KR19990081562A - Track number detection device of playback apparatus using light - Google Patents

Abstract

Signal frequency of the high frequency signal is detected by generating a sampling frequency higher than the high frequency signal detected in the track jumping process, and whether the signal level is increased or decreased between adjacent signal levels among the sampled signal levels. When the corresponding high frequency signal at the time point detects the positive peak portion and the negative peak portion, and if both the positive peak portion and the negative peak portion are detected, it is determined that one track is jumped.

Therefore, the number of jumped tracks can be detected accurately.

Description

Track number detection device of playback apparatus using light

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a track number detecting device of a reproduction apparatus using light, and more particularly, to accurately detect the number of jumping tracks from a track jump signal detected at track jump, so as to achieve a high speed track jumping operation. The present invention relates to a track number detection device of a playback device using light that enables the stable number of jumping tracks to be detected.

Representative methods of reproducing recorded information include magnetic and light. The method using magnetism is a method of detecting the arrangement of the magnetic material applied on the magnetic medium and reproducing information according to the polarity (or phase). The recording and reproducing operation is free in that it uses the arrangement of the magnetic material. Has the advantage.

In contrast, the light-based method refers to a method of scanning light onto a recording surface of a recording medium and reproducing information by detecting a state of diffuse reflection by a pit processed on the recording medium. In terms of processing, the information preservation efficiency is very good.

Representative storage media using optical methods include CD-ROM and DVD-ROM. Among such optical storage media, the CD-ROM stores a lot of information about 700 megabytes (MByte) or more per sheet. Accordingly, there is a need for the optical reproducing apparatus to quickly detect specific information among a large amount of information stored in the optical storage medium. Recently, since the optical reproducing apparatus is developed to reproduce the optical storage medium at a speed of 10 times or more, the necessity of fast information retrieval becomes a more urgent task.

A typical optical storage medium includes a plurality of sectors radially partitioned on a disk-shaped storage medium, and a plurality of tracks divided into concentric circles for each sector. The optical storage medium is rotated at an average speed of approximately 720 rpm, and is reproduced in a concentric manner from the center of the optical storage medium to the outer diameter by the optical reproducing apparatus.

At this time, in order to quickly retrieve the information recorded on the optical storage medium, a track jumping process is required in which a pick-up for reproducing the information recorded on the optical storage medium is reproduced by jumping between tracks. Since this process proceeds at high speed, the signal detected at the time of track jump becomes an analog signal of high frequency component. When the positive peak and negative peak portions of the analog signal are detected, the number of tracks that the pickup has jumped can be counted.

A conventional track number detection device that counts the number of tracks jumped in this manner is shown in FIG.

Referring to FIG. 1 schematically, in the optical storage medium 2 rotated by the spindle motor 1, the information recorded on the data recording surface by the pickup 3 is electrically converted. At this time, the photodiode in the pickup 3 is typically configured to sense the light reflected from the optical storage medium 2 in the state of 4 or 6 divided states, and thus is detected from each of the divided photo diodes. Accumulated data can be detected only by summating high frequency signals. Therefore, the high frequency synthesizing section 4 adds four or six high frequency signals supplied from the pickup 3 and synthesizes them.

The upper detector 5 and lower detector 6 detect the positive peak portion and the negative peak portion of the high frequency signal supplied from the high frequency synthesizer 4, respectively. This method is the same as the general envelope (envelope) waveform detection method as shown in FIG. 2, and the positive peak portion and the negative peak portion detected by the upper detector 5 and the lower detector 6, differential amplifier (7) Outputs an envelope waveform in analog form amplified by The envelope waveform of this analog form is converted into a square wave by the waveform shaper 8, this square wave is counted by the counter 9, and counting information is provided to the control unit 10. Therefore, the controller 10 can detect the number of tracks that the pickup 3 jumped to.

However, according to the conventional track number detection method, the following problem occurs.

That is, when the track jump function is performed through the high speed playback device, the high frequency signal detected at the time of track jump is very high. At this time, an irregular level signal may be detected when moving between tracks. In this case, when the signal difference between the level of the peak portion and the level of the next peak portion is large (as shown in "A" in FIG. 2), the upper detection unit 5 ) And the lower detection section 6 detect the peak portion in a state in which the peak portion having a low signal level is omitted (see FIG. 2). Therefore, the exact number of tracks cannot be detected, which causes errors in the track movement amount.

Accordingly, an object of the present invention is to solve such problems, and an object of the present invention is to generate a sampling frequency higher than a high frequency signal detected in a track jump process by a predetermined multiple to detect a signal level of a high frequency signal, and to sample each signal. The present invention provides a track number detection device of a playback apparatus using light that compares a level to detect a positive peak portion and a negative peak portion so that the number of jumped tracks can be accurately detected.

1 is a schematic block diagram of a conventional track number detecting apparatus;

2 is a waveform diagram for explaining a method of detecting a track number by a conventional track number detection apparatus;

3 is a schematic block diagram of a track number detecting apparatus according to the present invention.

<Description of the code | symbol about the principal part of drawing>

1: spindle motor 2: optical storage medium

3: pickup 4: high frequency synthesis section

9: counter 10: control unit

11: rotation speed detector 12: position detector

13: reference clock generator 14: filter

15: slope detection unit 16: delay group

16a to 16g: delay 17: first comparator

18: second comparator 19: first determination unit

20: second discriminating unit 21: logical multiplication device

A feature of the present invention for achieving the above object is an optical storage medium reproducing system in which an optical storage medium is chucked and rotated on a motor shaft, and the pickup reproduces information recorded on an information recording surface of the optical storage medium in which the pickup is rotated. A rotational speed detection unit for detecting a rotational speed of the motor; A position detector for detecting a current position of the pickup; A reference clock generator for generating a reference clock having a predetermined sampling frequency based on the speed information detected by the rotation speed detector and the position information detected by the position detector; A delay group composed of (2N-1) delay units, wherein N is a natural number, to delay the high frequency signal detected by the pickup during the track jump process for each sampling period of the reference clock output from the reference clock generator; Detects the signal level from the 0th delayed signal to the (N-1) th delayed signal by the first to (N-1) th delays configured in the delay group, and compares the increase or decrease of each adjacent signal level. A first comparison unit to perform; Detects the signal level from the Nth delayed signal to the (2N-1) th delayed signal by the Nth to (2N-1) th delays configured in the delay group, and compares each signal level to increase or decrease. A second comparison unit; A first discriminating unit which determines whether a zeroth order delayed time point of the high frequency signal is a positive peak portion according to a comparison result of the first comparing unit and the second comparing unit; A second discriminating unit which determines whether a zeroth-order delayed time point of the high frequency signal is a negative peak portion according to a comparison result of the first comparing unit and the second comparing unit; An AND product for performing an AND operation on the discrimination result of the first discriminating unit and the second discriminating unit; A counter for controlling whether an increase of a counting value is controlled according to an operation result of the AND product; And a control unit for detecting the number of tracks jumped by the pickup by receiving the counted value at the counter.

The filter unit may further include a filter unit for filtering the noise component included in the high frequency signal detected by the pickup and outputting the filtered noise component.

The apparatus may further include a slope detector configured to detect a slope of the high frequency signal filtered by the filter based on the sampling frequency of the reference clock output from the reference clock generator.

Also, the reference clock generator generates a reference clock having a sampling frequency larger by a predetermined multiple of the frequency of the high frequency signal detected by the pickup based on the speed information output from the rotation speed detector and the position information output from the position detector. Preferably, the predetermined multiple is preferably at least 2N times or more.

Further, the first comparator and the second comparator compare an arbitrary signal level sampled with a signal level at a sampling time delayed by one reference clock based on a sampling frequency output from the reference clock generator from the arbitrary signal level. Therefore, if the signal level of the sampling point delayed by one reference clock more than the arbitrary signal level is large, it is determined as logic "1". If the signal level of the sampling point delayed by one reference clock more than the arbitrary signal level is small, the logic It is preferable to determine "-1".

Further, the first comparator includes: a first comparison element for comparing whether the sum of the N determination results determined according to the increase or decrease from the 0th delayed signal to the (N-1) th delayed signal is at least "1" or more; It is preferable to include a second comparison element which compares whether the sum of the N determination results determined according to the increase or decrease from the 0th delayed signal to the (N-1) th delayed signal is at least "-1" or less.

The second comparator includes: a third comparison device for comparing whether or not the sum of the N determination results determined according to the increase or decrease from the N-th delayed signal to the (2N-1) -th delayed signal is at least "1" or more; It is preferable to include a fourth comparison element which compares whether the sum of the N determination results determined according to the increase or decrease from the 0th delayed signal to the (N-1) th delayed signal is at least "-1" or less.

In addition, the first determination unit receives the comparison result of the first comparison element and the comparison result of the fourth comparison element, respectively, and the comparison result of the first comparison element is "1" or more, and the comparison result of the fourth comparison element is "-1". "Only when it is below, it is desirable to determine that the 0th delayed time point of a high frequency signal is a positive peak part.

The second discriminating unit receives the comparison result of the second comparison element and the comparison result of the third comparison element, respectively, and the comparison result of the second comparison element is "-1" or less, and the comparison result of the third comparison element is "1". "Only in this case, it is preferable to determine that the 0th delayed time point of the high frequency signal is the negative peak portion.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the elements of each drawing, it should be noted that the same elements are denoted by the same reference numerals as much as possible even if they are displayed on different drawings. In addition, in the following description there are shown a number of specific details, such as components of the specific circuit, which are provided only to help a more general understanding of the present invention that the present invention may be practiced without these specific details. It is self-evident to those of ordinary knowledge in Esau. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

3 is a schematic block diagram of a track number detecting apparatus according to the present invention. In Fig. 3, the same reference numerals as those in Fig. 1 denote the same parts.

Referring to FIG. 3, the spindle motor 1 rotates the optical storage medium 2 at a preset rotation speed. The pickup 3 scans the light on the data recording surface of the rotating optical storage medium 2, receives the reflected light and converts the light into an electrical signal. At this time, the photodiode in the pickup 3 is divided into four or more. It is divided into to increase the light receiving efficiency of the reflected light.

The rotational speed detector 11 detects the rotational speed of the spindle motor 1, and the position detector 12 detects the current position of the pickup 3. The reference clock generator 13 generates a reference clock using the speed information of the spindle motor 1 detected by the rotation speed detector 11 and the position information of the pickup 3 detected by the position detector 12. At this time, the reference clock generator 13 generates a reference clock corresponding to a multiple of 20 times or more with respect to the output (high frequency signal) of the pickup 3 which can be detected through the speed information and the position information.

As described above, the high frequency synthesizing unit 4 adds and synthesizes a high frequency signal detected from a plurality of photodiodes divided in the pickup 3, and the filter unit 14 combines noise components included in the synthesized high frequency signal. Remove

The slope detector 15 detects the slope of the high frequency signal filtered by the filter unit 14 based on the reference clock generated by the reference clock generator 13. The plurality of delay groups 16 sequentially delays a high frequency signal output from the slope detector 15 at a sampling frequency corresponding to the reference clock based on the reference clock generated by the reference clock generator 13. The delayed signal components are supplied to the first comparator 17 and the second comparator 18, respectively. If the delay group 16 is composed of seven delayers 16a to 16g, it is assumed that the level of the original sampling signal that is not delayed and the level of the sampling signal delayed by one sampling clock and the sampling of two cycles The level of the sampling signal delayed by clock and the sampling signal delayed by three sampling clocks are supplied to the first comparator 17, respectively, and are delayed by the level of the sampling signal delayed by four sampling clocks and the sampling clock of five cycles. The level of the sampling signal and the level of the sampling signal delayed by the sampling clock of 6 cycles and the level of the sampling signal delayed by the sampling clock of 7 cycles are supplied to the second comparator 18, respectively.

The first and second comparators 17 and 18 compare each of the four sampling signals with each level increasing or decreasing, and if it is determined that the comparison result is increased, a logic "1" is given and the comparison result is decreased. If it is determined that a logic "-1" is given.

The first determination unit 19 determines whether the corresponding sampling section is the positive peak portion based on the comparison result of the first comparator 17 and the second comparator 18, respectively, and the second determination unit 20 Based on the comparison result between the first comparator 17 and the second comparator 18, it is determined whether the corresponding sampling section is a negative peak portion.

The AND product 21 performs an AND operation on each result determined by the first discriminating unit 19 and the second discriminating unit 20, and outputs the result to the counter 9, and the counter 9 is logical. The operation result output from the product element 21 is counted and the result is output to the controller 10.

Referring to the operation of the present invention having such a configuration as follows.

As the spindle motor 1 rotates, the optical storage medium 2 chucked on the motor shaft of the spindle motor 1 rotates at the same speed as the rotational speed of the spindle motor 1. The rotational speed detection unit 11 detects the rotational speeds of the different spindle motors 1 according to which area of the data recording surface of the optical storage medium 2 the pickup 3 is located, and uses the speed information as a reference clock generator 13. ) Then, the position detector 12 detects the current position of the pickup 3 and outputs the position information to the reference clock generator 13. Here, the information is recorded in the same area with the same density in the optical storage medium 2, and the amount of recording of the information increases as it goes to the outer circumferential surface of the optical storage medium 2. Therefore, since the amount of information reproduced by the pickup 3 increases, the sampling frequency of the reference clock generated by the reference clock generator 13 must increase.

The reference clock generator 13 detects the high frequency signal detected by the pickup 3 in the course of jumping the track based on the speed information provided by the rotation speed detector 11 and the position information provided by the position detector 12. Generate a reference clock with a frequency 20 times higher.

On the other hand, the data recorded on the optical storage medium 2 is converted into an electrical signal by a pickup 3 having a photodiode divided into four or more parts, which are converted into an electrical signal by the high frequency synthesizing section 4. By this, each electric signal dividedly detected is synthesized. At this time, the faster the pickup 3 jumps between tracks, the higher the electrical signal detected becomes a high frequency signal.

In the high frequency signal synthesized by the high frequency synthesizing section 4, the noise component is filtered through the filter unit 14, and the slope detection unit 15 detects the inclination of each sampling section of the high frequency signal. That is, the reference detector is supplied to the tilt detector 15 from the reference clock generator 13, and the tilt detector 15 corresponds to the reference clock based on the high frequency signal input through the filter unit 14 based on the reference clock. After sampling, the slope is measured using the difference between each sampled signal level. At this time, when the current signal level is greater than the sampled signal level by one cycle delay, the slope detector 15 outputs a control signal of logic "1", and the current signal level is less than the sampled signal level by 1 cycle delay. In this case, the slope detector 15 outputs a control signal of logic "-1".

The high frequency signals provided through the slope detector 15 are sequentially delayed by the sampling frequencies of the reference clocks by the respective delayers 16a to 16g in the delay group 16. Among these, the original signal, the first delayed signal, the second delayed signal, and the third delayed signal are supplied to the first comparator 17, and the signals from the fourth delayed signal to the seventh delayed signal are supplied to the second comparator 18. .

The first comparator 17 compares four signals (from the original signal to the third delayed signal) and determines whether the gradient is increased or decreased in the same manner as the logic signal detected by the gradient detector 15. Here, when comparing the slope between adjacent signals among the four signals, three comparison results are generated. Therefore, the first comparator 17 adds three comparison results to determine whether the value is "1" or more or "-1" or less. do.

The second comparator 18 compares four signals (from the fourth delayed signal to the seventh delayed signal) to determine whether the slope is increased or decreased in the same manner as the logic signal detected by the slope detector 15. Here, when comparing the slopes between the adjacent signals among the four signals, three comparison results are generated as in the case of the first comparator 17, so that the second comparator 18 adds three comparison results to " 1 " It is determined whether or not above or below "-1".

The first determination unit 19 receives the comparison result of the first comparator 17 and the comparison result of the second comparator 18 to determine whether the signal waveform from the original signal to the third delayed signal is a positive peak portion. . That is, if the comparison result of the first comparator 17 is "1" or more and the comparison result of the second comparator 18 is "-1" or less, the first determination unit 19 may change from the original signal to the third delayed signal. Determine that the signal waveform of corresponds to the positive peak portion.

In addition, the second determination unit 20 receives the comparison result of the first comparator 17 and the comparison result of the second comparator 18, respectively, and the signal waveform from the fourth delayed signal to the seventh delayed signal is negative. Determine authorization. That is, when the comparison result of the first comparator 17 is "-1" or less, and the comparison result of the second comparator 18 is "1" or more, the second determination unit 20 delays the seventh order from the fourth delayed signal. It is determined that the signal waveform up to the signal corresponds to the negative peak portion.

The logical AND element 21 receives the discrimination result of the first discriminating unit 19 and the discriminating result of the second discriminating unit 20 and performs logical AND operation. That is, if the result determined by the first determination unit 19 is the positive peak portion, and the result determined by the second determination unit 20 is the negative peak portion, the logical product element 21 generates an arbitrary logical operation result (for example, Outputs a logic " high ", and the counter 9 increments the counting value by the logical operation result output from the logical product element 21. At this time, the value counted by the counter 9 represents the number of tracks that the pickup 3 has jumped. The counter 9 value thus increased is provided to the controller 10, and the controller 10 may determine the number of tracks jumped by the pickup 3 based on the counting value provided from the counter 9.

On the other hand, the higher the sampling frequency of the reference clock generated by the reference clock generator 13, the more accurate counting operation can be performed, and this requires more delay. However, it is inefficient to install a large number of delayers in order to obtain sophisticated counting results. Therefore, it is preferable to install about 7 or 9 delayers in order to obtain a desirable counting result through a small number of delayers. Therefore, the number of tracks that the pickup 3 has jumped can be accurately detected.

As described above, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

As a result, according to the track number detecting apparatus of the reproducing apparatus using light according to the present invention, there are advantages as follows.

That is, a reference clock of a frequency higher than a high frequency signal detected at the time of track jump is generated, and the level of the high frequency signal is sampled corresponding to the sampling frequency of the reference clock, and the corresponding high frequency signal is sampled by the level of the sampled high frequency signal. By detecting the positive peak portion and the negative peak portion of, the more precise number of jumping tracks can be detected, thereby preventing the occurrence of errors during track jumping.

Claims (10)

An optical storage medium reproducing system in which an optical storage medium is chucked and rotated on a motor shaft, and the information is recorded on an information recording surface of the optical storage medium on which the pickup is rotated: A rotation speed detection unit detecting a rotation speed of the motor; A position detector for detecting a current position of the pickup; A reference clock generator for generating a reference clock having a predetermined sampling frequency based on the speed information detected by the rotation speed detector and the position information detected by the position detector; A delay group composed of (2N-1) delayers, wherein N is a natural number, to delay the high frequency signal detected by the pickup during the track jump process at every sampling period of the reference clock output from the reference clock generator; Detecting the signal level from the 0th delayed signal to the (N-1) th delayed signal by the first to (N-1) th delays configured in the delay group, and whether or not each adjacent signal level is increased or decreased. A first comparator for comparing a; Detecting the signal level from the Nth delayed signal to the (2N-1) th delayed signal by the Nth to (2N-1) th delays configured in the delay group, increases or decreases each adjacent signal level A second comparator for comparing a; A first discriminating unit which determines whether a zeroth order delayed time point of the high frequency signal is a positive peak portion according to a comparison result of the first comparing unit and the second comparing unit; A second discriminating unit which determines whether a zeroth order delayed time point of the high frequency signal is a negative peak part according to a comparison result of the first comparing unit and the second comparing unit; An AND product for performing an AND operation on the discrimination result of the first discriminating unit and the second discriminating unit; A counter for controlling whether an increase of a counting value is controlled according to the operation result of the logical product; And And a control unit which receives a value counted by the counter and detects the number of tracks jumped by the pickup. The method of claim 1, And a filter unit for filtering the noise component included in the high frequency signal detected by the pickup and outputting the filtered noise component to the delay group. The method of claim 2, And a slope detector which detects a slope of the high frequency signal filtered by the filter unit based on the sampling frequency of the reference clock output from the reference clock generator. The method of claim 1 or 3, wherein the reference clock generating unit, Generate a reference clock having the sampling frequency larger by a predetermined multiple of the frequency of the high frequency signal detected by the pickup based on the speed information output from the rotation speed detection unit and the position information output from the position detection unit; An apparatus for detecting the number of tracks of a playback apparatus using one light. The method of claim 4, wherein the predetermined multiple is At least 2N times or more of the track number detection apparatus of the reproduction apparatus using the light. The method of claim 1 or 3, wherein the first comparator and the second comparator, The signal level of the sampling time delayed by one reference clock is further compared with the sampled arbitrary signal level based on the sampling frequency output from the random signal level. If the signal level of the sampling time delayed by one reference clock is large, it is determined as logic "1". If the signal level of the sampling time delayed by the one reference clock is smaller than the arbitrary signal level, it is determined as logic "-1". A track number detection apparatus of a playback apparatus using light, characterized in that the determination. The method of claim 6, wherein the first comparator, A first comparison element for comparing whether the sum of the N determination results determined according to the increase or decrease from the zeroth order delayed signal to the (N-1) th order delayed signal is at least "1" or more; And Using the light including a second comparison element for comparing whether the sum of the N determination results determined according to the increase or decrease from the zeroth order delayed signal to the (N-1) th order delayed signal is at least "-1" or less Track number detection device of a playback device. The method of claim 6, wherein the second comparator, A third comparison element for comparing whether or not the sum of the N determination results determined according to the increase or decrease from the N-th delayed signal to the (2N-1) -th delayed signal is at least "1" or more; And Using light including a fourth comparison element for comparing whether the sum of the N determination results determined according to whether the increase or decrease from the zeroth delayed signal to the (N-1) th delayed signal is at least "-1" or less; Track number detection device of a playback device. The method of claim 7 or 8, wherein the first determination unit, When the comparison result of the first comparison element and the comparison result of the fourth comparison element are respectively applied, the comparison result of the first comparison element is "1" or more, and the comparison result of the fourth comparison element is "-1" or less. And the track number detection device of the reproduction apparatus using light, characterized in that it is determined only when the zeroth order delayed point of the high frequency signal is a positive peak portion. The method of claim 7 or 8, wherein the second determination unit, When the comparison result of the second comparison device and the comparison result of the third comparison device are respectively received, the comparison result of the second comparison device is "-1" or less, and the comparison result of the third comparison device is "1" or more. And the track number detecting device of the reproducing apparatus using light, characterized in that it is determined only when the zeroth order delayed point of the high frequency signal is a negative peak portion.