an effective means for overwriting.

Next, even in the long-time mode in which the tape running speed is changed to the normal □ (n is the number fill), the recording trunk pattern of each magnetic head is similar to that during normal running, and the recording trunk pattern is different from other tracks. Consider a case where complete overwriting does not occur.

Now, it is assumed that the central angle of the magnetic heads 7 and 8 in FIG. The recording track width in the standard mode is TW, and the track pitch, which is the amount by which the tape is fed while the rotating cylinder rotates 180'', is TP.The recording track width in the long time mode is TW2, and the track pitch is TP2. The conditions for the long-time mode recording track pattern to be similar to the standard mode recording track pattern shown in FIG. 5 can be found with reference to FIG. 7. That is, when the track pitch is TP, magnetic head 8
When the magnetic head 7 and the magnetic head 7 come to the same position on the cylinder rotation axis, the relative height difference between the magnetic head 8 and the magnetic head 7 is θ. In order to do so, the following two equations should be satisfied.

(180' TPl -TP2 from 11, +21 By the way, in order for the trunk patterns to be similar, n
Since there is a relationship n, 180' TP.

becomes. In addition, in order to obtain a track pattern as shown in Figure 5, there is a relationship TW, −−TP, so θ=
By substituting θ=90'', which becomes 90'', into (1), we obtain Δh=TW1--TP,=0. Therefore, the positions of the magnetic heads 7, 8, 9, and 10 on the rotating cylinder, with a central angle of 90° and a relative height of 0, are suitable for recording tracks in any long-duration mode where the tape feed is slower than in the standard mode. The patterns are similar, as shown in Figure 6.

Recording tracks 601 and 605 are recording tracks recorded by the magnetic head 7, and recording trunks 602 and 60
6 is a recording track recorded by the magnetic head 8, a recording track 603 is a recording track recorded by the magnetic head 9, and a recording trunk 604 is a recording track recorded by the magnetic head IO. However, in FIG. 6, the scale in the tape feeding direction is multiplied by one.

As described above, since a recording track pattern similar to the recording track pattern in the standard mode can be obtained even in the long-time mode, it is possible to suppress interference from adjacent tracks to a low level even when overwriting recording is performed.

Although the above example deals with the case where the track patterns are similar, a similar effect occurs in all cases where each track is not completely overwritten by other trunks.

Now, in the standard mode and the long time mode, the signals recorded as shown in FIGS. 5 and 6, respectively, are reproduced by the same magnetic head as when they were recorded. In FIG. 1, the signals reproduced by the magnetic heads 7 and 9 are lost to the FM demodulator 12, and its output becomes a signal in the form shown in FIG.
After being delayed by 1, the signal has the form shown in FIG. 2F. Further, the signals reproduced by the magnetic heads 8 and 10 are sent to the FM demodulator 13, and its output becomes a signal in the form shown in FIG. The signals in the formats shown in FIGS. 2F and 2 are switched by the switcher 15 every horizontal synchronization period to become the luminance signals and time-axis compressed color signals shown in FIGS. 2A and B, respectively, at the output terminal 16. and output from 17.

As in conventional examples such as M formant and βCAM, magnetic helmets 7, 8, 9 and 10 are respectively mounted close to each other on a rotating cylinder, and the standard mode recording track pattern is as shown in FIG. Sometimes the recording track pattern in long-time mode is impossible to record and play back because the video tracks overlap.

Note that in the above explanation, the luminance signal and the time axis compression multiplexed color signal were used as signals handled by the video signal recording device that records each of the video signals divided into two channels. A similar effect can be obtained even when the color difference signal is a frequency multiplexed signal. That is, the present invention is applicable to various video signal recording apparatuses in which the electromagnetic conversion section is capable of two-channel recording. That is, the input signal to the recording circuit system may be a luminance signal and two types of color signals, or may be an R signal, a G signal, or a B signal.
The present invention is applied even if the luminance signal and the line-sequential color signal are time-base compression multiplexed and are one-channel. Furthermore, the recording track pattern on the magnetic tape is not limited to the diagram shown in FIG.
A similar effect can be obtained by arranging the magnetic head so that the luminance signal and chrominance signal are recorded adjacent to the luminance signal and the chrominance signal is recorded adjacent to the chrominance signal. .

Effects of the Invention In a 2-channel component VTR, when the heads for 2-channel recording are mounted close to each other as in the conventional example, it is necessary to provide a guard band between the luminance signal track and the chrominance signal track, which reduces tape utilization efficiency. becomes worse. Furthermore, it is not possible to use a plurality of tape running modes such as a standard tape running mode and a long time mode during recording and reproduction.

However, as shown in the present invention, the shape of the running track of the magnetic head is such that each trunk is not completely overwritten by another track in both the standard mode and the long-time mode. position (center angle θ and relative height Δh of the two magnetic heads)
By matching the shape of the magnetic head with
In the standard mode and long-time mode, it is possible to record a luminance signal adjacent to a luminance signal and a chrominance signal adjacent to a chrominance signal on the recording track pattern on the magnetic tape, so cross-over between adjacent tracks is possible. Since the talk is significantly reduced, it is possible to record and reproduce good video.

[Brief Description of the Drawings] Fig. 1 is a block diagram of main parts in an embodiment of the present invention, Fig. 2 is a signal waveform diagram of each part in Figs. 1 and 3,
FIG. 3 is a block diagram of main parts in the conventional configuration, FIG. 4 is a recording trunk pattern diagram on a magnetic tape in the conventional configuration, FIG. 5 is a recording track pattern diagram in the standard tape running mode of the present invention, and FIG. 6 7 is a diagram of a recording track pattern in the long-time tape running mode according to the present invention, and FIG. 7 is an explanatory diagram for explaining the dimensions of the recording track and track pattern on the magnetic tape and the positional relationship of the magnetic head. 11.26...Cylinder rotation direction, 34...
...1 track pitch, 35...Track width, 36...Gart band, 37...
- IH (1 horizontal opening period). Name of agent: Patent attorney Toshio Nakao
ω lj around Q - Monument

Claims (2)

[Claims] (1) In a two-channel component helical scan magnetic recording and reproducing device that records and reproduces each of video signals divided into two channels and is equipped with a tape feed speed changeover switch, each of four specific magnetic heads on a rotating cylinder Recording and reproduction of video signals is carried out using the magnetic head mounted at a specific position on the rotating cylinder such that the running track of the magnetic tape is not completely overwritten by other tracks as the feeding speed of the plurality of magnetic tapes changes. A magnetic recording and reproducing method characterized by: (2) Among the four magnetic heads, the first and second magnetic heads and the third and fourth magnetic heads are each arranged at approximately symmetrical positions with respect to the cylinder rotation axis. A magnetic recording and reproducing method according to claim (1).