KR19990019820A - Data Loss Prevention Circuit for Optical Disk Damage - Google Patents

Abstract

The disclosed data loss prevention circuit relates to a circuit for preventing the loss of information of an optical disk recorded immediately after a portion where physical damage such as large and small pinholes are formed.

The data loss prevention circuit for damage to an optical disk according to the present invention is an RF signal waveform shaping circuit of an optical disk reproducing apparatus that detects information recorded on an optical disk using an optical pickup, and then reproduces and amplifies the RF signal into a pulse waveform. The RF amplification unit amplifies and outputs the RF signal output from the optical pickup, and increases the signal level of the RF signal loss part corresponding to the optical disk damage part of the output signal of the RF amplification part together with the output signal of the normal RF amplification part. RF signal correction unit to output, a capacitor to remove the DC component of the output signal of the RF signal correction unit, a slice that removes the noise contained in the AC component of the RF signal passing through the capacitor to convert the square wave pulse and output the waveform It is characterized by consisting of a circuit portion.

Therefore, the circuit of the present invention has the advantage that the information recorded immediately after the portion where the physical damage such as the big and small pinholes of the optical disk is formed is lost and the screen or sound can be abnormally reproduced.

Description

Data Loss Prevention Circuit for Optical Disk Damage

The present invention relates to a data loss prevention circuit due to damage of an optical disc.

More specifically, in the RF signal waveform shaping circuit of an optical disk reproducing apparatus which detects information recorded on an optical disk by using an optical pickup, reproduces and amplifies an RF signal, and converts the pulse waveform into a physical damage portion of the optical disk. By further increasing the signal level of the corresponding RF signal loss portion and providing an RF signal correction unit for outputting along with the normal RF signal, the information of the optical disc recorded immediately after the portion where physical damage such as large and small pinholes are formed is not lost. The present invention relates to a data loss prevention circuit for optical disk damage that can be prevented.

In general, an optical disc player such as a compact disc (CD), laser disc (LD), or digital video disc (DVD) uses optical pickup to inject laser light into the optical disc, detect and amplify the returned light, and shape the waveform. RF signal waveform shaping circuit is included.

1 is a block diagram showing a waveform shaping process of an RF signal reproduced from an optical disc in the optical disc reproducing apparatus.

As shown, the configuration and operation of the RF signal waveform shaping circuit for shaping the waveform of the RF signal detected by the optical pickup are as follows.

First, the optical disk 20 is rotated by the disk motor 10 as a medium for storing video and audio information.

As the optical disk 20 rotates as described above, the optical pickup 40 detects information recorded on the optical disk 20 causing a change in the amount of light incident through the objective lens 30, and reproduces the information as an RF signal.

The RF amplification and waveform processing unit 50 amplifies the RF signal detected and reproduced by the optical pickup 40 and converts it into a pulse waveform, followed by an EFM (Eight-to-fourteen modulation) demodulator and a digital phase-locked PLL. loop) to the circuit.

FIG. 2 is a block diagram showing the structure of the conventional RF amplification and waveform processing unit 50 in the block diagram of FIG. 1 showing the waveform shaping process of the RF signal reproduced from the optical disc in the optical disc reproducing apparatus.

As shown in the drawing, the conventional RF amplification and waveform processing unit 50 is output from the RF amplifier 51 and the RF amplifier 51 amplifying the output RF signal of the optical pickup 40 of FIG. Capacitor (C) that receives the amplified RF output signal as an input and removes the DC component, and zero-crossing the AC component of the RF signal that passed through the capacitor (C) to accurately adjust the duty of the RF signal It consists of the slice circuit part 53 which detects.

The operation of the conventional RF amplification and waveform processing unit 50 configured as described above is as follows.

In an RF signal waveform shaping circuit of an optical disk reproducing apparatus which detects information recorded on an optical disk by using an optical pickup, reproduces and amplifies an RF signal, and converts it into a pulse waveform, the RF amplifying unit 51 uses an optical pickup ( When amplifying and outputting the RF signal output from 40 of FIG. 1, the DC component of the amplified RF signal is removed by the capacitor C, and the AC component of the RF signal passing through the capacitor C is a slice circuit unit ( 53) the noise is removed and the waveform is shaped and applied to the EFM demodulation circuit and the digital PLL circuit as square wave pulses.

The reason why the RF signal amplified by the RF amplifier 51 passes through the capacitor C and the DC component is removed is zero-crossing for the slice circuit 53 to accurately detect the duty of the RF signal. ) To execute normally.

However, the RF signal amplified by the RF amplifying unit 51 in the operation of the conventional RF amplification and waveform processing unit 50 due to the characteristic of the capacitor flowing a rapid starting current to the change in the instantaneous applied voltage (see FIG. 5A). After passing through the capacitor C, the RF signal voltage immediately after the RF signal loss portion (section A of FIG. 5) corresponding to the physical damage portion of the optical disk is rapidly increased (see FIG. 5B).

Therefore, in this portion (section B of FIG. 5B), the zero-crossing by the slice circuit unit 53 may not be normally performed, resulting in an unstable EFM detection, which is a physical condition of an optical disk such as a large and small pinhole. It is recorded immediately after the damaged part, indicating the possibility of loss of information that should be detected normally.

In addition, the loss of information recorded immediately after the physically damaged portion of the optical disc causes a problem of abnormal reproduction such as cracking of a screen or sound to be normally reproduced.

Accordingly, an object of the present invention is to provide a data loss prevention circuit for optical disk damage which can prevent the loss of information of an optical disk recorded immediately after a portion where physical damage such as large and small pinholes are formed.

1 is a block diagram showing a waveform shaping process of an RF signal reproduced from an optical disc in an optical disc reproducing apparatus;

2 is a block diagram showing a conventional RF amplification and waveform processing unit of the block diagram of FIG.

3 is a block diagram showing an RF amplification and waveform processing unit according to the present invention in the block diagram of FIG.

4 is a circuit diagram illustrating an RF signal correction unit of FIG. 3 according to the present invention;

FIG. 5 is a waveform diagram of each part of FIG. 4.

* Explanation of symbols for main parts of the drawings

51: RF amplifier 52: RF signal correction unit

53: slice circuit portion C: capacitor

A feature of the data loss prevention circuit for optical disk damage according to the present invention for achieving the above object is to increase the signal level of the RF signal loss portion due to physical damage of the optical disk in the RF signal waveform shaping circuit of the optical disk reproducing apparatus The circuit further includes an RF signal correction unit for outputting the signal.

Hereinafter, a preferred embodiment of a data loss prevention circuit for damage to an optical disc according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram showing the configuration of the RF amplification and waveform processing unit 50 according to the present invention among the block diagrams of FIG. 1 showing the waveform shaping process of the RF signal reproduced from the optical disc in the optical disc reproducing apparatus.

As illustrated, the RF amplification and waveform processing unit 50 to which the present invention is applied includes an RF amplification unit 51 for amplifying an output RF signal of the optical pickup 40 of FIG. 1, and an RF amplification unit 51. RF signal correction unit 52 for receiving the amplified RF output signal output as an input, a capacitor (C) for removing the DC component of the corrected RF signal output from the RF signal correction unit 52, and a capacitor (C) It consists of a slice circuit 53 for accurately detecting the duty of the RF signal by zero-crossing the AC component of the RF signal passed through.

The operation of the data loss prevention circuit against optical disk damage with these components is as follows.

In an RF signal waveform shaping circuit of an optical disk reproducing apparatus which detects information recorded on an optical disk by using an optical pickup, reproduces and amplifies an RF signal, and converts it into a pulse waveform, the RF amplifying unit 51 uses an optical pickup ( When amplifying and outputting the RF signal output from 40) of FIG. 1, the RF signal correcting unit 52 increases the signal level of the RF signal loss part corresponding to the optical disk damaged part of the output signal of the RF amplifying unit 51. It outputs along with the output signal of the normal RF amplifier 51.

The DC component of the output signal of the RF signal corrector 52 is removed by the condenser C, and the AC component of the RF signal passing through the condenser C is square wave whose noise is removed and waveform-shaped by the slice circuit 53. The pulse is applied to the EFM demodulation circuit and the digital PLL circuit.

4 is a circuit diagram illustrating the RF signal correction unit 52 of FIG. 3, which is a block diagram showing the configuration of the RF amplification and waveform processing unit 50 according to the present invention. 5 is a waveform diagram of each portion A-E of FIG. 4.

In FIG. 5, Vref is an RF amplifying unit (51 in FIG. 3) output signal value when there is no reflected light from the optical disk, RFavg is an average value of the RF amplifying unit, and section A represents an RF signal loss corresponding to a damaged portion of the optical disk. .

As shown in FIG. 4, the RF signal corrector 52 according to the present invention performs the following configuration and operation, which will be described in detail with reference to the waveforms of FIG. 5.

The low pass filter unit LPF receives the output signal (FIG. 5A) of the RF amplification unit 51 of FIG. 3 as an input, converts the DC signal into a DC signal (FIG. 5D), and the comparator COMP sets the RF amplification unit ( The output signal of 51 is compared with a predetermined DC reference voltage Vdc, and the result is output (FIG. 5C).

Here, the comparator C0MP is configured to output a signal having a different level from that of the undamaged portion in the output signal portion (section A of FIG. 5) corresponding to the damaged portion of the optical disc. In order to output a high potential level signal.

The switch part S / W selectively outputs the output signal of the RF amplifier part (Fig. 5A) and the output signal of the low pass filter part (Fig. 5D) according to the result of the output signal of the comparator part (Fig. 5C). In the output signal (FIG. 5C) of the comparator unit COMP (FIG. 5C), the output signal (FIG. 5D) of the low pass filter unit is selected and output in the portion corresponding to the optical disk damage (section A of FIG. 5), and RF amplification in other portions. The negative output signal (Fig. 5A) is selected and output.

The output signal (FIG. 5E) of the switch unit S / W formed as described above is the output signal of the RF signal correction unit 52, and this signal passes through the capacitor C so that it can be zero-crossed in the slice circuit unit. While the direct current component of the signal is removed (FIG. 5F), the physical shape of the optical disk in the input waveform (waveform E) of the slice circuit section in the absence of the RF signal correction unit 52 according to the present invention as shown in FIG. The portion where the RF signal voltage immediately increases (see FIG. 5B) immediately after the RF signal loss portion (section A of FIG. 5) corresponding to the damaged portion is removed.

As a result, the input waveform (FIG. 5F) of the slice circuit section in the case where the RF signal correcting section 52 according to the present invention is not affected by the characteristics of the capacitor C, so that the output of the RF amplifier section corresponds to the optical disk damaged portion. Since the waveform immediately after the signal portion (section A in FIG. 5) maintains a normal value, the EFM detection is also normally performed.

As described above, according to the data loss prevention circuit for optical disk damage according to the present invention, the RF signal waveform shaping circuit of the optical disk reproducing apparatus increases the signal level of the RF signal loss part due to the physical damage of the optical disk, and together with the normal RF signal. By providing a circuit having an output RF signal correction unit, the information recorded immediately after a physical damage such as a large or small pinhole on the optical disk is lost, and the screen or sound can be prevented from being abnormally reproduced. There is.

Claims (4)

In an RF signal waveform shaping circuit of an optical disk reproducing apparatus which detects information recorded on an optical disk using an optical pickup, reproduces and amplifies an RF signal, and converts it into a pulse waveform, amplifying the RF signal output from the optical pickup. RF signal correction unit for outputting, RF signal correction unit for increasing the signal level of the RF signal loss portion due to the optical disk damage of the output signal of the RF amplification unit and outputs along with the output signal of the normal RF amplifier unit, the output signal of the RF signal correction unit Data loss prevention circuit for optical disc damage, comprising: a condenser that removes a DC component; and a slice circuit that removes noise carried by the AC component of the RF signal passing through the condenser, converts the waveform into a square wave pulse, and outputs the square wave pulse. . According to claim 1, wherein the RF signal correction unit, a low pass filter for converting the output signal of the RF amplification unit to a DC signal, and outputs a result of comparing the output signal of the RF amplifier and a predetermined DC reference voltage and outputs the result And a switch unit for selectively outputting an output signal of the RF amplification unit and an output signal of the low pass filter unit according to a result of the output signal of the comparing unit. 3. The data loss prevention circuit of claim 2, wherein the comparator outputs a signal having a different level from that of an undamaged portion in the output signal portion of the RF amplifier corresponding to the damage of the optical disk. The method of claim 2, wherein the switch unit selects and outputs an output signal of the low pass filter unit in a portion corresponding to an optical disk damage among the output signals of the comparison unit, and selects and outputs an output signal of the RF amplifier unit in other portions. Data loss prevention circuit for optical disc damage.