JPS6258043B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic reproducing device, and particularly in a device having magnetic heads having different azimuth angles and a head track width wider than a recording track, the present invention relates to a magnetic head with a maximum track width. The present invention provides a magnetic reproducing device which can achieve special reproduction of high-quality images and also secure sufficient tracking margin by scanning a recording track with the recording track protruding from the adjacent tracks on both sides. The purpose is to provide.

Generally, a VTR device, as shown in Figure 1,
First and second magnetic heads 2 and 3 are provided inside the guide drum 1 at diametrically opposite positions. The configuration is such that a magnetic tape 4 that is attached over an angular range and runs in the direction of the arrow X is scanned in an oblique direction to record and reproduce video signals.

One such VTR device is disclosed in Japanese Patent Application Laid-Open No. 104215/1983, in which magnetic heads are mounted whose head track width is wider than the recording track width and whose azimuth angles are different from each other. FIG. 2 shows the relative positional relationship between the magnetic head, tape, and recording track during recording and reproduction in this apparatus. The first and second magnetic heads 5, 6 are
They have opposite azimuth angles, and head track widths _W1 that are wider than the recording track width W and equal to each other. During recording, the first and second magnetic heads 5 and 6 each scan as shown by the solid lines in the figure and erase a track recorded by the other magnetic head, partially overlapping the track recorded by the other magnetic head _. , 7a ₂ , 7b ₁ , 7b ₂ are formed. During reproduction, the first and second magnetic heads 5, 6 align one end line 5a, 6a with the end of the recording track 7a ₁ , 7b _1, respectively, as shown by the broken line in the figure, and the opposite end 5b, 6a, respectively. Scanning is performed in a state in which 6b protrudes to the side of the track adjacent to the track being scanned. Here, the head track width W ₁ of the magnetic heads 5 and 6 (that is, the protrusion dimension a of the magnetic head toward the adjacent track) is determined so that the crosstalk component from the adjacent track is minimized.

Therefore, in this device, the recording track width is not determined by the magnetic head, and the dimensional accuracy of the magnetic heads 5 and 6 itself is not required to be exact, which is convenient for manufacturing the magnetic head and also improves the crosstalk suppressing effect. This has the advantage of being achievable.

Further, VTR devices are required to have higher performance, and are now designed to allow special playback, such as slow motion playback, with high-quality images. As one method for performing this high-quality special image reproduction, the present applicant first made the track widths of the first and second magnetic heads different, fed the tape intermittently, and while the tape was stopped, the first and second magnetic heads He proposed a method in which two magnetic heads scan the recording track, and has put this into practical use.

When the above-mentioned method is applied to the above-mentioned VTR apparatus, it is necessary to make the track widths of the first and second magnetic heads different, as shown in FIG. 3, for example. That is, the second magnetic head remains as is, but a wider magnetic head than the conventional one is used as the first magnetic head. That is, the track width _W2 of the magnetic head 7 is larger than the track width _W1 . Note that it is necessary to consider crosstalk during normal playback with respect to this track width _W2 , and the track width _W2 is set to be wider than the track width _W1 by the protrusion dimension a.

In this VTR device, the track scanning state of the magnetic head during reproduction is as shown by the broken line in FIG. That is, each magnetic head 7, 6
Since the scanning is performed along one side edge of the track, especially for the wide magnetic head 7, one end 7a of the magnetic head 7 is scanned.
is close to the track 7a ₂ adjacent to the track 7b ₁ which is adjacent to the track 7a ₁ scanned by the head, and the dimension d ₁ to the track 7a ₂ , that is, the tracking margin, is quite small. For this reason, VTR devices require higher precision and are difficult to assemble.

Therefore, the present invention has a structure in which the widest magnetic head is configured to scan tracks in a positional relationship that protrudes into adjacent tracks on both sides, thereby making it possible to perform special reproduction with high quality images without adversely affecting the tracking margin. An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 shows the relative positional relationship between the magnetic head, tape, and recording track in recording and reproducing modes. The first magnetic head 10 and the second magnetic head 11 are mounted in the guide drum with their lower edges 10a and 11a at the same height. In addition, the first magnetic head 10 and the second magnetic head 1
1 have opposite azimuth angles and head track widths W ₃ and W ₄ . The head track widths W ₃ and W ₄ are such that W ₃ >W ₄ and are both wider than the width W of the recording tracks 7a ₁ , 7a ₂ , 7b ₀ , 7b ₁ , and 7b ₂ and that the amount of crosstalk is minimized. It is stipulated in

In the case of an azimuth head, the relationship between the amount of crosstalk and the amount of protrusion of the head into the adjacent track is as shown in FIG. Here, crosstalk that tends to deteriorate image quality occurs when a black component is mixed into a white part, and FIG. 5 shows the relationship with respect to the above-mentioned crosstalk components. The amount of crosstalk is minimum when the protrusion dimensions to adjacent tracks are A ₁ and A ₂ . Here, the relationship A ₂ =2A ₁ holds; specifically, when the recording track width W is 20 μm, A ₁ =7 μm and A ₂ =14 μm.

That is, the track width W ₃ of the first magnetic head 10
is W+A ₂ , and the second magnetic head 11
The track width W ₄ is given as W+A ₁ .

During recording, the magnetic heads 10 and 11 scan as shown by solid lines in FIG. 4, forming recording tracks 7a ₁ , 7b ₁ , 7a ₂ , 7b ₂ as in the conventional case.

During reproduction, unlike during recording, the magnetic heads 10 and 11 scan the recording track in a relative positional relationship shown by broken lines with respect to the recording track. That is, the magnetic heads 10 and 11 rotate at a rotational phase that is delayed in the direction compared to the time of recording, and scan a position shifted by a distance D on the tape. The scanning position of the magnetic head can be shifted by automatically switching the delay amount of the drum pulse used for head servo in synchronization with the rotation of the magnetic head in conjunction with the playback operation, or by operating the tracking volume. This is easily done.

As a result, the upper edge 11a of the second magnetic head 11 coincides with the edges of the recording tracks 7b ₁ and 7b ₂ , and the lower edge 11b has a dimension A ₁ on one side of the adjacent track, that is, on the side of the recording tracks 7a ₁ and 7a ₂ . Scan with the image sticking out. As a result, the signals of the recording tracks 7b ₁ and 7b ₂ are reproduced with the amount of crosstalk from the adjacent tracks 7a ₁ and 7a ₂ on one side being minimized.

The first magnetic head 10 has upper and lower edges 10a,
The tracks 7a ₁ and 7a ₂ are scanned in a state in which the tracks 10b protrude by a dimension A ₁ into adjacent tracks 7b ₀ , 7b ₁ , 7b ₁ , and 7b ₂ on both sides of the tracks 7a ₁ and 7a ₂ , respectively.
Here, when the magnetic head protrudes into adjacent tracks on both sides of the track being reproduced, the amount of crosstalk changes depending on the phase relationship of the crosstalk discarded from both sides. In the present invention,
The protrusion dimensions on both sides are set so that the amount of crosstalk on each side is minimized, and although the amount of crosstalk varies depending on the phase relationship of the crosstalk picked up from both sides, it becomes the minimum value. As a result, the signals of the recording tracks 7a ₁ and 7a ₂ are also reproduced with the amount of crosstalk from the adjacent tracks on both sides thereof being minimized.

As a result, normal reproduction is performed with crosstalk being minimized, and high-quality images are reproduced.

Now, looking at the tracking margin during playback, among the first and second magnetic heads 10 and 11, the second magnetic head 11, which is the widthwise one, has a large tracking margin similar to that of the conventional magnetic head 6.
_d2 , and has a sufficient tracking margin _d3 (larger than the tracking margin _d1 in the conventional example) even for the wide first magnetic head 10. For example, when the recording track width is 20 μm, the first magnetic head 10
The track width W ₃ is 34 μm (=W+A ₂ ), and when the magnetic head 10 is scanned in the relationship shown in FIG. 3, the tracking margin d ₁ is only 6 μm, but the tracking margin in the case of the present invention is _d3 is 13μ
m, which is approximately twice that of the conventional case. Therefore, the assembly accuracy of the reproduction device is reduced accordingly, which is advantageous in terms of assembly and manufacturing.

Furthermore, the first magnetic head 10 and the second magnetic head 11 have different head track widths, so that slow motion, still images, and high-speed playback can be performed using the method proposed by the applicant. .

In the above embodiment, an apparatus configured to perform both recording and reproducing operations has been described, but the present invention can also be configured as a reproducing-only apparatus. Further, the number of magnetic heads is not limited to two, but may be three or more. In this case, at least the magnetic head with the maximum track width is in a relationship such that it protrudes toward adjacent tracks on both sides, like the magnetic head 10 described above.

As described above, the magnetic reproducing apparatus of the present invention includes a plurality of magnetic heads having different azimuth angles and different track widths, both of which are wider than the recording track width. By shifting the phase by a predetermined amount with respect to the recording track, for at least the magnetic head with the maximum head track width among the plurality of magnetic heads, the crosstalk component from the adjacent track is minimized to the adjacent tracks on both sides of the recording track scanned by the magnetic head. Since the recording track is scanned in a protruding manner, the dimensional accuracy of the magnetic head can be relaxed and crosstalk can be suppressed, and special playback can be performed with high-quality images while providing sufficient tracking margin. It has excellent features such as being able to take a large amount of heat and being convenient in terms of manufacturing accuracy of the device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of the guide drum portion of a VTR device, FIG. 2 is a diagram showing the relative positional relationship between a magnetic head and a recording track in a conventional magnetic reproducing device, and FIG. Figure 4 shows the relative positional relationship between the magnetic head and the recording track when the track width of the magnetic head is varied while maintaining the relationship between the magnetic head and the recording track. FIG. 5 is a diagram showing the relative positional relationship between the magnetic head and the recording track in one embodiment, and FIG. 5 is a diagram showing the relationship between the amount of crosstalk and the amount of protrusion. 10, 11...Magnetic head, _W3 , _W4 ...Head tracking width, _d3 ...Tracking margin.

Claims (1)

[Claims] 1 A plurality of magnetic heads having mutually different azimuth angles and head track widths both wider than the recording track width and different from each other are provided, and the entire plurality of magnetic heads are phase-shifted by a predetermined amount with respect to the recording track by a phase shifting means. At least the magnetic head with the maximum head track width among the plurality of magnetic heads scans the recording track in such a manner that it protrudes toward adjacent tracks on both sides of the recording track it scans so that crosstalk components from the adjacent tracks are minimized. A magnetic reproducing device characterized in that it is configured to.