JPS5814687A - Reproducer of information recording medium - Google Patents

Abstract

PURPOSE:To reproduce an information recording medium in a stable and assured way, by discriminating and reproducing a tracking control reference signal that discriminate the mutual relation for each reproducing track and producing a signal coincident with said reference signal. CONSTITUTION:An information recording medium 1 is rotated by a motor 3. The recording signal read by a stylus 4 discriminates and reproducing the tracking signals fp1 and fp2 via the BPF6-8 and supply them to a tracking servo circuit 10. The output of a synchronizing signal generator 12 is supplied to programmable frequency divider 13 and compared with the rotary signal given from a revolution detector in terms of phase to be applied to the motor 3. The reference signal for constant speed revolution to be fed to the motor 3 and the signal fp3 given from a BPF8 are supplied to reproducing circuit 18 that reproduces the tracking reference signal fp3 for discrimination of the mutual relation of each track. If the signal fp3 given from the BPF8 is erased, it is reproduced from the constant revolution reference signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information recording medium reproducing apparatus, in which a third tracking control reference signal is used to identify the mutual relationship between two types of tracking control reference signals and each reproduced track. Information recording that can reproduce an information recording medium extremely stably and reliably by having a circuit that discriminately reproduces a third tracking control reference signal from the recorded information recording medium and generates a signal that is in phase with it. The purpose of the present invention is to provide a media playback device.

The present applicant has previously disclosed in Japanese Patent Application No. 52-25260 and others that the main information signal and the Ml without forming a needle guide groove.
A disk-shaped information recording medium having an electrode function in which a third tracking control reference signal (hereinafter referred to as a "tracking signal") is recorded as a change in geometric shape, and relative to a reproducing needle having an electrode. We have proposed a reproducing device that reads and reproduces the main information signal and the first to third tracking signals as changes in capacitance by target sliding scanning. In addition, in the disc-shaped information recording medium proposed by the applicant, the Eirin signal and the like are recorded as main information signals in four fields per revolution on a spiral main track.
First and second trunking equalization signals f, 1 and f, having frequencies lower than the recording frequency band of the main information signal and different from each other.

are switched every rotation period of the recording medium, and are recorded by forming a sub-track in the middle between the adjacent main tracks in a burst pattern corresponding to the horizontal blanking period, At the switching connection of the lever f 11 f, , (which is within the vertical blanking period) is a third tracking signal f, for switching the tracking polarity of the tracking servo circuit.

is recorded at a level below a predetermined level so as not to affect the main information signal.

Figure 1 shows the recording trans of this disc-shaped information recording medium.
□This is a diagram schematically showing the recording arrangement relationship of the king signal. In the diagram, the ○ mark indicates the f, 1 (or f, 2) recording position, and the Δ mark indicates the f, 2 recording position.
(or f2.) indicates the recording position, and the solid line indicates the track center line of the main track. Further, the third tracking signal f, 3 is recorded at the position indicated by the broken line in FIG. That is, the third tracking signal fp3 is a periodic signal recorded at one rotation period of the disc-shaped information recording medium.

In the disc-shaped information recording medium reproducing apparatus described in L, the third tracking signal f9. For switching the tracking polarity of the tracking servo circuit, or during special playback such as fast-motion playback or slow-motion playback, or during high-speed search, the playback needle is forced to move one track pitch in the radial direction of the disc-shaped information recording medium. Because of the so-called kick that is transferred to the third tracking signal f3, even if noise around the frequency of fl is mixed into the reproduced signal, or if f and 3 are not reproduced due to dropouts, etc., the third tracking signal f3 is always accurately reproduced. ．． It is necessary to obtain the playback output FP3.

The present invention satisfies the above requirement H6'JJ, and the following
An embodiment thereof will be described with reference to FIGS. 5 to 5.

FIG. 2 is a block diagram of an embodiment of a disk-shaped information recording medium reproducing device to which the present invention is applied, and FIG. 3 is a partially enlarged view showing the reproduction state of the disk-shaped information recording medium and the reproduction needle shown in FIG. 1. A perspective view is shown. In both figures, 1 is a rotary information recording medium (hereinafter referred to as a "video disc") having the recording track pattern shown in the first figure and in which four fields of video signals per rotation are recorded on the main track; Turntable 2 shown in
The turntable 2 is cut into the ground and driven by the motor 3.
They are rotated synchronously at high speed. On the surface of the disk l, as shown in FIG. 3, there is a main information signal recording main track consisting of repeated flat surfaces 26 and pits 27, and a tracking signal fp1 recording sub-track indicated by 28 consisting of repeated pits and flat surfaces 26. A tracking signal fl2 recording sub-track is formed by repeating pits and a flat surface 26 as shown by 29, and the main information signal in the direction of the arrow has a field frequency of 60 Hz like the Nff'SO color video signal. 900r for video signal
pm (in addition, PAL method, SEOA
In the case of a color video signal such as M system, it is rotated at 750 rpm).

Reference numeral 4 denotes a playback needle, on the rear end surface of which an electrode 4a is fixed by vapor deposition, the bottom portion indicated by 4b slides on the contact surface of the disk l, and 1! The capacitance formed between the pole 4a and the disk 17 detects intermittent changes in the bit string and converts the high frequency signal f.
is conveyed along the spiral king track in the direction of the rotational axis of the disk 1 by a feed mechanism (IM not shown).

The above-mentioned high frequency <ti signal (leg recording signal) read by the regenerator 4 is supplied to bandpass filters 6, 7 and 8 through the preamplifier 5 shown in FIG. (not shown) and the video signal recorded on the main track is demodulated. The bandpass filters 6.7 and 8 are two filters having narrow bandpass characteristics to select the frequency of the tracking signals f, f and f,3, respectively. f,1 and f,2
are respectively supplied to the tracking servo circuit 1o.

The tracking servo circuit 10 receives a tracking signal f,1
A differential amplifier compares the levels of f and f2 and outputs a tracking error signal with a level corresponding to the amount of tracking deviation and a polarity corresponding to the direction of tracking deviation. At this time, the tracking polarity is switched by a tracking signal FP3 generated as described below every rotation period of the video disk l. The tracking error signal is supplied to the tracking coil 11 to correct the track deviation of the reproduction needle 4.

In the video disk reproducing apparatus proposed by the present applicant which performs the above operations during normal reproduction, this embodiment is designed to stably and reliably reproduce the tracking signal FP3.

That is, in FIG. 2, the motor 3 is rotated at a constant speed based on the output signal of the synchronous signal generator (hereinafter referred to as 1'-8SGJ) 12, but in this embodiment, the motor 3 is rotated at a constant speed. From the rotation reference signal to the tracking signal FP,
It is designed to generate . Here, 5SG12
It consists of a production circuit section for playing back NTSO color video discs, and a first frequency division circuit that divides this horizontal scanning frequency into a vertical scanning frequency of 60 Hz. The signal is output from the output terminal HD, and the first frequency dividing circuit is connected to the input terminal V, 5YNO-I.
When a signal is input to N, it is forcibly reset, and at this point a vertical synchronization signal is output to terminals V and 5YNO.
-OUT, and a vertical synchronizing signal is output from the output terminal VD at a timing three horizontal scanning cycles earlier than this.

A signal 9 with a horizontal scanning frequency of 15.734 kHz taken out from the output terminal HD of 5SG12 is supplied to a programmable frequency divider 13, where an external control signal (not shown) is applied.
After being frequency-divided by n or divided by n according to the frequency, the signal is supplied to the phase comparator 14 as a reference signal, and after having a phase ratio of 11R with the rotation detection signal from the rotation detector 15, it is sent to the motor 3 via the motor drive amplifier 16. is applied to and controls its rotation speed. Here, since the NTSO color image signal of 4 fields per rotation is recorded on the disk l, 1050 horizontal scanning lines are recorded per rotation, so at the normal rotation speed of 90 rpm, the rotation detector 15 Since 21 horizontal scanning lines are reproduced per pulse of the 50 rotation detection pulses taken out for one rotation of the disk, the frequency division ratio of the programmable frequency divider 13 is 1.
is set to

1 On the other hand, PAL method or SEOA with 4 fields per rotation
When reproducing a video disc on which an M system color video signal is recorded, 1250 horizontal scanning lines are recorded per rotation, so 25 horizontal scanning lines are reproduced for each rotation detection pulse. Programmable frequency divider 13
The frequency division ratio is set upward by 5. As a result, when playing a disc on which a PAL or SEOAM color video signal is recorded with a playback device that originally plays a disc on which an NTSO color video signal as described above is recorded, the playback horizontal The scanning frequency is controlled to be the horizontal scanning frequency of the NTSO system, which is predetermined for the playback device.

This allows PAL to be played without changing the circuit inside the playback device.
It is possible to play back a color video signal recording disk of 8 EOAM or 8 EOAM format (for details, see Japanese Patent Application No. 1983-61998 proposed by the present applicant).

In this way, the output signal of the output terminal HD of the 88G12 is used as a reference signal for the constant speed servo circuit of the motor 3, but in the present invention it is also used to generate the tracking signal FP, and for this purpose Above output terminal HD
The output signal from 5YNO-OUT, and the output signal from output terminal V obtained by frequency-dividing it by the first division circuit, the output signal from 5YNO-OUT, and the output signal from output terminal VD, which is output three horizontal scanning periods earlier than this. Output signal is FP, reproduction circuit 1
8.

FIG. 4 shows a specific embodiment of the FP and reproducing circuit. In the figure, 19 is a quaternary field counter which is a second frequency dividing circuit, and its counting input terminal is supplied with a signal from the output terminal VD of 58G12, and its reset terminal hole is connected to a D-type flip-flop, which will be described later. The output signal of step 24 is supplied. Therefore, the field counter 19 counts the vertical synchronizing signals and supplies a count value of 2 bits "00" to "ll" to the first field detector 20. The first field detector 20 generates a field identification signal that is at a high level during the period when the above numerical value is "00" in binary, and outputs a field identification signal to the FPs generator 2.
1 and one input terminal of SR type rough flip-flop 22
Supplied to set input terminal S. When a high level field identification signal is supplied to the set input terminal S, the SR type flip 70 tube 22 supplies a high level signal to one input terminal of the AND circuit 23 from the output terminal Q2. The other input terminal of the AND circuit 23 is supplied with tracking signals f and S that have been discriminated and separated from the playback signal of the video disc l by a bandpass filter 8 shown in side 2. At this time, a high level signal is generated and supplied to the data terminal of the D-type flip-flop 24. The clock input terminal OLK of the D-type flip-flop 24 is supplied with a signal from the output terminal HD of the 88G12.
A signal obtained by sampling the reproduced tracking signal f,3 with a horizontal scanning frequency signal appears at the output terminal Q3 of At the same time as resetting and synchronizing these, 88G 12/
7) It is supplied to the input terminals V and 5YNO-IN to reset the first frequency divider circuit inside the SSG.

5 is generated when this first frequency divider circuit is reset.
The vertical synchronization signal taken out from the output m of SG12, 5YNO-OUT', is supplied to the FP3 generator 21,
Here, a logical product with the field identification signal from the first field detector 20 is taken, and a detected tracking signal FP with a period of 4 fields is extracted, and is supplied to the tracking servo circuit lO shown in the second diagram. .

Therefore, for example, if the first field is detected at time t in FIG. 5 as shown in FIG.
FQ2 becomes high level as shown in FIG.
Figure (N is output as shown by al, and at this point Figure 5 (
As shown in 3), a reset signal is output from the output terminal Q, and here the 88G12 and FP3 regeneration circuit 18 are synchronized, and the output terminal VD of the 88G12 is output from the output terminal VD to 1V (v is the vertical scanning period) @aX5 (B ) is output and the signal shown in 5
Ru.

Therefore, from the FP3 generator 21, 31
After the input point of f, 3, shown in FIG.
Even if pulsed noise as shown in (a) is supplied to the AND circuit 24, it will not be sampled because the output terminal Q2 is at a low level, so no reset signal will be output from the output terminal Q, and the FP, is not generated incorrectly.

In addition, since the vertical synchronizing signal is output from the output terminal VD of 5SG12 at a timing 3 horizontal scanning cycles earlier than the time when f, 3 should originally come in, the output terminal Q2 is The amount of jitter, that is, becomes high level three horizontal scanning periods earlier, making it possible to sample f and s, so even though f and 8 are supplied from the bandpass filter 8, there is no possibility that they will not be sampled. . Also, as shown by a in the fifth section, f9. Even when the reproduction tracking signal f, 3 has disappeared due to dropout etc., despite the phase that should be reproduced, the output terminals of 88G12 HD, VD, , V, 8YNO-OUT (7) Ingeniously, a signal is generated and output at each cycle, and even if the field counter 19 is not reset, a 2-bit signal that becomes "00" after "11" is sent to the first field detector 20. In order to supply the tracking signal FP, the tracking signal FP is sent from the FP generator 21 at the same period as before.
, is generated and output. Therefore, tracking servo circuit 1
0 malfunction can be prevented.

As described above, according to this embodiment, there is no response to noise that comes in at a phase different from that of the reproduced tracking signals f,3, and the reproduced tracking signals f9. Even if the tracking signal FPs disappears due to dropout or the like, the tracking signal FPs can be normally generated and output.

As described above, the information recording medium reproducing apparatus according to the present invention uses a standard generated for rotating the recording medium at a constant speed so that the horizontal scanning frequency of the recorded video signal on the information recording medium is reproduced at a predetermined frequency. The vertical scanning frequency of the recorded signal is output at the time when the third tracking control reference signal is reproduced by dividing the signal using the first frequency dividing circuit number. generating a first signal and a second signal having the vertical scanning frequency that precedes the first signal by the maximum jitter included in the rotation of the recording medium reproducing device;
When the frequency of the second signal is divided by the second frequency dividing circuit to generate a field identification signal having the same period as the third tracking control reference signal, and the first signal and the field identification signal are generated at the same time. A detection tracking control reference signal is generated, and a synchronization control signal is generated using a field identification signal and a third tracking control reference signal that is discriminately separated from the reproduction signal of the recording medium. Second minute J! In order to include a circuit configured to synchronize each circuit with a constant value and output the detected tracking control reference signal synchronized with the discriminated and separated third tracking control reference signal at a constant cycle,
If the third tracking control reference signal cannot be separated from the reproduced signal or is not reproduced,
Furthermore, even if the playback timing is shifted due to jitter, etc., a reference signal for detection and tracking control that is accurately synchronized can be generated and output without loss, and the synchronization control signal is a flip-flop set by the field identification signal. and a third tracking control reference signal that is discriminately separated from the reproduction signal of the recording medium. Because it is set, it does not respond to pulse noise that has a phase different from that of the third tracking control reference signal, and the detection tracking control reference signal can be output extremely stably and reliably, so it is always stable. It has features such as being able to reliably reproduce information recording media.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the recording arrangement relationship of recording tracking signals in a disk-shaped information recording medium previously proposed by the present applicant, and FIG. 2 is a diagram showing a disk-shaped information recording medium reproducing apparatus to which the present invention is applied. Block system diagram showing the embodiment, FIG. 3 is the 1vl
FIG. 4 is a partially enlarged perspective view showing the reproducing state of the disc-shaped information recording medium and the reproducing needle shown in FIG. ) are signal waveform diagrams for explaining the operation of FIGS. 2 and 4, respectively. l... e video disk, 3... motor, 4... playback needle, 6-8 o/band filter, lo... tiger, tracking servo circuit, 12... synchronization signal generator (88G), 18...
FP, regeneration circuit, 19...fist field counter, 2
o...First field detector, 21...FP generator, 22, 24...Flippu 30 tube, 23@...AND circuit. Figure 1■

Claims (1)

[Claims] l. A main track on which the video signal is recorded, and first and second tracking control references having different frequencies located approximately in the middle between the center lines of adjacent tracks of the main track. It has a sub-track in which the signal is alternately switched and recorded for each main track, and a third track is provided on the main or sub-track at the switching connection portion of the first and second tracking control reference signals. In an apparatus for reproducing an information recording medium on which a tracking control reference signal is recorded, the recording medium is rotated at a constant speed so that the horizontal scanning frequency of the low recorded video signal of the information recording medium is reproduced at a predetermined frequency. The reference signal generated for this purpose is divided by the first frequency divider circuit, and when the third tracking control reference signal is reproduced, the first frequency of the vertical scanning frequency of the recorded video gI signal is output. 1 signal and a second signal of the vertical scanning frequency that precedes the first signal by the maximum jitter included in the rotation of the recording medium, and generates a second signal of the vertical scanning frequency. A frequency dividing circuit generates a field identification signal having the same period as the third tracking control reference signal, and
When the signal and the field identification signal are generated simultaneously, a detection tracking control reference signal is generated, and the field identification signal and a third tracking control reference signal that is discriminately separated from the reproduction signal of the recording medium are used. generate a synchronous control signal, and the synchronous control signal causes the first and second
A circuit configured to synchronize each of the frequency dividing circuits to a constant value and output the detected tracking control reference signal synchronized with the discriminated and separated third tracking control reference signal at a constant cycle. An information recording medium reproducing device characterized by: 2. The synchronization control signal is an AND circuit that is supplied with the output of the flip 70 set by the field identification signal and a third tracking control reference signal that is discriminated and separated from the reproduction signal of the recording medium. 2. The information recording medium reproducing apparatus according to claim 1, wherein the output signal is obtained by sampling the reference signal, and the flip 70 knob is set by the synchronization control signal.