KR19990050068A - Digital defect signal detection device of optical disc player - Google Patents

Abstract

The present invention relates to an apparatus for detecting a detection signal of an optical disc player for recognizing whether a defect occurs on a track when playing a program recorded on a track of an optical disc, and sampling an RF signal applied from the outside at a predetermined frequency. An A / D converter converting the digital signal into a digital signal; A buffer that sequentially stores the digital signals converted by the A / D converter and outputs the stored digital signals as data of predetermined predetermined bits; A first digital peak holder which detects a peak value of data output from the buffer and attenuates and detects a predetermined amount if there is no change in the data value for a predetermined period; A second digital peak that detects a peak value of the data output from the buffer and attenuates by a predetermined amount if there is no change in the data value for a predetermined period of time which is greater than a predetermined period of time in the first digital peak holder. holder; A subtraction unit which subtracts the peak value data detected by the second digital peak holder from the peak value data detected by the first digital peak holder; The present invention provides a digital defect signal detecting apparatus for an optical disc player comprising a third comparing unit which compares a subtracted value subtracted by the subtracting unit with preset reference data and generates a defect signal corresponding to the comparison result. It is possible to accurately calculate defects on the track being played, thereby improving the reliability of the optical disc player.

Description

Digital defect signal detection device of optical disc player

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc player, and more particularly, to a digital implementation of a defect signal detection device of an optical disc player for recognizing a defect on a track included in an optical disc during playback of an optical disc player. A digital defect signal detection apparatus of an optical disc player.

In general, an optical disc player is a device that reads data from an optical disc on which several gigabytes (GB) of video and audio data are recorded, for example, by MPEG-2 moving picture compression technology. Compared with the playback apparatus, it has been widely used for providing high quality and high sound quality and providing useful functions such as random access.

However, in the above-described optical disc player, if there is a disturbance such as a defect in the track or an impact from the outside during reproduction, the laser beam irradiated from the optical pickup unit is released from the track.

Therefore, the area where the laser beam does not deviate from the track, that is, the operating area of the tracking error signal that can be used in the tracking servo is less than 1/2 of the track pitch.

For example, in the case of a CD (Compact Disc), since the track pitch is 1.6 µm or less, the operating area of the tracking servo usable tracking error signal is very small, 0.8 µm or less.

Therefore, since the operating area of the tracking error signal is very small, if a defect is present in the track, the laser beam of the optical pickup portion is likely to leave the track.

At this time, a signal for detecting a defect in a track is called a defect signal, and when such a defect signal is applied to a system controller (not shown), the system controller short-circuits the tracking servo system or tracks the servo. Take care of defects such as responsiveness of the system.

Hereinafter, a defect signal detection apparatus according to the prior art will be described with reference to FIGS. 1 and 2 as follows.

Fig. 1 is a block diagram showing a defect signal detecting apparatus according to the prior art, and Fig. 2 is a signal waveform diagram showing signals of respective components of the defect signal detecting apparatus according to the prior art.

Referring to FIG. 1, the inverting amplifier 10 inverts the phase of an RF signal a applied from the outside, amplifies the signal level, and then amplifies the amplified and inverted RF signal b with a first peak holder. (Peak Holder 20) and the second Peak Holder (40) via the capacitor (30). In this case, the RF signal is a signal having a waveform shown in FIG. 2A and corresponds to the sum of the reflected light detected by each of the four photodiodes provided in the photodetector (not shown).

When the inverted-amplified RF signal is provided from the inverting amplifier 10 as shown in FIG. 2B, the peak holder 20 detects the peak value of the inverted-amplified RF signal, and has a first peak value signal having the waveform shown in FIG. 2C. To the comparator 50.

The capacitor 30 removes the DC (Direct Current) component of the inverted and amplified RF signal provided from the inverting amplifier 10 and provides it to the second peak holder 40.

The second peak holder 40 detects the peak value of the signal from which the DC (Direct Current) component of the inverted-amplified RF signal is removed and provides the comparison unit 50 with a second peak value signal having the waveform shown in FIG. 2D. do.

Thereafter, the comparison unit 50 compares the first peak value signal and the second peak value signal provided from the first peak holder 20 and the second peak holder 40, and compares the result of the comparison with a high or low value. ) Output by pulse. At this time, since the output pulse corresponds to the inverted-amplified RF signal, a high pulse indicates that a defect occurs in the track.

However, since the above-described defect signal detection device is composed of an analog circuit which is highly influenced by noise, its accuracy is poor, its configuration is complicated, and its control is difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to detect a digital defect signal of an optical disc player in which a defect signal detecting device for confirming the occurrence of a defect in a track during reproduction of the optical disc player is digitally implemented. To provide a device.

In order to achieve the above object, in the present invention, an RF signal applied from an external device in the detection signal detecting apparatus of an optical disc player for determining whether a defect occurs on the track when playing a program recorded on a track of the optical disc. An A / D converter for sampling a signal at a predetermined predetermined frequency and converting the signal into a digital signal; A buffer that sequentially stores the digital signals converted by the A / D converter and outputs the stored digital signals as data of predetermined predetermined bits; A first digital peak holder which detects a peak value of data output from the buffer and attenuates and detects a predetermined amount if there is no change in the data value for a predetermined period; A second digital peak that detects a peak value of the data output from the buffer and attenuates by a predetermined amount if there is no change in the data value for a predetermined period of time which is greater than a predetermined period of time in the first digital peak holder. holder; A subtraction unit which subtracts the peak value data detected by the second digital peak holder from the peak value data detected by the first digital peak holder; An apparatus for detecting a digital defect signal of an optical disc player, comprising: a third comparison unit configured to compare a subtracted value subtracted by the subtractor with preset reference data and generate a defect signal corresponding to the comparison result.

1 is a block diagram showing a defect signal detection apparatus according to the prior art;

Fig. 2 is a signal waveform diagram showing signals at respective constituent members of the defect signal detecting apparatus according to the prior art.

3 is a block diagram illustrating a digital defect signal detection apparatus of an optical disc player according to the present invention;

<Description of the symbols for the main parts of the drawings>

10: inverting amplifier 20: first peak holder

30: capacitor 40: second peak holder

50: comparison unit 100: A / D converter

200: buffer 300: digital first peak holder

310: first comparator 320: first counter

330 system control unit 340 storage unit

400: digital second peak holder 410: second comparison unit

420: second counter 500: subtraction part

600: third comparison unit

The above and other objects and advantages of the present invention will become more apparent from the following description with reference to the accompanying FIG. 3.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention. 3 is a block diagram illustrating an apparatus for detecting a digital defect signal of an optical disc player according to the present invention.

Referring to FIG. 3, an apparatus for detecting a digital defect signal of an optical disc player according to the present invention may include an RF signal generator 90, an A / D converter 100, a buffer 200, a first digital peak holder 300, The second digital bottom holder 400, the subtraction part 500, and the third comparison part 600 may be formed, and each of the constituent members may perform the following functions.

First, the RF signal generator 90 detects reflected light reflected from the optical disk by the laser beam irradiated to the optical disk by an optical pickup unit (not shown), and generates an RF signal corresponding to the detected reflected light. The generated RF signal is provided to the A / D converter 100.

The A / D converter 100 samples the RF signal provided from the RF signal generator 90 at a predetermined predetermined sampling frequency and converts the digital signal into a digital signal, and converts the converted digital signal into a serial in the buffer 200. To provide.

The buffer 200 sequentially stores the digital signals provided from the A / D converter 100, and when the predetermined data bits become predetermined, the stored digital signals are stored in the digital peak holder 300 and the digital bottom holder 400. to provide.

As shown in FIG. 3, the first digital peak holder 300 includes a first comparator 310, a first counter 320, a system controller 330, and a storage 340. It performs the following functions.

The first comparator 310 compares the digital data provided from the buffer 200 with previous data provided from the system controller 330, and, as a result of the comparison, the digital data having a large data value is the system controller 330 and the subtractor. To 500.

The first counter 320 is reset to 0 under the control of the system control unit 330 or accumulatively adds sequentially from 1.

The system controller 330 determines whether the digital data 330 provided from the first comparator 310 is the same as the previous data, and if the digital data 330 provided from the first comparator 310 is the same as the previous data, The counter 320 is controlled to accumulate and add to the first counter 320 by one. If the digital data provided from the first comparator 310 is different from the previous data, the changed digital data is stored in the storage unit 340. The first counter 320 is controlled to reset to zero. In addition, when the cumulative addition number in the first counter 320 reaches a preset reference value, the digital data stored in the storage unit 330 is subtracted by a predetermined value, and the subtracted data is stored in the storage unit 340. do.

The storage unit 340 stores peak values of digital data provided from the buffer 310 by the system controller 330.

Meanwhile, as illustrated in FIG. 3, the second digital peak holder 400 includes a second comparator 410, a second counter 420, a system controller 330, and a storage 340. Each plays the same role as the first digital peak holder, but sets the tolerance for the number of times the peak value having the same data value is applied to be longer than the first digital peak holder.

In the above, the operation process of the digital defect signal detecting apparatus of the optical disc player according to the present invention, which is composed of a plurality of constituent members performing the above functions, will be described in detail.

First, the RF signal generator 90 detects reflected light reflected from the optical disk by the laser beam irradiated to the optical disk by an optical pickup unit (not shown), and generates an RF signal corresponding to the detected reflected light. The generated RF signal is provided to the A / D converter 100. At this time, the RF signal will be generated as an analog signal.

The RF signal generated by the RF signal generator 90 is sampled at a predetermined sampling frequency preset by the A / D converter 100, thereby being converted into digital data corresponding to the signal level value of the RF signal, and the converted signal. Digital data is sequentially stored in the buffer 200.

Thereafter, when the digital data is stored in a predetermined predetermined bit, the stored digital data is provided to the first digital peak holder 300 and the second digital peak holder 400.

For example, if the data bit stored in the buffer 200 is set to 8 bits, when the digital data stored in the buffer 200 from the A / D converter 100 becomes 8 bits, the digital data in 8-bit units Is provided to the first comparator 310 of the digital peak holder 300 and the second comparator 420 of the digital bottom holder 400. Hereinafter, in order to help the understanding of the present invention, digital data will be described in units of 8 bits, and the first peak holder 300 and the second peak holder 400 perform the same functions, and thus only the differences will be described. Let's do it.

First, 8-bit digital data initially provided from the buffer 200 to the first comparator 310 is provided to the system controller 330 and the subtractor 500. In this case, the subtraction unit 500 is also provided with the subtraction unit 500 8-bit digital data provided from the second comparison unit 410, which will be described later.

The system controller 330 stores the 8-bit data provided from the first comparator 310 in the storage 300, and controls the first counter 320 to accumulate from 1.

Accordingly, the 8-bit data provided by the first comparator 310 is stored in the storage 340, while the first counter 320 starts accumulating addition under the control of the system controller 330. The cumulative value added by the one counter 320 will be one.

Thereafter, the value provided to the first comparator 310 may be digital data having a data value greater than previously provided digital data or digital data having a data value smaller than previously provided digital data, so that each case will be described. Shall be.

First, when 8-bit digital data is applied from the buffer 200 to the first comparator 310, the first comparator 310 may be configured to obtain the previous digital data and the buffer 200 from the system controller 330. The data values of the provided digital data are compared, and data having the larger data value among the two data is provided to the system controller 330 and the subtractor 500. At this time, the previous data value will be a value having a maximum value within a preset number of storage.

Meanwhile, in comparing the two data values, the first comparator 310 may compare the digital values of the entire 8-bit data, but may also compare the uppermost values with respect to the position values corresponding to each other.

For example, if the digital data provided from the buffer 200 is 10001001 and the previous data provided from the system control unit 330 is 01101110, the first comparator 310 may match the first value 1 of the data provided from the buffer 200. The first value 0 of the data provided by the system controller 330 is compared. At this time, since the digit value of the data provided from the buffer 200 is large, the first comparator 310 provides the system controller 330 and the subtractor 500 with the data 10001001 provided from the buffer 200.

On the other hand, the system control unit 330 receives the data from the first comparator 310 determines whether the same as the previous data stored in the storage unit 340. In this case, since the data provided by the first comparator 310 and the data stored in the storage 340 do not match, the system controller 330 stores the data applied by the first comparator 310 in the storage 340. ) And control the first counter 320 to reset to zero.

Accordingly, the first counter 320 resets the accumulated value up to zero under the control of the system controller 330.

On the other hand, if the digital data provided from the buffer 200 is 00101001 and the previous data provided from the system controller 330 is 01101110, the first comparator 310 may determine the first value 0 of the data 00101001 provided from the buffer 200 and the system. The first value 0 of the data 01101110 provided by the controller 330 is compared. At this time, since the digits of the two data are the same, the data values of the next digit are compared. That is, the second value 0 of the data 00101001 provided from the buffer 200 is compared with the second value 1 of the data 01101110 provided by the system controller 330. At this time, since the position value of the data provided by the system control unit 330 is large, the first comparator 310 provides the data control unit 330 and the subtraction unit 500 with the data 01101110 provided by the system control unit 330.

Meanwhile, the system controller 330 which receives the data 01101110 from the first comparator 310 determines whether it is the same as the previous data 01101110 stored in the storage 340. At this time, since the data provided by the first comparator 310 and the data stored in the storage unit 340 match, the system controller 330 maintains 01101110 stored in the storage unit 340 as it is, and accumulates as much as one. The first counter 310 is controlled to add.

Therefore, the first counter 310 counts by adding 1 by the accumulated value up to that time by the control of the system controller 330.

On the other hand, as described above, when the values provided by the first comparator 310 and the system control unit 330 are the same, and cumulatively added by the first counter 320, the system control unit 330 may perform the first counter ( In operation 320, it is determined whether the cumulative addition value has reached a predetermined number of times. In this case, the number of times preset in the second digital peak holder 400 may be set greater than the number of times preset in the first digital peak holder 300.

For example, if the number of times preset in the first digital peak holder 300 is five and the number of times preset in the second digital peak holder 400 is ten, the system controller 330 may control the first counter 320 and the first number. The cumulative added value is checked at the two counters, and the control for the first digital peak holder and the second digital peak holder is changed in correspondence with the cumulative added value.

That is, if the cumulative value added by the first counter 320 and the second counter 420 does not reach 5, the above-described process is repeated, but accumulated by the first counter 320 and the second counter 420. When the added value reaches 5, the system controller 330 controls the first counter 320 to reset the cumulatively added value up to 0, and the predetermined value preset from the data stored in the storage 340. As much as possible, the subtracted value is stored in the storage unit 340.

However, the system controller 330 causes the second counter 420 to accumulate and add as much as 1 as described above, while the data of the storage unit 340 that stores the data output from the second comparator 340 is intact. Keep it.

During the above-described operation, if the cumulative added value reaches 10 in the second counter 420, the cumulative added value is reset to 0, and the predetermined value is preset by the data stored in the storage unit 340. Subtract it. In this case, the preset value to be subtracted from the second digital peak holder 400 may be set larger than the first preset value.

That is, if the value preset to be subtracted from the first digital peak holder 300 is 0110 and the value stored in the storage unit 340 is 01101110, 0110 is subtracted from the data 01101110 stored in the storage unit 340 and subtracted from the data. The data 01101000 is stored in the storage unit 340. At this time, the first counter 320 also resets the cumulatively added value to zero under the control of the system controller 330.

In addition, if the preset value to be subtracted from the second digital peak holder 400 is 1111, and the value stored in the storage unit 340 is 00110101, 1111 is subtracted from the data 00110101 stored in the storage unit 340, and the subtracted value. The data 00100110 is stored in the storage unit 340. At this time, the second counter 420 also resets the cumulatively added value to zero under the control of the system controller 330.

As described above, the first digital peak holder 300 and the second digital peak holder 400 repeat the above-described process, thereby subtracting the 500 by holding the peak values of the digital data provided from the buffer 200 to different values. To provide.

Subsequently, the subtraction unit 500 subtracts the second peak value data provided from the second digital peak holder 9400 from the first peak value data provided from the first digital peak holder 300 by the above-described process, and subtracts the second peak value data provided from the second digital peak holder 9400. The data is provided to the third comparator 600. In this case, the subtraction unit 500 performs a subtraction operation, but it should be noted that the data simultaneously provided by the buffer 200 are subtracted from each other.

Thereafter, the third comparator 600 compares the subtracted data provided from the subtractor 500 with the preset reference data, and generates the comparison result as a defect signal of '1' or '0', and the occurrence thereof. Provides the determined defect signal to the system controller 330.

Accordingly, the system controller 330 refers to the defect signal output from the third comparator 600 to identify that a defect occurs on the optical disc track and detects that a predetermined signal level or less is detected, and performs an operation corresponding thereto. something to do.

According to the present invention described above, when a program recorded in a track of an optical disc is executed, a defect signal for determining whether a defect occurs in the track is detected by a digitally implemented circuit, so that a more precise defect signal can be detected by a simpler circuit. In addition, there is an effect that can be easily controlled by the system control unit.

Claims (2)

In the detection signal detecting apparatus of the optical disc player for recognizing whether a defect occurs on the track when playing a program recorded on a track of the optical disc, An A / D converter for sampling an RF signal applied from the outside to a predetermined frequency and converting the RF signal into a digital signal; A buffer that sequentially stores the digital signals converted by the A / D converter and outputs the stored digital signals as data of predetermined predetermined bits; A first digital peak holder which detects a peak value of data output from the buffer and attenuates and detects a predetermined amount if there is no change in the data value for a predetermined period; A second digital peak that detects a peak value of the data output from the buffer and attenuates by a predetermined amount if there is no change in the data value for a predetermined period of time which is greater than a predetermined period of time in the first digital peak holder. holder; A subtraction unit which subtracts the peak value data detected by the second digital peak holder from the peak value data detected by the first digital peak holder; And a third comparing unit which compares the subtracted value subtracted and calculated by the subtracting unit with preset reference data and generates a defect signal corresponding to the comparison result. The method of claim 1, wherein the first and second digital peak holder, A comparison unit comparing the data provided from the buffer with previous data and outputting larger data of the two data as a result of the comparison; A storage unit which stores data output from the comparison unit; A counter for counting the number of times the same data as the previous value is stored in the storage unit; A system controller which stores the data output from the comparator in the storage unit and decreases and stores the data output from the comparator by a predetermined value from the data stored in the storage unit when the number of times calculated in the count reaches a predetermined number of times. Digital defect signal detection apparatus of an optical disc player, characterized in that comprises a.