JPH0134432B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a disc-shaped information recording medium, and by recording audio signals of a first channel and a second channel so that discontinuous points are at different positions, It is an object of the present invention to provide a disk-shaped information recording medium that can select any of the audio signals of a channel and obtain continuous audio signals even during special playback.

In a disk-shaped information recording medium (hereinafter referred to as a "disk") on which video and audio signals are recorded in a spiral manner as information signals, a track that is reproduced in one rotation of the disk (hereinafter referred to as a track that is reproduced in one rotation of this disk) is used. Two programs with different contents are alternately recorded for each track (hereinafter referred to as "one track"), and during playback, the playback needle is forcibly moved one track pitch at the connection point of these different programs (hereinafter referred to as "one track"). It is possible to perform special playback such as transferring each track pitch by one track pitch (called a "kick") and playing back each program independently and continuously.

However, if the audio signals of each program are recorded in one channel on the above-mentioned disk, the disc will be interrupted at the connection point of different programs, that is, the discontinuity point of the audio signal. If the position where this kick is performed is set to the vertical blacking period of the video signal, the video signal will not be affected in any way even if the timing of the kick is slightly changed, but the audio signal will be discontinuous before or after the kick, making it difficult to hear. It's inconvenient.

The present invention solves the above-mentioned disadvantages,
This will be explained below with reference to the drawings.

In this disk proposed by the present applicant, the main information signal is recorded on a spiral main track without forming a needle guide groove, and the main information signal is recorded at a frequency lower than the recording frequency band of the main information signal. First and second tracking control reference signals (hereinafter referred to as "tracking signals") having different frequencies and in a burst form _P1 and _P2 are alternately switched every rotation period of the disk and are adjacent to each other. A sub-track is formed and recorded approximately in the middle between each track center line of the main track, and _P1 and
A third tracking signal is connected to _{the P2} switching connection.
This is a disk with an electrode function in which _P3 is recorded at a level below a predetermined level on the main or sub-track so as not to affect the main information signal.

Here, we will mainly explain a capacitance change detection readable disk in which a video signal and two channels of audio signals as the main information signals are recorded as bit strings that are intermittent at a rate of 4 fields per revolution. do. FIG. 1 is a diagram schematically showing the recording arrangement relationship of the recording tracking signals of the disk proposed by the applicant mentioned above. In the figure, the ○ mark indicates _{the P1} recording position, and the △ mark indicates _{the P2} recording position. show,
The solid line indicates the track center line of the main track, and the third tracking signal _P3 is recorded on the main or sub-track that intersects with the broken line.

Next, to explain the disk according to the present invention,
FIG. 2 shows a block system diagram of essential parts of an embodiment of the disk recording system according to the present invention. In the figure, audio signals of a first channel and a second channel are respectively input to input terminals 1 and 2. Here, different types of monaural audio signals are input to the input terminals 1 and 2, respectively. Further, 3 is a video signal input terminal.

The audio signal of the first channel that has entered the input terminal 1 is modulated by the frequency modulator 5 to a predetermined frequency (for example,
The carrier wave (3.43 MHz) is frequency modulated and becomes the FM audio signal of the first channel. At the same time, the second channel audio signal that has entered the input terminal 2 is frequency-modulated by a carrier wave of, for example, 3.73 MHz by the frequency modulator 6, and is converted into a second channel FM audio signal. These first and second channels
The FM audio signals are each supplied to a mixing circuit 7, where they are multiplexed with the video signal from the input terminal 3. Here, the video signal entering the input terminal 3 is
The band is set so that it does not overlap with the FM audio signal of the second channel. For example, the upper limit frequency is approximately
This is a composite color video signal in which a carrier color signal that has been low-band converted is band-sharing multiplexed into a high-frequency region of a luminance signal that is band-limited to about 3 MHz.

The multiplexed signal taken out from the mixing circuit 7 shown in FIG. 2 is supplied to a frequency modulator 8, where, for example,
After being made into a frequency modulated wave having a carrier wave shift bandwidth of 6.1MHz to 7.9MHz, it is outputted from the output terminal 9 as a main information signal.

The above-mentioned main information signal is applied to, for example, an optical modulator (not shown) to modulate the laser beam and convert it into a modulated optical beam, which is then applied to a photosensitive material coated on a synchronously rotating disc-shaped recording master. The light is focused and subjected to a well-known development process to form a main track in the form of a series of pits that are intermittent in accordance with the repetition frequency of the main information signal. Therefore, the video signal and the two channels of audio signals are recorded simultaneously on the same main track. Note that the tracking signals _P1 and _P2 are applied to a different optical modulator (not shown), which similarly modulates the laser light and converts it into a modulated light beam, and then outputs the tracking signals P1 and P2 to the sub-modulator of the intermittent pit row. A track is formed simultaneously with the main track. A disk is duplicated from a recording master through a well-known disk manufacturing process.

FIG. 3 schematically shows the information signal recording arrangement of one embodiment of the disk of the present invention. In this figure, as in Fig. 1, the ○ mark indicates _{the P1} recording position, and the △ mark indicates _{the P2} recording position.The main information signal is recorded on the spiral shown by the solid line, and the positions shown by the broken line and the dashed line are the video This is the recording position during the vertical blanking period of the signal, and the position indicated by the broken line is the recording position of the tracking signal _P3 . The video signal of the first program is recorded on the spiral from point a to point b on this disk (hereinafter referred to as "section ab"), and the video signal of the first program is recorded on the section bc, which has a different content from the first program. The video signal of the program is recorded, and the video signal of the first program is recorded in the sections cd and ef, the video signal of the second program is recorded in the sections de and fg, and the video signal of the first program is recorded in the section cd and ef. When the sections ab, cd, and ef are played back in this order, they become continuous, and similarly, when the second program is played back in the order of sections bc, de, and fg, they become continuous.

Next, the audio signal of the first channel is from point a to _P3
Point h via point h 1.5 fields ahead from the recording position
On the spiral (section ai) up to point i on the same radius as , the video signals corresponding to sections ab and cj are recorded, and the audio signal of the first channel of section if is assumed to be that of section hi. They are the same and correspond to the video signals in sections hb and cj. For this reason, point i
The audio signal of the first channel is discontinuous. Here, the audio signal is expressed as a function of time, and when time, which is an independent variable of the recorded audio signal, loses continuity at one point on the track, this point is called a discontinuous point. Also, the first section of section jk
The audio signal of the channel is continuous with that of section ij at point j, and the one corresponding to the video signal of sections jd and el is recorded, and the audio signal of the first channel of section kl is exactly the same as that of section jk. , and point k is a discontinuity point in the audio signal of the first channel.

The audio signal of the second channel is also the same as the first channel, and the audio signal of the second channel in section bc corresponds to the video signal in this section, and the audio signal in section cj
The audio signal of the second channel corresponding to the video signal of section dk is recorded, and the audio signal of the second channel of section jk is the same as that of section ij. Also,
The audio signals of the second channel in sections kl and lm correspond to the video signals in sections ke and fm, and
The audio signal of the channel is discontinuous at points j and l.

FIG. 4 shows a block system diagram of an example of a disc reproducing apparatus according to the present invention. In the figure, a high frequency signal (recorded signal) read by a reproducing needle 12 from a disk 11 rotating at high speed is amplified by a preamplifier 13, and then sent to a demodulation circuit 14, a band filter 15,
16 and _P3 detector 17, respectively. The demodulation circuit 14 demodulates the main information signal, which is a frequency modulated wave reproduced from the main track, separates the bands of the demodulated main information signal, and outputs the video signal of the main information signal from the input terminal 18a. The audio signals of the first channel and the second channel are respectively supplied to terminals S ₁ and S ₂ of the switch SW. switch
A signal specifying the first mode and the second mode is input to the SW from the input terminal 21a, and when the first mode is specified, the switch SW inputs the signal from the terminal _S1 .
and _S3 are connected to output the first channel audio signal from the output terminal 18b, and when the second mode is specified, the terminals _S2 and _S3 are connected to output the second channel audio signal. Output from terminal 18b. At the same time, the reproduction signal includes a tracking signal _P3 reproduced from the main track, a tracking signal _P1 reproduced from the sub-track according to the direction and amount of tracking deviation, and/or
_P2 is included, of which _P1 has a frequency selected by a band filter 15 and is supplied to a terminal 19a of the switching circuit 19, _P2 has a frequency selected by a band filter 16 and is supplied to a terminal 19b of the switching circuit 19, _P3 is frequency-selected by the _P3 detector 17, subjected to envelope detection, and then supplied to the control circuit 20. Input terminal 21b
Similarly to the input terminal 21a, a signal designating a first mode for selecting a first program or a second mode for selecting a second program designated by the operator is inputted to the control circuit 20. Supplied. The control circuit 20 multiplies the tracking signal _P3 from the _P3 detector 17 by 4 and sends it to the input terminal 21b.
When a signal specifying the first mode is supplied, two types of switching signals α and β shown in FIGS. 5A and B and a timing pulse γ shown in FIG. 5C are generated, and the timing pulse γ shown in FIGS. switching signals α, β
are supplied to the control signal input terminals 19c and 19d of the switching circuit 19, respectively, and the timing pulse γ of FIG. 5C is supplied to the kick pulse generator 22.
Further, when a signal specifying the second mode is supplied from the input terminal 21b, the switching signals α and β shown in FIGS. 5A and 5B are inverted, respectively, and have the waveforms shown in FIGS. 5D and E. Switching circuit 19
is supplied to terminals 19c and 19d. In FIG. 5A, the timing at which _P3 is supplied is indicated by an arrow.

The switching circuit 19 performs switching so that the tracking signal _P1 input to the terminal 19a is output from the terminal 19e when the control signal from the terminal 19c is at a high level, and from the terminal 19f when the control signal is at a low level. Switching is performed so that the tracking signal _P2 is output from the terminal 19f when the control signal from the terminal 19d is at a low level, and from the terminal 19e when it is at a high level. Terminal 19e of switching circuit 19,
_P1 or _P2 output from 19f is subjected to envelope detection in detection circuits 23 and 24, respectively, and then differentially amplified in differential amplifier 25 to become a tracking error signal and supplied to drive circuit 26. On the other hand, the timing pulse γ from the control circuit 20 is supplied to the kick pulse generator 22, where the regeneration needle 12
The drive circuit 26 is used as a kick pulse to transfer one track pitch toward the inner circumferential side of the disk 11.
supplied to The drive circuit 26 converts the tracking error signal into a desired drive power with a polarity corresponding to the direction of tracking deviation and a level corresponding to the amount of tracking deviation and applies it to the tracking coil 27, so that the switching signals α and β are respectively When the level is low or high, on the outer periphery of the regeneration needle 12.
Place the regeneration needle 12 on the disk 1 so that _P1 is on the inner circumference, and _P2 is on the inner circumference (when switching signals α and β are at high level and low level, _P2 is on the outer circumference and _P1 is on the inner circumference).
1 in the radial direction, and converts the kick pulse into driving power necessary for kicking to move the playback needle 12 to the upper inner circumferential side in the radial direction of the disk 11 by one track pitch.

Therefore, when a signal specifying the first mode is supplied from the input terminals 21a and 21b, the disk 11 is turned on at points b, d, and f shown in the third diagram, and sections ab, cd, and ef are continuously reproduced. Then, the video signal of the first program is extracted, and at the same time, the audio signal of the first channel, that is, the audio signal corresponding to the video signal of the first program is extracted. In this case, the sections ab, cd, ef and the cut point b,
Since there is no discontinuity point in the first channel audio signal at d and f, the reproduced first channel audio signal is continuous. Also, when a signal specifying the second mode is supplied, the third mode is
The sections bc, de, and fg are interrupted at points c and e in the figure, and the sections bc, de, and fg are successively reproduced, and the video signal of the second program and the corresponding audio signal of the second channel are extracted. In this case as well, since there are no discontinuous points in the second channel audio signal in the sections bc, de, fg and the kick points c and e, the reproduced second channel audio signal is continuous. Also,
Here, even if the second mode is specified while the section CD is being played, the playback needle 12 will move to the outer circumferential side at _P2 ,
Since it is tracked so that it becomes _P1 on the inner circumference side,
The program is automatically transferred from section CD to section bc or section de, and thereafter the second program is played.

In other words, since the discontinuous points i, k of the first channel audio signal and the discontinuous points j, l of the second channel audio signal are at different positions, the second channel audio signal is continuous at points i, k. However, at points i and l, the audio signals of the first channel are continuous, and by selecting and reproducing the first mode or the second mode, the audio signals of the first channel and the second channel are treated as continuous. Can be played.

The present invention is particularly suitable for application to a disk having an electrode function without forming a needle guide groove and a reproduction method thereof, which was previously proposed by the applicant. The present invention may also be applied to a disc played back using the present invention and a playback method thereof, and is not limited to the above-mentioned embodiments.

As described above, in the disc-shaped information recording medium of the present invention, the video signals of the plurality of programs and the corresponding audio signals of the plurality of channels are made into a predetermined signal form, and the video signals of the plurality of programs are alternately arranged on the spiral track. Disc-shaped information that is recorded by switching to a spiral track, and is reproduced by scanning a spiral track to reproduce the reproduction element by moving the reproduction element to a position adjacent to the spiral track in the radial direction so that the video signal of one of the programs is continuous. In a recording medium, every two consecutive rounds of a spiral track for each audio signal of a plurality of channels, the first round and the next round are recorded as the same content, and the audio signal expressed as a function of time is When a point on a spiral track where the audio signal is recorded with a loss of continuity is defined as a discontinuity point in the audio signal, multiple channels are recorded so that the audio signals of multiple channels do not lose time continuity at the same time during playback by scanning the playback element. Since each discontinuity point was recorded at a different position on the spiral track and at a position different from the switching position of the plurality of programs, even when performing special playback by kicking, the first channel or the second channel It is possible to select one of the audio signals of the track to make the audio signal of the track played in front of the kick the same, so that even if the kick is performed, a continuous audio signal can be played, and the audio It has the advantage of being able to always obtain a continuous audio signal without reproducing discontinuous points in the signal.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing the recording arrangement of tracking signals in a disc-shaped information recording medium previously submitted by the present applicant, and FIG. 2 shows the main part of one embodiment of the recording system of the disc of the present invention. Block system diagram. FIG. 3 is a diagram schematically showing the recording arrangement relationship of tracking signals and information signals in one embodiment of the disc of the present invention. FIG. 4 is a block system diagram of an example of a reproducing apparatus for reproducing the disc of the present invention. 5A to 5E are signal waveform diagrams of various parts of the reproducing apparatus shown in FIG. 4. 1, 2, 3, 21a, 21b...input terminals,
5, 6, 8... Frequency modulator, 7... Mixing circuit,
9, 18a, 18b...Output terminal, 11...Disk, 12...Regeneration needle, 15, 16...Band filter, 17... _P3 detector, 19...Switching circuit, 20...Control circuit, 22... ...Kick pulse generator, 23, 24...Detection circuit, 25...Differential amplifier, 26...Drive circuit, 27...Tracking coil, SW...Switch.

Claims (1)

[Claims] 1. Together with the video signals of a plurality of programs, the audio signals of a plurality of channels corresponding thereto are made into a predetermined signal format, and the video signals of the plurality of programs are alternately switched and recorded on a spiral track, and the spiral track is scanned. In a disc-shaped information recording medium, in which the video signal of one of the programs is continuously reproduced by moving a reproduction element to a position adjacent in the radial direction of the spiral track, each of the audio signals of the plurality of channels is For every two consecutive revolutions of the spiral track, the first revolution and the next revolution are recorded as the same content, and the audio signal expressed as a function of time is recorded with the continuity of the time lost. When a point on the spiral track is defined as a discontinuous point of the audio signal, the discontinuity of each of the plurality of channels is set so that the audio signals of the plurality of channels do not lose their temporal continuity at the same time during reproduction by scanning the reproduction element. A disc-shaped information recording medium characterized in that consecutive points are recorded at different positions on the spiral track and at positions different from switching positions of a plurality of programs.