JPS6158881B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Composite images can be created by using a video recording medium in which a spiral recording trace is formed on a disk or a video recording medium in which a spiral recording trace is formed on the circumferential surface of a cylinder. Recording and reproducing signals has been widely attempted in various video recording and reproducing systems.

By the way, when extracting a signal from a recording trace on a video recording medium, it is necessary for a pick-up element for signal reproduction to faithfully trace the recording trace on the video recording medium. If the recorded trace is in an abnormal state for some reason, the pick-up element for signal reproduction will be in a state where it will repeatedly reproduce the same recorded trace part and the development will not proceed further. In other words, the so-called locked group phenomenon may occur.

The above-mentioned locked group phenomenon occurs when recording marks on the video recording medium are formed in guide grooves provided on the video recording medium, and the reproduction needle provided on the pick-up element for signal reproduction In the case of a device that is designed to trace inside, this problem may be caused by abnormalities in the guide groove such as collapse or unevenness of the guide groove, or clogging of the guide groove by dust. In the case where the trace is traced in a non-contact manner by a pick-up element for signal reproduction, this is caused by deletion of the recorded trace on the video recording medium.

When the above-mentioned locked group phenomenon occurs in a playback device in which a pick-up element for signal reproduction is constantly sent, the pick-up element becomes locked group within a few seconds to several tens of seconds. If the pick-up element for signal reproduction is not constantly fed, the pick-up element cannot escape from the locked group.

The recording position of the vertical synchronization signal in a composite video signal in a spiral or spiral recording trace formed on a video recording medium is on the same radius in a series of recording traces, or in a straight line in a direction that crosses a series of recording traces. an additional signal having a constant repetition period that is different from either the rotation period of the recording medium or a period that is an integral multiple of the rotation period of the recording medium, is superimposed on the composite video signal. The above-mentioned locked group detection and release can be easily performed by using a recording/reproducing method using a video recording medium in which images are recorded. The details of the recording/reproducing method using a recording medium will be explained in detail.

FIG. 1a is a plan view of an example of the video recording medium 1 in which a spiral recording trace _l1 is formed on a disk, and FIG. This is a perspective view of an example of a video recording medium 2 formed with a spiral recording trace l ₂ , and in each of the above figures, the locations marked with an x in the recording traces l ₁ and l ₂ are as follows:
These are the recording positions of the vertical synchronization signals of the composite video signals recorded in the respective recording traces, and the recording positions of the vertical synchronization signals of the composite video signals recorded in the spiral recording traces in Figure 1a are are shown as being lined up on the same radius in a series of recording traces, and the vertical synchronization signal of the composite video signal recorded in the spiral recording trace in FIG. The recording positions are shown as being lined up on the same straight line (in the direction of the ridge of the cylinder) in a series of recording traces.

In the following description of the embodiment, in order to simplify the explanation, a spiral recording trace l ₁ is used as the video recording medium.
The explanation will be given by taking as an example only the case where a disc-shaped video recording medium 1 is used.
A quick read of the description of the technical contents of the present invention, which will be described later, will show that in carrying out the present invention, a cylindrical video recording medium 2 on which a spiral recording trace _l2 is formed may be used as the recording medium. It will be understood immediately.

In the description of the following embodiments, the composite video signal to be recorded and reproduced by the video recording medium 1 has a vertical scanning frequency of 60 Hz, and
A related explanation will be given by taking as an example a case as shown in FIG. 1A, in which a composite video signal for four vertical scanning periods is recorded and reproduced by a recording trace generated corresponding to one rotation of the video recording medium 1.

Now, in the recording and reproducing method using the video recording medium of the present invention, the recording position of the vertical synchronization signal in the composite video signal in the spiral recording trace ^l1 of the video recording medium 1 is the same in a series of recording traces. Vertical synchronization signal Sv in the composite video signal arranged radially and recorded in the recording trace
An additional signal Si having a constant repetition period different from the above is superimposed on the composite video signal and recorded on the video recording medium 1.

FIG. 2 is a block diagram of one embodiment of a recording device used when recording a composite video signal on a video recording medium, and in FIG.
3 is a video signal source, 4 is a synchronization signal source, and when the video signal S from the video signal source 3, the horizontal synchronization signal Sh, the vertical synchronization signal Sv, etc. from the synchronization signal source 4 are added in an adding circuit 7. , is converted into a composite video signal and given to the modulator 8 as usual, but the vertical synchronization signal Sv obtained from the synchronization signal source 4, for example, is sent to the adder circuit 7 by 1/N (however, N is The additional signal Si generated by the additional signal generator 6 is also given based on the pulse given to the down-down circuit 5 which counts down to a positive integer.
A composite video signal and an additional signal are output from the adder circuit 7.
A signal synthesized with Si, for example as shown in FIG. 3a, is applied to the modulator 8.

It goes without saying that the video signal source 3 described above may be a signal source of a color video signal;
In Fig. a, the additional signal Si added to the composite video signal every N fields is shown as being inserted during the vertical blanking period of the field to be inserted. This additional signal Si may be inserted within the blanking period of the horizontal synchronization signal at a specific time position for every N fields.

The composite video signal to which the additional signal Si has been added is converted into, for example, a frequency modulated wave by the modulator 8 and then applied to the adder circuit 9, where the audio signal from the audio signal source 10 is modulated by the modulator 11. After being added to the modulated wave signal, it is amplified in a recording amplifier 12, and then recorded on the master disc 0 of the video recording medium disc. Then, a disc-shaped video recording medium 1 (video disc) is reproduced using a stamper made through various processes based on the master disc 0 described above.

As an example, FIG. 4 shows that an additional signal Si having a period five times the vertical scanning period in the composite video signal (a repetition frequency that is 1/5 of the repetition frequency of the vertical synchronization signal) is applied to every 5 fields in the composite video signal. Considering a video recording medium 1 in which a composite video signal inserted during the vertical blanking period is recorded for four vertical scanning periods in one cycle, the composite video recorded on the video recording medium 1 is In the signal, a circle mark is placed at the position of the vertical blanking period in which the additional signal Si is inserted during the vertical blanking period.
Mark the position of the vertical blanking period where the additional signal Si is not inserted during the vertical blanking period with an x mark.
This is a model of record trace l ¹ .

FIG. 5 is a block diagram of one embodiment of a reproducing apparatus for reproducing signals from the video recording medium 1. In FIG. 5, 13 is a pickup element;
14 is a preamplifier, and a pickup element 13
The signal picked up from the video recording medium 1 by the preamplifier 14 is amplified by the preamplifier 14 and then applied to the video demodulation circuit 15 and the audio demodulation circuit 17.

The audio signal demodulated by the audio demodulation circuit 17 and the composite video signal demodulated by the video demodulation circuit 15 and then converted into a desired signal form via the video processing circuit 16 are transferred to the RF converter 1.
8 is sent to the output terminal 20 as a TV signal according to a predetermined TV system. Reference numeral 19 denotes a synchronization separation circuit, which separates a synchronization signal from the output signal from the video demodulation circuit 15 and supplies it to the video processing circuit 16 for video processing. It is supplied to the synchronization signal separation circuit 21.

From the vertical synchronization signal separation circuit 21, a vertical synchronization signal Sv as shown in FIG. The monostable multivibrator 22 described above has a gate pulse Pg for the gate 23.
{Fig. 3c} The gate 23 converts the additional signal Si from the output signal of the video demodulation circuit 15 into the third signal by the gate pulse Pg described above.
It operates to extract as shown in Figure d.

Therefore, the output signal from the gate 23 in the case of the above example when the video recording medium 1 does not cause the locked group phenomenon is an additional signal appearing every five vertical scanning periods, as shown in FIG. 6a. This becomes the signal sequence Si. In Figure 6a, 1
V, 5V, etc. represent one vertical scanning period and five vertical scanning periods, respectively.

In addition, if a locked group phenomenon occurs in the video recording medium 1, where the needle always jumps outward and moves to the next recording trace in the area indicated by arrow A in FIG. As shown in FIG. 7a, the output signal from the gate 23 becomes the additional signal after time _t2 , as shown in FIG. 7a.
It is in a state where Si does not appear. Note that the times t ₁ , t ₂ , etc. shown on the time axis in FIG. 6 are caused by a locked group phenomenon in which the signal reproducing pickup element picks up the recording trace l ₁ of the video recording medium 1 shown in FIG. 4. These are reproduction times t ₁ , t _{2 .} . . of the additional signals Si that are sequentially reproduced from the recording trace l ₁ of the video recording medium 1 when tracing in _the direction of the arrow W without _causing The indications . . . are sequentially added to successive additional signal positions indicated by circles in the recording trace _l1 of the video recording medium 1 shown in the fourth figure. And the record trace of the video recording medium 1 shown in the fourth diagram above.
t ₁ , t ₂ shown in successive additional signal positions in l ₁
In the _following explanation, a display such as .

Now, from the recording trace _l1 in the video recording medium 1 shown in FIG. The arrangement mode is an additional signal sequence Si as shown in FIG. 4, the locked group is in the form represented by the arrow A in FIG.
There is an additional signal Si in the signal repeatedly reproduced by
In addition to the case where the gate 23 outputs a signal as shown in FIG. 7a, which does not contain any As shown in the figure, the stylus tip always jumps from a specific position in the recording trace where the pick-up element 13 for signal reproduction is located to an adjacent recording trace on the outside, causing a locked group phenomenon. In the signal whose portion is repeatedly reproduced by the pick-up element 13, an additional signal sequence as shown in FIG. In addition, if the signal is obtained as an output signal of 23, a locked group is generated by inserting multiple recording traces, and the signal arrangement shown in Fig. 6a, Fig. 7a, and Fig. 8a is shown above. A signal in which the signals are combined on the time axis is obtained as the output signal of the gate 23.

Furthermore, although this does not result in a locked group phenomenon, mistracking occurs in which the pick-up element 13 jumps from the middle of a certain recording trace to an adjacent recording trace inside, as shown by the arrow in FIG. Even in this case, the output signal from the gate 23 is the sixth signal indicating the normal tracking state described above.
For example, an additional signal train having an arrangement as shown in FIG. 9A, which is different from the additional signal train having the arrangement shown in FIG. 9A, can be obtained.

As mentioned above, the cases in which the pick-up element 13 for signal reproduction is accurately tracking the recording trace on the video recording medium 1 and the case in which it is not are shown in each figure a in FIGS. 6 to 9. As shown in FIG. 2, the arrangement of the additional signal Si appearing as the output from the gate 23 on the time axis is different, so the arrangement of the additional signal Si appearing as the output side of the gate 23 differs depending on the repetition period of the additional signal Si appearing on the output side of the gate 23. By extracting a different signal, it can be used as a tracking state detection output. In the circuit arrangement shown in Fig. 5, the above tracking state detection output can be obtained from two retriggerable single units connected in series. This is achieved using a circuit containing a stable multivibrator.

That is, in the circuit arrangement shown in FIG. 5, the additional signal Si column appearing on the output side of the gate 23 is
is applied as a trigger signal to the retriggerable monostable multivibrator (hereinafter sometimes referred to as R・T・M・M) 24, and also The output signal from the T.M.M 24 is applied to the second R.T.M.M. 25 as its trigger signal.

The first R・T・M・M24 outputs a pulse with a pulse width of τ ₁ every time a trigger signal is input to it, and the second R・T・M・M2
5 outputs a pulse with a pulse width of τ ₂ every time a trigger signal is input to it.

The above-mentioned first and second R・T・M・M24,2
The pulse widths τ ₁ and τ ₂ of the pulses generated each time a trigger signal is applied in step 5 are determined by the interval between successive additional signals Si when inserted into a composite video signal, that is, the period of the additional signal Si. , N times the vertical scanning period V, that is, when expressed as NV, the period NV of the additional signal Si
are shown as follows.

{(N-1)V+△V}<τ ₁ <NV…(1) NV<τ ₂ <(N+1)V…(2) Note that ΔV in the above formula (1) is one vertical scanning period V This is an expression used to indicate a shorter period of time.

As in the above example, when the repetition period of the additional signal Si inserted into the composite video signal is 5 vertical scanning periods, that is, 5V, the first R.T. The pulse width τ ₁ of the pulse to be generated each time a trigger signal is applied in the M・M24 is determined by equation (1), within the range of (4V + △V) < τ ₁ < 5V, for example 4.5V.
and the second R.T.M.M.
The pulse width τ ₂ of each pulse to be generated each time a trigger signal is applied in 25 is (2)
According to the formula, the voltage is set in the range of 5V<τ ₂ <6V, for example, 5.2V.

Incidentally, like other examples discussed below,
When the repetition period of the additional signal Si inserted into the composite video signal is 3 vertical scanning periods, that is, 3V, the trigger is triggered at each of the first and second R, T, M, and M24, 25. The pulse widths τ ₁ and τ ₂ of the pulses to be generated each time a signal is applied are set to, for example, 2.5V and 3.2V, respectively.

When the repetition period of the additional signal Si inserted into the composite video signal is 5V, the gate 23 described above
In the state shown in FIG. 6a, in which the additional signal Si is output at intervals of 5 V from the gate 23, that is, in the state where the pickup element 13 correctly follows the recording trace of the video recording medium 1, the additional signal Si is output from the gate 23. 5
The first R・T・M・M to which the additional signal Si sent out at time intervals of V is given as a trigger signal one after another
24, an output pulse P as shown in FIG.
1a is sent out, which causes the second R.T.
When M.M25 is triggered, the second R.T.
A constant high level output signal P2a as shown in FIG. 6c is sent from the M.M25.

Next, the pick-up element 13 for signal reproduction is
When a locked group that moves to an adjacent outer recording trace as shown by arrow A in the video recording medium ₁ shown in FIG. , t ₂ , but since no additional signal is output after that, the first R・T・M・M24
The output pulse P1b from the second R.T.M.M.25 becomes as shown in FIG.
2b becomes as shown in FIG. 7c in the locked group state.

Furthermore, the additional signal Si output from the gate 23
In the case where the arrangement on the time axis is as shown in FIG. 8a, that is, the pickup element 13 for credit reproduction moves to the adjacent outer recording trace at the part indicated by the arrow B in the video recording medium 1 shown in FIG. 4. When a locked group phenomenon occurs in a shifting manner {the locked group phenomenon occurs at the arrows C, D, and H in Figure 4.
When a group phenomenon occurs, the arrangement of the additional signal Si output from the gate 23 on the time axis is not much different from that shown in FIG. 8a, so the arrow mark in FIG. The operation of each part when a locked group occurs in the parts indicated by , d, and e will also be explained with reference to Figures 8 a to c. It may also be represented by an explanation of the operation of
Output pulses from the first R・T・M・M24 in } where descriptions of individual waveform diagrams and explanations for the cases where locked groups occur in parts D and E are omitted. P1c and the output signal P2c from the second R・T・M・M25
etc., as shown in FIG. 8b and FIG. 8c, respectively.

In addition, the pickup element 13 for signal reproduction is
When moving to an adjacent inner recording trace as indicated by the arrow in the video recording medium 1 shown in FIG. 4, an additional signal sequence Si as shown in FIG. 9a is sent out from the gate 23, and accordingly , the first and second R.T.
The M/Ms 24 and 25 output a pulse P1d and an output signal P2d as shown in FIGS. 9b and 9c, respectively.

FIG. 6c shows the output signal P2a from the second R.T.M.M.25 when the tracking state of the recording trace _l1 by the pick-up element 13 for signal reproduction is normal, and the pick-up for signal reproduction The second R・ when the tracking state for the recording trace l ₁ by the element 13 is not normal.
Output signals P2b, P2c from T・M・M25,
As can be readily seen by comparing the waveforms with each of Figures c in Figures 7 to 9 showing P2d, when the tracking state is normal, the second R.T.
M・M25 is a constant high level output signal P2a
On the other hand, if the tracking state is not normal, a low level signal is output from the second R.T.M.M.

By the way, when we look at the low level signal output from the second RTM M25 when the tracking state is not normal, the signal generated in response to the locked group state is more Signals P2b and P2c shown in Figures 7c and 8c have a longer low level period than the signals generated corresponding to the non-locked group state. This becomes clear when comparing the signal P2d shown in FIG. 9c.

Therefore, if the output signal from the second R.T.M.M. Accordingly, if the tracking state is not normal, the second R.
It can be seen that it is possible to easily discriminate whether the low level signal output from the T.M.M.25 is caused by a locked group condition.

That is, in the circuit arrangement shown in FIG. 5, the output signal from the integrating circuit 26 exhibits a slightly negative value corresponding to the locked group state, and also corresponds to the case other than the locked group state. Therefore, by selecting the level of the output signal from the integrating circuit 26 using a predetermined voltage value as a reference, it is possible to correctly detect the locked group state. can.

In the circuit arrangement shown in FIG. 5, the output signal from the integration circuit 26 described above is given to the drive circuit 29 via a switch circuit 27 (the reason for providing this switch circuit and other necessary matters will be described later). , the drive circuit 29 uses its output to drive a release device 30 for releasing the signal reproducing pickup element 13 from the locked group state.

The drive circuit 29 described above generates a drive signal for driving the release device 30 when a locked group release command signal is applied to it, and is composed of, for example, a monostable multivibrator and an amplifier. The first
0 Monostable multivibrator 29 as shown
A Schmitt trigger circuit 29a may be arranged before the circuit 29b. In addition, in FIG. 10, 29c is an amplifier.

The drive circuit 29 is configured to output one drive signal each time a locked group release command is given, but the operation of the drive circuit 29 can be made even more reliable. To do this, for example, every time the drive circuit 29 operates, the integrating circuit 26 may be returned to a normal state (in the case of the example, the integrating circuit 26 is charged to a positive voltage). This can be achieved, for example, by a monostable multivibrator 29, as shown in FIG.
This can be easily achieved by simply configuring the output of b to be returned to the input side of the integrating circuit 26. As a result, the release device 30 is driven by the drive signal from the drive circuit 29, and the release device 30 is used for signal reproduction. The drive circuit 29 is made insensitive to the disturbance in the playback signal that inevitably occurs when the pick-up element 13 is forcibly moved to the adjacent recording track, and the drive circuit 29 is made insensitive to the disturbance in the playback signal that inevitably occurs when the pick-up element 13 is forcibly moved to an adjacent recording track. It becomes possible to reliably prevent the occurrence of an undesirable abnormal operation such as the operation of the terminal 29.

FIG. 11 shows a release device 3 that performs an operation such as forcibly moving the pickup element 13 for signal reproduction to another recording trace by a drive signal from a drive circuit 29.
In FIG. 11, 13a is the bottom plate of the casing of the pick-up element 13, and 13b is a through hole bored in the bottom plate 13a of the casing. Then, the regeneration needle 13d attached to the tip of the cantilever 13c of the pick-up element 13 is inserted into the above-mentioned through hole 13b.
It is in contact with the recording trace provided in the guide groove of the video recording medium 1 through the recording medium 1 .

Two bearings 30b provided on the bottom plate 13a of the housing,
30c is rotatably supported by an L-shaped shaft 30d, and this L-shaped shaft 30d is supported by a spring 30e stretched between its bent end and the bottom plate 13a of the casing. It is biased in the direction of arrow X in the figure. Further, the bent end of the L-shaped shaft 30d is connected to the operating rod of the plunger 30a by a thread 30g. So, plunger 30
When actuated by the drive signal sent from the drive circuit 29, the thread 30g is moved by the plunger 30.
The action of the operating rod a pulls it in the direction of the arrow Y in the figure, and as a result, the L-shaped shaft 30d rotates in the direction opposite to the arrow X in the figure against the elasticity of the spring 30e. move.

A cam plate 30f is attached to the L-shaped shaft 30d.
is installed, so the plunger 3 mentioned above
Due to the rotation of the L-shaped shaft 30d during the operation 0a, the cantilever 13c is lifted by the cam surface of the cam plate 30f, and the cantilever 1
A force is applied to 3c in the direction in which the pick-up element 13 moves.

As a result, the playback needle 13d rises from the guide groove of the video recording medium 1 and is forcibly moved to another guide groove, so that the locked group state is released. It goes without saying that the drive signal necessary for the operation of the plunger 30a described above should have a duration such that the above-described unlocking operation of the locked group can be performed satisfactorily.

Now, as is clear from the above, in the release device 30, when the drive signal is supplied from the drive circuit 29, the playback needle 13 of the pick-up element 13
The locked group state can be canceled by forcibly moving the guide groove d to another guide groove, but if the drive signal from the drive circuit 29 is not in the locked group state. It is undesirable for the release device 30 to operate as a result of being sent out. Switch circuit 27 in the circuit arrangement shown in FIG.
The release device 3
This switch circuit 27 is provided to prevent terminal 2 from operating.
Opening/closing is controlled by a control signal supplied to 8.

That is, the terminal 28 of the switch circuit 27 is connected to the terminal 28 of the switch circuit 27 so that the playback device operates according to the normal playback mode, and the switch circuit 27 is connected only when the playback signal is at a predetermined signal level or higher.
Even when the playback device is operated in the normal playback mode, the playback needle of the pick-up element is lowered onto the recording trace of the video recording medium 1. In the case of a previous no-signal condition, a low playback signal level, a signal loss, or a situation where the rotational speed of the video recording medium is other than the normal rotational speed, the results of sensing each condition will be displayed. The switch circuit 27 is turned off by the control signal generated based on the control signal, and the playback device is set to a playback mode other than the normal playback mode, such as still playback mode, slow motion playback mode, and quick playback mode. A control signal is provided to the terminal 28 so that the switch circuit 27 is turned off even when reproduction is performed in a reproduction mode such as a motion reproduction mode.

Note that if a signal drop occurs in the additional signal Si, it will also cause a malfunction, so the switch circuit 27 must be turned off in this case as well. The probability that the signal will occur at all four locations is low, and normally it will be absorbed by the integrating operation in the integrating circuit 26 and will not cause a malfunction. It is also possible to leave it as a state.

The explanation so far has been about how the vertical synchronizing signal is arranged in the video recording medium 1, how the additional signal is arranged,
Also, the mode of movement of the playback needle between recorded traces, etc.
Each case was for the case shown in Fig. 4, but the manner in which the vertical synchronization signal and additional signals are arranged, the manner in which the playback needle moves between recorded tracks, etc. are different from the case shown in Fig. 4. It goes without saying that even if they are different, the tracking state can be detected satisfactorily.

For example, in a video recording medium as shown in FIG. 4, even if the locked group is two to four grooves, it is possible to detect it by the means described above. However, in the case of a locked group that spans two or more grooves, the second R.
Since the period in which the output signal from T.M.M25 is at low level becomes shorter, the locked
It is possible to distinguish between a low-level signal that occurs when a group phenomenon occurs and a low-level signal that occurs due to something other than a locked group phenomenon (a signal that occurs when the playback needle flies in the direction of the groove that it is scheduled to follow). The time constant in the integrating circuit 26 is set so that it appears clearly in the output of the integrating circuit 26.

Furthermore, FIG. 12 shows the video recording medium 1 in the case where the additional signal Si superimposed on the composite video signal recorded on the video recording medium 1 is added every three vertical scanning periods. , furthermore, the first
Figures a to c in Figures 3 to 16 are
2. An additional signal sequence in the reproduced signal from the video recording medium 1 as shown in FIG.
Output pulse from T・M・M24 {b in each figure
Figure } and the output signal from the second R.T.M.M25 {Figure c in each figure} are shown, respectively.

FIG. 13 above shows the case where the recording trace of the video recording medium 1 as shown in FIG. 12 is traced by the pick-up element 13 in a normal tracking state, and FIG. When the video recording medium 1 such as the one shown in FIG.
When the video recording medium 1 as shown in the figure causes a locked group in the manner shown by the arrow in FIG. 12, FIG. Each of the cases in which the pick-up element 13 that is following the trace moves to a recording trace located ahead in the traveling direction in the manner shown by the arrow N in FIG. 12 is shown.

Each waveform diagram shown in FIGS. 13 to 16,
Comparing the waveform diagrams shown in FIGS. 6 to 9 described above with respect to the video recording medium 1 shown in FIG. In the case of the state where the
Comparing the waveform diagrams shown in each b and c of the figure with the waveform diagrams shown in each b and c of Figs. 14 to 16, it is found that Some differences can be seen regarding the state in which the output signal from the device is at a low level.

However, even in the case of a video recording medium 1 as shown in FIG. 12 in which a composite video signal on which an additional signal is superimposed every three vertical scanning periods is recorded, if the pickup element 13 correctly traces the recording trace,
In other words, the second R.T.M.M. in the normal tracking state and in the other case.
The output signal from the second R.T.M.M.25 is distinguishable from the output signal from the second R.T.M.M. , it is possible to distinguish between cases that correspond to the state of the locked group and cases that do not, based on the difference in the total value of the low level period of the output signal (on the output side of the integrating circuit 26, (signals with clear level differences can be obtained), in this respect,
It can be said that there is no difference between the composite video signal recorded on the video recording medium shown in Figure 4 and the composite video signal recorded on the video recording medium shown in Figure 12. A comparison shows that the two differ in terms of ease of discrimination and slowness of response in an inverse relationship.

Note that the signal form of the additional signal Si to be superimposed on the composite video signal is as described in the above-mentioned embodiments, that is, in the form of a pulse as shown in Fig. 3a. In addition to signal formats in which one signal is inserted every N vertical scanning periods,
For example, by inserting pulses with gradually different pulse widths or pulse height values in each vertical scanning period during N vertical scanning periods, the N pulses can be used to It is possible to use an additional signal in a signal form in which two additional signals are formed and one additional signal Si is inserted every N vertical scanning periods, or in any other arbitrary signal form.

As is clear from the above explanation, in the recording/reproducing method using the video recording medium of the present invention, by superimposing a specific additional signal on the composite video signal, the pick-up element for signal reproduction can record data on the video recording medium. It is possible to easily detect whether or not the track is being followed in a normal tracking state, and it is also easy to release the locked group using the detection output. According to the method of the present invention, it is possible to easily provide a video recording medium recording and reproducing device that can always record and reproduce in good condition a video disk that is prone to malfunction due to dust adhesion or scratches. do.

[Brief explanation of the drawing]

Figures 1a and b, 4, 12, etc. are plan views or perspective views of the video recording medium, respectively.
The figure is a block diagram of one embodiment of the recording device.
Figure 3 a-d, Figure 6 a-c, Figure 7 a-c
Figures 8a-c, Figures 9a-c, Figures 13a-c, Figures 14a-c, Figures 15a-c
16A to 16C are explanatory waveform example diagrams, FIG. 5 is a block diagram of one embodiment of the reproducing device, FIG. 10 is a block diagram of an example configuration of the drive circuit, and FIG. FIG. 11 is a perspective view of one embodiment of the release device. 1, 2...video recording medium, 3...video signal source,
4...Synchronization signal source, 6...Additional signal generator, 7,
9...Addition circuit, 13...Pickup element, 2
2, 29b... Monostable multivibrator, 23
...gate, 24...first re-triggerable
Multivibrator, 25... Second retriggerable multivibrator, 26... Integrating circuit, 27... Switch circuit, 29... Drive circuit,
29a...Schmitt trigger circuit, 30...release device, 30a...plunger, 30g...thread,
30f...cam plate, 13c...cantilever, 1
3d...Reproduction needle, 1l, 2l...Record trace.

Claims (1)

[Claims] 1. The recording position of the vertical synchronization signal in a composite video signal in a recording trace formed in a spiral or spiral shape on a video recording medium is on the same radius in a series of recording traces, or on the same radius in a series of recording traces, or in a series of recording traces. The additional signal is arranged in a straight line in a direction across the trace and has a constant repetition period that is different from either the rotation period of the recording medium or a period that is an integral multiple of the rotation period. means for extracting an additional signal from a reproduced signal from a video recording medium recorded superimposed on a composite video signal, a repetition period of the additional signal recorded on the video recording medium, and reproduction from the video recording medium. means for generating a tracking state detection output based on the difference with the repetition period of the additional signal extracted from the signal; A video recording medium comprising means for forcibly moving a pick-up element used for reading signals from the video recording medium to another recording trace position to be reproduced from now on based on the detection output. Recording and playback method used. 2. The recording position of the vertical synchronization signal in a composite video signal in a spiral or spiral recording trace formed on a video recording medium is on the same radius in a series of recording traces or in a straight line across a series of recording traces. An additional signal arranged on a line and having a constant repetition period different from either the rotation period of the recording medium or a period that is an integral multiple of the rotation period is superimposed on the composite video signal. a means for extracting an additional signal from a playback signal from a video recording medium recorded on the video recording medium, a repetition period of the additional signal recorded on the video recording medium, and an addition signal extracted from the playback signal from the video recording medium; A means for generating a tracking state detection output based on the difference with the repetition period of the signal, and a detection output when the tracking state is not in a normal tracking state generated by the tracking state detection output generating means described above. , a recording and reproducing method using a video recording medium, comprising means for forcibly moving a pick-up element used to read signals from the video recording medium to another recording trace position to be reproduced from now on. In this method, a video recording medium is used which is provided with a means for moving the pick-up element only when the normal playback signal read by the pick-up element is output at a predetermined level or higher during playback in the normal playback mode. Recording and playback method.