KR20050121055A - Method for dynamically adjusting balance of tracking errors of a optical disk player in a car audio system - Google Patents

Abstract

The present invention relates to a method for dynamically adjusting a tracking balance of an optical disc player for car audio, comprising the steps of: operating a reproduction mode of the optical disc player, performing tracking control of the optical pickup in the reproduction mode; Determining the arrival of the tracking balance adjustment condition; inputting a tracking balance adjustment command when the tracking balance adjustment condition is reached; and adjusting the tracking balance according to the tracking balance adjustment command. According to the present invention, problems such as the optical pickup leaving the track or jumping to another track due to the temperature rise in the interior and the periphery, etc. during the use of the optical disk player for car audio can be solved.

Description

How to dynamically adjust the tracking balance of an optical disc player for car audio {METHOD FOR DYNAMICALLY ADJUSTING BALANCE OF TRACKING ERRORS OF A OPTICAL DISK PLAYER IN A CAR AUDIO SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc player for car audio, and more particularly, to a method of adjusting a tracking error in response to a temperature rise in or around the car audio in an optical pickup of an optical disc player for car audio.

Techniques for controlling the optical pickup of the optical disc player include focusing control and tracking control. The focusing control adjusts the objective lens when the disc vibrates in the up and down direction, thereby changing the relative distance variation between the disc and the objective lens. The tracking control is a technology for controlling the optical pickup to accurately follow the track of the disc.

In the case of tracking control, in order to calculate an accurate tracking error, the E / F balance must be adjusted so that the center value of the tracking error is always the reference value. The E / F balance is intended to adjust tracking errors caused by the effects of sensitivity deviations of the two photodetectors (E, F), optical errors such as beam splitters, and other noises. Is set manually or automatically.

FIG. 1 shows a tracking error detection circuit of a conventional optical disc player having a balance automatic adjustment function disclosed in Korean Patent Registration Publication No. 149342, and the sensor unit 21 is a main optical detector 21a for reading a signal from the optical disc. And auxiliary photodetectors 21b and 21c for reading tracking errors from the optical disc.

The operation of the conventional tracking error detection circuit shown in FIG. 1 is as follows.

When the tracking balance adjustment command (TBAC) is input from the system control unit to the digital signal processing unit (DSP) 24 of the tracking servo after the focus pull, the digital signal processing unit 24 slits jumps the pickup during the optical operation. The tracking balance error is calculated using the signal input from the tracking error amplifying unit 28. When the tracking balance error is calculated, the digital signal processing unit 24 outputs a pulse signal corresponding thereto to the low pass filter unit 25. The low pass filter 25 removes the high frequency component of the pulse signal input from the digital signal processing unit 24 and converts it into a direct current signal, and outputs it to the balance adjustment signal generator 26.

When a DC signal is input from the low pass filter unit 25, the balance adjustment signal generator 26 generates a signal obtained by adding the DC signal to a reference voltage and a signal obtained by subtracting the DC signal from a reference voltage. Output to the variable gain amplifier 27. The first and second current-voltage converters 22 and 23 convert the fine current signals inputted from the auxiliary photodetectors 21b and 21c of the sensor unit 21 into voltage signals, respectively, and the variable gain amplifier 27. Will output

If there is a tracking balance error, a tracking error occurs even if the pickup tracks the track correctly during optics, so that the output signals of the first and second current-voltage converters 22 and 23 have different values.

At this time, the gains of the variable gain amplifiers 271 and 272 are adjusted according to the signals input from the balance adjustment signal generator 26 so that the output signals of the first and second variable gain amplifiers 271 and 272 become equal. . That is, when the output voltages of the first and / or second variable gain amplifiers 271 and 272 are higher than the reference voltage, the gain is decreased, and the output voltages of the first and / or second variable gain amplifiers 271 and 272 are lower than the reference voltage. In this case, the tracking balance is adjusted by increasing the gain.

In this state in which the tracking balance is adjusted, when a tracking error occurs, a voltage difference occurs between the outputs of the first and second current-voltage converters 22 and 23, and the first and second current-voltage converters ( The output signals of 22 and 23 are applied to the tracking error amplifier 28 via the variable gain converter 27. The tracking error amplifier 28 generates and outputs a tracking error signal TE by synthesizing and amplifying signals input from the first and second variable gain amplifiers 271 and 272.

In the tracking error detection circuit of FIG. 1 described above, the automatic adjustment of the balance is applied once at the time of mass production of the optical disk player, so that automatic mass production is possible.

On the other hand, since car audio is installed in a narrow space inside a vehicle, the use temperature condition is higher than that of other optical disk players. Therefore, a tracking balance error occurs subsequently due to internal heat generation or an increase in peripheral temperature during reproduction of the optical disc. Accordingly, only the tracking balance set at the time of shipment of the car audio optical disc player could not solve the problem of the optical pickup leaving the track or jumping to another track while the car audio is in use.

SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a method for eliminating a tracking balance error caused by a temperature rise in the interior and the periphery, etc. during use of an optical disc player for car audio.

According to the present invention, there is provided a method for dynamically adjusting a tracking balance of an optical pickup provided in an optical disc player for car audio, the method comprising operating a playback mode of the optical disc player, and tracking the optical pickup in the playback mode. Performing control, determining the arrival of the tracking balance adjustment condition, inputting a tracking balance adjustment command when the tracking balance adjustment condition is reached, and adjusting the tracking balance according to the tracking balance adjustment command. It includes.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals refer to like or similar components throughout the drawings.

FIG. 2 illustrates a configuration of a circuit for adjusting the tracking error balance according to a preferred embodiment of the present invention, and description of the same configuration as the circuit illustrated in FIG. 1 will be omitted.

As shown in FIG. 2, the balance adjustment circuit of the tracking error according to the preferred embodiment of the present invention further includes a balance controller 300 that determines an adjustment period, and the balance controller 300 includes a temperature sensor 350, From the timer 360, the car audio micom 370, or the like, the adjustment cycle determination unit 310 determines whether the adjustment cycle or the condition is reached, and the tracking servo according to the determination result of the condition arrival from the adjustment cycle determination unit 310. An adjustment command unit 320 for inputting a tracking balance adjustment command TBAC to the DSP 24 is included. The balance controller 300 may be implemented as some functions of the car audio microcomputer 370.

FIG. 3 shows a flowchart of a method for periodically adjusting a tracking balance during reproduction of an optical disc according to a preferred embodiment of the present invention, and the balance adjustment method of FIG. 3 will be described with reference to FIG.

First, when a reproduction mode for reproducing data recorded on the disc is started in step S100, the sensor unit 21 reads a signal from the disc, and tracking control is performed according to the start of the reproduction mode (S110). .

Referring to step S110 in more detail, first, the current corresponding to the amount of light detected by the auxiliary photodetectors 21b and 21c of the sensor unit 21 is first and second current-voltage conversion circuits 22 and 23. Is provided. The first and second current-voltage conversion circuits 22 and 23 convert the input current value into a voltage value and output the voltage value. The first and second current-voltage conversion circuits 22 and 23 convert the current value into voltage values output from the first and second current-voltage conversion circuits 22 and 23. The tracking error is calculated accordingly. Subsequently, tracking servo control is performed according to the calculated tracking error.

If the adjustment period determination unit 310 of the balance controller 300 determines that the tracking balance adjustment period and / or the condition have been reached during the reproduction of the optical disc (S120), the adjustment command unit 320 of the balance controller 300 causes the adjustment to be performed. The tracking balance adjustment command TBAC is applied to the DSP 24 to perform balance adjustment (S130). If the tracking balance adjustment period has not been reached, the playback mode of step S100 is continued.

The arrival of the tracking balance adjustment period and / or the condition is based on the information provided from the temperature sensor 350, the timer 360, the car audio microcomputer 370, or the like, for example, when the optical disc such as a CD is repeatedly played back. When the completion of one repetition or the completion of a certain number of repetitive playbacks, the completion of a predetermined number of song playbacks, the completion and return of the playback of the outermost data track of the optical disc, and / or in advance You can select when a tracking error occurs over the specified value. For example, if the sensor 350 for detecting the temperature is installed in the inside of the optical disc player or the like, it may be set to have reached the tracking balance adjustment period when the temperature rises above a certain temperature.

In the tracking balance adjustment step (S120), a tracking balance adjustment command (TBAC) is input to the digital signal processing unit (DSP) 24 of the tracking servo, and the digital signal processing unit 24 slit jumps the optical pickup according to the command. The tracking balance error is calculated using the signal input from the tracking error amplifying unit 28.

The digital signal processor 24 provides the low pass filter 25 with a pulse signal corresponding to the calculated tracking balance error. As described above, the low pass filter 25 outputs the direct current component of the pulse signal input from the digital signal processor 24 to the balance adjustment signal generator 26.

The balance adjustment signal generator 26 generates a signal obtained by adding a DC signal output from the balance adjustment signal generator 26 to a reference voltage and a signal obtained by subtracting the DC signal from a reference voltage, and converting the signal into a variable gain amplifier. Enter in (27). The first and second current-voltage converters 22 and 23 convert the fine current signals inputted from the auxiliary photodetectors 21b and 21c of the sensor unit 21 into voltage signals, respectively, and the variable gain amplifier 27. The gains of the variable gain amplifiers 271 and 272 are adjusted to be equal by the signals input from the balance adjustment signal generator 26. That is, when the output voltages of the first and / or second variable gain amplifiers 271 and 272 are higher than the reference voltage, the gain is decreased, and the output voltages of the first and / or second variable gain amplifiers 271 and 272 are lower than the reference voltage. In this case, the tracking balance is adjusted by increasing the gain.

As described above, according to the present invention, by dynamically eliminating the tracking balance error caused by the temperature rise in the interior and the periphery, etc., during the use of the car audio optical disc player, the optical signal is repeatedly reproduced by the car audio optical disc player. It is possible to solve the problem of the pickup leaving the track or jumping to another track.

1 is a block diagram of a circuit for adjusting the balance of tracking errors in accordance with the prior art.

2 is a block diagram of a circuit for adjusting a balance of tracking error in accordance with a preferred embodiment of the present invention.

3 is a flowchart of a method for periodically adjusting a tracking balance during playback of an optical disc according to a preferred embodiment of the present invention.

Claims (2)

A method of dynamically adjusting the tracking balance of an optical pickup provided in a car audio optical disc player, Operating a playback mode of the optical disc player; Performing tracking control of the optical pickup in the reproduction mode; Determining the arrival of the tracking balance adjustment condition; When the tracking balance adjustment condition is reached, inputting a tracking balance adjustment command; Adjusting a tracking balance according to the tracking balance adjustment command Optical pickup tracking balance adjustment method of an optical disc player for car audio comprising a. The method of claim 1, And the tracking balance adjustment condition includes a case in which a tracking error of a predetermined value or more occurs.