JPH07105111B2 - Video disc and its playback device - Google Patents

Description

The present invention relates to a video disc on which a television video signal is recorded and a reproducing apparatus for the same.

[Conventional technology]

Recently, a disc for recording information at high density has been developed and commercialized. Typical examples are video discs and digital audio discs. There are several types of such methods, but in the case of an optical video disc, the television video signal has a sync tip level of 7.6MHz,
By modulating the frequency of the 8.1 MHz carrier so that the white level becomes 9.3 MHz, the accompanying left and right stereo signals, bilingual signals, and other audio signals are generated at 2.3 MHz.
And recorded by frequency modulating a 2.8 MHz carrier. On the other hand, the spectrum of the EFM signal of the left and right stereo audio signals converted to PCM in the optical digital audio disc occupies a band of about 2 MHz or less. In the video disc, the band below 2 MHz is almost free, so that such EFM signal can be frequency division multiplexed and recorded on the video disc.

Recently, it has been considered to record a predetermined digital data signal in addition to a voice signal on such an optical digital audio disc. In this case, for example, information can be recorded in units of blocks as shown in FIG. That is, one block consists of 2352 bytes, and the first 12 bytes are used as a sync signal. In this sync signal, for example, the first and last 1 bytes are 00, and the middle 10 bytes are all
It is set to FF (hexadecimal number display), and such sync pattern does not occur except for sync. The next 4 bytes are used as a header. 2048 bytes following the header are used as user data. The next 288 bytes of user data are auxiliary data including error detection code, P, Q parity and the like. All data other than sync are interleaved.

The frequency of this block is 75 Hz (cycle is about 13.3 ms).
Therefore, it basically has no correlation with the frequency of the video signal frame of 29.97HZ (the cycle is about 33.4 ms).
Therefore, when such a digital data signal is frequency-multiplexed and continuously recorded on a video disc, it is impossible to synchronize the television video signal and the digital data signal.

[Problems to be solved by the invention]

Therefore, for example, in a disc in which a signal of one frame consisting of the first field and the second field is recorded in one rotation, the pickup jumps one track in the vertical blanking interval (Fig. 5 (a)) immediately after the second field. When the digital data signal is played back while the video signal recorded on that track is reproduced as a still picture, the digital data signal becomes discontinuous when jumping back one track, so the data required for deinterleaving after the jump. Data cannot be reproduced in a section of about 11 to 12 ms until the length is read (Figs. 5 (b) and 5 (c)). Conversely, the readable effective data length is about 21 ms in the ideal case where the sync position of the digital data signal happens to be substantially coincident with the vertical sync signal position of the video signal (Fig. 5 (b)). In the worst case where the timings of both are shifted, it will be about 6 ms (Fig. 5 (c)), 400
It will change in the cycle of the frame (about 13.3s). Therefore, if one block of digital data is recorded in correspondence with one frame of television video signal and the corresponding digital data signal is played back while playing back the video signal as a still image, the pickup jumps back, resulting in the data. Occasionally, there is a dropout, and there occurs a frame in which the digital data signal of the block cannot be completely reproduced. Therefore, it is necessary to associate the vertical sync signal of the video signal with the sync position of the digital data signal for each frame, which is not only complicated but also causes uncorrectable dropouts, etc. It was difficult to reproduce completely.

Therefore, the present invention has been made in view of the above problems, and an object thereof is to accurately reproduce a still image even when the frame start position and the block start position are not synchronized during recording. Provided are a video disc capable of reproducing a television video signal and a corresponding digital data signal, and further capable of accurately reproducing a still image and a digital data signal even if there is a dropout or the like, and a reproducing apparatus thereof. Especially.

[Means for solving problems]

In order to solve the above problems, the video disc of the first invention corresponds to a television video signal and a block having a length shorter than a length corresponding to one frame of the television video signal and not synchronized with the frame. In a video disc in which a digital data signal divided into block digital data signals is frequency-divided and recorded as a multiplexed signal in the same track, the same television video signal is recorded in a plurality of the frames, and In the track section corresponding to a plurality of frames, a plurality of the blocks in which the same block digital data signal is recorded are recorded.

The reproducing apparatus of the second invention is divided into a television video signal and a block digital data signal corresponding to a block having a length shorter than one frame of the television video signal and not synchronized with the frame. In a reproducing device for reproducing a video disc in which a digital data signal is frequency-divided and recorded as a multiplex signal in the same track, the same television video signal is recorded in a plurality of the frames as the multiplex signal. At the same time, a pickup (10) for reproducing the multiplex signal from the video disc in which a plurality of the blocks in which the same block digital data signal is recorded in the track section corresponding to the plurality of frames is recorded, First signal processing means (12, 15) for separating and demodulating the television video signal from the multiplexed signal Second signal processing means for separating the digital data signal from said multiplexing signal, to demodulate (20, 2
1) and a control means (19) for controlling the operation of the pickup (10) so as to reproduce the multiplexed signal while repeatedly tracing the track section corresponding to the plurality of frames.
While the pickup (10) is tracing the track section, one of the blocks is selected based on the block digital data signal output from the second signal processing means (20, 21). Extraction means (19, 22, 23) for extracting the block digital data signal of the block.

[Action]

According to the video disc of the first invention, at the time of recording, the same television video signal is recorded in a plurality of frames of the television video signal, and the same block is recorded in the track section corresponding to the plurality of frames. A plurality of blocks in which digital data signals are recorded are recorded.

Therefore, if the television video signal of at least one frame of the plurality of frames in the track section can be played back when the television video signal of the track section is played back as a still image, the still picture can be reliably played back. it can. Furthermore, at the time of recording, a part of the block digital data signal corresponding to the plurality of blocks recorded in the track section cannot be accurately reproduced because the start position of the frame and the start position of the block are not synchronized. However, the digital data signal can be accurately reproduced by reproducing the block digital data signal of at least one other block included in the track section.

According to the reproducing apparatus of the second invention, the pickup (10)
Reproduces the multiplexed signal from the video disc of the first invention, and the first signal processing means (12, 15) outputs it to the second signal processing means (20, 21).

Then, the first signal processing means (12, 15) separates the television video signal from the reproduced multiplexed signal and demodulates it.

Further, the second signal processing means (20, 21) separates the digital data signal from the reproduced multiplexed signal and demodulates it.

At this time, the control means (19) controls the operation of the pickup (10) so as to reproduce the multiplexed signal while repeatedly tracing the track sections corresponding to a plurality of frames.

Thereby, the extraction means (19, 22, 23) is based on the block digital data signal output from the second signal processing means (20, 21) while the pickup (10) is tracing the track section. , A block digital data signal of one block is extracted from a plurality of blocks.

Therefore, when the television image signal corresponding to a plurality of frames is repeatedly reproduced as a still image, if the television image signal of at least one frame among the plurality of frames can be reproduced, the still image reproduction is surely performed. You can Further, even if a part of the block digital data signal corresponding to the plurality of blocks recorded in the track section cannot be accurately reproduced because the start position of the frame and the start position of the block are not synchronized at the time of recording, By reproducing the block digital data signal of at least one other block included in the track section, the digital data signal can be accurately reproduced.

〔Example〕

Next, preferred embodiments of the present invention will be described with reference to the drawings.

(1) Recording of Signal on Disc First, recording of a signal on the disc will be described with reference to FIG.

FIG. 2 shows a block diagram of a recording apparatus for recording information on the video disc of the present invention. That is, the television video signal and the left and right stereo audio signals are respectively modulated by the modulator 1,
It is frequency-modulated by 2 and 3 and input to the adder 4. Reference numeral 5 is a detection circuit for detecting a vertical synchronizing signal from the input video signal. The output signal of the detection circuit 5 controls the memory 6 which stores a predetermined input digital data signal. The output signal of the memory 6 is, for example, EFM modulated by the encoder 7, and then input to the adder 4. Therefore, in the adder 4, the FM signal of the video signal, the FM signal of the audio signal of 2 channels, and the EFM signal of the digital data signal are added, respectively, and supplied to the optical modulator 8, and as a result, a laser light source (not shown) is output. The laser beam is modulated according to the signal and is irradiated onto the disk 9 so that the signal is recorded.

Then, the operation will be described. The video signal and the audio signals of the two channels are frequency-modulated by the modulators 1, 2 and 3, respectively, and then added by the adder 4. The video signal is the same signal in a plurality of frames (for example, two frames). On the other hand, the detection circuit 5 detects the position of the vertical synchronizing signal of the video signal. In the case of a normal television video signal, since one screen is composed of the odd field and the even field following it, the position of the vertical synchronizing signal changing from the even field to the odd field is detected. However, the detection output is output once in a plurality of frames (for example, two frames).

On the other hand, the input digital data signal is written and stored in the memory 6 in correspondence with the clock signal, and a block digital data signal corresponding to a block of 2352 bytes is generated. At this time, the memory 6 is substantially the same until the detection signal is input once every two frames from the detection circuit 5 (the user data may be the same, and the address information of the memory to be stored is included). The header does not necessarily have to be the same) to generate and output the block digital data signal. When a new detection signal arrives from the detection circuit 5, block digital data signals corresponding to the contents of the next block are sequentially generated. The digital data signal blocked by the memory 6 is input to the encoder 7, where it is interleaved and further EF
After being M-modulated, it is input to the adder 4. Therefore, the output signal from the adder 4 is a superimposed signal of the FM-modulated video signal, the EFM-modulated 2-channel audio signal, and the EFM-modulated digital data signal. Since such a superposed signal is input to the optical modulator 8 to modulate the recording light, a signal corresponding to the superposed signal is recorded on the disk 9.
That is, the same video signal is recorded over two frames, and the same block digital data signal is recorded in each block existing in the section of the two frames. Further, the positions of the first vertical sync signal of the video signal of the two frames and the first sync position of the digital data signal are freely set, and an operation for matching the timings of both is not particularly performed.

(2) Signal Reproduction from Disc Next, signal reproduction from the disc will be described with reference to FIGS. 1, 3, and 4.

FIG. 1 shows a block diagram of the reproducing apparatus. A pickup 10 irradiates the disc 9 with a laser beam, receives the reflected light, and outputs a reproduction signal. Regeneration
The RF signal is output through the amplifier 11, of which the FM carrier component of the video signal passes through the bandpass filter 12 as the first signal processing means and is supplied to the demodulator 15 for frequency demodulation. There is. The demodulated video signal is supplied to a CRT or the like (not shown) and is input to the detection circuit 18, where the vertical synchronization signal, frame number, etc. are detected.
The detection signal is input to the control device 19 such as a microcomputer as a control means and an extraction means. The FM carrier components of the audio signals of the two channels are supplied to the demodulators 16 and 17 via the bandpass filters 13 and 14, respectively, and are frequency-demodulated there before being output. Further, the EFM signal component is separated by the low-pass filter 20 as the second signal processing means, supplied to the decoder 21, where the EFM demodulation is performed and output to the memory 22 as the extraction means. Reference numeral 23 is a detection circuit as an extraction means for detecting a sync signal from the digital data signal stored in the memory 22.

Next, the operation of the reproducing apparatus will be described.

The pickup 10 irradiates the disc 9 with light and receives the reflected light to reproduce the information recorded on the disc 9.
This reproduction signal is passed through the amplifier 11 to the bandpass filter 1
It is supplied to 2, 13, and 14, and the carrier of the video signal and the carrier of the left and right audio signals are separated and extracted. These signals are further supplied to demodulators 15, 16 and 17, respectively, and demodulated into a CRT,
It is output to a speaker or the like.

Now, for example, if a predetermined frame number is specified and input,
The controller 19 transfers the pickup 10 in the radial direction of the disc 9 and starts the search operation. The detection circuit 18 is a demodulator 15
The frame number is detected from the demodulated signal output by and is input to the control device 19. The control device 19 stops the search operation when the designated frame number is detected, and causes the pickup 10 to jump back, for example, to repeatedly trace a plurality of frames (for example, two frames) starting from the frame number, The video signal recorded there is reproduced. That is, for example, when one frame of video signal is recorded in one rotation, the jumpback operation is performed once in two rotations. Since the same video signal is recorded in two frames, a still image is reproduced at this time.

On the other hand, the EFM signal components recorded corresponding to the plurality of frames in which still images are reproduced are separated and extracted by the low-pass filter 20, and demodulated by the decoder 21. The controller 19 sends a control signal to the memory 22 to store the demodulated digital data. It is assumed that the digital data signals recorded corresponding to the plurality of frames that are being repeatedly traced have the timings shown in FIG. 3, for example. That is, the same video signal B
There are 6 blocks in which the same block digital data signal b corresponding to the video signal B is recorded in the section of 2 frames in which is recorded. The first block is the beginning of the block and the last block is the last block. The trailing edge of each is missing, and only the middle block is completely recorded. In addition, a part of such a block may be lost due to the jumpback operation of the pickup 10 to the inner circumference of two tracks. Therefore, if the block digital data signal forming one block is missing and the data cannot be completely reproduced, the same operation is performed for the digital data signal corresponding to the next block. Since the same block digital data signal is recorded in each block in the section extending over two frames, even if the timing of the sync position between the vertical synchronizing signal of the video signal and the digital data signal is the worst, at least one block Is completely reproducible. Therefore, it becomes strong against uncorrectable dropouts and the like. In this way, the digital data corresponding to one block is completely reproduced. If such block digital data controls the operation of the reproducing device, it is input to the control device 19 and a predetermined operation is performed, and if it relates to an audio signal or a video signal, a speaker, CR
Supplied to T etc.

In the above description, the case where the video signal of 1 frame per one rotation is recorded in the digital 9 has been described as an example, but the present invention is not applicable even when the video signal of 2 frames per one rotation is recorded. It is possible.

〔effect〕

As described above, according to the first and second aspects of the present invention, the television image is not synchronized with the gestation position of the frame of the television image signal and the start position of the block of the digital data signal. Even in the case of a video disc in which a multiplexed signal of a signal and a digital data signal is recorded, when reproducing a television video signal and a digital data signal while repeatedly tracing a plurality of consecutive frames of the video disc, If the television video signal of at least one frame of the plurality of frames can be reproduced, still image reproduction can be surely performed. Further, even if a part of the block digital data signal corresponding to the plurality of blocks recorded in the track section cannot be accurately reproduced because the start position of the frame and the start position of the block are not synchronized at the time of recording, By reproducing the block digital data signal of at least one other block included in the track section, the digital data signal can be accurately reproduced.

Therefore, it is possible to omit the step of synchronizing the start position of the frame and the start position of the block at the time of recording, and to accurately and surely reproduce the still image and the digital data signal even if there is a dropout or the like. You can

[Brief description of drawings]

FIG. 1 is a block diagram of the reproducing apparatus of the present invention, FIG. 2 is a block diagram of the recording apparatus, and FIG. 3 is a schematic explanatory view showing the positional relationship between the video signal block and the digital dealer signal block. FIG. 5 is a schematic configuration diagram of conventional digital data, and FIG. 5 is a schematic explanatory diagram showing a positional relationship between the video signal and a block of the digital data signal. 1, 2, 3 ... Modulator, 4 ... Adder 5 ... Detection circuit, 6 ... Memory 7 ... Encoder, 8 ... Optical modulator 9 ... Disk, 10 ... Pickup 11 ... Amplifier 12 , 13, 14 ...... Band pass filter 15, 16, 17 …… Demodulator 18 …… Detection circuit, 19 …… Control device 20 …… Low pass filter 21 …… Decoder, 22 …… Memory 23 …… Detection circuit

Claims (2)

[Claims] 1. A television video signal and a digital data signal divided into block digital data signals corresponding to blocks having a length shorter than a length corresponding to one frame of the television video signal and not synchronized with the frame. In a video disc in which is frequency-divided and recorded as a multiplex signal in the same track, the same television video signal is recorded in a plurality of the frames, and the same track section corresponding to the plurality of frames is recorded in the same track section. A video disc having a plurality of the blocks recorded with the block digital data signals. 2. A television video signal and a digital data signal divided into block digital data signals corresponding to blocks having a length shorter than one frame of the television video signal and not synchronized with the frame. In a reproducing apparatus for reproducing a video disc in which is frequency-divided and recorded as a multiplex signal in the same track, the same television video signal is recorded in a plurality of the frames as the multiplex signal and A pickup (10) for reproducing the multiplex signal from the video disc having a plurality of the blocks in which the same block digital data signal is recorded in the track section corresponding to the frame of A first signal processing means (12, 15) for separating and demodulating a television video signal; Second signal processing means (20, 21) for separating and demodulating the digital data signal from the signal and the pickup for reproducing the multiple signal while repeatedly tracing the track section corresponding to the plurality of frames ( Control means (19) for controlling the operation of 10), and the block digital data output from the second signal processing means (20, 21) while the pickup (10) is tracing the track section. A reproducing apparatus comprising: an extracting unit (19, 22, 23) for extracting the block digital data signal of one block from the plurality of blocks based on a signal.