JPH01218289A - Crosstalk measuring method for video disk reproducing device and its measuring disk - Google Patents

Abstract

PURPOSE:To measure crosstalk through the application of the method to the CLV system by extracting a beat frequency component of a part caused with a beat due to leakage of a signal from inner and outer adjacent tracks. CONSTITUTION:A signal at a white level at the upper side of the screen is extracted from a pickup detection signal outputted from a CDV player 10 by an extraction circuit 12 and a signal at a white level at the lower side of the screen is extracted by an extraction circuit 20. The extracted white signal is given to crosstalk meters 14, 22, a synchronizing signal is eliminated by blanking circuits 16, 24 and a component in 1.2MHz corresponding to a beat frequency between white and black level signals is extracted by band pass filters 18, 26. The beat frequency component outputted from the crosstalk meters 14, 22 is added by an adder 28 and fed to a level meter 30.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention measures crosstalk in playback devices such as CDV (CD with video) and LV (Laser Vision Disc) using a CLV (Constant Linear Velocity) disc. The present invention relates to a method and a measuring disk thereof.

rPrior art] In disc playback devices such as CDV and LV, when one of the lens elements of the pickup is tilted, the reading spot, which should normally be focused on a minute circular spot, has a tail like a bud (common aberration). ), if the direction of the tail is in the disk radial direction, it overlaps with the adjacent track and reads the signal, causing Talostalk interference. In order to prevent this, it is necessary to quantitatively measure the amount of talostoke and correct the inclination of the optical axis of the pickup lens during the manufacturing process of the disc playback device.

A conventional method for measuring crosstalk in a disc playback device is to use a measurement disc recorded using the CAV (constant rotational velocity) method.

As shown in Figure 2, there is a frame L-1 consisting of an image in which the screen is divided into left and right halves, one of which is black and the other white, and an image that is entirely white except for the center border. Create a frame L consisting of a frame L, and a frame L÷1 consisting of an image obtained by inverting the image of frame L-1, and print these three frames consecutively on the disk in one rotation per frame as shown in Figure 3. frame L as a still (STI).
It is designed to be played repeatedly in LL > mode.

According to this, as shown in the enlarged view in FIG. 3, the part of the white signal in front of the boundary line of frame L (the part A on the image of frame L in FIG. 2) has the part of frame L-1. The black signal leaks in, and the black signal of frame L+1 leaks into the white signal part on the right side of the boundary line (part B), and these crosstalks are caused by the white images A and B on the image of frame N.
appears as beet stripes.

Therefore, the video signal of parts A and B of frame N is passed through a blanking circuit that removes the horizontal synchronization signal and vertical synchronization signal, and then passed through a bandpass filter that passes only the beat component.For example, the white signal is (IRE is a unit representing brightness and saturation), the recording bit is 9.
If the black signal is 3MHz carrier and the black signal is 0IRE, the recorded pit will be an 8.1MHz carrier and the beat frequency will be 9.3-8.1=1.2MHz, so set the passband of the bandpass filter to 1.2MHz. .

If the optical axis of the pickup lens is adjusted so that the sum of the beat components of the A and B portions is minimized, crosstalk interference can be reduced.

[Problem to be solved by the invention]

The conventional crosstalk measuring method uses a CAM disc, and is not suitable for players such as CDV players that are dedicated to CLV discs.

Furthermore, as shown in FIG. 2, this method has the disadvantage that it is troublesome to prepare a measurement disk because images with completely different patterns must be created for each frame.

The present invention solves such drawbacks in the conventional technology, and can be applied to players exclusively for CLV discs, and also enables crosstalk measurement of disc playback devices that can facilitate the creation of measurement discs. It is an object of the present invention to provide a method and a measuring disk thereof.

[Means to solve the problem]

The crosstalk measurement disk of the present invention can process a color-divided image divided into N (a positive odd number of 3 or more) in the direction adjacent to the video scanning line, with the field between adjacent tracks being approximately M/N (M
This is a linear velocity-fixed video disc in which pulse frequency modulation is continuously recorded at rotational speed positions such that recording is performed with a relative shift of =1.2, . . . , N-1).

Further, the crosstalk measuring method of the present invention detects a video signal before pulse frequency demodulation from the video disc, and detects a portion of the color-divided image where a beat occurs due to signal leakage from an adjacent inner track; The beat frequency components of the portions where beats occur due to signal leakage from adjacent tracks on the outer circumferential side are extracted, and the amount of crosstalk between adjacent tracks of the disc playback device is measured.

[For production]

To measure crosstalk by identifying the direction of leakage, it is necessary to separate the parts where beats occur due to signal leakage from the inner adjacent track and the parts where beats occur due to signal leakage from the outer adjacent tracks. The relationship between the signal of a trace track and the signal of its adjacent track must be defined in such a way that the relationship between the signal of a trace track and the signal of its adjacent track must be defined. Both of (a) and (b) are incompatible because the signal of the trace track and the signal of the adjacent inner and outer tracks are the same signal and do not generate a beat. Furthermore, in both cases (c) and (d), since the signal of the trace track is different from the signal of the adjacent inner and outer tracks, a beat is generated, but since it is not possible to distinguish whether the leak is from the inner or outer side, they are also incompatible.

Therefore, in order to cause beats due to leakage from either the outside or the outside, the relationship between the signals with the adjacent tracks must be as shown in Figure 5, i.e., the signal of the adjacent track on either the outside or the outside is the signal of the trace track. Same as,
The other signal needs to be in a different state from the trace track signal.

In this way, since beats are caused by crosstalk from tracks on different sides of the signal, it is possible to identify from which side the signal is leaking.

In order to create the relationship shown in Figure 5, the number of image divisions must be a positive odd number of 3 or more, that is,
Divide the image into even numbers, such as white, black, etc. as shown in Figures 6 and 7.
If the white and black are divided into four parts (the deviation from the adjacent track is 1/4 field in the case of Fig. 6, and 2/4 field in the case of Fig. 7), the relationship with the signal of the adjacent track will be different. Also, even if the number of divisions is an odd number but there is no shift between adjacent tracks, the non-conforming state shown in FIG. 4 will occur and the method cannot be adopted. That is, in order to create the relationship shown in FIG.
, 2, ..., N-1).

Therefore, in the present invention, as shown in the means for solving the above problems, as a measuring disk, N is provided in the direction adjacent to the video scanning line.
(Positive odd number of 3 or more) A divided color divided image is divided into adjacent tracks with a field distance of approximately M/N (M=1.2,...
, N-1), continuous pulse frequency modulation recording is performed at rotational speed positions where the recording is performed with a relative shift of an amount of (N-1). As a result, when this position is played back, a beat due to signal leakage from the inner adjacent track will occur in a specific divided part of the color divided image, and a beat will occur in the other specific divided parts from the outer adjacent track. Beats occur due to signal leakage from the disc, and the amount of crosstalk between adjacent tracks of a disc playback device can be measured by identifying the direction of the leakage.

According to this, it can also be applied to a player exclusively for CLV discs. In addition, there is no need to record different image patterns for each frame, and the same image can be recorded.
For example, it is sufficient to take a color-separated image by actual photographing or the like and record the image signal on a disk, thereby making it possible to easily create a disk.

[Example 1] An example of the present invention will be described below. Here, CDV
28, a case will be described in which a measurement image is recorded in which the screen is vertically divided into three parts: white, black, and white. In order to measure crosstalk using three divided images (white, black, white), the signal arrangement should be as shown in Figures 9 and 10. In Figure 9, the deviation from the adjacent track is 1/ In the case of 3 fields, FIG. 10 shows the case of 2/3 fields. In the case of Fig. 9, the white part (a>
The black signal from the outer track leaks into the lower part (c), causing a beat, and the black signal from the inner track leaks into the lower white part (c), causing a beat.

In the case of Fig. 10, the black signal from the inner track leaks into the upper white part (a) and causes a beat, and the black signal from the outer track leaks into the lower white part (c). The signal leaks in and creates a beat. Therefore, the white part above (
a> and the beat component of the lower white part (C) are extracted, and the optical axis of the pickup lens is adjusted so that the sum of these components becomes the minimum.

Let us consider the positions where the states shown in FIGS. 9 and 10 are obtained in the CDV standard. As shown in FIG. 11, a CDV consists of an audio section and a video section, both of which are recorded in the CLV format. The rotation speed of the video section is 45 rps at the video program start position, and when a three-part image is recorded at this position, the relationship shown in FIG. 9 is obtained. The recording pattern on the disk at this time is shown in FIG. In other words, at this position, one field is the length of 3/4 revolution, so 60 fields/second x 3/4 revolution = 45 r
pm, causing a 1/3 field shift from the adjacent track, and the black signal from the adjacent track on the outer circumferential side leaks into the signal of the white part (a) on the image, causing the lower white part (C
) The black signal from the adjacent track on the inner circumferential side leaks into the signal. FIG. 12 shows the pickup detection signal at this position.

In the pattern shown in Figure 8, the rotation position at the start of the field returns to the original position every 2 frames and 3 rotations, so when using this pattern, in the playback mode, jump 3 tracks every 3 rotations and return to the original position. You can perform measurements by repeating playback to return to . In this case, the pattern shown in FIG. 1 is recorded not only for three revolutions to be traced, but also for at least one revolution before and after the trace.

An example of crosstalk measurement using a disc recorded with the pattern shown in FIG. 8 is shown in FIG. 1, which shows a pickup detection signal (RF
As for the double signal, the white (a) signal on the upper side of the screen is extracted by the extraction circuit 12. Further, the extraction circuit 20 extracts the white (b) signal at the bottom of the screen. The extracted white (a) signal is input to the crosstalk meter 14, synchronization signals (vertical synchronization, horizontal synchronization) are removed by the blanking circuit 16, and the beat frequency of the white signal and black signal is changed by the bandpass filter 18. The corresponding 1 and 2 MHz components are extracted.

On the other hand, the white (b) signal is input to the crosstalk meter 22, the synchronization signals (vertical synchronization, horizontal synchronization) are removed by the blanking circuit 24, and the white (b) signal is passed through the bandpass filter 26, which corresponds to the beat frequency of the white signal and black signal. 1,2M- components are extracted.

The beat frequency components output from the crosstalk meters 14 and 22 are added by an adder 28 and then sent to a level meter 30.
is supplied to To adjust the optical axis of the optical pickup, etc., refer to the indication on the level meter 30 and adjust it so that it is at its minimum.

Incidentally, as a recording pattern on a disk that can obtain the three-division 2/3 field shift relationship shown in FIG. 10, for example, the one shown in FIG. 13 can be considered.

In this case, one field has 315 revolutions, so 60
Record at a rotational position of field/second x 315 revolutions = 36 rps. Also, if the track jump is performed 6 times every 6 rotations of 5 frames, the device returns to the original position, and measurement can be performed by repeat playback.

[Embodiment 2] In the above embodiment, the case where the screen is divided into three is shown, but the number of divisions can be increased.6For example, when dividing the screen into five as shown in Fig. 14, the relationship with the signals of adjacent tracks is The deviation from the adjacent track, which may be defined as shown in FIGS. 15 to 17, is 115 fields in the case of FIG. 15, 215 fields in FIG. 16, and 315 fields in FIG. Note that a shift of 415 fields is also possible. In the case of FIG. 15, a beat occurs in white (a) due to leakage of black signal from an adjacent track on the outer circumference side, and a beat occurs in white (e) due to leakage of black signal from an adjacent track on the inner circumference side. Therefore, the optical axis of the optical pickup may be adjusted so that the sum of these beat components (a) and (e) is minimized.

In the case of Fig. 16, beats occur in white (a) and black (b) due to leakage of the black signal and white signal from adjacent tracks on the inner circumference, respectively, and in black (d) and white (e), beats occur on the outer circumference, respectively. Beats occur due to leakage of white and black signals from adjacent tracks. Therefore, these (a), (b), (d), (e
The optical axis of the optical pickup may be adjusted so that the sum of the beat components in ) or the sum of one of the beat components in (a) and (b) and one of the beat components in (d) and (e) is minimized.

In the case of Fig. 17, beats occur in white (a) and black (b) due to leakage of the black signal and white signal from adjacent tracks on the outer circumference, respectively, and in black (d) and white (e), beats occur on the inner circumference, respectively. Beats occur due to leakage of white and black signals from adjacent tracks.2. Therefore, these (a), (b), (d), (e
The optical axis of the optical pickup may be adjusted so that the sum of the beat components in ) or the sum of one of the beat components in (a) and (b) and one of the beat components in (d) and (e) is minimized.

Examples of recording patterns on the disk that provide the relationships shown in FIGS. 15 to 17 are shown in FIGS. 18 to 20, respectively.
In the case of Fig. 8, one field is 5/6 rotations, so recording is performed at a rotational position of 60 fields/second x 5/6 rotations = 50 rps. Furthermore, if the instrument jumps 5 tracks every 5 revolutions of 3 frames, it will return to its original position and measurement can be performed by repeat playback.

In the case of Figure 19, one field is 5/7 revolutions, so 60 fields/second x 577 revolutions! = recorded at the rotational position of t43rps. Also, for every 10 rotations of 7 frames, 1
A zero track jump returns it to its original position, allowing it to be measured by repeat playback.

In the case of FIG. 20, since one field is 5/8 rotation, it is recorded at a rotational position of 60 fields/second x 5/8 rotation = 37.5 rps. Furthermore, if the position is shifted by 5 track jumps every 5 rotations of 4 frames, it returns to the original position, and measurement can be performed by repeat playback.

[Embodiment 3] An embodiment in which the screen is divided into seven parts as shown in FIG. 21 will be described. In the case of dividing into seven, for example, the relationship with the signals of adjacent tracks may be defined as shown in FIGS. 22 to 24. In the case of FIG. Figure 23 is 2/7 field, 1st
Figure 7 is a 3/7 field. In addition, 4/7.5/7
．． A shift of 6/7 fields is also possible.

In the case of FIG. 22, a beat occurs in white (a) due to leakage of black signal from an adjacent track on the outer circumference side, and a beat occurs in white (g) due to leakage of black signal from an adjacent track on the inner circumference side.

Therefore, the optical axis of the optical pickup may be adjusted so that the sum of these beat components (a) and (g) is minimized.

In the case of Fig. 23, beats occur in white (a) and black (b) due to leakage of the black signal and white signal from adjacent tracks on the inner circumferential side, respectively, and in black (f) and white (g), beats occur on the outer circumferential side, respectively. Beats occur due to leakage of white and black signals from adjacent tracks. Therefore, these (a), (b), (f), (g
The optical axis of the optical pickup may be adjusted so that the sum of the beat components in ) or the sum of one of the beat components in (a) and (b) and one of the beat components in (f) and (g) is minimized.

In the case of Fig. 24, beats occur in white (a), black (b), and white (C) due to leakage of the black signal, white signal, and black signal from adjacent tracks on the outer circumferential side, respectively, and white (d) and black Beats occur in (f) and white (g) due to leakage of the black signal, white signal, and black signal from the inner adjacent track, respectively. Therefore, these (a), (b), (c), (e), (f), (
The sum of the beat components of g) or (a), (b), (c)
any one or two of the beat components and (e)
, (f), and (g), the optical axis of the optical pickup may be adjusted so that the sum of any one or two of the beat components is minimized.

Examples of recording patterns on the disk that provide the relationships shown in FIGS. 22 to 24 are shown in FIGS. 25 to 27, respectively.
In the case of Figure 5, one field is 7/8 rotations, so it is recorded at a rotational position of 60 fields/second x 7/8 rotations = 52.5 rps. In addition, by performing 7 track jumps every 7 rotations of 4 frames, it returns to its original position and can be measured by repeat playback.

In the case of FIG. 26, since one field is 7/9 rotations, it is recorded at a rotational position of 60 fields/second x 7/9 rotations to 47 rps. Further, if the track jump is performed 14 times every 14 rotations of 9 frames, the device returns to the original position, and measurement can be performed by repeat playback.

In the case of FIG. 27, since one field is 7/10 rotations, it is recorded at a rotational position of 60 fields/second x 7/10 rotations = 42 rps. Also, if the track jump is performed 7 times every 7 rotations of 5 frames, the device returns to the original position, and measurement can be performed by repeat playback.

[Example of change]

In the embodiment described above, the screen is divided into a repeating pattern of white and black, but it is also possible to divide the screen into other colors.

Further, in the above embodiment, the present invention is applied to a CDV, but it can also be applied to various video disc playback devices such as LV.

〔Effect of the invention〕

As explained above, according to the present invention, crosstalk can be measured by applying to the CLV method. In addition, there is no need to record different image patterns for each frame.
Since it is sufficient to record the same image, in the case of ρI, it is sufficient to take a color-separated image using live photography, etc., and record the image signal on a disk.
Disc creation can be facilitated.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention in which crosstalk is measured using a disc recorded in the pattern shown in FIG. 8. FIG. 2 is a diagram showing a conventional measurement image. FIG. 3 is a diagram showing a recording pattern on a disk that realizes the image of FIG. 2. FIG. 4 is a diagram showing the signal arrangement on the disk that is incompatible with the cross 1 to 3 measurements, respectively. FIG. 5 is a diagram showing the signal arrangement on the disk, each suitable for crosstalk measurement. FIGS. 6 and 7 are diagrams each showing the positional relationship of signals with adjacent tracks when the image is divided into even numbers. FIG. 8 is a diagram showing a recording pattern on a disk showing an embodiment of the present invention, and shows an example of a pattern that realizes the positional relationship shown in FIG. 9. FIGS. 9 and 10 are diagrams showing the positional relationship of signals with adjacent tracks for realizing a three-part image, respectively. FIG. 11 is a diagram showing the standard for the number of revolutions of a CDV. FIG. 12 is a diagram showing a reproduction signal of the recording pattern of FIG. 8. FIG. 13 is a diagram showing an example of a recording pattern on a disk that realizes the positional relationship shown in FIG. 10. FIG. 14 is a diagram showing a five-divided image showing another embodiment of the present invention. FIGS. 15 to 17 are diagrams showing the positional relationship of signals with adjacent tracks for realizing the 5-divided image shown in FIG. 14, respectively. FIGS. 18 to 20 are diagrams showing examples of on-disk recording patterns that realize the positional relationships shown in FIGS. 15 to 17, respectively. FIG. 21 is a diagram showing a seven-part image showing another embodiment of the present invention. FIGS. 22 to 24 are diagrams showing the positional relationships of signals with adjacent tracks for realizing the seven-divided image shown in FIG. 21, respectively. FIGS. 25 to 27 are diagrams showing examples of recording patterns on the disk that realize the positional relationships shown in FIGS. 22 to 24, respectively. FIG. 28 is a diagram showing a three-part image showing an embodiment of the present invention. 10...CDV player, 14.22...Crosstalk meter, 28...Adder, 30...Level meter.

Claims (2)

[Claims] (1) A color-divided image divided into N (a positive odd number of 3 or more) in the direction of adjacent video scanning lines, where the field between adjacent tracks is approximately M/N (M = 1, 2,..., N-1). A video signal before pulse frequency demodulation is detected from a constant linear velocity video disc that is continuously recorded using pulse frequency modulation at rotational speed positions where the data is recorded with a relative shift of . The beat frequency components of the portion where beats occur due to signal leakage from the inner adjacent track and the portion where beats occur due to signal leakage from the outer adjacent track are extracted respectively, and the beat frequency components are extracted from the portion where beats occur due to signal leakage from the adjacent tracks on the outer side. A method for measuring crosstalk in a video disc playback device, characterized in that the amount of crosstalk in a video disc playback device is measured. (2) A color-divided image divided into N (a positive odd number of 3 or more) in the direction of adjacent video scanning lines, where the fields between adjacent tracks are approximately M/N (M = 1, 2,..., N-1). A constant linear velocity type that is made by continuous pulse frequency modulation recording at rotational speed positions that are recorded with a relative shift of . Disc for measuring crosstalk in video disc playback equipment.