JPH07162894A - Chrominance signal crosstalk reducing method in vtr or the like - Google Patents

Abstract

PURPOSE:To sufficiently reduce crosstalk from an adjacent track for a chrominance signal by reducing the chrominance signal by a head dedicated for chrominance signal reproduction whose azimuth angle is a little larger than that of a head by which the chrominance signal is recorded on a track to be reproduced. CONSTITUTION:The difference 1 deg. of the azimuth angles of the heads C, D dedicated for chrominance signal reproduction and the heads A, B recording the track being in reproduction exists, and a reproduced chrominance signal level on a channel side desired to obtain is not decreased. The crosstalk from the adjacent track is reduced by the azimuth angle increasing from 12 deg. to 13 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color signal crosstalk reducing method in a home VTR (video tape recorder) or the like.

[0002]

2. Description of the Related Art Conventionally, in a home-use VTR, heads whose azimuth angles are opposite to each other are used to sequentially scan successive tracks on a video tape, and azimuth loss is used to cross adjacent tracks. It reduces talk. FIG. 2 shows an example of a video head, where 1a and 1b are gaps and w is a track width.
The gaps 1a and 1b have an angle θ with respect to a line L perpendicular to the running direction of a video tape (not shown). This angle θ is called an azimuth angle, and VHS · VT
At R, it is 6 °. FIGS. 2A and 2B show heads in which the azimuth angles are opposite to each other. FIG. 3 shows the azimuth loss with respect to the azimuth angle, and it can be seen that the loss is large when the frequency is high.

[0003]

In the VTR that reduces crosstalk by utilizing the azimuth loss as described above, the azimuth loss due to the azimuth angle is considerably large for the recording luminance signal located in the high frequency band, and the adjacent tracks are adjacent to each other. However, since the color signal has a low frequency band, it is not possible to expect a sufficient crosstalk suppression effect. By the way,
If a dedicated color signal reproducing head having a width narrower than that of the recording track is provided, crosstalk from an adjacent track can be sufficiently reduced, but the narrowing of the width also reduces the level of the reproduction signal.

The present invention eliminates the above-mentioned drawbacks, and also provides a color signal crosstalk reducing method in a VTR or the like which can sufficiently reduce crosstalk from adjacent tracks with respect to color signals. It is intended.

[0005]

In order to solve the above problems, a color signal crosstalk reducing method in a VTR or the like according to the present invention uses a head having azimuth angles opposite to each other as in a home VTR. A VTR which reproduces a recorded color signal by low-pass conversion by reducing the crosstalk from an adjacent track by utilizing azimuth loss by sequentially scanning each track on a video tape. For example, the color signal is reproduced by a dedicated head for color signal reproduction, in which the azimuth angle is slightly larger than the head that recorded the color signal on the track to be reproduced, without causing a substantial decrease in the reproduced color signal level. It is characterized by doing.

[0006]

In the color signal crosstalk reducing method as described above, the dedicated head for reproducing the color signal has a small difference (eg, 1 °) in azimuth angle from the head recording the track being reproduced. There is no reduction in the reproduced color signal level on the side of the channel that is about to be tried. According to FIG. 3, when the frequency is 629 kHz, there is almost no azimuth loss in the azimuth angle range of approximately 0 to 1 °. However, crosstalk from adjacent tracks can be reduced by the increased azimuth angle.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. According to the VHS standard, the azimuth angle of the head is 6 °, and the relative azimuth angle of the head scanning adjacent tracks is 12 °. A luminance signal and a color signal are recorded and reproduced by these heads A and B. In the present invention, the heads A and B record the luminance signal and the color signal and reproduce the luminance signal. In addition to these heads A and B, dedicated heads C and D for color signal reproduction are used to reproduce color signals. The azimuth angle of the dedicated heads C and D is 7 °, and the relative azimuth angle of the dedicated heads C and D for scanning the adjacent tracks is 14 °. Therefore, the relative azimuth angle between the head A (or B) recording the track being reproduced by the dedicated head C (or D) and the dedicated head C (or D) is 1.
And the relative azimuth angle between the head B (or A) recording a track adjacent to the track being reproduced by the dedicated head C (or D) and the dedicated head C (or D) is 13 °. Is.

According to FIG. 3, when the frequency is 629 kHz, there is almost no azimuth loss when the azimuth angle is 1 °. For this reason, the reduction of the reproduction signal level from the track to be reproduced is negligible. On the other hand, according to FIG. 3, it can be seen that the crosstalk from the adjacent track where the azimuth angle is 13 ° is reduced as compared with the case where the azimuth angle is 12 °. Therefore, the ratio of the color signal level when the color signal recorded by the head A is reproduced by the head A and the crosstalk of the color signal reproduced by the head A of the color signal recorded by the head B is more than Of the ratio of the color signal level when the color signal recorded by the head A is reproduced by the dedicated head C and the crosstalk of the color signal reproduced by the dedicated head C of the color signal recorded by the head B. It becomes bigger.

Although the above description is about the crosstalk of the color signal, the crosstalk of the luminance signal from the adjacent track is reduced by using the dedicated heads C and D. Further, regarding the luminance signal of the track to be reproduced, since this is a high frequency component, even if the azimuth angle is 1 °, the azimuth loss is considerably large, and it is mixed in the color signal reproduced by the dedicated heads C and D. The luminance signal component is suppressed. The color signals reproduced by the heads C and D are preferably time-matched with the reproduction luminance signals from the heads A and B. Further, although the above-mentioned embodiment is for the VTR, the present invention can be applied to a reproduction-only machine.

[0010]

As described above, according to the present invention, the azimuth angle is slightly larger than that of the head in which the color signal is recorded on the track to be reproduced within a range in which the reproduced color signal level is not substantially reduced. Since the color signal is reproduced by the dedicated head for reproducing the color signal, it is possible to sufficiently reduce crosstalk from the adjacent track regarding the color signal.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining an embodiment of the present invention.

FIG. 2 is a schematic front view showing a conventional video head.

FIG. 3 is a generally known characteristic diagram showing azimuth loss with respect to azimuth angle.

[Explanation of symbols]

 A, B head C, D dedicated head

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[Procedure amendment]

[Submission date] August 25, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: Method for reducing color signal crosstalk in VTR and the like

Claims (1)

[Claims] 1. A home VTR, in which heads whose azimuth angles are opposite to each other are used to sequentially scan successive tracks on a video tape, and azimuth loss is used to cross from adjacent tracks. In order to reduce the talk, in a VTR or the like which reproduces a color signal recorded by converting to a low frequency band, it is more effective than a head recording a color signal on a track to be reproduced.
A method for reducing color signal crosstalk in a VTR or the like, wherein a color signal is reproduced by a dedicated head for reproducing a color signal whose azimuth angle is slightly larger within a range that does not cause a substantial decrease in the reproduction color signal level.