JPS6346932Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention reproduces information signals from a disk, such as a digital audio disk, which has a spiral recording track on which address information is recorded along with program information. A control signal for performing a so-called track jump operation, which is used in a disc playback device and causes the information reading means to rapidly move the reading position on the disc in a direction across the recording track. The present invention relates to an information reading position control signal generation circuit that generates an operation signal.

BACKGROUND TECHNOLOGY AND PROBLEMS In optical digital audio disks, digitized audio signals are used as program information, and are stored on a spiral recording track, such as an array of pits, along with address information. recorded so that it can be read optically. A disk reproducing device used for reproducing information signals from such a disk moves the reading position of the information reading means on the disk, that is, the information reading position, by one track at a time in a direction across the recording tracks. , one track jump operation can be performed, for example, the information reading position is brought to a specific address position by repeating one track jump operation, and the information signal from the disk is moved to that specific address position. It is made possible to play back from the address position.

Such a one-track jump operation applies control to correct the deviation of the information reading position from the center of the recording track of the disk, that is, the tracking error, to the tracking error signal that changes according to the tracking error. With the tracking serve mechanism released,
A track jump operation signal, which is formed by a drive pulse for moving the information reading position in a direction across the recording track and a braking pulse added afterwards to brake the movement caused by the drive pulse, moves the information reading position. This is done by supplying the tracking control means provided to cause the movement.

FIG. 1 shows a main part of an example of an optical disc reproducing apparatus incorporating a track jump control section for performing the above-mentioned one-track jump operation. Here, for example, a disk 1, which is an optical digital audio disk as described above, is attached to a disk mounting section 2, and the disk mounting section 2 is attached to the rotating shaft of a disk rotation motor 3, and the disk 1 is rotated by this disk rotation motor 3 at a constant linear velocity.

The information reading means 4 is configured, for example, to cause a laser beam to enter the disk 1 and to receive a reflected laser beam from the disk 1 that is modulated according to information recorded thereon, and A focus control means for controlling the convergence state of the laser beam on the disk 1, and a light beam drive for moving the arrival position of the laser beam on the disk 1, that is, the information reading position, in a direction across the recording track of the disk 1. an optical head 5 provided with tracking control means forming means;
The reflected laser beam from the optical head 5 is detected and reproduced information signal S and tracking error signal S _t
and a light receiving section 6 that generates a focus error signal S _f .

In the so-called normal playback state in which the information reading means 4 continuously reads information from the disk 1 along the recording track, a focus error signal S _f from the light receiving section 6 is transmitted to the light receiving section 6. is supplied to the input end of the focus control circuit 7 from one of its output ends, and a control signal corresponding to the focus error signal S _f is obtained at the output end of the focus control circuit 7, which is provided in the optical head 5. The tracking error signal S _t from the light receiving section 6 is supplied to the light beam control circuit 8 from the other output end of the light receiving section 6, and the tracking error signal S t is supplied to the focus control means to perform focus control. A control signal corresponding to _t is obtained at the output end of the optical beam control circuit 8, and this is transmitted to the optical head 5.
The tracking control is performed by being supplied to a tracking control means provided in the. By properly performing both of these controls, an appropriate normal playback operating state can be maintained.

By the way, when the aforementioned one-track jump operation is performed, the command signal _S1 is supplied from the track jump operation command section 9 to one input terminal of the one-track jump operation signal generation circuit 10.
This one-track jump operation signal generation circuit 10
A tracking error signal S _t from the light receiving section 6 is supplied to the other input terminal of the one track jump operation signal generating circuit 10.
At the output of , a one-track jump operation signal _PJ is obtained which is formed on the basis of the command signal _S1 and the tracking error signal _St. When this one-track jump operation signal P _J is supplied to the optical beam control circuit 8, the drive signal corresponding to the one-track jump operation signal P _J becomes the control signal according to the tracking error signal S _t . Instead, the drive signal is obtained at the output end of the light beam control circuit 8 and is supplied to tracking control means provided in the optical head 5. As a result, the laser beam incident on the disk 1 is moved, for example, from the position shown by the solid line to the position shown by the broken line in FIG.
The recording track is moved by one recording track in the direction across the recording tracks of the recording track.

Conventionally, one track jump operation signal
A control signal generating circuit as shown in FIG. 2 has been proposed as a one-track jump operation signal generating circuit 10 for generating _PJ . In this conventionally proposed control signal generation circuit, the track jump operation command unit 9 is connected to the terminal 11 as shown in FIG.
A command signal _S1 as shown in FIG.
12 set terminals S (referred to as S-RF.F). As a result, S-RF.F12 is set, and its output becomes a high level h, as shown in FIG. 3B. This high level h output is supplied to the negative phase input terminal of the operational amplifier section 13,
The polarity is inverted and obtained at the output terminal 14. This is then supplied to the light beam control circuit 8, and from the light beam control circuit 8 a control signal for moving the information reading position in a direction across the recording track is supplied to the tracking control means provided in the optical head 5. Track jump operation is started. That is, the information reading position begins to move in a direction across the recording tracks from one recording track to an adjacent recording track.

On the other hand, a tracking error signal S _t from the light receiving section 6 is supplied to the terminal 15 . After the command signal _S1 is supplied to the terminal 11, a one-track jump operation is performed, so the information reading position moves from the center of a certain recording track to between the adjacent recording track. As the tracking error increases, the level of the tracking error signal S _t increases to the positive side as the tracking error increases, and vice versa as the tracking error increases. It decreases and becomes zero at time T when the information reading position reaches the middle between a certain recording track and the adjacent recording track. That is, a zero cross point is taken. This tracking error signal S _t is supplied to the level comparator 16 and compared with the zero level, and the output of the level comparator 16 is the tracking error signal.
When the level of S _t is equal to or higher than the zero level, it becomes a high level. Therefore, the output of the level comparator 16 is at time T
It falls from a high level to a low level,
This is supplied to the edge detection section 17, from which an edge pulse is obtained at time T, and this edge pulse is supplied to the reset terminal R of the S-RF.F12. As a result, S-
RF・F12 is reset and its output is
As shown in FIG. B, the level l falls to a low level. Therefore, at the output end of S-RF F12, there is a driving pulse P _D of high level h having a width t _D from the rise of the command signal S ₁ to time T as shown in FIG. 3B.
will be obtained. Pulse P _D for this drive
During this period, the information reading position will be driven from one recording track to the adjacent recording track, and a driving pulse P _D ' will be obtained at the output terminal 14 in response to the driving pulse P _D. .

The monostable multivibrator 18 is triggered by the fall of this driving pulse P _D , and its output is output for a preset operating time t _B of the monostable multivibrator 18, as shown in FIG. 3D. Take the high level h. That is,
At the output of the monostable multivibrator 18, a braking pulse P _B of a high level h having a width t _B is obtained from the instant T. This braking pulse P _B is supplied to the positive phase input terminal of the operational amplifier section 13, and is led out to the output terminal 14 with the same polarity. Then, this is supplied to the light beam control circuit 8, and from the light beam control circuit 8, a control signal that acts to restrain the movement of the information reading position is supplied to the tracking control means provided in the optical head 5, and the information is The movement of the reading position across the recording track is braked. Therefore, a braking pulse P _B ' is obtained at the output terminal 14 in response to the braking pulse P _B . At this time, the information reading position is braked from the point where it passes the halfway point between a certain recording track and an adjacent recording track, and the information reading position is stopped on this adjacent recording track, and the one-track jump operation is completed. Therefore, as shown in FIG. 3C, the level of the tracking error signal rapidly increases to the negative side after time T, and then as the information reading position moves toward the center of the adjacent recording track, gradually decreased,
When the information reading position moves to the adjacent recording track and the one track jump operation is completed, the normal level is returned.

In this way, the output terminal 14 is
The driving pulse P _D ′ is the braking pulse as shown in
The control signal formed by being switched at time T to P _B ′
P _j is obtained. This is then used as the one-track jump operation signal _PJ , and the information reading position is driven to the middle between the recording tracks based on the drive pulse _PD ' and the braking pulse _PB ', and then braking is performed. A one track jump operation is performed.

However, in an actual one-track jump operation, as mentioned above, at the time T when the tracking error signal _St takes the zero cross point, the drive pulse
If P _D ' was switched to the braking pulse P _B ', the switching from driving to braking for the information reading position would be too slow and sufficient braking would not be obtained to stop on the adjacent recording track. There was a problem in that it was difficult to perform a stable one-track jump operation.

Therefore, before the tracking error signal S _t from the terminal 15 is supplied to the level comparator 16, the phase is advanced by passing it through a high-pass filter so that the time point T at which the zero cross point is taken is earlier than actually. Based on the zero-crossing point of the tracking error signal that has been advanced, the drive pulse P _D ' is switched to the braking pulse P _B ' before the information reading position reaches the middle between the recording tracks. It is possible to do so. However, in this case,
The influence of the noise component included in the tracking error signal S _t is emphasized by the high-pass filter, making it easy for malfunctions to occur in the level comparison section 16.
There is a problem in that the switching from the drive pulse P _D ' to the braking pulse P _B ' becomes unstable, and as a result, a stable one-track jump operation cannot be performed.

Purpose of the invention In view of the above, the present invention provides an information reading position control capable of generating an improved one-track jump operation signal that can perform one-track jump operation in a disc playback device extremely stably. The purpose of this invention is to provide a signal generation circuit.

Summary of the invention The information reading position control signal generation circuit according to the invention is for moving the reading position on the disk by the information reading means, that is, the information reading position in a direction across a recording track formed in a spiral shape on the disk. A driving pulse generating section that generates a driving signal pulse such that the information reading position has a trailing edge at a time point between two adjacent recording tracks, and the driving signal is based on the driving signal at the information reading position. A braking pulse generating section that generates a braking signal pulse for braking movement for a predetermined period after the trailing edge of the driving signal pulse, and outputs of both the driving pulse generating section and the braking pulse generating section. a combining section arranged on the side and generating the driving signal and the braking signal in succession according to the driving signal pulse and the braking signal pulse; and a combining section between the braking pulse generating section and the combining section or between the combining section. The waveform shaping section is disposed on the output side and makes the amplitude of the leading edge of the braking signal larger than the amplitude of the trailing edge. In this way, the waveform shaping section is provided,
Since the amplitude of the leading edge of the braking signal following the trailing edge of the driving signal is made large, the information reading position control signal obtained from the circuit according to the present invention allows the information reading position to be moved by the driving signal. Braking by the braking signal is performed extremely effectively,
It is possible to stably perform a one-track jump operation in which the information reading position is rapidly moved from one recording track to an adjacent recording track.

Example Examples of the present invention will be described below.

FIG. 4 shows an example of an information reading position control signal generation circuit according to the present invention, and this circuit includes, for example,
It is used as the one-track jump operation signal generating circuit 10 shown in FIG. In FIG. 4, parts corresponding to those shown in the conventional circuit of FIG. 2 are given the same reference numerals as those in FIG. 2
In addition to the circuit shown in the figure, the edge detection section 17 and S
- An AND gate 20 is arranged between the set terminal S of RF・F12, and the output terminal of the edge detection section 17 is connected to one input terminal of the AND gate 20, and the command signal from the terminal 11 is connected to the other input terminal. The output end of the monostable multivibrator 21 to which S ₁ is supplied is connected, and a waveform shaping section 22 is further arranged between the monostable multivibrator 18 and the positive phase input terminal of the operational amplifier section 13. It has a configuration corresponding to . here,
The waveform shaping section 22 includes a differential operation section 23 and an amplification section 24.
It is formed by.

When this example is used as the one-track jump operation signal generation circuit 10 shown in FIG.
When the command signal _S1 as shown in FIG. It takes a high level h as shown in . Further, a tracking error signal S _t is supplied to the terminal 15, but this tracking error signal S _t normally includes a noise component n, as shown in FIG. 5C.
From the level comparison section 16, a pulse output P _O including a pulse in response to the noise component n as shown in FIG. 5D is obtained. Gotoku no Edge Pulse
P _E will be obtained. When the edge pulse P _E obtained by the edge detection section 17 is directly supplied to the reset terminal R of the S-RF F12, the S-RF F12 is set by the command signal _S1 and the information reading position is set. Immediately after the movement of the disk 1 in the direction across the recording track starts, a tracking error signal is sent from the edge detection section 17.
The edge pulse P _E generated by the noise component n in S _t resets the S-RF F12, resulting in a malfunction in which its output falls to the low level l shown in Figure 5B. There is a risk that this may occur. In this example, such malfunctions are prevented, and a tracking error is detected based on the fact that the information reading position that started moving in the direction across the recording tracks of disk 1 reaches the middle between the recording tracks. Time T when signal S _t takes zero cross point
An AND gate 20 and a monostable multivibrator 21 are provided in order to ensure that the S-RF F12 is reset only in the following conditions.

The output P _M of the monostable multivibrator 21 is normally at a high level h, as shown in FIG. 5F, and only when the command signal S ₁ is supplied.
The low level l is maintained for a predetermined time _tN from the rise of the command signal _S1 . This time t _N is the command signal
After S ₁ is supplied to the terminal 11, the edge detection unit 17
is the noise component n in the tracking error signal S _t
The period of time required for the edge pulse _PE to cease to occur is considered to be longer than that due to the Then, the AND gate 20 is turned off during a time t _N in which the output P _M of the monostable multivibrator 21 takes a low level l. Therefore, after the command signal _S1 is supplied to the terminal 11 and the S-RF F12 is set, the first edge pulse from the edge detection section 17 is supplied to the reset terminal R via the AND gate 20. P _E is obtained at time T.
In this way, S-RF F12 is ensured to be reset at time T, and at its output, as shown in FIG. 5B, in the description of the circuit of FIG. As mentioned above, a driving pulse P _D having a width t _D and a trailing edge at time T and having a high level h is reliably obtained. Based on this driving pulse _PD , the information reading position is driven to the middle between a certain recording track and an adjacent recording track, similar to the case of the circuit shown in FIG.

Then, from the monostable multivibrator 18, as shown in FIG. 5H, a predetermined width t is generated from the trailing edge of the driving pulse P _D as described in the explanation of the circuit in FIG. A braking pulse P _B having _a high level h is obtained. This braking pulse P _B is supplied to the waveform shaping section 22 . The waveform shaping section 22 uses the operation of the differential operation section 23 to shape the leading edge of the braking pulse P _B , that is,
The amplitude of the rising portion is increased, and at the output end of the waveform shaping section 22, the braking pulse P _B is obtained by making the amplitude of the leading edge larger than that of the trailing edge. A waveform-shaped braking pulse _PX as shown in FIG. 1 is obtained.

The driving pulse P _D obtained as described above
The waveform-shaped braking pulse _P As _shown in _{FIG .} A control signal P _j ' is obtained which is formed by successively forming a braking pulse P _X ' whose amplitude is larger than that of the trailing edge.
And this is the 1 track jump operation signal P _J
Based on the drive pulse P _D ′, driving is performed from a certain recording track at the information reading position to the middle between the adjacent recording track, and then, based on the braking pulse _P Braking is applied to the movement of the information reading position, resulting in a one-track jump operation. In this case, the braking pulse
Since the leading edge of P _X ′ has a large amplitude, the leading edge of this braking pulse _P It is forced to slow down. Then, the movement of the information reading position is further braked by another part of the braking pulse P _X ' having a smaller amplitude than the leading edge part, and
The information reading position is stopped. By using such a braking pulse P _X ', the information reading position is moved from a certain recording track in a direction across the recording track, and when the information reading position reaches the middle between the adjacent recording tracks, the information reading position is moved. Even if braking is applied to the recording track, the braking is sufficiently effective and the information reading position is stably stopped on the adjacent recording track. In other words, a stable one-track jump operation is performed.

FIG. 6 shows another example of the information reading position control signal generation circuit according to the present invention. This example is also used, for example, as the one-track jump operation signal generation circuit 10 shown in FIG. 1, and parts corresponding to those shown in FIG. However, in this example, in place of the waveform shaping section 22 disposed between the monostable multivibrator 18 and the positive phase input terminal of the operational amplifier section 13 in the example of FIG. Amplifying section 13
A waveform shaping section 25 consisting of a differential operation section is disposed between the output end of the output terminal 14 and the output terminal 14 . In this example, a driving pulse P D obtained from the S-RF F12 as shown in FIG. 7A, similar to that shown in FIG. 5B, and a driving pulse P _D obtained from the monostable multivibrator 18, be able to,
As shown in FIG. 7B, a braking pulse P _B similar to that shown in FIG. 5H is applied to the operational amplifier unit 1.
A driving pulse P _{D '} obtained by inverting the polarity of the driving pulse P _D as shown in FIG. 7C is supplied to the negative phase input terminal and positive phase input terminal of No. , a braking pulse P _B ' obtained corresponding to the braking pulse P _B are successively formed to obtain a control signal P _j . This control signal P _j is then supplied to the waveform shaping section 25 that performs a differential operation, and the amplitudes of its falling and rising parts are
The waveform is shaped so that it is increased compared to other parts. As a result, the output terminal 14 has the seventh
As shown in Figure D, the driving pulse _P A control signal whose waveform is formed by a braking pulse P _B ″ whose waveform is shaped to be larger than the amplitude of
P _j '' is obtained, which is taken as the one-track jump operation signal P _J .

The waveform-shaped braking pulse P _B '' in this waveform-shaped control signal P _j '' is similar to the waveform-shaped braking pulse P _X ' obtained in the example of FIG. Therefore, 1 obtained by this example
Also by the track jump operation signal _PJ , the fourth
Similarly to the case with the one-track jump operation signal P _J obtained in the example shown in the figure, a stable one-track jump operation signal P
A jump operation is performed.

In order to strongly brake the movement of the information reading position, it is conceivable to increase the amplitude of the entire braking pulse, not just the leading edge, but in such a case, , the braking action becomes excessive, making it difficult to stably stop the information reading position at a desired location, which is undesirable.

Effects of the invention As is clear from the above explanation, by using the control signal obtained by the information reading position control signal generation circuit according to the invention as a one-track jump operation signal in a disc playback device,
After the driving state for moving the information reading position, a great braking effect is obtained at the beginning of the braking state for braking the movement, and it is possible to make the information reading means perform an extremely stable one-track jump operation. can. Moreover, in the information reading position control signal generation circuit according to the present invention,
In forming the control signal that performs the stable one-track jump operation as described above, a drive signal for moving the information reading position in a direction across the recording track of the disk and a control signal for changing the information reading position based on the drive signal are generated. Switching between the braking signal and the braking signal to apply braking to the movement is done by detecting the point at which the tracking error signal takes the zero cross point without causing any malfunction due to noise components, making this switching easy and reliable. There are advantages to doing so.

[Brief explanation of the drawing]

Fig. 1 is a block diagram schematically showing the main parts of an example of an optical disc playback device with a built-in track/jump control section, Fig. 2 is a connection diagram showing a conventional control signal generation circuit, and Fig. 4 is a connection diagram showing an example of the information reading position control signal generation circuit according to the present invention, and FIG. 5 is an operation of the example shown in FIG. 4. A waveform diagram is provided for explanation, FIG. 6 is a connection diagram showing another example of the information reading position control signal generation circuit according to the present invention, and FIG. 7 is provided for explanation of the operation of the example shown in FIG. 6. FIG. In the figure, 1 is a disk, 4 is an information reading means, 8
1 is a light beam control circuit, 10 is a 1-track jump operation signal generation circuit, 12 is S-RF・F, 13
16 is an operational amplifier section, 16 is a level comparison section, 17 is an edge detection section, 18 and 21 are monostable multivibrators, 20 is an AND gate, and 22 and 25 are waveform shaping sections.

Claims (1)

[Scope of utility model registration request] A driving signal pulse for moving the reading position on the disk by the information reading means in a direction across the recording track formed in a spiral shape on the disk is applied so that the reading position is between two adjacent recording tracks. a driving pulse generating section that generates a driving pulse having a trailing edge at a certain point in time, and a driving pulse generating section that generates a driving pulse that has a trailing edge at a certain point in time; a braking pulse generating section that generates a predetermined period of time after the trailing edge; and a braking pulse generating section that is disposed on the output side of the driving pulse generating section and the braking pulse generating section, and is responsive to the driving signal pulse and the braking signal pulse. a combining unit that generates the driving signal and the braking signal in succession; and a combining unit that generates the driving signal and the braking signal in succession, and is arranged between the braking pulse generating unit and the combining unit or on the output side of the combining unit, and An information reading position control signal generating circuit comprising a waveform shaping section configured to make the amplitude larger than the amplitude of the trailing edge.