JPS604632B2 - Method for reproducing television signals from rotating recording media - Google Patents

Description

[Detailed Description of the Invention] In recent years, there has been research and development on recording and reproducing information signals that occupy a wide frequency range for recording and reproducing various information signals, and efforts have been made to record and reproduce information signals with high recording density on information recording media. Research and development on so-called high-density recording, which records and plays back, has become more active, and high-density recording of information signals is being carried out using disc-shaped or cylindrical information recording media, that is, rotating recording media. It is well known that a large number of various recording and reproducing methods for performing reproduction have been proposed.

Among them, disc-shaped rotating recording media (disc-shaped information recording media...
・Various systems for high-density recording of information signals using disks (hereinafter sometimes abbreviated as disks) and their reproduction are reaching the stage of practical use. By the way, when the main information signal to be recorded and reproduced by a rotating recording medium is a television signal (hereinafter, television is referred to as TV), the rotation period of the rotating recording medium is the target for recording and reproduction. As an integer multiple of the field period (vertical scanning period) of the TV signal to be recorded, the TV signal to be recorded and reproduced in the recording trace formed on the rotating recording medium by one rotation of the rotating recording medium. Normally, a signal corresponding to a time length that is an integral multiple of one vertical scanning period is recorded, but the rotation period of the rotating recording medium is the vertical scanning period of the TV signal to be recorded and reproduced. If the number of rotations is made equal to
Various problems such as vibrations occur, a high degree of precision is required for the rotating recording medium, it is impossible to increase the recording capacity, and it is difficult to implement various automatic controls. Because of this, the rotation period of the rotating recording medium is such that a plurality of vertical scans of the TV signal to be recorded and reproduced are recorded on the recording trace formed on the rotating recording medium by one rotation of the rotating recording medium. It is designed so that signals over a period (multiple field periods) can be recorded, and looking at the known recording and reproducing methods that have been announced so far, it is possible to record TV signals on discs that have been announced so far. In many playback systems, TV signals for two vertical scanning periods are recorded on the recording trace during one revolution of the disc, and also, using a grooved disc, information from the recording trace is recorded. In a known system in which a signal is output by detecting a change in capacitance value, a TV signal for eight vertical scanning periods is recorded in a recording trace during one revolution of the disk. In the recording and reproducing method of TV signals using the above-mentioned disc, 1
T according to the scanning standard such that the field is 1/6 sand
The rotational speed of the disk when recording and reproducing V signals is 180 pm in the former method described above, and 45 pm in the latter method.

When the disk rotation speed is high, the various problems mentioned above occur, so it is desirable to set it low in order to solve the problems mentioned above. A decrease in the rotational speed of the disc causes a shortening of the recording wavelength of the recording signal on the disc, which causes problems such as the inability to read information signals from the disc if the resolution of the reproduction element is low. Another problem is that it is not possible to use a recording device that uses a light beam at low cost when recording information signals on the master disk, and there is also the problem that the same recorded trace is repeatedly reproduced during playback, resulting in a still image. Inconveniences also arise when trying to obtain .

If the playback device is an optical playback device, the diameter of the light spot irradiated onto the disk for negotiating information signals from the disk depends on the wavelength of the light emitted from the light source used. Therefore, if the recording wavelength of the recording signal on the disk is shortened due to a decrease in the number of rotations of the disk, the information signal on the disk cannot be measured.

For this reason, in optical recording and reproducing systems, the disk is usually rotated at a relatively high rotational speed such that one frame (two fields) of TV signal is recorded during one rotation of the disk. This causes the various problems mentioned above.

On the other hand, in a recording/reproducing system that negotiates information signals from a disk by detecting changes in capacitance, the thickness of the electrode of the playback needle that slides against the disk and competes for information signals is reduced. By doing this, even if the recording wavelength of the recording signal on the disk becomes shorter due to a decrease in the rotational speed of the disk, information signals from the disk can be exchanged without any problem. In this method, 4 frames (8 frames) are recorded during one rotation of the disk.
Some discs have also been announced that rotate the disc at a low rotational speed so that TV signals (field) can be recorded.

When the rotational speed of the disc is lowered in this way, desirable results such as increasing the playing time of the disc (increasing the recording capacity of the disc) and reducing wear on the playback needle that comes into sliding contact with the disc are achieved. Although it can be obtained,
The drawback is that an inexpensive recording device using laser light cannot be used for recording, and an expensive electron beam recording device is required for recording information signals. Furthermore, if the disc is of a non-groove type, it is possible to rapidly move the reproducing element in the vertical direction of the disc when reproducing information signals from the disc. In addition to being able to access signals randomly, the playback mode can also be set to still image playback mode, slow motion playback mode, and various other playback modes, making it possible to use disk-based information signal recording and playback devices in many ways. The advantage is that it can be used for the intended purpose.

The applicant company has carefully considered the advantages and disadvantages of various information signal negotiation methods, the advantages and disadvantages of different disk configurations, and many other conditions, and as a result, has been able to easily obtain stable playback results. , and can provide playback equipment at low cost.
In addition, as a method for recording and reproducing information signals using a disk that also allows searching for various information signals, the information signal is read from the disk by detecting changes in capacitance value, and the disk is made into a grooveless type. Further, it is assumed that two frames (four fields) of a TV signal to be recorded and reproduced exist in the recording trace formed during one rotation of the disk, and furthermore, a tracking We have been promoting development research and practical research on systems that allow the playback stylus to accurately track the recording trace under control, and have achieved great results so far. We have also filed many patent applications.

This method of recording and reproducing information signals on discs by the applicant's company uses a non-grooved disc, which enables random access, as well as so-called playback of still images, slow motion images, etc. Trick play is also possible, and since the disc is driven and rotated at a relatively low rotational speed, wear on the playback stylus is not a major problem, the recording capacity is sufficient, and information on the disc is Signals can also be recorded in real time using an optical recording device using a laser beam.
Furthermore, the disc is excellent in that deformation that occurs during disc manufacturing or storage has little effect on playback operations.

However, since the TV signal recorded during one revolution of the disc consists of 2 frames (4 fields), the portion where the image content of the TV signal recorded on the disc changes and the switching of the reference signal for tracking control. If the parts are recorded in an unrelated state, for example, when the information signal of that part is reproduced as a still image, a still image in which the two image contents are mixed will be reproduced.

A concrete explanation of this is as follows.

That is, in FIG. 1, Fa,, Fa2..., Fb.
F et al...Fc. , Fc2..., etc. are each one field period (
1 vertical scanning period), and the subscript alphabetic characters (a, b
, c) are used to distinguish between TV signals of different programs (different image contents, e.g., baseball, volleyball, swimming, etc.), and furthermore, the above-mentioned Fa,
, Fa2..., etc., indicate the order of field signals according to each program, and as this disk D rotates in the direction of arrow If we assume that the information signal recorded on this disc ○ is to be played back in still image playback mode, the playback signal that is played back in that case will always be an image of the same program. A still image does not necessarily depend only on the content. In the still image reproduction mode, it is necessary for the reproduction needle to repeatedly reproduce information signals from the same recording trace formed in correspondence with one revolution of the disc. The TV signal with the corresponding 4-field period may not necessarily be the same program's image content, depending on the path taken by the playback needle when playing back the still image from the disc ○. A four-field TV signal is not necessarily reproduced repeatedly, and in some cases the image contents of two programs may appear superimposed in one still image.

To specifically explain the above points regarding Fig. 1, the arrow
The reproduction needle for reproducing information signals from the disc D rotating in the same direction moves in the outer circumferential direction of the disc D every rotation of the disc D so that the same recording trace can be repeatedly reproduced in the still image reproduction mode. The locations that are driven and displaced by one track pitch are the reference signal switching locations for tracking control, and these locations are a-0, b-0, c-0, d- on disk D in FIG. It is one of the four locations corresponding to the four radii indicated by 0, and it is the 4 location mentioned above.
The timing of switching the reference signal for tracking control is determined by the setting of the switching timing of the reference signal for tracking control when recording the information signal on the disc. Radius of the disk in Figure 1 a-0, b-0, c-0
, d-0, the still image reproduction signal to be reproduced is, for example, Fa, , Fa2, Fa3, Fa.
4 (signal switching position is half a-0)
), Fa2, Fa3, Fa4, Fb, etc. (if the signal switching position is radius b-0), F
a3, Fa4, Fb,, FQ line return (if the signal switching position is radius c-0), or Fa4,
Fq, Fb2, Fb3 lines are switched (if the signal switching position is radius d-0).In the above example, the still image signal from the TV signal of the same program can be obtained from the disk. Disc D for every revolution of D
This is only the case where the playback stylus is displaced by one track pitch toward the outer circumference of the disc at the radius a-0 position.Other than the above cases, completely different image contents from two programs are mixed. Therefore, it is clear that still image reproduction is of no use in this case.

The above problem also occurs when still images are reproduced by recording address signals on the disk and searching for information.

The present invention has been made for the purpose of solving the above-mentioned problems, and the specific contents of the method for reproducing TV signals from a rotating recording medium of the present invention will be explained below with reference to the attached drawings. do.

FIG. 2 is a block diagram showing an example of the configuration of a recording system used to record TV signals on a rotating recording medium. 3, the removal of laser beam drift, the removal of laser beams, and the control of the light amount in all directions of the diameter of the disk master Da are performed here (this optical modulator 3 is described in Japanese Patent Laid-Open No. 52 76003), is applied to the optical modulator 4 via the half mirror 12, is intensity modulated by the signal to be recorded and reproduced in the optical modulator 4, and is then applied to the reflecting mirror 5. , 6 and an objective lens 7, a light spot of a minute diameter whose intensity is modulated by the signal to be recorded and reproduced is imaged onto the photoresist layer of the master disc Da of the disc. The master disc ○a is rotated by a motor M at 900 revolutions per minute, and therefore the master disc Da has a two-frame period (
4 field period) signal is 1 of the master Da of the disc.
It will be recorded in the record trace formed by the rotation.

The modulation signal given to the optical modulator 4 is the output signal of the adder 11, and the output signal of the adder 11 is the pilot signal fp3 (pre-recorded so as to line up on a specific radius of the disk). This pilot signal fp3 is used as a reference signal for the rotational phase of the disc, as a timing signal for switching between the two tracking signals fp, fp2, and as a timing signal for switching the program of the TV signal to be recorded and reproduced. Alternatively, it is also used as a reference signal for switching the signal of each two frames of the TV signal to be recorded and played back) and the TV signal edited into a TV signal in units of two frames by the electronic editing device EC. and an FM modulated wave from the FM modulator 10 based on the audio signal accompanying the TV signal, an address signal from the address signal generator 9, and the like.

The relative relationship on the time axis of each of the above-mentioned signals constituting the modulation signal supplied to the optical modulator 4 is as follows:
TV edited in units of frames (4 fields)
Just as the pilot signal fp3 exists at a specific position in the vertical blanking period immediately before the video signal of the first field of the first frame in the signal, and within the vertical blanking period of each field. It is as if there is an address signal (40 bits, for example) for each.

Now, in FIG. 2, the laser beam reflected by the half mirror 12 is applied to the reference signals fp, , fp2 ( After receiving intensity modulation by pilot signals fp,, fp2),
A light spot with a minute diameter is imaged onto the photoresist layer on the master Da of the disk via the reflecting mirror 14, the polarizing prism 15, the reflecting mirror 6, the imaging lens 7, and the like.

The two pilot signals fp, fp2 mentioned above may be sent out in the form of a continuous signal or in the form of an intermittent signal, but in either case. In order to prevent beat interference or other negative effects on the main information signal due to the presence of the pilot signal, care must be taken in determining the signal level of the pilot signal and the insertion position of the pilot signal on the time axis. It takes.

In the example shown in the second figure, the two pilot signals fp, fp2 used as reference signals for tracking control and the pilot signal fp3 used as a reference signal for the rotational phase of the disk are connected to terminals in the example shown in the second figure. 16 (with a frequency value of 3.5795)
49 MHz) is frequency-divided by frequency dividers 17 to 19.

The fractional display shown in each frequency divider 17 to 19 in FIG. 2 is an example of the frequency division ratio in each frequency divider 17 to 19. If the frequency dividers 17 to 19 each have a frequency division ratio as shown in the figure, the frequency value of each pilot signal obtained from each frequency divider 17 to 19 is such that the pilot signal fp is 715.909.
KHz, pilot signal fp2 is 511.363 arcHz
, the pilot signal fp3 becomes 275.34961 KHz. When the frequency values of each pilot signal fp, to fp3 are associated with the frequency value of the color subcarrier as described above, there is an advantage that the degree to which the presence of the pilot signal adversely affects the main information signal can be reduced. is obtained.

FIG. 3 is a frequency allocation diagram showing an example of the relationship between the occupied frequency band F by the main information signal and each pilot signal fp, to fp3.

In the recording system shown in FIG. 2, pilot signals fp·,f
p2 is alternately supplied to the adder 26 by the switching circuits 22 and 21 in synchronization with the rotation of the original adjacent Da of the disc, and the master Da of the disc has a spiral or concentric recording trace due to the TV signal and the above-mentioned A pilot signal f is placed between two adjacent recording traces of the TV signal.
A spiral or circular trace is formed by p, , fp2.

Switching of each of the switching circuits 21 and 22 is controlled by control signals applied to terminals 24 and 25.

FIG. 4 is an explanatory diagram showing a model of the state of recording traces on a disc D created based on the master disk Da of the disc on which information signals are recorded by the recording system shown in FIG.
In FIG. 4, FR, FR2, etc. indicate the signals of each frame of the TV signal recorded on the disc D, and the subscripts 1 and 2 indicate the order of the frames.
In FIG. 4, pilot signals fp3 are recorded side by side on a specific radius of the disk D, and a vertical line erasure period precedes the video signal of each field in the TV signal of the sequentially recorded frames. are also positioned so as to be aligned in a specific direction of the disk D, respectively. Address signals are recorded at specific positions within each vertical blanking period, and TV signals for each two frames in each recording trace formed by each rotation of the disk D are recorded. In this case, the field signal that includes the pilot signal fp3 during the blanking period preceding the video signal is always the first field signal in a particular frame. In addition, if the signal recorded on the disc D is a signal used to reproduce a still image, the T
1 from the position of pilot signal fp3 when editing the V signal.
In the recording trace formed by the rotation, field signals having the same image content are returned and recorded by four lines, and furthermore, TV signals of different programs are recorded.
When the signals are recorded continuously on the disk D in time series, when editing the TV signal in the electronic editing device EC,
The TV signal of each different program has a pilot signal fp in the first field of its first frame.
This is done so that recording can begin immediately after the recording position No. 3. As is clear from Figure 4,
Pilot signals fp, , fp for tracking control
2 are sequentially and alternately switched every rotation of the disk D with reference to the recording position of the pilot signal fp3 on the disk D.
Record traces Tfp, , Tfp2 are sequentially formed by p, , fp2.

In this way, the TV signal recorded on disk D,
The two pilot signals for tracking control are:
In both of these systems, the time position of the pilot signal fp3 is used as the recording timing reference, and for this reason, even if a still image is played back when playing back the disc D, the above-mentioned problems occur. There isn't.

Next, the structure of the modulation signal supplied to the optical modulator 4 from the adder 11 will be explained.

In FIG. 2, reference numeral 8 denotes an information signal source, and this information signal source 8 is, for example, a TV camera, VTR, or other video signal generating device. Accompanying audio signals etc. are output. The electronic editing device EC stores the signals of the first field of each frame of the TV signal supplied from the information signal source 8 at a specific radial position on the master Da of the L disk (radial position where the pilot signal fp3 is aligned and recorded). ), and the audio signal accompanying the TV signal is output as the signal accompanying the TV signal.

Now, when the electronic editing device EC electronically edits the TV signal sent from the information signal source 8 into a TV signal in a signal format suitable for playing still images on the disk D, the electronic editing device RC The signal of one field period of the TV signal supplied to the camera is repeated four times to obtain a TV signal of two frame period, or the TV signal of one frame period obtained from a still image is repeated twice to obtain a T of two frame period.
For example, in the case where a TV signal for still image playback having different image content is recorded for each recording trace formed by each revolution of the master disc Da of the disc, each TV signals for still image reproduction having two frame periods each having different image contents are recorded on the master disc Da of the disc as continuous TV signals on the time axis.

In addition, if the TV signal recorded on the disc is one in which TV signals from multiple programs appear sequentially on the time axis, all the TV signals for each program are divided into integral multiples of two frame periods. In addition, the first field of the TV signal of the first two frame periods of the TV signal of each program is necessarily aligned on a specific radius on the master disc Da of the disc. Pilot signal fp recorded in
This will cause it to be recorded immediately after 3.

In this way, by recording the TV signal on the rotating recording medium, the TV signal recorded on the master disc ○a has a TV signal of two frame periods as a unit, and the beginning of the TV signal of each unit is The TV signals of the field are always recorded following the pilot signal fp3 which is recorded aligned on a specific radius on the master disc Da of the disc. Electronic editing device EC
The TV signal from and the audio signal accompanying the TV signal are given as modulation signals to the FM modulator 10, and the FM modulated wave output from the FM modulator 10 is supplied to the adder 11 from the switching circuit 20. The pilot signal fp3 and the address signal from the address signal generator 9 are added and supplied to the optical modulator 4.

The pilot signal fp3 added in the adder 11 is added in the adder 11 in each unit of the TV signal, which is supplied from the electronic editing device EC and has a TV signal of two frame periods each as described above. The timing and time length of the transmission are determined by the switching circuit 20 so that the video signal of the first field of the first frame is superimposed on the TV signal at a specific time position within the vertical blanking period immediately before the video signal. , switching circuit 2
The above switching operation of 0 is controlled by a control signal applied to its control terminal 23. Further, the address signal added to the TV signal in the adder 11 is T
It is controlled by the electronic editing device EC so that it is inserted at a specific time position within each vertical blanking period of the V signal.

5A to 5E are waveform diagrams for explaining the operation of the recording system, and FIG. 5B is a diagram showing the insertion position (in this diagram, the TV signal is shown as a video signal for easy understanding), and FIG. FIG. 5C is a waveform diagram of the pilot signal fp3 sent from the switching circuit 20, and FIG. An example of the waveform of the control signal, FIG.
FIG. 2 is a waveform example diagram of pilot signals fp, fp2 sent out from FIG.

In FIG. 4, a model is shown in which the form and recorded content of the recording traces of the disc D created based on the master disk Da on which information signals are recorded by the recording system shown in the second diagram described above are clearly shown. Vblk is the recorded portion of the vertical blanking period, Sv is the recorded portion of the vertical synchronization signal, fp3
indicates a recorded portion of the pilot signal fp3, and Sad indicates a recorded portion of the address signal, respectively, and arrow X in the figure indicates the rotation direction of the disk. FIG. 6 is a block diagram showing an example configuration of a playback system, in which the disk D
is rotated at a speed of 900 revolutions per minute in the direction of the arrow x in the figure by a rotary drive mechanism (not shown), and on the top surface of the disk D is a reproduction device that detects the information signal of the disk D as a change in capacitance value. The needle 33 is in contact with a predetermined pressing force, and the information signal read by the reproduction needle 33 is given to the front layer amplifier 36.

34 is a cantilever, and 35 is a tracking control drive mechanism for driving and displacing the reproducing needle 33 in the middle direction of the recorded trace.

The tracking control drive mechanism 35 drives and displaces the reproducing needle 33 in the middle direction of the recorded trace in accordance with the tracking control signal, and at the same time drives and displaces the reproducing needle 33 in the extending direction of the recorded trace in accordance with the jitter correction signal. A smooth drive mechanism (
For example, it is a desirable mode of implementation to provide the following. For example, the regeneration needle 33 equipped with an electrode for collecting information signals is disclosed in Japanese Patent Application No. 5
1-1137216 and Japanese Patent Application No. 52-22764 can be used satisfactorily.

The signal picked up by the reproducing needle 33 and amplified by the front layer amplifier 36 is a frequency modulated wave by the main information signal {third
} and pilot signals fp, ~fp3, which occupy the frequency band F in the figure, and the main information signals are given to the signal processing circuit 38 via the Takagi monkey wave generator 37; Then, the necessary signal processing is performed and the main information signal to be recorded and reproduced {for example, a composite color video signal and an audio signal accompanying it} is sent to the output terminal 39, and the signal is sent to the address signal detection section 60. The pilot signals fM to fp3 are transmitted to the reduction filter 4.
Automatic gain control circuit 41 (AGC circuit 4 1) through 0
The output signal from the AGC circuit 41 is applied to the band wave generators 42 to 44, and the band wave wave generator 42 outputs a pilot signal fp, and the band wave wave generator 43 outputs a pilot signal fp. The pilot signal fp2 is further outputted from the Obijo Kashiwa device 44, and the pilot signal fp3 is outputted.

The pilot signal fp is given to the gutter switching circuit 48 via the bell adjuster 45, and the pilot signal fp2
The polarity switching circuit 48 sends the pilot signal fp to the detection circuit 50 and sends the pilot signal fp2 to the detection circuit 50 according to the switching control signal supplied to the control terminal 49. Alternatively, the pilot signal fp may be provided to the detection circuit 51 and the pilot signal fp2 may be provided to the detection circuit 50. A control terminal 49 of the polarity switching circuit 48 is supplied with a switching control signal from a switching control signal generating circuit 56 .

That is, in order to use the playback stylus 33 to pick up the main information signal in the recorded trace on the disc D, when the playback stylus 33 is placed on a certain recorded trace on the disc D, the playback stylus 33 detects the recorded trace. In the state of accurate tracking, the reproducing needle 33 reads the two pilot signals fp, fp2 as having the same magnitude, and the reproducing needle 33 reads the two pilot signals fp, fp2 as being of equal magnitude. In the state, the magnitude of one of the two pilot signals fp,, fp2 is larger than the other one, but
At this time, the tracking control drive mechanism 35 drives and displaces the reproducing needle 33 in the direction of the recording trace so that the two pilot signals fp, fp2 are equally reproduced in the tracking control circuit.

On the other hand, when the playback stylus 33 advances to the next record trace to read the main information signal, the pie The state of change in the relative magnitude of the pilot signals fp, fp2 is the state of change in the relative magnitude of the pilot signals fp, fp2 that occurs when the reproducing needle 33 deviates in the middle direction on the recording trace described above. It has exactly the opposite relationship to the state of change. Therefore, when the reproducing needle 33 advances to the next recording trace in order to read information signals from successive recording traces on the disc D, the relative magnitude changes of the pilot signals fp, fp2 occurring for the successive recording traces occur. The polarity of the tracking control depending on the state needs to be reversed by the polarity switching circuit 48 for each recording trace one after the other. The switching control signal generation circuit 56 supplies switching control signals of desired polarity to the control terminals 49 of the polarity switching circuit 48 so that the switching control for the recorded traces can be performed well. It is.

The above-mentioned detection circuits 50, 51 (rectifier wave circuits 50, 51
) is given to a differential amplifier 52, and a tracking error signal is sent out from the differential amplifier 52. The tracking error signal from the difference amplifier 52 is sent to the phase compensation circuit 5.
3, the signal is compensated to suit the operating characteristics of the tracking control drive mechanism 35, and then amplified by the drive amplifier 54 and supplied to the tracking control drive mechanism 35 as a tracking control drive signal. A kick pulse is supplied to the drive amplifier 54 from a control terminal 55, and when the kick pulse is supplied to the control terminal 55, the tracking control drive mechanism 35 moves the reproduction needle 33 from the recorded trace being tracked at that time. Move to another record.

Needless to say, the direction of movement of the regeneration needle 33 due to the kick pulse applied to the control terminal 55 changes depending on the polarity of the kick pulse. In the example of FIG. 6, the drive amplifier 54 is also provided with a kick pulse generated by the control section 29 during the random access reproduction mode. The control unit 29 includes a comparator 2 which indicates the result of comparing the reproduced address signal detected by the address signal detection unit 60 and the set address signal from the address signal setting unit 27 in the comparator 28.
A kick pulse corresponding to the output signal from 8 is output. Note that the output of the control section 29 described above is also given to a speed control circuit (not shown).

In the playback device, the playback mode generates various pulses such as a sea bream pulse and a kick pulse, which are required when the playback mode is a so-called trick play playback mode, such as a still image playback mode, a slow motion image playback mode, etc. These various pulses are made into a pilot signal fp3 extracted by a bandpass filter 44.
It is generated based on the time position of .

That is, the pilot signal fp3 extracted by the band waver 44 is rectified into a square wave by the detection circuit 47, and is given to the switching control signal generation circuit 56.

The switching control signal generation circuit 56 also has a control terminal 5.
7 is configured to receive command pulses from an operation panel (control panel), and the switching control signal generation circuit 56 receives a command pulse from the operation panel.
Various necessary control pulses are generated using the pilot signal fp3 as a time reference. When the disk D on which information signals have been recorded by the recording system as shown in the second figure is played back by the playback system configured as shown in the sixth figure, the TV signals of different programs recorded on the disk D are reproduced. , each having a length that is an integral multiple of a 2 frame (4 field) period, and the signals of the first field of the TV signals of each of the different programs are recorded in alignment on a specific radius of the disc ○. The T of the program recorded on disk D is recorded at the position following the recording position of the pilot signal fp3, which is the reference for the rotational phase.
Even if the V signal is a continuous TV signal for normal picture playback,
Alternatively, even in the case of a TV signal for still image playback, if it is played back in the still image playback mode, a still image can always be obtained from only the TV signal of the program targeted for playback, and the playback method of the present invention According to this method, the above-mentioned conventional problems do not occur.

It should be noted that a magnetic disk is used as the disk, and a magnetic head is used to record TV signals on the magnetic disk D.Therefore, a magnetic head is used to record and form a recording trace due to the TV signal, and also to record pilot signals fp, fp2. Therefore, the recording trace by the pilot signals fp, fp2 is T
This book describes a magnetic recording and reproducing method in which records are formed on a magnetic disk at the same time as a recording trace by a V signal, and a TV signal and a pilot signal are simultaneously output from a magnetic disk using a single magnetic head. The invention may be applied.

In this case, the output signals of adder 11 and adder 26 in the recording system shown in FIG. A single reproducing magnetic head may be attached to the tip of the magnetic head 34, and the output signal of the magnetic head may be applied to the front amplifier 36. Furthermore, it goes without saying that the reproduction method of the present invention may be implemented for reproduction using an optical recording and reproduction method.

As is clear from the above detailed explanation, in the method for reproducing TV signals from a rotating recording medium of the present invention, the TV signal to be recorded and reproduced on the rotating recording medium is Two frame periods (
4 field periods) as a unit recording signal, which has been edited in chronological order in advance so as to have a time length that is an integral multiple of the unit recording signal, and the edited TV Specifying the recording position of the vertical blanking period immediately preceding the video signal of the first field period of the first two frames in the edited TV signal when the signal is recorded on a rotating recording medium. The first part to be recorded on the rotary recording medium at the recording position of the reference signal of the rotational phase of the rotary recording medium, and at the recording position of the reference signal of the rotational phase of the rotary recording medium. By switching the reference signal for the second tracking control, when the still image playback mode is selected during playback, a still image based on the TV signal of one program is always obtained. According to the present invention, the above-mentioned problems are satisfactorily solved, and the address signal is recorded during the vertical erasure period of the TV signal to perform random access. Even when necessary information is quickly read out from a large amount of information, it is possible to always accurately obtain an information signal having the image content of the associated program.

[Brief explanation of the drawing]

1 and 4 are plan views of a disk showing recorded traces as models, FIG. 2 is a block diagram showing an example configuration of a TV signal recording system for a rotating recording medium, and FIG. 6 is a rotating FIG. 3 is a block diagram showing an embodiment of a method for reproducing TV signals from a recording medium, FIG. 3 is a frequency allocation diagram of signals, and FIGS. 5 a to 5 e are diagrams showing example waveforms of signals. 1... Laser light source, 2, 5, 6, 14... Reflecting mirror,
3, 4, 13... Light modulator, 7... Imaging lens, 8...
・Information signal source, 9...Address signal generation circuit, 10.
...FM modulator, 11, 26...Adder, 17-19
...Frequency divider, 20-22...Switching circuit, Da...
Master disc, M...Motor, EC...Electronic editing device, D...Disc, 33...Reproduction needle, 34...Cantilever, 35...Tracking control drive device, 3
6... Front direct amplifier, 42-44... Obijo Sarunami device, 4
8... Polarity switching circuit, 56... Switching control signal generation circuit, 47, 50, 51... Detection circuit, 54... Drive amplifier, 60... Address signal detection section, 27... Address Signal setting section, 28... Comparator, 29... Control section. Figure 1: Younger brother Z Figure 3: Younger brother Mu Figure 5: Group 6

Claims (1)

[Scope of Claims] 1. A spiral or concentric record trace recorded on a rotating recording medium by a television signal to be recorded and reproduced corresponds to each revolution of the above-mentioned rotating recording medium. A television signal is recorded for each of four vertical scanning periods of the television signal to be recorded and reproduced, and is recorded in an intermediate portion between adjacent recording traces of the television signal. Reference numbers for first and second tracking control, which have different frequency values, are included in each one of the rotating recording media in the recording trace based on the reference signal for spiral or concentric tracking control. Reproduction of information signals from a rotating recording medium recorded in a state in which the signals are sequentially and alternately switched corresponding to the rotation is performed by a reproducing element that tracks the recorded trace of the television signal under the operation of a tracking control system. A method for reproducing television signals such that the television signals recorded on a rotating recording medium that are to be recorded and reproduced should be used as signals for each program and for still image reproduction. For each information content, a signal of four vertical scanning periods is used as a unit of recording signal, and is edited in chronological order in advance so that the signal has a time length that is an integral multiple of that unit of recording signal, and the above-mentioned editing is also performed. A specific part of the recording position of the vertical blanking period located immediately before the video signal of the first one vertical scanning period in the television signal that is displayed is at the recording position of the reference signal of the rotational phase of the rotating recording medium. Further, the reference signal for the first and second tracking control to be recorded on the rotating recording medium is switched at the recording position of the reference signal of the rotational phase of the rotating recording medium. and reproducing signals from a rotating recording medium in which the edited television signal, reference signals for the first and second tracking controls, and reference signals for the rotational phase of the rotating recording medium are recorded. In this process, the operation mode of the tracking control system and the drive displacement operation of the reproducing element in various reproduction modes are controlled by control signals created based on the reference signal of the rotational phase read from the recording trace of the rotating recording medium. A method for reproducing television signals from a rotating recording medium. 2. The rotation according to claim 1, which detects an address signal for information retrieval recorded within a recording position of a predetermined vertical blanking period in a unit recording signal and reproduces a desired information signal. A method for reproducing television signals from recording media.