JPS6149745B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information signal recording medium and its recording and reproducing apparatus, and relates to an information signal recording medium and a recording and reproducing apparatus for the same.
An information signal recording medium that is sequentially switched at a rotation period and recorded on the same track along with an information signal can be recorded by mechanical cutting, electron beam cutting, etc. It is an object of the present invention to provide a device that can perform tracking control operations extremely stably and reliably without using a circuit for signal switching, and can reproduce information signals with high quality.

The present applicant previously disclosed in Japanese Patent Application No. 51-38809 and its divisional application that a main information signal is recorded in a geometric shape on a recording medium using one modulated beam out of a plurality of modulated beams. As a change, a reference signal for tracking control is recorded continuously on a spiral or concentric main track, and a reference signal for tracking control is recorded approximately in the middle between each track center line of this main track using another modulated beam. We proposed a method for reproducing it. As a result, during reproduction, the reference numbers reproduced from both sides of the main track are discriminately reproduced from among the reproduced signals reproduced by a well-known method using a reproduction scanner (signal pickup section) such as a light beam or a scanning needle. A tracking control signal is obtained based on this, and the main information signal is reproduced from the main track while performing the tracking control operation. According to the method proposed by the present applicant, since the needle guide groove can be eliminated, the sliding contact area of the scanning needle with the recording medium can be increased, especially when applied to a capacitance change detection type recording medium. However, it is possible to extend the life of the scanning needle and the recording medium, and when the recording signal is a video signal, it can be used for various purposes such as still image playback, slow motion playback, quick playback, high-speed cueing, and random access using address codes. When the recording signal is an audio signal, it has features such as high-speed track position search when selecting songs, random access, etc. even when recording it in PCM or multi-channel. .

Now, as the tracking control reference signal (hereinafter also referred to as tracking signal),
When f _p1 and f _p2 of different single frequencies are used and these are sequentially and cyclically switched and recorded every rotation period of the rotating recording medium, the reference signal f _p
1. Record a third reference signal f _i as an index pulse during playback corresponding to the switching position of f _p2 ,
During reproduction, it is essential to differentially reproduce the reference signal f _i and, based on this, to switch the tracking control polarity of the reproduced reference signals f _p1 and f _p2 every rotation period.
Therefore, in order to perform tracking control stably, stable reproduction of the above-mentioned index reference signal f _i is essential, and there is no possibility that the reproduced reference signal f _i will be disturbed or accompanied by large level fluctuations. , or if detection and reproduction are not performed for some reason, the sequential tracking control direction for the control polarities of f _p1 and f _p2 of the reproducing scanner will not be determined, and the tracking servo will not be performed stably. Each time the needle is removed, a phenomenon of needle skipping occurs, which significantly impairs the quality of reproduction.

In addition, in the method proposed by the present applicant, the main information signal is a so-called audio disk in which only the audio signal is recorded in a super high frequency with a sufficiently wide dynamic range using multi-channel or long-time PCM, and a television. By using at least the same playback device as the so-called video disk on which signals are recorded, and by adding the necessary amplifier system, the above-mentioned audio disk and video disk can be made compatible without changing the mechanical system at all. It is most desirable to be able to play along with it. Therefore, in order for the method proposed by the present applicant to satisfy the above requirements, it is necessary to use the tracking control reference signals f _p1 and f _p2 regardless of the periodicity of the video signal or the aperiodicity of the audio signal. about,
It is also necessary to match the conditions for recording the index reference signal f _i on the audio disc and the video disc.

Furthermore, it goes without saying that the reference signal f _i needs to be regenerated stably as described above, but the differential regeneration from the regenerated signal can be done using as simple a circuit configuration as possible.
It is desirable to detect it consistently and reliably.

Furthermore, even if the width of the electrode part of the scanning needle is sufficiently narrower than the track width of the main track, or even if the diameter of the light beam spot is sufficiently smaller than the track width of the main track, the above index reference The signal f _i must be regenerated stably and reliably. That is, for example, the main track is recorded as a change in geometric shape, and f _i is f _p
At the same time as ₁ and f _p2 , a flat disk recorded approximately midway between each track center line of the main track,
When reading and reproducing changes in capacitance by relative scanning of the scanning needle, the performance of the tracking servo is improved by 60 dB (1000:1) and 400 dB on the disk.
If there is an eccentricity of μm, the tracking accuracy is 0.4μ
It has been confirmed by the applicant's experiments that this is m. In other words, as a tracking control device that electronically controls the scanning needle to follow the main track, it is preferable to make the scanning needle follow the ideal center line of the main track, but in reality, complete tracking control is not performed; Tracking control is performed with the scanning needle meandering by about 0.4 μm. Therefore, the width of the electrode portion of the scanning needle in sliding contact with the disk is larger than the track pitch of the main track (in this specification, track pitch refers to the distance in the track width direction between the scanning center lines of adjacent main tracks). It is clear that unless the width is made narrower by at least 0.4 μm, simultaneous reproduction will occur across adjacent main tracks, resulting in beat disturbance in the reproduced signal. Therefore, as for the width of the electrode part of the scanning needle, it is necessary to take into account variations in the width of the electrode part due to manufacturing variations or wear of the scanning needle, and allow for a margin for the width of the electrode part. As an example, in order to reproduce a 60-minute main information signal from one side of a disk with a diameter of 30 cm at a rotation speed of 900 rpm, the main information signal and the reference signal f _p1 ,
When recording f _p2 and _fi , the track pitch is 1.4 μm and the width of the electrode portion of the scanning needle is 0.4 to 1.0 μm.

However, when reproducing a disc with a flat surface using a scanning needle having an electrode portion width smaller than the track pitch as described above, the index reference signal f _i is not recorded on the main track. The playback situation is extremely unstable, with constant level fluctuations in conjunction with the tracking situation, and in extreme cases, the playback level of f _i drops to a noise level and disappears. Therefore,
Since the reference signals f _p1 and f _p2 are not switched at predetermined positions, and the scanning needle is not forcibly moved in the track width direction during special playback, which will be described later, the tracking servo function is disturbed. It is clear that stable tracking control cannot be performed.

Furthermore, according to the information signal recording and reproducing method proposed by the applicant mentioned above, two systems in total are required at the time of recording: a recording system for the reference signals f _p1 , f _p2 , f _i and a main information signal recording system. Therefore, when recording by dividing the laser beam, the recording optical system becomes complicated.
Furthermore, it is difficult to record using mechanical cutting or electron beam cutting.

The present invention has solved all of the above-mentioned problems, and each embodiment thereof will be described below with reference to the drawings.

FIG. 1 shows a block system diagram of an embodiment of a recording apparatus for an information signal recording medium according to the present invention. Here, for convenience of explanation, an example will be described in which an NTSC color video signal is recorded as an information signal on a disk, which is a recording medium, along with an audio signal.
In Fig. 1, the NTSC color video signal is input to input terminal 1, the luminance signal has its upper limit frequency band-limited, the carrier color signal is low-frequency converted to 2.56MHz, which will be described later, and after these are band-sharing multiplexed, voice carrier f
A frequency modulated signal obtained by frequency modulating a composite signal obtained by mixing _A1 and f _A2 in an appropriate level relationship is input.

On the other hand, a signal f _sc of a color width carrier frequency of 3.58 MHz of an NTSC color video signal enters the input terminal 2 and is supplied to frequency dividing circuits 3, 4, and 5, respectively. The frequency is divided by 1/5 by frequency dividing circuit 3 and extracted.
A single frequency signal f _p1 of 715.9 kHz, a single frequency signal f _{p2 of 511.4 kHz which was frequency-divided by 1/7 and extracted by the frequency divider circuit 4, and a single frequency signal f p2} of 511.4 kHz which was frequency-divided by 3/35 and extracted by the frequency divider circuit 5. The single frequency signal f _p3 of 306.8 kHz is supplied to each switch circuit 6, where it is sequentially and cyclically switched every one rotation period of the recording master 15, which will be described later, by a switching pulse from a terminal 7. Only the one-frequency signal is supplied as a tracking signal to the mixer 8, as will be described later, where it is multiplexed (superimposed) with the frequency modulated signal from the input terminal 1. The multiplexing ratio of the single frequency signals f _p1 , f _p2 , f _p3 with respect to the frequency modulated signal is, for example, approximately -20 dB, thereby preventing the influence of these single frequency signals on the frequency modulated signal.

The multiplexed signal taken out from the mixer 8 is amplitude-controlled by a limiter (not shown) and is supplied to the optical modulator 11 into a so-called duty cycle modulation signal wave of a rectangular wave.

Next, the recording optical system will be described. A laser beam emitted from the laser light source 9 is incident on the optical modulator 11 via the optical modulator 10 for adjusting the light amount. Since the duty cycle modulation signal wave is applied as a modulation signal to this optical modulator 11, a modulated light beam modulated by this modulation signal is emitted from this optical modulator 11. This modulated light beam is sequentially reflected by the reflecting mirrors 12 and 13, and then enters the full aperture of the objective lens 14, thereby striking the photosensitive agent coated on the disc-shaped recording master 15, such as glass, which is rotating synchronously. The light is focused and focused.

The recording master 15 is placed on a turntable 16, and is rotated at a speed of, for example, 900 rpm by a motor 17.
The entire master disc 15, turntable 16, and motor 17 are continuously transported in the direction of arrow X at a predetermined pitch by a transport mechanism (not shown). Therefore, the above 1.
The output multiplexed signal of the mixer 8 is recorded in a spiral track from the outer circumference to the inner circumference by the modulated light beam of the book.

As the recording master 15, turntable 16, and motor 17 are moved in the direction of arrow X, a DC voltage corresponding to the displacement position caused by the movement is extracted from a displacement position detector 18 made of a potentiometer. This DC voltage is appropriately amplified by a DC amplifier 19 and applied to the optical modulator 10 for adjusting the light amount, and the optical beam spot of the recording master 15 focuses the light intensity of the laser beam from the laser light source 9 onto the recording master 15. control according to the position in the radial direction. Thereby, compensation is made so that the light beam spot is not affected by the difference in relative linear velocity depending on the position of the recording master disk 15 in the radial direction.

The recording master disk 15 exposed to light as described above is subjected to a well-known development process and a disk manufacturing process to produce a recorded disk, which is an information signal recording medium of the present invention. This recorded disk is, for example, a disk that has no needle guide groove, has a flat surface, and has an electrode function, and the superimposed signal is read and reproduced as a change in capacitance by relative sliding contact scanning with a scanning needle. For example, countless pits are formed on a disc base material made of polyvinyl acetate (PVAC), which is interrupted by spiral tracks, and a metal layer with a thickness of, for example, 40 nm is provided on top of the pit to serve as an electrode. A thick dielectric coating is applied. Note that instead of providing the metal layer, other materials may be used to provide the electrode function.

FIG. 2 shows an example of the frequency spectrum of a signal recorded by the recording device shown in FIG. In the same figure,
is the 2.3 MHz carrier shift frequency band of the frequency-modulated luminance signal, f _a is the 6 MHz frequency corresponding to the sync chip, f _b is the 6.7 MHz frequency corresponding to the pedestal, and f _c is 8.3 MHz corresponding to the white peak. Indicates frequency in MHz. Further, _L and _U indicate the lower sideband and upper sideband of the frequency-modulated luminance signal. _L and _U indicate the lower sideband and upper sideband of signals obtained by further frequency modulating the audio carriers f _A1 and f _A2 . Here, the audio carriers f _A1 and f _A2 are, for example,
It is a signal obtained by frequency modulating the carrier waves of 3.43MHz and 3.73MHz with an audio signal, and its frequency spectrum is shown as. That is, the audio signal is frequency modulated twice.

Furthermore, it shows the band of a low-pass converted carrier color signal that is band-sharing multiplexed to a luminance signal whose upper limit frequency is band-limited to about 3MHz, and in this embodiment, as an example, it is 2.56MHz (=5/7f _sc )±. It occupies the 500kHz band. In addition, _L is the first sideband generated by frequency modulation of the low-pass converted carrier color signal in the band shown by , and _U is the second sideband.
Indicated by _L and _U , respectively.

In FIG. 2, the frequency spectrum indicated by the solid line is the frequency spectrum of the signal recorded on the disk.

Note that f _p1 , f _p2 , and f _p3 are located in open frequency bands on the lower side of band _L.

The tracking signals f _p1 , f _p2 , f _p3 are divided into 1/1 of the horizontal scanning frequency by frequency dividing circuits 3, 4, and 5, respectively.
Since the frequency is selected to be an odd multiple of 2, there is a frequency interleave relationship with the luminance signal (horizontal scanning frequency), and the band is different from the low frequency converted carrier color signal band. Therefore, f _p1 , f _p
2. If f _p3 is switched every disk rotation period as described above to record continuously,
In order to reduce the beat interference caused to the video signal,
Although it is necessary to lower the recording level to some extent, it is possible to secure a recording level that provides a sufficient S/N ratio. In this way, when f _p1 , f _p2 , and f _p3 are recorded as continuous signals, there are advantages such as improving the accuracy and stability of tracking servo during reproduction and also being able to continuously detect jitter.

In addition, in the embodiment shown in the first figure, the recording master 1
5. For the turntable 16 and motor 17,
The optical system such as the objective lens 14 may be configured to be moved in the direction opposite to the arrow X. Furthermore, according to the method of the present invention, the information signal and the tracking signals f _p1 , f _p
2 and f _p3 are respectively recorded on the same track, it goes without saying that a laser beam can be used as in the above embodiment, but an electron beam can also be used instead of a laser beam. can also perform mechanical cutting. Furthermore, compared to a recording method using a plurality of light beams, the circuit configuration of the recording system can be simplified.

Next, embodiments of the information signal recording medium reproducing apparatus according to the present invention will be described. As shown in a partially enlarged perspective view of the disk recorded in the above manner, the surface of the disk 20 has a geometric structure in which flat portions 21 and oblong pits (recesses) 22 are repeated alternately. It has a certain shape. This change in geometrical shape forms a spiral track, and the information signal consisting of the NTSC color video signal and audio signal and the single frequency tracking signal f _p1 , f _p2 , f _p3 are tracked on the disk. Tracking signals that are sequentially switched every rotation period and synthesized in time series are multiplexed and recorded on the same spiral track. In addition, in Figure 3, t ₁ , t ₂ ,
t ₃ , t ₄ , and t ₅ indicate helical tracks formed per rotation of the disk 20. Further, a sliding surface 23b of a scanning needle 23 is in contact with the disk 20, and the scanning needle 23 slides relative to the disk 20 to read a slight change in capacitance. The sliding contact surface 23b has a sharp apex 23c as an introduction part, and an electrode part 23 formed on the rear end surface.
It is a flat surface including a, and the sliding surface 23
The area b is selected to be large enough so that a plurality of pits 22 can be brought into sliding contact at the same time in order to maintain a long needle life.
However, as mentioned above, at least disk 2
The width of the electrode section 23a on 0 is one pit 2.
The width is selected to correspond to the width of No. 2.

The recorded signal on the disk 20, which is picked up as a slight change in capacitance by the scanning needle 23, is converted into an electrical signal using a well-known technique, and then converted into the original NTSC color video signal and audio using a well-known signal processing technique. The signal is demodulated. here,
Even when the scanning needle 23 is correctly scanning a track, any two of the tracking signals f _p1 , f _p2 , f _p3 may be generated as crosstalk not only from the scanning track but also from the adjacent tracks on both sides. Various types of tracking signals are detected. As an example, the detection level is approximately -15 to - of the tracking signal detected from the track being scanned.
It has been confirmed through experiments by the applicant that it can be detected on the order of 20 dB. Therefore, the tracking signal detection level detected as crosstalk is on the order of about -35 to 40 dB with respect to the carrier level of the reproduction information signal of the scanning track. Note that crosstalk is greater at low frequencies.

FIG. 4 is a block system diagram showing the main parts of the first embodiment of the reproducing apparatus of the present invention, in which the electric signal picked up by the scanning needle 23 is inputted from the input terminal 25, and is input to the pan-dopass amplifiers 26, 27 and 28. are supplied respectively. Bandpass amplifier 26, 27,
28 respectively. bandpass amplifier 26,
27 and 28 have steep passband center frequencies at required frequencies f _p1 , f _p2 , and f _{p3 ,} respectively, and tracking signals f _p1 , f _p2 , and f _p3 are provided at their output ends. appear. When the scanning needle 23 is accurately scanning the track, the tracking signal f p1 shown in FIG. 5A appears at the output end of the bandpass amplifier 26, and the tracking signal f _p1 shown in FIG. A tracking signal f _p2 shown in B appears, and a tracking signal f _p3 shown in C in the same figure appears at the output terminal of the bandpass amplifier 28.
appears. In FIGS. 5A to 5F and FIGS. 7A to 0 described below, T ₁ , T ₂ , T ₃ , and T ₄ are the times when the tracks t ₁ , t ₂ , t ₃ , and t ₄ shown in FIG. 3 are scanned. It is assumed that tracking signals f _p1 , f _p2 , f _p3 , and f _p1 are recorded in tracks t ₁ , t ₂ , t ₃ , and t ₄ together with information signals, respectively. That is, among the output signals of the bandpass amplifiers 26 to 28 shown in FIGS. 5A to 5C, the time width of one rotation of the disk 20 is determined by the tracking signal obtained from the track being scanned by the scanning needle 23, which has a large amplitude. , and the portion where the amplitude is small is a tracking signal obtained as crosstalk from the tracks on both sides of the track being scanned by the scanning needle 23.
It has a time width of two rotations. Also, among the output signals of the bandpass amplifiers 26 to 28, among the tracking signals obtained as the above-mentioned crosstalk, a signal with a width of one rotation immediately before the portion with large amplitude is a tracking signal from the track after the scanning track. Also, the signal with a width of one revolution immediately after the portion with large amplitude is the tracking signal from the track immediately before the scanning track (for example, when scanning track _t2 , the signal of the bandpass amplifier 26 is At the output end, as shown in FIG. 5A, the crosstalk f _p1 from the previous track _t1 appears, and at the same time, at the output end of the bandpass amplifier 28, as shown in FIG. Crosstalk f _p3 from track t ₃ appears).

The tracking signals f _p1 , f _p2 , separated by the band pass amplifiers 26, 27, 28,
f _p3 is a bandpass amplifier 29, 30, 3 having the center frequency of the pass frequency band at f _p1 , f _p2 , f _p3
1 and is further amplified here before being supplied to the switch circuit 38. On the other hand, the output tracking signals f _p1 , f _p2 , f _p3 of the bandpass amplifiers 26 , 27 , 28 are sent to the envelope detection circuit 32 ,
After being subjected to envelope detection by 33 and 34, the signal is supplied to waveform shaping circuits 35, 36 and 37, where a large amplitude portion is extracted. This results in
The waveform shaping circuit 35 takes out the pulse shown in FIG. 5D, the waveform shaping circuit 36 takes out the pulse shown in FIG. 5E, and the waveform shaping circuit 37 takes out the pulse shown in FIG. It is applied as a switching pulse to the switch circuit (analog switch) 38, and the outputs of the bandpass amplifiers 29, 30, and 31 are switched during the "H" level period.

That is, when scanning the track _t1 in which f _p1 is recorded as the tracking signal, only the output signal of the waveform shaping circuit 35 becomes "H" as shown in FIG. 5D.
level, and the output tracking signal f _p2 of the bandpass amplifier 30 is sent to the envelope detection circuit 40.
and output tracking signal f _p3 of the bandpass amplifier 31 to the envelope detection circuit 3.
The switch circuit 38 is switched to supply the power to the power source 9. Furthermore, when scanning the track _t2 in which f _p2 is recorded, only the output signal of the waveform shaping circuit 36 is shown in FIG.
As shown in FIG. 2, the signal becomes "H" level, and the output tracking signal f _p1 of the bandpass amplifier 29 is supplied to the envelope detection circuit 39, and the output tracking signal f _p3 of the bandpass amplifier 31 is supplied to the envelope detection circuit 40. The switch circuit 38 is then switched. Furthermore, when scanning the track _t3 in which f _p3 is recorded, only the output signal of the waveform shaping circuit 37 becomes "H" level as shown in FIG. f _p1 is supplied to the envelope detection circuit 40, and the output tracking signal f _p2 of the bandpass amplifier 30 is supplied to the envelope detection circuit 39.

In this way, the input of the envelope detection circuit 39 is always supplied with a tracking signal obtained as crosstalk from the adjacent track one rotation earlier (on the outer circumferential side) than the track being scanned, and the envelope detection circuit 39 A tracking signal obtained as crosstalk from an adjacent track one rotation later (on the inner circumferential side) than the track being scanned is always applied to the input of the circuit 40. Therefore, the signals obtained by envelope detection by the envelope detection circuits 39 and 40 are sent to the differential amplifier circuit 4, respectively.
1, a desired tracking control signal is extracted from the differential amplifier 41. This signal is applied from an output terminal 42 to a well-known tracking control mechanism (not shown) for the scanning stylus 23, thereby causing the scanning stylus 23 to always accurately scan on a track.

Although it has been confirmed through experiments by the applicant that desired tracking control is possible with the above circuit configuration, there remains room for further improvement in the sensitivity of tracking control. That is, in the above embodiment circuit, the phase relationship between the switching control signal of the switch circuit 38 (shown in FIGS. 5 D to F) and the input signal to be switched (shown in FIGS. 5 A to C) is determined by the signal processing system. It is difficult to achieve complete matching due to differences in rotation or uneven rotation. Therefore, if the phases of the two signals do not match, the switching timing of the switch circuit 38 is shifted, and the tracking signal obtained from the track being scanned by the scanning needle 23 at the output end of the switch circuit 38 is delayed for a short time. However, it appears. This signal is an unnecessary error signal for tracking control, and even though it only occurs for a fairly short time, it has a higher level compared to the tracking signal obtained as crosstalk, so tracking control It disturbs the

As a countermeasure against the above phenomenon, the phase relationship between the two signals inputted to the switch circuit 38 is made to match as much as possible in the circuit system, but even then, regarding the tracking signal from the scanning track generated at the output terminal of the switch circuit 38, for example, At the input portions of the bandpass amplifiers 29, 30, and 31, it is desirable to use an amplitude limiting circuit for limiting the amplitude of the tracking signal from the scanning track and eliminating it as much as possible within a range that does not damage the signal portion due to crosstalk. Alternatively, each output signal of the waveform shaping circuits 35, 36, and 37 may be used to generate a required gate pulse by a monostable multivibrator to remove the unnecessary error signal.

On the other hand, as an active solution to prevent the generation of the above-mentioned unnecessary error signal, in the recording system shown in the first diagram, the tracking signal is kept for a possible time (for example, about 100 μs) at the switching part of the tracking signal. An information signal recording medium may be created in which there is no signal. In the reproduction system of this information signal recording medium, by configuring the circuit so that the phase shift between both input signals of the switch circuit 38 is contained between the no-signal portion, an error signal that does not require supervision can be eliminated. It is also possible to configure the switch circuit 38 so as not to output it.

FIG. 6 shows a block system diagram of the main parts of another embodiment of the reproducing apparatus of the present invention. In the figure, the same components as those in FIG. 4 are denoted by the same reference numerals, and the explanation thereof will be omitted. In FIG. 6, 43, 44, 45 are the output signals of the waveform shaping circuits 35, 36, 37 (D in FIG. 7,
This is a rising edge detection circuit that detects the rising edges of the signals (shown in E and F), and outputs the signals shown in G, H and I in FIG. This allows OR
As shown in FIG. 7J, the circuit 46 outputs pulses having a period equal to the time required for one revolution of the disk 20. Here, FIGS. 7A to 7C are respectively 5th
Similar to the signal waveforms shown in FIGS. A to C, output signal waveforms of the bandpass amplifiers 26, 27, and 28 are shown.

By the way, as described above, when switching the tracking signal for each revolution of the disk 20, an unnecessary error signal may be generated and the tracking may be disturbed.
The output pulse of the OR circuit 46 will produce several pulses in succession that produced one pulse. Therefore, in this example,
The output pulse of the OR circuit 46 is supplied to a gate circuit 47 using a monostable multivibrator, where
Two or more pulses are prevented from being output during the period from when one output pulse of the OR circuit 46 is generated until the disk 20 rotates once. Furthermore, this gate circuit 47 also has the effect of making it insensitive to noise when a dropout or the like occurs in a signal.

One pulse is extracted from the gate circuit 47 for each rotation period of the disk 20 regardless of the tracking state, and the repetition frequency is stepped down to 1/3 by the 1/3 countdown circuit 48, as shown in FIG.
On the other hand, the pulse delay circuit 49
As a result, the pulse is delayed by a predetermined time sufficiently shorter than the time required for one revolution of the disk 20, and the pulse is generated as shown in FIG. 7L. 1/3 countdown circuit 48
The output pulse of is inputted to the data input terminal D of the shift register 50, while the pulse delay circuit 49
The output pulse is applied to the clock pulse input terminal C of the shift register 50. Therefore, three types of pulses are extracted from the shift register 50, as shown in FIG. It can be done. These three types of pulses are applied as switching pulses to the switch circuit 38, and only the tracking signals obtained as crosstalk from the tracks on both sides of the scanning track are extracted from the switch circuit 38, and only the tracking signals obtained as crosstalk from the tracks on both sides of the scanning track are extracted. The switching circuit 38 is controlled by switching so that the tracking signals from the adjacent tracks are always applied to the envelope detection circuit 39, and the tracking signals from the adjacent tracks on the inner circumferential side are always applied to the envelope detection circuit 40. .

According to this embodiment, even if the unnecessary error signal occurs near the tracking signal switching recording portion, the gate circuit 47 outputs one pulse per revolution of the disk 20. 4. Unlike the circuit shown in the figure, the tracking is disturbed and the scanning needle 23 is blown to another track, and then the scanning needle 23 is blown off to another track, and then the scanning needle 23 returns to a stable state.In this embodiment, once a stable tracking state is entered, the disk Even if the scanning needle 23 is blown off due to an unnecessary error signal that occurs once per rotation of the scanning needle 20, the scanning needle 23 is forcibly returned to the track that should normally be tracked, so that normal tracking control can be performed. That is, bandpass amplifier 2
Even if the scanning needle 23 is temporarily skipped due to the phase difference between the output signals of 9 to 31 and the output signal of the shift register 50, it is only for a short time, and if the information signal is a video signal, the vertical line return line Since the data can be fully stored within the erasing period, no problems will occur on the screen. Furthermore, by appropriately selecting the delay times of the bandpass amplifiers 29 to 31, the phase difference can be made extremely small.

In addition, as another embodiment of the present invention, the disk 20
For example, a pilot signal _fp4 of several cycles is recorded to obtain one reference pulse for each rotation of It is also possible to further simplify the circuit. The method of coding the pilot signal f _p4 is as follows: f _p1 to f
As with _p3 , duty cycle modulation is used, or if the information signal is a video signal, one of the video signals recorded per rotation is used.
It is also possible to input it as a burst signal of the frequency of the video signal band in a particular V.BLK.

Furthermore, in the above embodiment, the tracking signal f _p1
Although the case where ~f _p3 is recorded together with an information signal by the duty cycle modulation technique has been described, a signal obtained by simply superimposing these signals may also be recorded. Furthermore, if duty cycle modulation is difficult, recording may be performed using a composite signal obtained by electrically adding an information signal (carrier) and a tracking signal. However, in this case, if there is an inconvenience that unevenness occurs on the disk surface due to the period of the tracking signal, it is desirable to record the waveform with a flattened one-sided envelope of the composite signal. In addition, the above three types of tracking signals f _p1 , f _p2 , f _p3 are superimposed as burst signals linked to the horizontal retrace period of the video signal in order to prevent problems such as cross-modulation interference with the video signal. May be recorded. Furthermore, although the tracks on the recording master disk 15 and the disk 20 have been described as being spiral, they may also be formed in concentric circles.

The information signal recording medium according to the present invention is shown in FIGS.
As explained in the figure, it does not have to be of the capacitance change detection type, and may be a disk that is reproduced using a light beam or a disc-shaped magnetic recording medium. Furthermore, the method of the present invention can also be applied to the case where only an audio signal is recorded and reproduced as a high-quality, multi-channel signal with a high dynamic range as the information signal to be recorded. Furthermore, tracking signals f _p1 , f
_p2 and f _p3 are not limited to single frequency signals, but can also use a certain narrowband FM signal (for example, a signal frequency modulated with an audio signal), and the point is that the tracking signal must at least be used for tracking control. It is only necessary to record and reproduce the signal in the obtained signal form.

As described above, in the information signal recording medium of the present invention, the information signal and the first, second, and third tracking signals having mutually different frequencies are sequentially and cyclically switched every rotation period, and are recorded in time series. A concentric or spiral track is formed on a flat surface by multiplexing and recording one tracking signal with a no-signal period provided at the switching connection part of the tracking signal synthesized with the tracking signal. Since the recording conditions for the first to third tracking signals can be made the same regardless of the type of information signal, no changes can be made to all types of information signal recording media using a single reproducing device. It can be replaced without any compatibility. Further, the recording device for an information signal recording medium according to the present invention multiplexes the above-mentioned one tracking signal onto this information signal at a level lower than a predetermined level than the information signal level, and converts this multiplexed signal into an information signal by a single recording means. Since concentric or spiral tracks are formed on the recording medium for recording, it is possible not only to use a single light beam as the recording means, but also to use a single electron beam or even mechanical cutter. The information signal recording medium can still be recorded, and since the recording means is single, the recording system can be constructed more easily and at a lower cost than the recording method proposed by the applicant. By recording the period, an error signal that may occur in the tracking control signal due to a phase shift between the reproduction tracking signal and its switching control signal during reproduction near the tracking signal switching recording part can be contained in the non-signal period. It is possible to prevent the output from being generated.

Further, in the information signal recording medium reproducing apparatus according to the present invention, the first reproduction tracking signal reproduced from the track being scanned by the signal pickup section and the track being scanned are obtained as crosstalk from the adjacent tracks on both sides. The above-mentioned signal obtained by separately reproducing the other two types of second and third reproduction tracking signals, respectively, and switching the switch circuit with the signal detected based on the level difference of the first to third reproduction tracking signals. The first reproduction tracking signal and the second and third reproduction tracking signals are detected, and the amplitude of the first reproduction tracking signal is increased to a level approximately equal to the level of the second and third reproduction tracking signals. limited or no signal;
A reproduction tracking signal from an adjacent track on the outer circumference side of the scanning track is supplied to a first detection circuit, and a reproduction tracking signal from an adjacent track on the inner circumference side is supplied to a second detection circuit. The information signal is reproduced from the track being scanned while the signal pickup section is controlled by the signal obtained by supplying the outputs of the first and second detection circuits to the differential amplifier. The second signal obtained as crosstalk from the tracks on both sides
Also, a regeneration circuit that switches the polarity of the third regeneration tracking signal every rotation period can be completely eliminated.
Therefore, the circuit configuration of the reproduction system can be simple and inexpensive, and since there is no need to reproduce the pulse recorded once per rotation for polarity switching, tracking is possible even when this pulse is not detected and reproduced. Tracking control can be performed stably without malfunctions in control operations, and disturbances in tracking control based on the phase difference between the second and third reproduction tracking signals supplied to the switch circuit and switching pulses can be greatly reduced. can be suppressed to

Further, in the reproducing apparatus of the present invention, each rising edge of the first reproduction tracking signal waveform is detected to generate one pulse per revolution of the information signal recording medium, and this pulse is used to control the switch. A circuit switching signal is generated to switch a switch circuit, and the second and third reproduction tracking signals are supplied to the first and second detection circuits through this switch circuit, so that one of the information signal recording media
Tracking signal switching for each rotation period Regardless of the occurrence of an unnecessary error signal at the time of playback near the recorded part, the signal pickup unit can be forcibly returned to the track that should be normally scanned, and the information signal can be changed from the video signal. In this case, the above-mentioned deviation from the track of the signal pickup section and forced return operation are performed within the vertical blanking period.
The video signal can be reproduced with a good S/N ratio without adversely affecting the reproduced image, and from the above, the information signal recording medium records the information signal as a change in geometric shape and reproduces it by detecting the change in capacitance. It has a number of features that make it particularly suitable for application.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the recording device of the present invention, FIG. 2 is a diagram showing an example of the frequency spectrum of a signal to be recorded by the device of the present invention, and FIG. 3 is an information signal according to the present invention. FIG. 4 is a block system diagram showing an embodiment of the reproducing apparatus of the present invention, and FIGS. 5A to 5F show signals for explaining the operation of FIG. 4, respectively. FIG. 6 is a block system diagram showing another embodiment of the reproducing apparatus of the present invention, and FIGS. 7A to 7A are signal waveform diagrams for explaining the operation of FIG. 6, respectively. 1... Recording composite signal input terminal, 2... Color subcarrier frequency input terminal, 6, 38... Switch circuit, 14... Objective lens, 15... Recording master, 2
0...Disc, 23...Scanning needle, 25...Reproduction signal input terminal, 26-31...Band pass amplifier, 42...Error signal output terminal for tracking control.

Claims (1)

[Claims] 1. A tracking signal in which an information signal and first, second, and third tracking signals having different frequencies are sequentially and cyclically switched every rotation period and synthesized in time series. An information signal recording characterized in that a concentric or spiral track is formed on a flat surface, in which a single tracking signal with a no-signal period is provided at the switching connection portion of the track is multiplexed and recorded. Medium. 2. The first, second, and third tracking signals having different frequencies are switched in a cyclical manner every rotation period of the information signal recording medium to be recorded, and synthesized in time series, and at the switching connection part. A tracking signal provided with a non-signal period is multiplexed onto the information signal at a level lower than a predetermined level than the information signal level, and this multiplexed signal is concentrically or spirally tracked onto an information signal recording medium by a single recording means. 1. A recording device for an information signal recording medium, characterized in that the information signal recording medium is formed and recorded. 3. The information signal and the first, second, and third tracking signals having different frequencies are switched cyclically every rotation period and are synthesized in time series. An information signal recording medium formed on a flat surface is relatively scanned by a signal pickup section through a concentric or spiral track recorded by multiplexing one tracking signal having a signal period; The first reproduced tracking signal reproduced from the track being scanned by the signal pickup section and the track being scanned are combined with two other types of second signals obtained as crosstalk from adjacent tracks on both sides.
and a third reproduction tracking signal, respectively, and the first reproduction tracking signal obtained by switching a switch circuit using a signal detected based on a level difference between the first to third reproduction tracking signals. detecting the second and third reproduction tracking signals and limiting the amplitude of the first reproduction tracking signal to a level approximately equal to the level of the second and third reproduction tracking signals or setting the first reproduction tracking signal to a level that is substantially equal to the level of the second and third reproduction tracking signals; , among the detected second and third reproduction tracking signals, the reproduction tracking signals from adjacent tracks on the outer circumferential side than the scanning track are supplied to the first detection circuit, and the reproduction tracking signals from the adjacent tracks on the outer circumferential side than the scanning track are supplied to the first detection circuit; A reproduction tracking signal from an adjacent track is supplied to a second detection circuit, and the outputs of the first and second detection circuits are supplied to a differential amplifier, and the signal obtained is used to control the tracking of the signal pickup section. 1. A reproducing apparatus for an information signal recording medium, characterized in that the information signal is reproduced from a track being scanned. 4. A patent characterized in that the signal pickup section is a scanning needle that scans in sliding contact with the information signal recording medium and detects the signal recorded on the track as a change in capacitance. A reproducing apparatus for an information signal recording medium according to claim 3. 5 The information signal and the first, second, and third tracking signals having mutually different frequencies are switched cyclically every rotation period and are synthesized in time series. An information signal recording medium formed on a flat surface is relatively scanned by a signal pickup section through a concentric or spiral track recorded by multiplexing one tracking signal having a signal period; The first reproduced tracking signal reproduced from the track being scanned by the signal pickup section and the track being scanned are combined with two other types of second signals obtained as crosstalk from adjacent tracks on both sides.
and a third reproduction tracking signal, respectively, and detecting the rising edge of each of the first reproduction tracking signal waveforms to generate one pulse per revolution of the information signal recording medium; A switch circuit is switched by a signal generated using the pulse, and a reproduction tracking signal from an adjacent track on the outer circumference side of the scanning track is transmitted through the switch circuit. A first detection circuit is supplied, and a reproduced tracking signal from adjacent tracks on the inner circumferential side is supplied to a second detection circuit, and the outputs of the first and second detection circuits are connected to a differential amplifier. 1. A reproducing apparatus for an information signal recording medium, characterized in that the information signal is reproduced from the track being scanned while the signal pickup section is tracked by a signal supplied to the recording medium. 6. A patent characterized in that the signal pickup unit is a scanning needle that scans in sliding contact with the information signal recording medium and detects the signal recorded on the track as a change in capacitance. A reproducing apparatus for an information signal recording medium according to claim 5. 7. The information signal is a signal consisting of a video signal,
The reproduction of the information signal recording medium according to claim 5 or 6, characterized in that the switching of the switch circuit by the pulse is performed within the vertical blanking period of the video signal. Device. 8 The information signal and the first, second, and third tracking signals having mutually different frequencies are switched cyclically every rotation period and are synthesized in time series. A tracking signal with a signal period and a pilot signal for obtaining information once per rotation period are multiplexed and recorded to form concentric or spiral tracks on a flat surface. The recorded information signal recording medium is relatively scanned by a signal pickup unit, and the first reproduced tracking signal reproduced from the track being scanned by the signal pickup unit and the track being scanned are mutually adjacent tracks on both sides. The other two types of second and third reproduction tracking signals obtained as crosstalk from the transmission are separately reproduced, the pilot signal is reproduced, and the signal created using the reproduced pilot signal is used to control the switch circuit. of the second and third reproduction tracking signals from adjacent tracks on the outer periphery side of the scanning track is supplied to the first detection circuit through the switch circuit, and The reproduction tracking signal from the adjacent tracks on the inner circumferential side is supplied to a second detection circuit, and the outputs of the first and second detection circuits are supplied to a differential amplifier, and the signal obtained is used to pick up the signal. 1. A reproducing apparatus for an information signal recording medium, characterized in that the information signal is reproduced from the track being scanned while controlling the tracking of the information signal recording medium. 9. A patent characterized in that the signal pickup section is a scanning needle that performs sliding scanning relative to the information signal recording medium and detects the signal recorded on the track as a change in capacitance. A reproducing apparatus for an information signal recording medium according to claim 8. 10. The information signal is a video signal, and the switching of the switch circuit by the reproduction pilot signal is performed within the vertical blanking period of the video signal. A reproducing device for an information signal recording medium according to item 8 or 9.