KR100203634B1 - Apparatus for compensating radio frequency signals in an optical disk player - Google Patents

Abstract

The present invention relates to an apparatus for compensating high frequency signals of an optical disc player, comprising: detecting a level of an RF signal output from the RF signal amplifier 15, and detecting the level of the RF signal outputted from the RF signal amplifier 15 and comparing the preset level with a preset reference level; The comparator 20, the microcomputer 30 for generating a control signal according to the level detection and comparison signal provided from the comparator 20, and from the RF amplifier 15 in accordance with the control signal of the microcomputer 30 It is configured to include an error compensation unit 40 for compensating for the error of the RF signal to be output, there is an advantage that can be properly compensated for the error signal generated in the high frequency component due to the poor manufacturing of the disk.

Description

High Frequency Signal Compensator for Optical Disc Player

1 is a schematic circuit diagram of an optical pickup and detection section and a high frequency signal amplification section in a conventional optical disc player.

2A-2C show RF and EFM signals in an optical disc player.

3 is a circuit diagram of an optical pickup and detection unit and a high frequency signal amplifying unit in an optical disc player employing a high frequency signal compensation device according to the present invention.

* Explanation of symbols for main parts of the drawings

5 optical pickup unit 10 optical detection unit

15: RF signal amplification unit 20: level detection and comparison unit

30: microcomputer 40: error compensator

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc player, and more particularly, to an apparatus for compensating high frequency signals of an optical disc player for compensating for a specific frequency band of a radio frequency (RF) signal outputted at the time of reproduction in an optical disc player.

Conventional optical disc playback devices, i.e., optical disc players, include a compact disk player (CDP), a laser disk player (LDP) and a compact disk graphic player (CDGP). In general, a compact disc player is a device that can only play audio, and a laser disc player and a compact disc graphics player are devices that can play both video and audio at the same time. Video compact disc players capable of playing video and audio have also been developed and used. Recently, digital video disk (DVD) players using MPEG-2 moving picture compression technology have been developed. Handwriting bar with moving picture in 12cm optical disc Bit (giga byte: GB) can be played by recording the data in the capacitor and also a trend that continued to develop to the performance improvement.

On the other hand, such an optical disc reproducing apparatus reproduces the image and / or audio recorded on the optical disc and outputs it through the screen and / or the speaker, and has a higher signal-to-noise ratio than the conventional image and / or audio reproducing apparatus. There are many advantages such as signal reproduction with image quality and / or sound quality, no noise caused by irregular reproduction and modulation, very little distortion, no ghost and random access. There is a trend that is widely spread.

On the other hand, in such optical disks, digital video and audio data representing video and / or audio are recorded in predetermined grooves called pits on the optical disk.

Such a pit is generally 0.4 to 0.5 [mu] m in width for a CD or VCD, and there are nine steps of a pit to a pit interval (the length of the pit) from 3T to 11T, where T represents the length of one clock pulse. In the case of a CD or VCD, the clock pulse frequency is 4.3218 MHz, so in the case of a disc whose linear velocity is recorded at 1.25 m / s, T is about 0.2892 μm (T = 1.25 / 4.3218) and the pit length is at least 0.8677 μm. (3T) and a maximum of 3.1815 μm (11T). On the other hand, the interval between the feet is 1.6 μm, and the height of the pit is about 0.1 μm.

As a result, a signal read out on the disc during optical disc reproduction consists of components of 3T to 11T.

1 is a schematic circuit diagram of an optical pickup and an optical detector and a high frequency signal amplifier in a conventional optical disc player.

The optical signal picked up from the optical pickup unit 5 is provided to the optical detector 10, and the optical detector 10 detects the amount of light of the picked optical signal provided from the optical pickup unit 5 and converts it into an electrical signal. It outputs to a radio frequency (RF) signal amplifier 15. The high frequency signal amplifier 15 amplifies the weak electrical signal provided from the light detector 10 by a predetermined level and outputs the RF signal as an analogized digital signal to a digital signal processor (not shown). Then, the digital signal processor restores the RF signal provided from the high frequency signal amplifier 15 to an eight-to-fourteen modulation (EMF) signal.

On the other hand, the RF signal output from the RF signal amplifier 15 is distributed in the frequency band of 196 KHz to 720 KHz, and is composed of 3T to 11T components as described above.

That is, as shown in FIG. 2A, the signals are symmetrical with respect to the reference level.

By the way, the signal recorded on the optical disk may deteriorate the RF signal due to defects or external impact in the manufacturing process of the disk, in which case an error occurs in the EFM signal.

That is, as shown in FIGS. 2B and 2C, when the RF signal is symmetric with respect to the reference level, the EFM signal is normally restored but degraded due to manufacturing defects, that is, the RF signal is not symmetric with respect to the reference level. EFM signal is not restored normally when is output. In other words, as shown in FIG. 2C, the RF signal hits the lower end of the reference level, causing an error in the EFM signal.

However, such an error due to deterioration on the disk mainly occurs in high frequency components, that is, 3T to 4T components, of signals recorded on the disk.

Accordingly, the present invention provides an apparatus for compensating high frequency signals of an optical disc player for compensating for a deteriorated RF signal due to such a bad production of a disc so that a normal EFM signal can be restored to facilitate playback. There is a purpose.

According to a preferred embodiment of the present invention for achieving this object, an optical pickup unit for picking up a signal recorded on an optical disk, an optical detector for converting the optical signal picked up by the optical pickup unit into an electrical signal and outputting the electrical signal; The RF generated by a defect in the production of the disc when the disc is reproduced in an optical disc player including a high frequency signal amplifier for amplifying an output signal of the optical detector by a predetermined level and outputting a radio frequency (RF) signal. A high frequency signal compensating apparatus of an optical disc player for compensating for an error of a signal, comprising: detecting a level of an RF signal output from the RF signal amplifying unit and comparing the level with a preset reference level and outputting the comparison signal; Generating a control signal according to a comparison unit and a comparison signal provided from the level detection and comparison unit; In response to the control signal Com, and the microcomputer includes an error compensation unit for compensating the error of the RF signal outputted from the RF amplifying section.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic circuit diagram of an optical disk player employing a high frequency signal compensating apparatus for an optical disk player according to a preferred embodiment of the present invention.

As shown in FIG. 3, the present invention includes a level detection and comparison unit 20, a microcomputer 30, and an error compensator 40.

Meanwhile, in FIG. 3, the same parts having the same functions as the components shown in FIG. 1 have the same reference numerals, and description thereof will be omitted.

The level detecting and comparing unit 20 detects the level of the RF signal provided from the RF signal amplifying unit 15 and compares the detected level with the reference level, so that the comparison signal, that is, the degree to which the RF signal deviates from the reference level. The corresponding comparison signal is output to the microcomputer 30.

Then, the microcomputer 30 provides the control signal to the error compensator 40 according to the comparison signal provided from the level detection and comparator 20.

On the other hand, the error compensator 40 includes a capacitor C in which resistors Rx, Ry, and Rz connected in series with each of the switches SW1, SW2, and SW3 are connected in parallel and connected in series.

Accordingly, the microcomputer 30 receives a switching control signal for switching the switches SW1, SW2, and SW3 of the error compensator 40 according to the comparison signal provided from the level detection and comparator 20. ), And the switches SW1, SW2, and SW3 of the error compensator 40 are turned on / off according to the control signal.

According to the on / off of the switches SW1, SW2, and SW3, the abnormal RF signal is a normal RF in which a high frequency band is amplified by the respective resistors Rx, Ry, and Rz and the capacitor C and is symmetric to the reference level. Will output a signal.

In addition, the parallel connection of three resistors Rx, Ry, and Rz connected in series with the three switches SW1, SW2, and SW3 turns on / off the switches SW1, SW2, and SW3 according to the degree of error compensation. This is to properly compensate the RF signal by the resistors having different values.

As a result, the error compensator 40 is composed of the resistors Rx, Ry, and Rz and the capacitor C, and serves as a high pass filter that emphasizes high frequency components while varying the frequency band. That is, the band adjustment is possible by the combination of the resistors Rx, Ry, Rz and the capacitor C according to the on / off of the switches SW1, SW2, SW3.

In addition, the level detecting and comparing unit 20 generates a comparison signal, that is, an error signal, to the microcomputer 30 when the specific frequency band of the RF signal cannot maintain the 70% level of the 11T component. 30 may generate a control signal to the error compensator 40 to control the switches SW1, SW2, and SW3 on / off so that the RF signal is symmetrically positioned at the reference level.

On the other hand, the values of the resistors (Rx, Ry, Rz) and the capacitor (C) can be set by the manufacturer varies according to the characteristics of the system.

Therefore, the present invention has the advantage of appropriately compensating and reproducing an error signal generated from a high frequency component due to a disc manufacturing failure or the like.

While the invention has been shown and described with reference to certain preferred embodiments, those skilled in the art will recognize that various modifications and changes can occur without departing from the spirit and scope of the invention as set forth in the following claims.

Claims (4)

An optical pickup section 5 for picking up signals recorded on the optical disc, an orphan detector 10 for converting and outputting an optical signal picked up by the optical pickup section 5 into an electrical signal, and the optical detector section 10 When a playback is performed in an optical disc player including a high frequency signal amplifying unit 15 that amplifies an output signal of a power by a predetermined level and outputs a radio frequency (RF) signal, In the high frequency signal compensator of an optical disc player for compensating for an error of the RF signal, a level of the RF signal output from the FR signal amplifier 15 is detected and compared with a preset reference level to compare the error signal thereof. A level detection and comparator 20 for outputting the; A microcomputer 30 generating a control signal according to the comparison signal provided from the level detection and comparing unit 20; And an error compensator (40) for compensating for errors in the RF signal output from the RF amplifier (15) in accordance with the control signal of the microcomputer (30). The resistor (Rx, Ry, Rz) of claim 1, wherein the error compensator (40) is connected in series with three switches (SW1, SW2, SW3) that are turned on / off according to a control signal of the microcomputer (30). ) Is a parallel connection, and a high frequency signal compensation device for an optical disc player, characterized in that it comprises a condenser (C) connected in series at the rear end thereof. 3. The apparatus of claim 2, wherein the error compensator is a high pass filter. 4. The apparatus of claim 3, wherein the high pass filter (40) is capable of adjusting the band according to on / off of the switches (SW1, SW2, SW3).