JPS59207440A - Track retrieving device - Google Patents

Abstract

PURPOSE:To obtain a track cross signal even with an intermittent pit train like a continuous groove by obtaining a binary coded signal from the data train cross signal which crossed the record data and producing an interpolation signal of a signal omission part based on said binary coded signal. CONSTITUTION:A binary coded signal is obtained from the data train cross signal obtained when a light beam crosses the record data, and an interpolation signal for signal omission part is produced by an interpolation signal generator 17 based on said binary coded signal. It is possible to obtain a track cross signal like in a case where a continuous groove or data is produced even in case where the record data train is formed with an intermittent pit train only. In such a way, a track can be automatically retrieved from the record data train formed on an optical disk with a simple and inexpensive constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a track search device that automatically searches for a track from a recorded data string formed on an optical disk.

[Technical background of the invention and its problems] As a conventional track search device, the head feeder is attached to 9 machine drawings. There is a system in which the track on which the optical head is located can be indirectly determined by scanning the 1% k F'71. However, this track search device is only 1ir.
In addition to having problems with the history of a, l'l f, it also had many problems, such as a complicated structure.

Therefore, recently, a circular or spiral groove is formed on the original disk, and a row of information recording pits is formed in this groove. This occurs when the beam crosses the above tptt.
A system has been proposed in which a track search is performed by detecting a track sequence.

However, since the above disk necessarily forms one groove in addition to the bit string, the structure of the original disk itself is the core 4'A'#.
Not only that, but the recorded music is also incompetent.

[Purpose of the invention]

The purpose of the present invention is to automatically search for a track from a recorded data string formed on an original disk.
jA It's about being together.

[Category of Invention 1 Provisional] In order to achieve the above object, the present invention is constructed as follows! +! It is called jta. That is, as the optical head moves in the disk radial direction, a data string cross signal indicating that the light beam crosses the recorded data string on the optical disk is obtained by the photodetector and differential amplifier, and this is used as a reference. The ratio is 1fi2 and it becomes two-dimensional. Then, each level of the data string cross signal corresponding to the falling P edge and rising 9 edge of the binarized signal is held by turning off the sampling and holding circuit, and the level difference between the three held signals is obtained. At the same time, the time width from the rising edge of the binary signal to the rising edge is measured. and the level difference and time of the upper d-21; 1 based on the product
lfJ In the data string cross signal corresponding to the period from the falling edge of the record to the rising 9th edge,
A track cross signal is obtained by obtaining a signal to be interpolated and using this interpolation key signal to compensate for the signal missing part of the previous 61 data string cross signal. In this way, even if the recorded data string consists of only intermittent bit strings, it is possible to obtain a track cross signal that is the same as if the data were formed without continuous grooves. There is.

[Embodiments of the invention]

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention. In the figure, reference numeral 1 denotes a disk-shaped optical disc which is driven to rotate at a constant speed by a spindle motor 2. As shown in FIG. Reference numeral 3 denotes an optical head that is movable in the radial direction of the disk 1 by a head transport mechanism such as a whirlpool morph (not shown). This optical head 3 is
The laser beam emitted from the laser diode 4 is converted into parallel light by the collimating lens 5, passes through the entire beam slittor 6, and enters the IA wavelength plate 7, and 11:! , after converting the tangentially polarized light into circularly polarized light, it is focused by the objective lens 8 and is directed to the recording surface of the disk l as a beam 7j? As a matter of fact, it is designed to emit light u, 1'. Then, the germs reflected from the recording surface of the disk 1 are incident on the 1/4 wavelength plate 7 through the Taimaki Luns 8 through i + ij in a path opposite to that of the total incident light, and the circular rays are generated. Convert back to direct h1 light. This inversely converted reflected light if:
°It will be out of alignment. This light is split in two directions at right angles by a beam splitter 6, passes through a lens 9, and enters a photodetector 10. The photodetector 1O has a light receiving area divided into two parts, and each light receiving area can be used to output signals from each other.

The output signal of the optical head 3, i.e. -f4<hanger 1
Each output signal from 0 becomes a differential input of a differential amplifier 1). In this way, a data string cross signal is obtained from the differential amplifier 1, which indicates that the optical beam has crossed the recording data string.

Now, as shown in FIG. 2(a), track T1. In a compilation in which a data string in which recording bits P are intermittently formed at T2... is recorded, as the optical head 3 moves, the beam spot S crosses the data string as shown by the arrow. shall be taken as a thing. Then, as shown in FIG. 2(b), only the part where the recording bit P exists is shown by a solid line from the differential increaser 1 transmitter l.
In the data string 7, a bow rvi has occurred and a signal missing portion N has occurred as shown by the broken line in the portion where the recorded bit P does not exist.
No. 16 is obtained.

Let's return to Figure 1. The output of the differential amplifier 11, that is, the data string cross signal is sent to the sampling hold circuit 12.1.
3 and the pressure comparator 14. The other input of the voltage converter/mother 14 ☆j^l I/'Ci-i
From terminal Z4a to positive/negative comparison reference level'width;l]2+E
, -B are given. Therefore, now ゛rjL
As shown in FIG. 3A, one input terminal of the pressure comparator 14 receives V 1 ) + F during one breath t7.

At time t2, it has a voltage value of V 2 ) -1-E,
It is assumed that a signal with a built-in voltage value of zero is input between tf and t2. Then, as shown in FIG. 3B, the 'voltage converters 14' reach the "0" level at time t1,
A binary signal that becomes "1" level at time t2 is output σ.

This binary signal is Zanf 0 Ring Gurus generation 1141s
supplied to The sampling pulse generator 15 generates all the sampling pulses as shown in FIG. At the same time, a sampling pulse as shown in the third diagram is generated at the rising edge of the binary number 1 (l+, ¥1 point t2) and is applied to the purple sampling hold circuit 13.

Therefore, the sampling hold (b) path 12 is at the time t.
Hold the input signal level V 1 f at l,
The sampling hold circuit 13 holds the input signal level V 2 at time t2. The signal level held by each of the sampling and holding circuits 12 and 13 is subtracted by V2-Vl in a subtraction function 16, and a signal indicating the level difference is supplied to one input terminal of an interpolation signal generator 17. Does this interpolation cause Tominari? A missing length signal from a missing length measuring device 18 is applied to the other input terminal of the input terminal 17. Missing long hand? 14II device 8 receives the 21111 signal from the AjJ torque converter 14, sets t2-tf to high, and then sends out a signal indicating the IFI width. Thus, the interpolation signal generator 17 generates a level difference signal of V2-Vl and a level difference signal of t2-tl.
As input, the missing length signal becomes (V, ?-V7)t, and the interpolation signal becomes ?. A generator 19 is generated and fed to one input terminal of the Calorizer 19. 7Jl '32- "The output of the sampling hold circuit 12, that is, the signal at the level Vl is applied to the other input terminal of the circuit 19.

Therefore, the adder 19 outputs the signal JJ corresponding to the shaded area in FIG. This analog switch 2
As another input of θ, the output signal of the differential amplifier 11, that is, the hatched part in FIG. The analog switch 20 receives the missing length signal from the missing length measuring device 18 as a gold switching signal, and the period in which the missing length of the upper Mc2 is given is the missing length signal from the missing length measuring device 19. The output signal is passed through, and the output signal of the delay circuit 2) is passed during the other periods.

The signal that has passed through the analog switch 20 is converted into a smooth sine wave, that is, a track cross signal, by a low-pass filter 22, and is then applied to a cross pulse generator 23. The cross/cross generator 23 adjusts the beam spot S to the track T1 . T2...-(C-) Generates a cross pulse indicating that it has been crossed, and applies this to the voice coil motor speed controller 24. A speed IUυ control signal is given to the disc coil motor to control the motor speed.

In this device (ft), it is possible to obtain a track cross signal similar to the case where continuous grooves are formed from the bit strings formed intermittently on the disk (1) and (yt). The speed control of the academic head 3, etc. can be performed accurately.

Moreover, this device does not require the provision of a school for indicating the head position unlike in conventional equipment, and there is no need to form grooves on the tedious original disk. il: Can be produced.

Note that the present invention is not limited to the above-mentioned embodiment. For example, in the above embodiment, the i3'lJ to which the present invention is applied is shown in the case where only the recording bit string is formed on the optical disk, but the data other than the recording bit string on the original disk is l'Jf. It goes without saying that the present invention can also be applied to the case where the groove b is formed continuously.

〔Effect of the invention〕

According to the present invention, a binary No. 16 is obtained from a data string cross signal indicating that a light beam crosses recorded data, and a signal for interpolating a signal missing portion in the data string cross signal is obtained based on this binary signal. Since the track cross signal is obtained by forming the interpolation signal and interpolating the signal missing part with this interpolation signal, even if the recorded data string is made up of only intermittent bit strings, , A/(Also, it is possible to generate the same trunk cross signal as when continuous grooves or data are formed.In this way, tracks can be automatically searched from the recorded data string formed on the original disk. This also makes it possible to provide a track search device that has a simple configuration and can be manufactured at low cost.

[Brief explanation of the drawing]

1 to 3 are diagrams showing the configuration of an embodiment of the present invention,
FIG. 1 is a block diagram showing the configuration, FIGS. 2(a) and 2(b) are diagrams showing the detection state of a data string cross signal, and FIG. 3 is a signal waveform diagram for explaining the i-interpolation signal forming means. 1...Original disk, 2...Spindle motor, 3.
...Optical head, 4...Laser diode, 5...
Collimelt lens, 6... Beam sgrit, 7...
・1/4r7N long plate, 8...Objective lens, 9...Lens, 10...Photodetector, 11...Differential amplifier,)4
...'flI pressure contour lake, 19... Tome calculation.

Claims (1)

[Claims] A means for obtaining a data string cross signal indicating that the original beam has crossed the recorded data string on the optical disk as the optical head moves in the disk radial direction, and a means for obtaining a data string cross signal obtained by this means at a reference level. means for binarizing the signal by reducing the ratio f; means for retaining all levels of the data string cross signal corresponding to the falling edge and rising edge of the signal binarized by this means; means for obtaining the level difference of the NiiHa signal held by the means; means for measuring the time width from the falling 9th edge to the rising edge of the binarized No. 1d; and the distance between jl and ji measured by the measuring means. an interpolation means for obtaining a signal for interpolating a signal missing portion in the data string cross signal corresponding to the interval 1υ from the falling edge to the rising edge based on the width and the level difference of the three signals; and this interpolation means C? ! a track cross signal by interpolating a signal missing part of the data string cross signal with a track cross interpolation signal;
search device 13'.