KR19980023452A - Tracking Gain Control Device and Method of Optical Disc Player - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking gain control apparatus and method for an optical disc player, comprising: an optical pickup unit (10) for outputting a current signal corresponding to the amount of light reflected from the disk and picked up; and a current provided from the optical pickup unit (10). An IV converter 12 for converting a signal into a voltage signal, a tracking error detector 14 for detecting a tracking error (T.E) from a voltage signal provided from the IV converter 12, and a tracking error detector 14 A low pass filter for removing high frequency noise components from the output signal of the tracking gain adjusting unit 20 and the tracking gain adjusting unit 20 by adjusting the tracking error signal output from the tracking gain signal according to the set tracking gain. LPF 22), a comparison unit 24 for comparing the output signal of the LPF with a preset reference value and outputting the comparison signal as a logic signal, and according to the comparison signal provided from the comparison unit 24. It includes a microcomputer 26 for providing control signals to control and determine the king gain as the tracking gain adjustment section 20, and configuration.

Therefore, the present invention can automatically determine the tracking gain to an appropriate value every time the optical disc player is used, and can improve the performance of the tracking servo by controlling the amplitude level of the tracking error signal equally regardless of the state of the disc. It works.

Description

Tracking Gain Control Device and Method for Optical Disc Player

The present invention relates to a tracking servo of an optical disc player, and more particularly, to an apparatus and method for controlling a tracking gain of an optical disc player for appropriately controlling a tracking gain for smoothly performing a tracking servo in an optical disc player.

Typical optical disk players include a compact disk player (CDP: cmpact disk player), a laser disk player (LDP: laser disk player), a compact disk graphic player (CDGP: compact disk graphic player), and a video contact disk player (VCDP). : video compact disk player) is developed and used. In general, compact disk players are devices that can play audio only. Laser disk players, compact disk graphics players, and video compact disk players are devices that can play video and audio simultaneously. to be.

Recently, digital videp disks (DVDs) using MPEG-2 moving picture compression technology have been developed, which are gigabytes of gigabytes (GBs) including moving pictures in an optical disc of 12 cm, such as a current CD. Data can be recorded and reproduced, and there is a continuing trend to improve its performance.

On the other hand, such optical disc players reproduce images and / or audio recorded on the optical disc and output them through a screen and / or a speaker, and have a higher signal-to-noise ratio than conventional image and / or audio reproducing apparatus, resulting in better image quality. And / or can reproduce signals with sound quality, generate no noise due to irregular reproduction and modulation, and have very little distortion and random access without ghosts. There is a trend that is spreading.

On the other hand, in such an optical disc player, optical is used to read data recorded on the disc. In order to accurately read the data recorded on the optical disc, reproduction must be performed while accurately following a track of a pitch formed on the optical disc. .

That is, during playback, tracking control should be made to accurately follow the track of the optical disk on which the light is rotated. If such tracking control is not performed smoothly, light reading data may be lost to other tracks due to impact or disturbance during playback, and sound may be cut off or the screen may be blurred.

Among such optical disc players, a compact disc (CD) player and a video compact disc (VCD) player will be described as an example.

CD players and VCD players are equipped with a tracking servo device for accurately tracking tracks of 1.6 μm pitch formed by recording data on CDs and VCDs, and are required to be corrected by tracking servos in CD and VCD players. ± 70 μm is determined, taking into account the eccentricity that occurs when manufacturing the disc and when mounting the disc to the player.

In the case of tracking servo, this eccentricity of ± 70 μm should be suppressed to ± 0.1 μm.

On the other hand, in order to smoothly perform the tracking servo, a tracking gain must be determined. In the related art, the tracking gain is determined by adjusting a variable resistor connected in parallel with a tracking error detector during a VCD or CD manufacturing process. If the tracking gain is distorted by external or internal factors, it is difficult to compensate it accurately.

Accordingly, the present invention has been conceived in view of the related art, and an object of the present invention is to provide an apparatus and method for controlling a tracking gain of an optical disc player, which enables to automatically control a tracking gain value for smoothing a tracking servo in an optical disc player. To provide.

According to a preferred embodiment of the present invention for achieving this object, in the optical disk player tracking gain control apparatus for automatically adjusting the tracking gain for smoothing the tracking servo in the optical disk player, the light reflected from the disk A tracking error (TE) from an optical pick-up section for picking up the signal and outputting a current signal according thereto, an IV changing section for converting the current signal provided from the optical pick-up section into a voltage signal, and a voltage signal provided from the IV converting section. A tracking error detector for detecting a tracking gain value, a tracking gain value determined according to a tracking error signal provided from the tracking error detector, and controlling and outputting the tracking error signal according to the determined tracking gain value; High frequency noise signal from output signal of tracking gain control part A low pass filter (LPF) to remove and the output signal of the low pass filter unit is compared with a predetermined reference value to generate a logic signal of 'high' or 'low' accordingly. And a microcomputer for generating a control signal to the tracking gain adjusting unit according to a logic signal provided from the comparator and allowing the tracking gain adjusting unit to adjust a tracking gain value.

According to another preferred embodiment of the present invention for achieving the above object, in the optical disk player tracking gain control method for automatically adjusting the tracking gain for smoothing the tracking servo in the optical disk player, (a) Turning off all servo control and setting the tracking gain to the minimum value; (b) driving a timer to start counting and tracking error according to the set tracking gain value until the counted time reaches a predetermined time; Counting the number of times a signal value is greater than or equal to a preset reference value; (c) determining whether the number of times the tracking error signal value is greater than or equal to a preset desired number is greater than the preset reference value; and (d) the tracking error signal value; The number of times that is equal to or greater than the preset reference value is preset. Fixing the set gain value to a tracking gain value if the number is equal to or greater than the number; and (e) if the number of times the tracking error signal value is greater than or equal to the preset reference value is less than a preset desired number, the set tracking gain value is one of settable gain values. Determining a maximum value inch, and if the maximum value is the maximum value, fixing an intermediate value among the settable tracking gain values as a gain value; If it is not the maximum value, the tracking gain value is increased by one step, and the steps (b) to (e) are repeated.

1 is a view showing a tracking gain control apparatus of an optical disk player according to an embodiment of the present invention.

2 is a detailed flowchart of a tracking gain control method of an optical disc player according to a preferred embodiment of the present invention.

* Explanation of the math code in the main part of the drawing

10: optical pickup section 12: I-V conversion section

14: tracking error detection unit 20: tracking gain control unit

22: low pass filter 24: comparator

26: Micom 30: Compensator

40: switching unit 50: driving unit

OP: operational amplifier R: resistance

Q: transistor

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

1 is a schematic circuit diagram of a tracking gain control apparatus of an optical disc player according to the present invention.

As shown in FIG. 1, the tracking gain control apparatus of the optical disk player according to the present invention includes an optical pickup unit 10 and an optical pickup unit 10 that output current signals corresponding to the amount of light reflected from the disk and picked up. An IV converter 12 for converting a current signal provided by the signal into a voltage signal, a tracking error detector 14 for detecting a tracking error TE from a voltage signal provided from the IV converter 12, and a tracking error detector. A tracking gain adjusting unit 20 for adjusting the tracking gain signal output from the tracking error signal 14 and outputting the tracking gain control unit, and a low pass filter for removing high frequency noise components from the output signal of the tracking gain adjusting unit 20; LPF 22), a comparator 24 for comparing the output signal of the LPF with a preset reference value and outputting a comparison signal as a logic signal, and tracking according to the comparison signal provided from the comparator 24 In the configuration and includes a microcomputer 26, which provides a control signal for adjusting and determining as the tracking gain adjustment section 20.

In addition, the compensator 30 compensates for the tracking error from the tracking error signal provided from the tracking gain adjusting unit 20, and the switching unit 40 is switched in accordance with the switching control signal of the microcomputer 26 to compensate from the compensator 30. Substantially blocks or provides a compensation signal provided to the driving unit 50 for driving the tracking servo.

That is, in order to implement the present invention, all other servo control except focus servo must be turned off.

Therefore, in order to implement the present invention, first, the microcomputer 26 generates a control signal to the switching unit 40 to turn off the switching unit 40 so that the output signal of the compensator 30 is not provided to the driving unit 50. The control signal TG1, TG2, TG3, TG4 is controlled by the transistors Q1, Q2, Q3, and Q4 constituting the tracking gain control unit 20, so that the actual tracking servo is not made until the proper tracking gain is determined. ) To set the tracking gain value to the minimum value.

When the operation for adjusting the tracking gain is started after this process, the optical pickup elements E and F constituting the optical pickup unit 10 pick up the light reflected by the side beam for tracking control, and the amount of light Each of the current signals is output to the first operational amplifier OP1 and the second operational amplifier OP2 constituting the IV converter 12, respectively.

OP1 and OP2 convert current signals provided from E and F into voltage signals, respectively, to the respective terminals of the third operational amplifier OP3 through the tracking error detection unit 14, that is, the resistor R3 and the resistor R4. To provide.

OP3 compares and amplifies the voltage signals provided from OP1 and OP2 and outputs a tracking error signal. The tracking error signal is adjusted by a set gain value of the tracking gain adjusting unit 20 so that the compensator 30 and To LPF 22.

The tracking gain adjuster 20 includes one resistor R10 having a predetermined value connected in series with the output terminal of the tracking error detector 14, and a resistor R6, R7, R8, and R9 having a predetermined value at the collector terminal, respectively. It consists of a predetermined number of NPN or PNP type transistors connected, and its gain value is determined according to the control signal of the microcomputer 26. In addition, the transistors Q1, Q2, Q3, and Q4 and the resistors R6, R7, R8, and R9 connected thereto and their numbers can be determined according to the manufacturer's intention. When the number of transistors and resistors increases, It will be appreciated that more precise control of tracking gain can be achieved.

Meanwhile, the compensator 30 compensates and outputs a tracking error signal adjusted through the tracking error adjusting unit 20 as described above.

The LPF 22 removes the high frequency noise component of the tracking error signal provided through the tracking error controller 20 and provides the comparator 24 to the comparator 24.

The comparator 24 compares the output signal of the LPF 22 with a preset reference value and detects a value higher than the preset reference value, and the logic of the 'high' to a predetermined port of the microcomputer 26, for example, the SENCE port. Provide a signal.

In addition, the microcomputer 26 drives a built-in timer (not shown) to count the number of 'high' signals (hereinafter, referred to as 'SENCE high') signals input to the SENCE port for a predetermined time.

According to the present invention, the microcomputer 26 fixes the previously set tracking gain value to the tracking gain value when the SENCE high signal is input from the comparator 24 more than a predetermined number of times for a predetermined time. The transistors Q1, Q2, Q3, and Q4 are turned on or off by generating a control signal 'high' or 'low' to the transistors Q1, Q2, Q3, and Q4 constituting the controller 20. After setting the gain value one step higher than the previously set tracking gain value, the above-described process is repeated to detect a gain value to which the 'SENCE high' signal is input for a predetermined number of times or more for a predetermined time, and then set the gain value to that value. Fix it.

On the other hand, even if the gain value is set to the maximum value during this process, if the 'SENCE high' signal is not detected more than the preset number of times during the preset time, the microcomputer 26 generates a control signal to the tracking gain control unit 20. The tracking gain control unit 20 forcibly fixes an intermediate value among the gains that can be set by the tracking gain control unit 20. When the gain value is set to the maximum value, if the 'SENCE high' signal is not detected more than the preset number of times during the preset time, This is because the tracking error signal is out of the control range of the tracking gain.

That is, according to the present invention, the tracking gain value is fixed to a value where the number of occurrences of the tracking error signal more than the reference value occurs more than the predetermined number of times, thereby controlling the amplitude level of the tracking error signal to be almost the same regardless of the state of the disc. .

When the tracking gain value is determined through the above-described operation, the microcomputer 26 generates a control signal to the switching unit 40 to turn on the switching unit 40, and accordingly, the output signal of the compensator 30 Provided to the driver 50 is a real tracking servo is made.

2 is a flowchart of a tracking gain control method of an optical disc player according to another exemplary embodiment of the present invention.

In step S10, the microcomputer 26 generates a control signal to turn off all servos except the focus servo.

When the step S10 is completed, in step S20, the tracking gain value is set to the minimum value among the settable tracking gain values, and the process proceeds to step S30.

Then, in step S30, the microcomputer 26 starts counting after initializing the internal timer, and in step S40, the signal 'SENCE high' input from the comparator 24 is detected and counted.

In operation S50, it is determined whether the counted time of the timer reaches a predetermined time. In step S50, if the counted time of the timer does not reach the preset time, the flow returns to step S40 to perform the flow. If the counted time of the timer reaches the preset time, the flow proceeds to step S60. It is determined whether the 'SENCE high' signal is more than a predetermined number of times.

In step S60, if the 'SENCE high' signal is greater than or equal to a predetermined number of times, the process proceeds to step S90. If the 'SENCE high' signal is less than the predetermined number of times, the process proceeds to step S70.

When the process proceeds from step S60 to step S90, the gain value set in step S20 is fixed to the tracking gain value for the tracking servo and the flow ends.

On the other hand, if the process proceeds from step S60 to step S70, it is determined in step S70 whether the set tracking gain value is the maximum among the set gain values. In step S70, if the set gain value is the maximum value, the process proceeds to step S100 to fix an intermediate value among the settable gain values as the gain value for the tracking servo and terminate the flow.

In addition, in step S70, if the set gain value is not the maximum value, the process proceeds to step S80. In step S80, the tracking gain value is increased by one step, and then the flow returns to step S30 to perform the flow again in step S30. In step S90, if the 'SENCE high' signal is detected more than a predetermined number of times during the predetermined time in step S60, the tracking gain value for the tracking servo is set in step S90 as described above. Set to and end the flow.

As described above, the present invention can automatically determine the tracking gain determined in the prior art every time an optical disc player is used, and by controlling the amplitude level of the tracking error signal equally regardless of the state of the disc, There is an effect that can improve the performance of the tracking servo.

Claims (6)

A tracking gain control apparatus for an optical disk player for automatically adjusting a tracking gain for smoothing a tracking servo in an optical disk player, An optical pickup unit 10 which picks up the light reflected from the disk and outputs a current signal according thereto; An I-V converter 20 for converting a current signal provided from the optical pickup unit 10 into a voltage signal; A tracking error detector (14) for detecting a tracking error (T.E) from the voltage signal provided from the I-V converter (20); A tracking gain controller 20 which determines a tracking gain value according to the tracking error signal provided from the tracking error detector 14 and adjusts and outputs the tracking error signal according to the determined tracking gain value; A low pass filter (LPF 22) for removing the high frequency noise signal from the output signal of the tracking gain adjusting unit 20; A comparator 24 for comparing the output signal of the low pass filter unit 22 with a predetermined reference value and generating a logic signal of 'high' or 'low' accordingly; Optical including a microcomputer 26 for generating a control signal to the tracking gain adjusting unit 20 in accordance with the logic signal provided from the comparator 24 so that the tracking gain adjusting unit 20 adjusts the tracking gain value. The tracking gain control device of the disc player. The method of claim 1, The tracking gain adjustment unit 20, A resistor (R10) having a predetermined value connected in series with the output terminal of the tracking error detector (14); A tracking gain control apparatus for an optical disc player, comprising a plurality of transistors connected in parallel with each other, one base end having a predetermined value connected to each collector terminal, and each base end connected to the microcomputer (26). The method of claim 1, The tracking gain control unit (20) is a tracking gain control device of the optical disc player to determine the tracking gain value by the transistor is turned on or off to the control signal of the microcomputer (26). The method of claim 2, The tracking gain control apparatus of the optical disc player, characterized in that each transistor constituting the tracking gain adjusting unit (20) is an NPN type. The method of claim 2, The tracking gain control apparatus of the optical disc player, characterized in that each transistor constituting the tracking gain adjusting unit (20) is a PNP type. A tracking gain control method of an optical disc player for automatically adjusting a tracking gain for smoothing a tracking servo in an optical disk player, (A) turning off all servo control except focus and setting tracking gain to a minimum; (B) counting the number of times a tracking error signal value according to the set tracking gain value is greater than or equal to a preset reference value until the counted time reaches a predetermined time by driving a timer; (C) determining whether the number of times that the tracking error signal value is greater than or equal to the preset reference value is greater than or equal to a predetermined number of times; (D) fixing the set gain value to a tracking gain value if the tracking error signal value is greater than or equal to a predetermined number of times that is greater than or equal to the preset reference value; (E) If the number of times the tracking error signal value is greater than or equal to the preset reference value is less than the predetermined number of times, it is determined whether the set tracking gain value is the maximum among the settable gain values. Fixing to a gain value; (F) If the number of times that the tracking error signal value is greater than or equal to the preset reference value is less than a predetermined desired number and the set gain value is not the maximum value, increase the tracking gain value by one step and set the step (b) to (e). Repeating the tracking gain control method of the optical disc player.