JPH0583738A - One set of video disk, video disk generator and video disk reproducing device - Google Patents

Abstract

PURPOSE:To provide one set of video disk, its generator and its reproducing device for a high definition television signal with higher picture quality and longer recording time than those of a conventional device. CONSTITUTION:A low pass filter 3 limits bands of a luminance signal and two color difference signals. Then a time axis expansion circuit 4a and a signal share circuit 4b convert the signals into a 3-channel signal. Each channel signal is recorded on different video disks 14,15,16. In the reproduction system, the signals from the three video disks are simultaneously reproduced, The reproduced 3-channel signals are restored into a luminance signal and two color difference signals by the action of the time axis compression circuit and the signal share circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a set of video discs for high definition television signals, a video disc making apparatus and a video disc reproducing apparatus.

[0002]

2. Description of the Related Art For example, in a high-definition television signal proposed by the Japan Broadcasting Corporation, the bandwidth of the luminance signal and the bandwidth of each color difference signal of red and blue are considerably wide, and the total bandwidth is the current NTSC. It is much wider than the standard television signal.

When recording a television signal having such a wide bandwidth on a video disc, measures such as increasing the number of revolutions of the video disc, shortening the wavelength of recording laser light, and narrowing the track pitch are taken. I need.
However, practical technology for implementing such measures is still insufficient.

Therefore, there has been proposed a recording method for realizing a good image quality within the range of the current band (Japanese Patent Laid-Open No. 104095/1990).

In this method, the band is reduced for the luminance signal by the time-axis expansion process, and the color-difference signal is subjected to the time-axis compression process by utilizing the signal for each horizontal scanning period. And the same as the band of the luminance signal after the time axis expansion processing, the luminance signal and two color difference signals are multiplexed to obtain a two-channel signal, and these two-channel signals are recorded on the double spiral track of the video disc, respectively. It was something to do.

[0006]

However, the conventional method has a problem that the recording time for one video disk is short. For example, it took about 8 minutes for the constant angular velocity rotation method (CAV method) and about 15 minutes for the constant linear velocity method (CLV method).

This is because the recording band is reduced, but the high-definition television signal is recorded, so that the band cannot be greatly reduced in consideration of the image quality.
Moreover, since the recording is performed by the double spiral, the track pitch is limited by the arrangement of the optical system and the like.
Further, even if two beams are obtained by using a diffraction grating and a double helix is realized, if the track pitch is set to a safe value, the angle between the two beams must be increased, and therefore the wavelength is lengthened. This is because the recording amount is limited.

Further, according to the above-mentioned conventional method, although the image quality is as high as possible, the luminance signal and 2
Since the two-channel signal is formed from the individual color difference signals, the luminance signal and the color difference signals are considerably band-limited, and it is inevitable that the image quality is deteriorated.

The present invention has been made in consideration of the above points, and an object of the present invention is to provide a set of video discs having a higher image quality and a longer recording time than conventional ones. Another object of the present invention is to provide a video disc creating apparatus capable of producing such a set of video discs. Further, the present invention aims to provide a video disc reproducing apparatus capable of reproducing such a set of video discs.

[0010]

In order to solve such a problem, a set of video discs according to the first aspect of the present invention performs a time axis expansion process and a signal distribution process on a luminance signal in a high definition television signal. Of the two channel signals thus formed, a first video disc on which one channel signal is recorded, a second video disc on which the other channel signal is recorded, and a color difference signal in a high-definition television signal. And a third video disc on which a channel signal formed by performing a multiplex process is recorded.

The video disc producing apparatus according to the second aspect of the present invention expands the luminance signal in the high-definition television signal in the time axis so as to produce the set of video discs according to the first aspect of the present invention. Channel signal forming means for alternately distributing the converted luminance signals to form first and second channel signals and thinning and selecting two color difference signals to form a third channel signal; The channel signal is recorded on the first video disc and the second
And recording means for recording the third channel signal on the third video disc.

The video disc reproducing apparatus according to the third aspect of the present invention is to reproduce the set of video discs according to the first aspect of the present invention.
The pickup means for picking up the third channel signal and the picked up first and second channel signals are time-axis compressed and alternately selected and combined to reproduce the original luminance signal, and at the same time, the third picked up signal is picked up. The channel signal is divided into two color difference signals, and the channel signal decomposing means for reproducing the two color difference signals by interpolating the horizontal scanning period in which the color difference signals are thinned by the divided color difference signals.

[0013]

According to the first aspect of the present invention, the signals are distributed and recorded on three video discs for the purpose of prolonging the recording time of high-definition television signals and improving the image quality. In this case, in order to equalize the bands of the luminance signal and the two color difference signals in the recording signal, the luminance signal is subjected to the time axis expansion processing. Further, in order to record on three video discs, signal distribution processing for converting a luminance signal and two color difference signals into a three-channel signal is performed.

In the second aspect of the present invention, the channel signal forming means expands the luminance signal in the high-definition television signal on the time axis and distributes the time axis-converted luminance signal to divide the first and second channel signals. Together with forming
The two color difference signals are thinned out and selected to form the third channel signal, and the recording means forms the first channel thus formed.
Recording the channel signal of the first video disc, recording the second channel signal of the second video disc,
The third channel signal is recorded on the third video disc to create a set of three video discs.

In the third aspect of the present invention, the pickup means picks up the first to third channel signals recorded on the set of video discs, and the channel signal decomposing means picks up the first and third picked up signals. The second channel signal is time-axis compressed, and the original luminance signal is reproduced by alternately selecting and synthesizing the same, and the picked-up third channel signal is distributed to two color difference signals, and the color difference signals are distributed according to the distributed color difference signals. The two color difference signals are reproduced by interpolating the horizontal scanning period in which is thinned out.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below in the order of a video disk producing apparatus and a video disk reproducing apparatus with reference to the drawings.

FIG. 1 shows the construction of the producing apparatus. The high-definition television signal picked up by the video camera 1 for the high-definition television signal at the recording site is given to the digital video tape recorder 2a. For example, the luminance signal is 30 MHz, and the red and blue color difference signals are Each is recorded on video tape at 15 MHz.

Such a video tape is a digital video tape recorder 2b provided at the site of making a video disc.
Is loaded and played. The reproduced luminance signal and the two color difference signals are given to the low-pass filter circuit 3, the luminance signal is band-limited to 22 MHz, and each color difference signal is band-limited to its half, 11 MHz. The luminance signal and the two color difference signals that have passed through the low-pass filter circuit 3 are provided to the 3-channel conversion circuit 4.

The 3-channel conversion circuit 4 is functionally divided into a time axis conversion circuit 4a and a signal distribution circuit 4b,
In response to the timing control by the timing control circuit (synchronization control circuit) 5, the input luminance signal and the two color difference signals are converted into 3-channel signals.

FIG. 2 is an explanatory diagram of making three channels.
Here, FIGS. 2A1 to 2A3 and 2B1 to 2B2.
2 shows the luminance signal Y and the two color difference signals PB and PR.
It is described according to the notation method shown in (C1) to (C3).

In the case of this embodiment, the luminance signal and the two color difference signals are converted into 3-channel signals every two horizontal scanning periods.

The input luminance signals (Y1, Y2, Y3, ...) Shown in FIG. 2 (A1) are doubled in time axis by the time axis expansion circuit 4a (compressed to 1/2 in band). ), And by the signal distribution circuit 4b shown in FIG.
It is alternately assigned to the first channel signal shown in 1) and the second channel signal shown in FIG. 2B2. Note that the time axis expansion processing and the distribution processing are actually executed in parallel. In this way, the luminance signals (Y1, Y3, ...) In the front horizontal scanning period of two horizontal scanning periods have a time axis of 2
The time axis of the luminance signals (Y2, Y4, ...) In the rear side horizontal scanning period is doubled and inserted into the second channel signal.

On the other hand, for the input blue difference signal shown in FIG. 2 (A2), the signals (B1, B3, ...) In the front horizontal scanning period in the two horizontal scanning periods are selected by the signal distribution circuit 4b. 2B3 is inserted in the first half horizontal scanning period of the next two horizontal scanning periods in the third channel signal shown in FIG. 2B3, and the input red difference signal shown in FIG. The signals (R2, R4, ...) During the horizontal scanning period on the side are signal distribution circuits 4
It is selected by b and inserted in the latter half horizontal scanning period of the next two horizontal scanning periods in the third channel signal.

In this way, the first to third channel signals shown in FIGS. 2B1 to 2B3 are obtained and output from the 3-channel conversion circuit 4.

Here, the reason why the signal is converted into a three-channel signal is that in the case of this embodiment, three video discs are used, and each channel signal is a recorded video signal for each video disc. Become.

The reason why the two channels out of the three channels are used for the luminance signal is that the luminance signal is more important than the color difference signal in terms of image quality.

Further, for the luminance signal, the time axis is expanded to reduce the band to 1/2 (thus 11 MHz), and for the color difference signal, the signal is selected every other horizontal scanning period. This is because the recording band is made uniform by the signal.

The reason why the recording band common to the luminance signal and the color difference signal is 11 MHz is as follows. Considering the level of practical application at the present time, the band of the recording signal is 23 MHz or less due to the restrictions of the optical system and the like. Since the band of 3 MHz or less is used for the audio signal, the recording signal band for the video signal is 3 to 23M.
It becomes Hz. Since a recording signal band after FM modulation, which will be described later, needs to have such a band, each channel signal needs to be narrower than this. Here, when the band of the channel signal is selected so that both sidebands are sufficient,
The band of the channel signal is narrow, resulting in deterioration of image quality. On the other hand, when all the bands of 3 to 23 MHz are assigned to the one sideband, the reproduction of the low frequency component, which is a particular problem in image quality, becomes insufficient. Therefore, as described above, the band of each channel signal is selected to be 11 MHz.

FIG. 3 shows the spectrum of a recording signal for such a channel signal.

The respective channel signals output from the 3-channel conversion circuit 4 are given to the first to third output drive circuits 6 to 8, respectively.

The above-mentioned digital video tape recorder 2
The audio signal reproduced by b is audio P
After being applied to the CM modulator 9 and modulated, it is distributed to three channels and applied to each output drive circuit 6, 7, 8.

Each of the output drive circuits 6, 7 and 8 applies a timing control circuit 5 to a channel signal for a video signal.
Under the control of, the control signal generating circuit 10 generates various control signals (address signals, etc.) and then FM-modulates them.
Furthermore, channel signals for audio signals are combined, and then limited to a predetermined band through recording and amplification processing,
The obtained recording signal of each channel is applied to the corresponding recording optical system 11, 12, 13.

Thus, the first to third master disks 1
Each channel recording signal is recorded in 4-16. In addition,
Each motor (not shown) that rotationally drives the master disks 14 to 16 is controlled to rotate in synchronization by a synchronous driver circuit (not shown) that receives a control signal from the timing control circuit 5 and controls rotation.

The first to the third created by the above configuration
A known method can be applied to create the first to third video discs from the master discs 14 to 16 of No. 1, and the description thereof will be omitted here.

FIG. 4 shows a reproducing apparatus for a set of three video discs thus formed, and the reproducing structure will be described below with reference to FIG.

The three motors 21 to 23, whose rotations are controlled by the common drive synchronization controller 20, are respectively the first, second and third video disks 24, 25 and 2.
6 is rotationally driven. Each video disc 24, 25, 26
Optical heads 27, 28 and 29 are provided so as to face the recording surface. The channel recording signals picked up by the optical heads 27 to 29 are amplified by the corresponding reproduction preamplifiers 30 and 3132 and then given to the corresponding FM demodulators 33, 34 and 35, and the audio signals are also reproduced. It is provided to the PCM demodulator 36.

The audio PCM demodulator 36 separates and extracts the audio components and then PCM demodulates the 3-channel audio signal to obtain the original audio signal and outputs it to, for example, a high-definition television receiver (not shown).

The FM demodulators 33, 34 and 35 perform FM demodulation after removing the audio band, for example.

The respective channel signals containing the components of the video signal and the control signal thus obtained are respectively associated with the drive control signal separating circuits 37, 38, 3 respectively.
Given to 9. Each drive control signal separation circuit 37, 3
Reference numerals 8 and 39 decode the track number contained in each channel signal and give it to the drive synchronization controller 20, and detect the burst signal contained in the channel signal and give it to the drive synchronization controller 20.

The drive synchronization controller 20 controls the drive of the motors 21 to 23 and the drive of the optical heads 27 to 29 in the radial direction based on these signals.

Each channel signal that has passed through each drive control signal separation circuit 37-39 is divided into three channels.
Given to. The three-channel decomposition circuit 40 is functionally composed of a signal distribution circuit 40a and a time axis compression circuit 40b.

FIG. 5 is an explanatory diagram of the disassembly processing by the channel disassembly circuit 40.

The signal distribution circuit 40a unifies the luminance signals in the first and second channel signals shown in FIGS. 5 (A1) and (A2) and also makes the third channel signal shown in FIG. 5 (A3). For the above, the two color difference signals that have been inserted are distributed, and the color difference signals in the horizontal scanning period thinned out in the video disc creating apparatus are interpolated to obtain the color difference signals as shown in FIGS. 5 (B2) and (B3). Reproduce. The time axis compression circuit 40b compresses the time axis of the luminance signal in the first and second channel signals to 1/2 (expands twice in band). Note that the processing for the luminance signal by the signal distribution circuit 40a and the time axis compression circuit 40b is executed in parallel and in an integrated manner, and the luminance signal as shown in FIG. 5B1 is reproduced.

The luminance signal and 2 thus reproduced
The individual color difference signals are also given to, for example, a high-definition television receiver not shown.

Therefore, according to the above-mentioned embodiment, the luminance signal and the two color difference signals are converted into the signals of three channels, and the signals of each channel are recorded and reproduced on each video disk set of three. Therefore, the recording time of the video disc can be lengthened as compared with the conventional method.

Since each surface of the video disk may be a single spiral track, it is not necessary to provide two optical systems facing one surface of the video disk so as to be close to each other. Thus, the track pitch can be narrowed, and the recording time can be lengthened also from this point.

Further, since the recording is not performed by the double helix as in the conventional case, a diffraction grating for separating the laser beam into two is unnecessary, and the wavelength of the laser beam is not restricted by the diffraction angle. The recording time can be shortened, and the recording time can be lengthened also from this point.

Further, since the recording is divided into three video discs for recording, the band limitation is relaxed accordingly.
A wider band than before can be used and the image quality can be improved.

From the luminance signal and the two color difference signals,
The method of forming the three-channel signal is not limited to that of the above embodiment.

[0050]

As described above, according to the present invention, a time axis conversion process and a signal distribution process are performed on a luminance signal and two color difference signals in a high definition television signal to obtain a three channel signal. Since each channel signal is distributed and recorded on different video discs and reproduced, the recording time can be lengthened and the image quality can be improved as compared with the conventional technique.

[Brief description of drawings]

FIG. 1 is a block diagram showing a creation configuration of a set of video discs according to an embodiment.

FIG. 2 is an explanatory diagram of the three-channel conversion method.

FIG. 3 is a spectrum diagram of a recording signal according to the above embodiment.

FIG. 4 is a block diagram showing a reproducing structure of a video disc according to the embodiment.

FIG. 5 is an explanatory diagram of a 3-channel decomposition method.

[Explanation of symbols]

4 ... 3 channelization circuit, 4a ... Time axis expansion circuit, 4b
... Signal distribution circuit, 14 to 16 ... Master disk, 24
26 ... Video disc, 40 ... 3-channel disassembly circuit, 40a ... Signal distribution circuit, 40b ... Time axis compression circuit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // H04N 7/00 A 9070-5C

Claims (3)

[Claims] 1. A first video recording one channel signal of two channel signals formed by subjecting a luminance signal in a high-definition television signal to time-axis expansion processing and signal distribution processing. A disc, a second video disc on which the other channel signal is recorded, and a third video disc on which a channel signal formed by performing a multiplex process on the color difference signal in the high definition television signal is recorded. A set of video discs characterized by 2. A luminance signal in a high-definition television signal is expanded on a time axis, and the luminance signal whose time axis is converted is alternately distributed to form first and second channel signals, and two color difference signals are provided. Channel signal forming means for thinning and selecting to form a third channel signal, and recording the first channel signal on the first video disc and the second channel signal on the second video disc. A recording means for recording the three channel signals on a third video disc, to produce the set of video discs according to claim 1. 3. Pick-up means for picking up first to third channel signals recorded on the set of video discs according to claim 1, and a time axis for the picked-up first and second channel signals. The original luminance signal is reproduced by compressing and alternately synthesizing, and the picked-up third channel signal is divided into two color difference signals, and the color difference signals are thinned out by the distributed color difference signals. A video disc reproducing apparatus provided with a channel signal decomposing means for interpolating a scanning period and reproducing two color difference signals.