JPH06195902A - Information recording and reproducing device and tracking control circuit for this device - Google Patents

Abstract

PURPOSE:To perform exact tracking by placing a recording and reproducing means on a desired track and releasing the control stop of a movement control means to count traversed tracks in the section where the polarity of tracking servo is positive. CONSTITUTION:A CPU 2 stops the control of a control circuit 15. Simultaneously, a signal pickup 4 is relatively moved in the breadthwise direction of tracks by a driving circuit 16 and is placed on a desired track. At this time, the number of traversed tracks is counted from the output of a tracking error detector 6 based on the state of the binarized output level of an on-track signal detector 8, and the signal pickup 4 is placed on the desired track, and the control stop of the circuit 15 is released. Consequently, traversed tracks are counted in the section, where the polarity of tracking servo is positive, to accurately track the desired track.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking control circuit of an information recording / reproducing apparatus and an information recording / reproducing apparatus for performing tracking control by a tracking error signal and an on-track signal.

[0002]

2. Description of the Related Art In recent years, various information recording / reproducing apparatuses for recording / reproducing information on / from a disc-shaped information recording medium have been developed. In these information recording / reproducing apparatuses, it is necessary to allow a signal pickup to access a target track on an information recording medium in order to obtain predetermined information.

For example, as disclosed in Japanese Unexamined Patent Publication No. 4-32470, conventionally, in order to perform the above-mentioned access operation at high speed, the number of crossed tracks during the movement of the signal pickup is counted and the target track is directly accessed. Was being done.

A conventional example will be described below with reference to the drawings.

As shown in FIG. 6, a tracking control circuit 100 of a conventional information recording / reproducing apparatus detects a tracking deviation amount and outputs a tracking error signal (hereinafter referred to as TES) 102.
A track servo circuit 103 for controlling the tracking servo system, and a tracking actuator 105.
The power stage 104 for driving the TES 102, the TES zero-cross detector 106 that detects the zero-cross of the TES 102 and outputs the TES zero-cross signal 107, and the microcomputer 108 that controls the tracking servo system.

Further, an on-track detector 110, which detects whether the signal pickup (not shown) is on-track or off-track and outputs an on-track signal 111, is provided with a recording read from a disc-shaped information recording medium. The signal level (amplitude) of the information signal is divided into "H" and "L" at a certain threshold level. Further, the tracking control circuit 100 uses the TES
The edge of the zero-cross signal 107 is detected and the edge signal 11
An edge detector 112 that outputs 3 and a flip-flop 114 that latches the on-track signal 111 with the edge signal 113 and outputs an on-track latch signal 115 are provided.

In the conventional tracking control circuit 100 having the above-described structure, a case where a normal track jump is performed will be described.

As shown in FIG. 7, the microcomputer 108 cuts the track servo loop of the track servo circuit 103 (FIG. 7C) and sends a track kick pulse for kicking the tracking actuator 105 to a desired direction to the power stage 104. A command is issued, a track jump is started, and the TES 102 and the on-track signal become a signal having an amplitude of a predetermined level or more by a track guide provided on the information recording medium in order to cross the track (FIG. 7).
(A) and (b)).

When the track jump is started, the TES zero-cross signal 1 is detected by the edge detector 112 during the track jump in order to detect the number of tracking jumps.
The edge of 07 is detected, and the flip-flop 114 latches the on-track signal 111 by the edge signal 113. Then, the microcomputer 108 counts the on-track latch signal 115 from the flip-flop 114, and the track jump amount is controlled by this count number.

More specifically, as shown in FIG. 8, the information recording medium is provided with a plurality of tracks 121 concentrically and a track guide 122 for guiding the tracks. During the track jump, the track guide is provided. 12
The on-track signal (TADD) 111 has the maximum amplitude at the two positions (FIG. 8A), and the TES 102 makes a zero-cross at the track guide 122 position and the center position of the track 121 (FIG. 8B).

Although the TES 102 makes a zero-cross at two positions in this way, if the tracking servo has the opposite polarity at the position of the track guide 122 and the positive polarity at the center position of the track 121 (FIG. 8C), the signal is In order to track the pickup to the center of the track 121, it is necessary to pull in the tracking servo when the polarity of the tracking servo is positive.

Therefore, for example, a signal pickup is shown in FIG.
Access from the left to the right, the TADD111 is binarized at the threshold level A (see FIG. 8).
(D)) is the "H" section, the DTES signal obtained by binarizing the TES 102 at the threshold level B (Fig. 8 (e)).
7 rises, counts up (or counts down), and conversely, when the signal pickup accesses from right to left in FIG. 7, the DTADD signal (FIG. 8 (f)) becomes "
When the DTES signal (FIG. 8 (g)) falls in the H "section, the count-up (or count-down) is performed.

When the count-up (or count-down) is performed in this way and the count value matches the predetermined count value,
As shown in FIG. 9, since the tracking servo cannot be turned on in a region where the polarity of the tracking servo is opposite polarity, the tracking servo is turned on by detecting the first change in the DTES signal after matching the predetermined count value.

[0014]

However, as shown in FIG.
As shown in, if the signal pickup runs backward due to disturbance or the like after the counts match, the count value deviates from the target track, the tracking servo ON timing is erroneously detected, and the target track cannot be reached. There is a risk. In addition, when the tracking servo is turned on in a section where the polarity of the tracking servo is opposite, the tracking servo system becomes oscillating, and in the worst case, it may move over a plurality of tracks or may oscillate and become uncontrollable. There is also.

The present invention has been made in view of the above circumstances, and is an information recording / reproducing device capable of reliably counting crossing tracks and accurately tracking a desired track in a section where the polarity of the tracking servo is a positive polarity. An object is to provide a tracking control circuit and an information recording / reproducing apparatus for the apparatus.

[0016]

According to another aspect of the present invention, there is provided a tracking control circuit for an information recording / reproducing apparatus, which rotates a disk-shaped recording medium 3 having a plurality of tracks concentrically to serve as recording / reproducing means. In the tracking control circuit 1 of the information recording / reproducing apparatus for recording / reproducing information by scanning the signal pickup 4 in the track direction, a drive circuit 16 as a moving means for relatively moving the signal pickup 4 in the track width direction. And a tracking error detector 6 as a tracking signal detecting means for detecting the positional deviation between the scanning position of the signal pickup 4 and the track, and binarizing the signal from the signal pickup 4 at a predetermined binarization level. Depending on whether the scanning position of the signal pickup 4 is on-track or off-track. Based on the output of the on-track signal detector 8 and the tracking signal detector 8 as on-track detection means for detecting whether or not the drive circuit 16 is controlled so that the scanning position of the signal pickup 4 is always located on the track. Control circuit 15 as movement control means
And a CPU 2 as a control means for stopping the control of the control circuit 15.

According to another aspect of the present invention, there is provided an information recording / reproducing apparatus in which a disk-shaped recording medium 3 having a plurality of concentric tracks is rotationally driven so that a signal pickup 4 as recording / reproducing means is scanned in the track direction. Thus, in the information recording / reproducing apparatus for recording / reproducing information, the drive circuit 16 as a moving means for relatively moving the signal pickup 4 in the width direction of the track, and the signal pickup 4
The tracking error detector 6 as a tracking signal detecting means for detecting the positional deviation between the scanning position of the track and the track, and the signal from the signal pickup 4 are binarized at a predetermined binarization level to thereby obtain the signal pickup 4 Based on the output of the on-track signal detector 8 and the tracking signal detector 8 as an on-track detection means for detecting whether the scanning position of is the on-track position or the off-track position, the scanning position of the signal pickup 4 And the control circuit 1 as a movement control means for controlling the drive circuit 16 so that the drive circuit 16 is always positioned on the track.
The tracking control circuit 1 is composed of a CPU 2 as a control means for stopping the control of 5.

[0018]

In the tracking control circuit 1 of the information recording / reproducing apparatus of the present invention, the CPU 2 stops the control of the control circuit 15 and causes the drive circuit 16 to relatively move the signal pickup 4 in the width direction of the track. When positioning on a desired track, the number of crossing tracks is counted from the output of the tracking error detector 6 based on the state of the binarized output level of the on-track signal detector 8.
Since the signal pickup 4 is positioned on a desired track and the control of the control circuit 15 is released, the crossing track is surely counted in the positive polarity section of the tracking servo, and the desired track is accurately tracked. You can

In the tracking control circuit 1 of the information recording / reproducing apparatus, the CPU 2 stops the control of the control circuit 15 and causes the drive circuit 16 to relatively move the signal pickup 4 in the width direction of the track. When located on a desired track, a tracking error detector at each binarized output level output every time one track is crossed based on the state of the binarized output level of the on-track signal detector 8. Since the number of crossing tracks is counted by taking the logical sum of the output levels of 6 and the signal pickup 4 is positioned at a desired track and the control of the control circuit 15 is released, the polarity of the tracking servo is in the positive polarity section. , It can count the traverse tracks surely and can immediately pull it into the tracking servo to accurately obtain the desired track. It can be tracked having to click.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 relate to an embodiment of the present invention, FIG. 1 is a block diagram showing the configuration of a tracking control circuit of an information recording / reproducing apparatus, and FIG. 2 is a flow chart showing the processing flow of the CPU of FIG. 3, FIG. 3 is a flow chart showing the flow of processing of the counting operation of FIG. 2, and FIG. 4 is a timing chart explaining the operation of the tracking control circuit of FIG.

As shown in FIG. 1, the tracking control circuit 1 of the information recording / reproducing apparatus of this embodiment comprises a CPU 2 for controlling a tracking servo and a laser beam or the like on a recording medium 3 for optically recording / reproducing information. The objective lens 4a
Tracking error detector 6 that detects a tracking deviation amount from a signal pickup 4 that detects information via a tracking error signal (hereinafter, referred to as TES) 5 and whether the signal pickup 4 is on track. An on-track signal detector 8 that detects whether it is on an off-track and outputs an on-track signal 7 that is an analog signal, and a DTES signal that is a binarized signal by comparing the TES 5 and the ground level (threshold level B). A comparator 10 for outputting 9 and an on-track signal 7 and a comparator 14 for comparing a threshold level A output of a threshold level setter 12 set by the CPU 2 and outputting a DTADD signal 13 which is a binarized signal; A control circuit 15 for switching the operation / non-operation of the track servo, And a drive circuit 16 for No. to the pickup 4 access operation, the control circuit 15 is the C
The drive circuit 16 is controlled by switching the track servo state based on the ON / OFF signal 17 from the PU 2.

When the track servo is ON and the access operation to the target track is started when the track servo is in the ON state, the CPU 2 processes the threshold of the on-track signal 5 to the threshold level setter 9 in step S1 as shown in FIG. Set the level. Then, in step S2, the number of track jumps to the target track is set in the internal memory. Then, in step S3, the track servo is turned OFF, and in step S4, the ON / OFF signal 17 causes the control circuit 15 to control the operation of the drive circuit 16 to drive the drive circuit 16. In step S5, a track counting operation for counting the number of crossed tracks is performed. In step S6, it is determined whether the count value matches the number of track jumps. If they do not match, the process returns to step S4 to repeat the series of processes. If they match, the process proceeds to step S7, the track servo is turned on, and the process ends.

Next, details of the processing flow of the counting operation in step S5 will be described with reference to FIG.

In the counting operation, it is determined in step S21 whether the DTADD signal 13 has changed from "L" to "H". If it does not change, step S21 is repeated. If it has changed, the process proceeds to step S22. When the level of the DTES signal 9 is
ES1]. Then, in step S23, DTA
It is determined whether the DD signal 13 has changed from "H" to "L". If it does not change, step S23 is repeated. If it has changed, the process proceeds to step S24, and the DTE at that time is detected.
The level of the S signal 9 is changed to the address of the internal memory [DTES
2].

Next, in step S25, the address [DTE
S1] stores the value "DTES1" and the address [DTS
ES2] is compared with the value "DTES2" stored in
If they match, the process returns to step S21 to repeat a series of processes, and if they do not match, the process proceeds to step S26. In step S26, since the change of the DTES signal 9 is different depending on the access direction of the signal pickup 4, the DT
If the change of the ES signal 9 is from "H" to "L", the countdown process (or countup process) is performed. If the change of the DTES signal 9 is from "L" to "H", the countup process (or countdown process) is determined. . If the count-up process is determined in step S26, the process proceeds to step S27, and if the count-down process is determined,
It proceeds to step S28.

In the case of count-up processing, step S2
In step 7, it is determined whether or not the level of the DTADD signal 13 is "L". If it is not "L", the process returns to step S22 to repeat the series of processing, and if it is "L", step S22.
Proceed to 29. In step S29, the level of the DTES signal 9 is stored, and in step 30, it is determined whether the level of the DTES signal 9 has changed. If it has not changed, the process returns to step S27 to repeat a series of processes, and if it has changed, the process goes to step S31. The process proceeds and counts up, and the processing of the count operation ends.

Similarly, in the case of the countdown process, it is determined in step S28 whether or not the level of the DTADD signal 13 is "L", and if it is not "L", the process returns to step S22 to repeat a series of processes and "L". In the case of ", it progresses to step S32. In step S32, the level of the DTES signal 9 is stored. In step 33, it is determined whether the level of the DTES signal 9 has changed. If the level has not changed, the process returns to step S28 to repeat the series of processing, and if it has changed, to step S34. The process proceeds and counts up, and the processing of the count operation ends.

By performing such processing, as shown in FIG. 4, in the case of the count-up processing, the level of the DTADD signal 13 is from "L" to "H" at the rising and falling of the "H" section. Of the change in the DTES signal 9 and the level of the DTADD signal 13 in the "L" section,
The detection of a change in the DTES signal 9 from "H" to "L" is AN
It counts up under the D condition (FIGS. 4D and 4E).
Similarly, in the case of countdown processing, DTADD signal 1
When the level of 3 is the rise and fall of the "H" section, the change of the DTES signal 9 from "H" to "L" is detected, and the level of the DTADD signal 13 is "L" section,
The detection of a change in the DTES signal 9 from L "to" H "is AN
The countdown is performed under the condition D (FIGS. 4F and 4G).
4 (a) to 4 (c) are shown in FIG. 8 (a) of the conventional example.
The description is omitted because it is the same as that of FIG. 8 (c).

As described above, according to this embodiment, DTAD
The condition that the level of the DTES signal 9 at the rising edge and the falling edge of the D signal 13 is "H" is different, and DT is at the level of the DTADD signal 13 is "L".
By ANDing with the condition that the level of the ES signal 9 changes, the tracking servo polarity can be reliably counted in the positive polarity section, and at the same time when the count value matches the target count value, the tracking servo pull-in can be started. Therefore, the signal pickup can be reliably and accurately tracked on the track without detecting the pull-in timing of the tracking servo.

Next, the second embodiment will be described. Figure 5
6 is a timing chart for explaining the operation of the tracking control circuit according to the second embodiment. Since the second embodiment is almost the same as the first embodiment and only the method of counting the number of tracks by the CPU 2 is different, only different points will be described.

In the second embodiment, as shown in FIG. 5, the CPU 2 adds or subtracts the count value while the level of the DTADD signal 13 is in the "L" section and the level of the DTES signal 9 is changing. Specifically, when the track jump is instructed, the CPU 2 causes the CPU 2 to raise the rising edge of the DTES signal 9 when the DTADD signal 13 is at the “L” level (that is, in the off-track state). Is counted as +1 (or -1), and the falling edge of the DTES signal 9 is counted as -1 (or +1) .Others are the same as in the first embodiment.

As described above, according to the second embodiment, in addition to the effect of the first embodiment, even if the vehicle runs backward due to disturbance or the like, the count value is subtracted to ensure that the polarity of the tracking servo is positive. You can count with, and you can count crossing tracks accurately.

In the above embodiment, information is recorded / reproduced on / from the optical recording medium. However, the present invention is not limited to this. A magnetic recording medium may be used, and information recording / reproduction is performed on a disc-shaped recording medium having a track guide. If it is a reproducing apparatus, the tracking control circuit of the information recording / reproducing apparatus of this embodiment can be applied.

Although the threshold level is set for each access operation in the above embodiment, the threshold level may be set only once when the information recording medium is inserted. Further, in the same information recording medium, the threshold level may be determined from a plurality of on-track signal levels to absorb characteristics, variations, etc. in the information recording medium to perform more stable track operation.

Further, as a method for determining the threshold level, the on-track signal level in the track servo pull-in state is multiplied by a constant coefficient, or a constant is added, or the maximum value of the on-track signal and the track servo pull-in state are determined. There is a method of following the on-track signal level between the on-track signal levels.

[0037]

As described above, according to the tracking control circuit of the information recording / reproducing apparatus of the present invention, the control means is
When the control of the movement control means is stopped, and the recording / reproducing means is relatively moved in the track width direction by the moving means to position it on a desired track, based on the state of the binarized output level of the on-track detecting means. The number of crossing tracks is counted from the output of the tracking signal detecting means, the recording / reproducing means is positioned on a desired track, and the stop of the control of the movement control means is released, so that the polarity of the tracking servo is a positive polarity section, There is an effect that the number of crossing tracks can be surely counted, and a desired track can be accurately tracked.

Further, the control means stops the control of the movement control means, and when the moving means relatively moves the recording / reproducing means in the width direction of the track so as to position it on a desired track, the on-track detecting means. Based on the state of the binarized output level of, the number of traversing tracks is calculated by taking the logical sum of the output levels of the tracking signal detection means at the respective binarized output levels output every time one track is crossed. It is possible to count, position the recording / reproducing means on a desired track, and release the stop of the control of the movement control means, so that the polarity of the tracking servo is a positive polarity section, the crossing track is surely counted, and immediately. Can be pulled into the tracking servo,
There is an effect that a desired track can be accurately tracked.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a tracking control circuit of an information recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a processing flow of a CPU of FIG.

FIG. 3 is a flowchart showing a processing flow of a counting operation of FIG.

FIG. 4 is a timing chart illustrating an operation of the tracking control circuit of FIG.

FIG. 5 is a configuration diagram showing a configuration of a tracking control circuit of an information recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 6 is a configuration diagram showing a configuration of a tracking control circuit of an information recording / reproducing apparatus according to a conventional example.

FIG. 7 is an explanatory diagram explaining the access operation of FIG. 6;

FIG. 8 is a timing chart illustrating the operation of the tracking control circuit of FIG.

9 is a timing chart for explaining the tracking servo pull-in by the tracking control circuit of FIG.

10 is a timing chart for explaining tracking servo pull-in at the time of stray by the tracking control circuit of FIG.

[Explanation of symbols]

 1 Tracking control circuit of information recording / reproducing apparatus 2 CPU 6 Tracking error detector 8 On-track signal detector 9 DTES signal 10 Comparator 12 Threshold level setting device 13 DTADD signal 14 Comparator 15 Control circuit 16 Driving circuit

Claims (4)

[Claims] 1. A tracking control circuit of an information recording / reproducing apparatus for recording / reproducing information by rotationally driving a disk-shaped recording medium having a plurality of tracks concentrically and scanning the recording / reproducing means in the track direction. Moving means for relatively moving the recording / reproducing means in the width direction of the track; tracking signal detecting means for detecting a positional deviation between the scanning position of the recording / reproducing means and the track; Two signals at a predetermined binarization level
On-track detecting means for detecting whether the scanning position of the recording / reproducing means is on-track position or off-track position by digitizing, and the recording / reproducing means based on the output of the tracking signal detecting means. Comprises a movement control means for controlling the movement means such that the scanning position of the movement position is always on the track, and a control means for stopping the control of the movement control means, wherein the control means controls the movement control means. When the recording / reproducing means is relatively moved by the moving means in the width direction of the track and is positioned at a desired track while stopping the above, based on the state of the binarized output level of the on-track detecting means. The number of crossing tracks is counted from the output of the tracking signal detecting means, and the recording / reproducing means is positioned at a desired track. Tracking control circuit of the information recording and reproducing apparatus characterized by releasing the stop of the control of the movement control means. 2. When the control means stops the control of the movement control means, and the recording / reproducing means is relatively moved in the width direction of the track by the moving means so as to be positioned on a desired track, Based on the state of the binarized output level of the on-track detection means, the logical sum of the output levels of the tracking signal detection means at each binarized output level output every time one track is crossed is calculated. 2. The tracking control of the information recording / reproducing apparatus according to claim 1, wherein the number of traverse tracks is counted, the recording / reproducing means is positioned at a desired track, and the stop of the control of the movement control means is released. circuit. 3. An information recording / reproducing apparatus for recording / reproducing information by rotationally driving a disk-shaped recording medium having a plurality of tracks concentrically and scanning the recording / reproducing means in the track direction. Moving means for relatively moving the means in the width direction of the track, tracking signal detecting means for detecting a positional deviation between the scanning position of the recording / reproducing means and the track, and a signal from the recording / reproducing means to a predetermined value. 2 at the binarization level
On-track detecting means for detecting whether the scanning position of the recording / reproducing means is on-track position or off-track position by digitizing, and the recording / reproducing means based on the output of the tracking signal detecting means. A tracking control circuit that includes a movement control unit that controls the movement unit so that the scanning position of the unit is always located on the track, and a control unit that stops the control of the movement control unit. When the control of the movement control means is stopped and the recording / reproducing means is relatively moved by the moving means in the width direction of the track to position it on a desired track, the binary output level of the on-track detecting means The number of crossing tracks is counted from the output of the tracking signal detecting means based on the state of The desired is positioned on the track, the information recording and reproducing apparatus characterized by releasing the stop of the control of the movement control means. 4. The on-track detection means changes a predetermined binarization level for binarizing a signal from the recording / reproducing means according to the recording medium. Information recording / reproducing device.