JPH0413246A - Production of video disk or reproducing method thereof - Google Patents

Abstract

PURPOSE:To allow long-time reproducing and to eliminate the need for the interleave processing for compensating drop-outs by equally distributing and recording line sequential color video signals respectively in line periods on a 1st disk rotating in one direction and a 2nd disk rotating in the other direction. CONSTITUTION:The one video information obtd. by alternately equally dividing the line sequential color video signals in the line periods and the other video information are selected. The one video information is recorded on the 1st disk D1 rotating in one direction and the other video information is recorded on the 2nd disk D2 rotating in the other direction. The 1st and 2nd disks or the reproduced disks thereof are adhered and fixed with the reproducing surfaces thereof positioned on the outer side. The double-fold high-grade video signals are reproduced without inverting the disk in this way and the need for the special interleave processing for the purpose of compensating the drop-outs is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method for manufacturing or playing a video disc that enables long-time playback.

(b) Conventional technology A disc method for recording broadband high-definition video signals without changing the baseband is to divide the high-definition video signal into two channels and use two adjacent recording beams to record the divided video information. A method of independently modulating and recording the signal has been widely used. As a result, this recording disk forms double spiral recording tracks, and the recording band is halved.

When reproducing this recording disk, the reproduction information reproduced by two adjacent reproduction beams is combined to form the original high-quality video signal.

(c) Problems to be Solved by the Invention In the conventional example described above, the rotational speed of the disc can be set to 1772 when playing the disc, but on the other hand, the playing time is 1, /' 2, making it difficult to play for a long time. .

Furthermore, since information is simultaneously recorded on adjacent recording tracks, there is a risk that playback information may be lost at the same time due to dropouts. To compensate for this dropout, different interleaving processing is required for each track, and the recording circuit also The circuit also becomes complicated.

(d) Means for solving the division problem Therefore, the present invention provides a first disk that rotates in one direction and a second disk that rotates in the other direction for transmitting line-sequential color video signals to a disk.
The first feature is that recording is performed on each disk at line intervals, and the original line-sequential color video signal is formed by simultaneously playing back both sides of the disk, which is formed by recording line-sequential color video signals on the front and back sides. This is the second feature.

(e) According to the present invention, line-sequential color video signals are distributed at line intervals, one piece of information is distributed to the first disk that rotates in one direction, and the other information is distributed to the second disk that rotates in the other direction. Each disc is recorded independently and fixed with adhesive. Furthermore, during reproduction, a reproduction beam is irradiated on both sides, and the simultaneously reproduced reproduction information is combined and converted into the original line-sequential color video signal.

(F) Embodiment Hereinafter, the present invention will be explained according to an embodiment in which the present invention is adopted in a video denosk for recording and reproducing high-quality video signals.

[Configuration of Signal Recording Apparatus] In this embodiment, a recording apparatus as shown in FIG. 1 is used to record a high-quality video signal.

In this embodiment, a high-definition VTRI is used as a high-definition video signal source.
Use. This high-quality VTRI is an analog VTR that reproduces and derives high-quality baseband video signals recorded on video tape using the built-in crystal oscillation circuit 2 as a reference signal.
The high-quality video signal consists of a 20MHz luminance signal and 1
Consists of two 0MHz color signal systems. If a digital VTR is used instead of this analog VTR, the luminance signal band will be 30MHz and the color signal band will be 15MHz.In order to record all of this information without omission, the recording frequency will be higher than in this embodiment. A recording device with a wide band is required.

In addition to the high-definition video signal, the high-definition VTR reproduces and derives an address code signal with a frame period recorded in the control track, and also outputs the crystal oscillation circuit 2.
The oscillation output (48.6 MHz) is also derived. This oscillation frequency corresponds to 1440 times the horizontal frequency of the high-quality video signal.

The signal obtained from the high quality VTRI is input to the recording encoder 3. This recording encoder 3 inputs two systems of color signals to a line sequential circuit 4, a luminance signal to a time division multiplexing circuit 5, and an address code to an address code detection circuit 6.

The line sequential circuit 4 alternately selects color signals in line periods in synchronization with the address code and the synchronization signal to form and derive line sequential color signals.

The line-sequential color signal is input to the time-base compression circuit 7 and is time-base compressed three times during the horizontal retrace period of the luminance signal from which both ends of each line are partially removed. The line-sequential compressed color video signal is time-division multiplexed in the time-division compression multiplexing circuit 5 and converted into one system of line-sequential high-quality color video signal signals having almost the same arrangement as the MUSE signal, and is then used for signal selection. It is input to circuit 8.

The signal selection circuit 8 selects line-sequential high-quality color video signals every other line in accordance with the recording surface designation signal, and time-division multiplexes the address code onto a specific line in the vertical retrace period. Note that this selection results in selecting only signal lines compressed and multiplexed with the same color signal according to the recording surface designation signal, and the same color information is recorded on the same surface.

The selected signal is time-axis expanded by a factor of two in the time-axis expansion circuit 9 and is input to the frequency multiplexing circuit 10 as a signal with a band of about L2 MHz.

The frequency multiplexing circuit 10 frequency-multiplexes the pilot signal generated by the burst signal generating circuit 12 onto the bank pouch of the horizontal matching signal by frequency division by six periods. Incidentally, the burst signal generating circuit 12 divides the crystal oscillation output by 1/'6 to 8. A pilot signal of 1N1Hz is generated.

The frequency multiplexed output has an FM deviation range of 15.43 to 17.
The F
M modulated. The FM modulation output is supplied to an optical video disc recorder 15 as a recording signal.

Further, the recording encoder 3 includes a reference signal generation circuit 13 for changing the frequency of the reference signal according to the address code to keep the recording linear velocity constant, and a reference signal generation circuit 13 for clearly identifying the recording end of the recording track on the disk record. A termination signal generation circuit 14 is provided for each.

The reference signal specifies the rotational angular velocity of the disc in accordance with the address code, and as a result, when playing back and front sides of a bonded disc at the same time, the linear velocity of the recording track at the same address is always the same. It will match.

Further, the end signal generation circuit 14 detects the end of recording from the address code and sends the end signal to the reference signal generation circuit 1.
3 and is input to the video disc recorder 15,
The reference signal generation circuit 13 fixes the reference signal frequency after the termination signal is input.

Movement control means 16 in the video disc recorder 15
In the initial state, the optical recording means 17 is defined at the innermost circumference of the disk D, and when recording starts, the first optical recording stage 17 is moved toward the outer circumference along the guide rail at a speed inversely proportional to the PG pulse period. It's forcing me. Furthermore, the movement control means 16 also detects position information in the radial direction using a built-in decoder, and corrects the movement speed by comparing the detected position information and the address code.

It goes without saying that the movement control means 16 may be driven by inputting a reference signal and moving the optical recording means 17 at a speed proportional to the reference signal frequency or its frequency-divided output.

The recording means 17 optically modulates the recording signal during the recording period to form a recording track, and operates the mark signal generation circuit 19 at the recording end signal generation timing. This mark signal generation circuit 19 detects the period from the final PG pulse generation timing to the end signal generation timing,
The subsequent PG pulse generation timing is delayed by the corresponding period, and a mark signal of a predetermined frequency is intermittently generated for a certain period. Therefore, the optical recording means 17
A visible end mark T is formed outside the recording end E (see FIGS. 2 and 3).

The disk motor 20 rotates the disk D at a predetermined angular velocity in an initial state, and inputs the supplied reference signal and the FG pulse derived from the disk motor 20 to the phase comparator circuit 21 at the start of recording. The phase is compared. The phase comparison output is input to a motor drive circuit 22, which controls the rotation of the disk motor 20 in accordance with the reference signal frequency. Furthermore, the motor drive circuit 2
2, the polarity of the drive voltage is inverted based on the recording surface designation signal, and the rotation direction of the disk D is reversed in accordance with the recording surface designation signal.

Therefore, when the first disk D1 is loaded and a surface designation signal is generated, the disk motor 20 is rotated clockwise to form recording tracks counterclockwise from the inside to the outside. An end mark T is formed outside the recording end (see FIG. 2).

Incidentally, the recorded signals are the luminance signal of every l line and P,
It's a signal.

Next, when the second disk is loaded and a specified signal on the back side is generated, the disk motor 20 is driven to rotate counterclockwise, and the recording trunk is formed laterally from the inside to the outside. Then, an end mark T is formed outside the recording end (see FIG. 3).

Note that the recorded signals are the luminance signal of every other line and P,
It's a signal.

[Adhesive Formation of Double-Sided Discs] The discs recorded in the above-described procedure and their duplicate discs are adhesively fixed with the playback side facing outward.

In the first embodiment, when this adhesive fixing is performed, the end marks on the front and back sides are made to coincide with each other and are then adhesively fixed. In this way, when aligning the end marks, if you irradiate the playback beam to the same position on the front and back of the disc and play back at the same time, the time lag in the playback information will be reduced, and the delay means for timing alignment will be stored. The capacity can be reduced, and in some cases, it is even possible to omit this delay means.

However, if accurate adhesive fixation cannot be achieved even with positioning, or if there are large fluctuations in the recording timing during recording, the reproduction information on the front side or the reproduction information on the back side may take precedence.

Therefore, during reproduction, it is necessary to provide delay means on both reproduction signal lines.

Therefore, for example, if you glue and fix the end mark on the front side in a clockwise direction ahead of the end mark on the back side so that the playback information on the front side always precedes the playback information on the back side,
Only the reproduction information on the front side needs to be delayed and the reproduction circuit becomes simple.

In the case of adhesion in any of the embodiments, the end mark is used as an index for positioning, but in the first embodiment, it is particularly necessary to use a measuring jig or the like to perform adhesive fixation with high precision.

[Configuration of Reproducing Apparatus] The configuration of a reproducing apparatus for simultaneously reproducing the double-sided disc according to the above-mentioned embodiment from the front and back sides will be described below with reference to FIG.

As is clear from the figure, in a video disc player,
Double-sided discs are installed correctly on both sides. The disk motor 23 is rotating at a predetermined speed in an initial state.

Further, the first pick-up 24 on the front side and the second pick-up 25 on the back side are controlled by the first tracking control means 26 and the first tracking control means 27, respectively.
defined on the innermost periphery of the disk Dl and the second disk D2,
The reproduction beam illuminates the same position on both sides.

When a reproduction operation is performed, the reproduction outputs of the two pickups are inputted to the first FM demodulation circuit 28 and the second FM demodulation circuit 29, respectively, and are FM demodulated.

The first demodulated output is input to a 10th-pass filter 30, a first sync separation circuit 32, a first address detection circuit 34, and a first burst gate circuit 36, respectively. Similarly, the second demodulated output is input to the 20th-pass filter 31, the second sync separation circuit 33, the second address detection circuit 35, and the second burst gate circuit 37, respectively.

Each address detection output is input to the first tracking control circuit 26 and the second tracking control circuit 27, respectively, and when a difference occurs in the address detection timing, a reproduction track is changed.

Further, the synchronization separation output is input as a burst gate pulse to a first burst gate circuit 36 and a second burst gate circuit 37, respectively, to separate the burst signal multiplexed at the synchronization tip.

Each burst signal is transmitted to the first synchronous oscillation circuit 38 and J
The signal is intermittently input to the I2 synchronous oscillation circuit 39 and converted into a continuous signal with a frequency three times that of the burst signal. This continuous signal is used as a write clock.

Therefore, the AD conversion timing of the first AD conversion circuit 40 and the second AD conversion circuit 41 which respectively input each low-pass output is performed in synchronization with each continuous signal.

Further, each continuous signal is inputted to a first write control circuit 42 and a second write control circuit 43, respectively, and a first delay means 4 provided for jitter correction, timing alignment, and time axis extension.
4 and a write address signal of the second delay means 45.

The first delay circuits 44 each have a first color memory 4
4a and an 11th!4 degree memory 44b are provided to store color information and brightness information in separate memories. The second delay circuit 43 also includes a second color memory 45a and a second brightness memory 45b, and stores color information and brightness information in separate memories.

On the other hand, when reading, luminance information is read out alternately from two luminance memories at twice the speed of storage, and color information is read out from each color memory at two-thirds the speed of storage, two times per line period. It is necessary to read the data once at a time. Therefore, in this embodiment, the output of the crystal oscillation circuit 46, which oscillates at twice the frequency of the continuous signal, is input to the continuous control circuit 47, and the luminance signal information and the two systems of color signal information are read out to achieve simultaneous synchronization. are doing.

The read information is input to a first DA conversion circuit 48 for luminance, a second DA conversion circuit 49 for PR, and a third DA conversion circuit 50 for P.

Each DA conversion output is input to a 30th bus filter 51 for luminance, a 40th bus filter 52 for P, and a 50th bus filter 53 for PB, respectively.
It is derived after removing conversion noise.

Further, in order to control the rotational speed of the disk, the frequency-divided output of the continuous signal emitted from the second synchronous oscillation circuit 39 is used as a comparison signal, and the frequency-divided output of the crystal oscillation output is used as a reference signal and the phase is outputted to the phase comparison circuit 54. A comparison is made. The phase comparison output is supplied as a control input to a motor drive circuit 55, and rotation control of the disk motor 23 is executed.

(G) Due to the effects of the invention, according to the present invention, the disc can be rotated without reversing.
The high-quality video signal can be played back, and there is no need for special interleave processing to compensate for the mud and knob-outs that tend to occur, which is a huge benefit.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a recording side circuit according to an embodiment of the present invention;
FIG. 2 is a schematic explanatory diagram of the front disk, FIG. 3 is a schematic explanatory diagram of the rear disk, and FIG. 4 is a schematic diagram of the reproduction side circuit.

Claims (2)

[Claims] (1) Line-sequential color video signals are alternately distributed in a line period to select one video information and the other video information, record the one video information on a first disk rotating in one direction, and A method for manufacturing a video disc, characterized in that the other video information is recorded on a second disc rotating in the other direction, and the first and second discs or their duplicate discs are adhesively fixed with their playback surfaces facing outward. (2) A video disc in which line-sequential color video signals are distributed and recorded on the front and back sides at line intervals is played back simultaneously from both the front and back sides, the playback information of at least one side is stored, and the readout timing is set to the other side. 1. A method for reproducing a video disc, characterized in that a line-sequential reproduced color video signal is formed by alternately synthesizing reproduction information with matching timing and matching reproduction information.