KR100480629B1 - Track balance adjusting method and apparatus in optical disk player for decreasing the unbalance detecting error of tracking error signal - Google Patents

Abstract

Disclosed are a track balance adjusting method and apparatus of an optical disc reproducing apparatus for reducing an unbalance detection error of a tracking error signal. A track balance adjustment method of an optical disc reproducing apparatus for reducing an unbalance detection error of a tracking error signal according to the present invention is a track balance adjustment method of an optical disc system that detects an unbalance value of a tracking error signal and adjusts a track balance.

(a) counting a tracking error signal for a predetermined period of time and accumulating the counting value to detect an unbalanced value; And

(b) adjusting the balance of the tracking error signal according to the unbalance value.

The track balance adjusting method and apparatus of the optical disc reproducing apparatus for reducing the unbalance detection error of the tracking error signal according to the present invention have an advantage of stably adjusting the track balance by reducing the detection error of the tracking error signal.

Description

Track balance adjusting method and apparatus in optical disk player for decreasing the unbalance detecting error of tracking error signal

The present invention relates to a track balance adjusting method and apparatus of an optical disc reproducing apparatus, and more particularly, to a track balance adjusting method and apparatus of an optical disc reproducing apparatus for reducing an unbalance detection error of a tracking error signal.

An optical disc reproducing apparatus is a device for reproducing data recorded in an optical disc such as a compact disc (CD) and a digital video disc (DVD). The reproducing principle of the optical disc reproducing apparatus is that the pickup element irradiates a laser beam along a track on the optical disc, detects the presence or absence of pits by the change in intensity of reflected light, and reproduces the stored digital data according to the detection result.

One example of such an optical disc reproducing apparatus is shown in FIG.

1 is a block diagram schematically showing a general optical disc player.

As shown in FIG. 1, the optical disc reproducing apparatus includes a spindle motor 12, a pick-up unit 13, a driver 14, an RF amplifier unit 15, a servo unit 16, and a DSP ( and a digital signal processor (D / A converter) unit 17, an electric shut prove (ESP) unit 18, and a memory 19.

The spindle motor 12 rotates the disk 11, and the pickup 13 irradiates a laser beam along the track of the disk 11 and detects reflected light.

Although not shown in FIG. 1, the pickup part 13 includes a sled motor, a focus part and a tracking part. The sled motor moves the disk 11 diagonally, and the focus unit focuses the laser beam on the track of the disk 11. The tracking unit tracks the track of the disc 11.

The driver 14 controls the operations of the spindle motor 12 and the pickup unit 13.

The RF amplifier unit 15 converts the reflected light into an electrical signal and outputs a data signal and various error signals. The servo unit 16 converts the data signal and the error signals into digital signals, and outputs various control signals in response to the error signals. The servo unit 16 performs operations such as spindle control, sled control, focus control, tracking control, etc. by the control signals.

The servo unit 16 also outputs the digital data signal to the DSP and DAC unit 17.

The DSP and DAC unit 17 restores the audio signal from the digital data signal, converts it into an analog signal, and outputs the audio signal.

The ESP unit 18 compresses and stores the digital data signal in the memory 19, decompresses the stored digital data signal, and outputs the decompressed digital data signal to the DSP and DAC unit 17 in units of a predetermined data amount. To prepare for no data input state due to impact.

FIG. 2 is a circuit diagram illustrating an implementation example of a tracking error signal generator that is a part of the RF amplifier illustrated in FIG. 1.

As shown in FIG. 2, the tracking error signal generator 20 includes photodiodes 21 and 22, I / V (current / voltage) converters 23 and 24, a differential amplifier 25 and resistors ( Rf, Rv).

The photodiodes 21 and 22 generate currents I _F and I _E in response to the F beam and the E beam of the reflected light detected by the pickup unit 13, respectively. The I / V converters 23 and 24 convert and output the currents I _F and I _E into voltages V _F and V _E , respectively.

The I / V converters 23 and 24 may be configured as amplifiers, and the amplifiers are gain adjusted by the resistance values of the resistors Rf and Rv, respectively.

The differential amplifier 25 outputs a tracking error signal TE by amplifying the voltage difference between the voltages V _F and V _E.

Here, the F-beam and the E-beam are sub-beams arranged before and after the pit column progression direction of the disk with respect to the main beam (M beam) used for the restoration of the data signal, and the tracking error signal TE It is used to detect it.

3 is a diagram illustrating a waveform of a general tracking error signal.

In general, the track balance is adjusted before the optical disc reproducing apparatus performs a reproducing operation. To this end, the optical disc player adjusts the track balance by calculating a track unbalance value from the tracking error signal.

The tracking error signal is detected by the tracking error signal generator 20 shown in FIG. In order to detect a tracking error signal, the spindle motor 12 and the focus section are turned on, and the sled motor and tracking section are turned off.

Then, the disk 11 is repeatedly moved left and right by the eccentricity of the disk 11, so that a tracking error signal TE as shown in FIG. 3 is generated.

The tracking error signal TE is divided into a positive tracking error signal and a negative tracking error signal based on the reference voltage VREF. The tracking error signal has a peak voltage (+ VTE _PK ) of a positive tracking error signal and a peak voltage (-VTE) of a negative tracking error signal based on the reference voltage VREF as shown in FIG. 3A. _PK ) is preferably mutually symmetrical. As shown in FIG. 3B, when the peak voltages + VTE _PK and -VTE _PK are asymmetric with respect to the reference voltage VREF, any one of the tracking error signal TE The margin on the side is reduced. In FIG. 3B, the margin of the negative tracking error signal is smaller than the margin of the positive tracking error signal.

When the margin of the tracking error signal TE is reduced, the track control range is reduced, so that track control outside the track control range is impossible.

In general, the tracking error signal TE is a tracking error, as shown in FIG. 3B due to the difference in the amount of light between the F beam and the E beam and the gain difference between the I / V converters 23 and 24. The center voltage VTEC and the reference voltage VREF of the signal TE have an offset.

Therefore, in order for the tracking error signal TE to be symmetrical with respect to the reference voltage VREF, it is necessary to match the center voltage VTEC of the tracking error signal TE with the reference voltage VREF.

A conventional method of adjusting the track balance such that the tracking error signal TE is symmetrical with respect to the reference voltage VREF will be described with reference to FIGS. 4 and 5 as follows.

4 is a flowchart 100 illustrating an example of a track balance adjustment process of an optical disc system according to the prior art, and FIG. 5 is a waveform of a tracking error signal for explaining a track balance adjustment process of an optical disc system according to the prior art. It is a figure which shows.

The flowchart 100 is performed in the following process.

As shown in FIG. 4, when the tracking error signal TE is received 101, the servo unit determines whether the tracking error signal TE satisfies a setting condition (102). Here, only the tracking error signal TE whose frequency range and amplitude T _Length satisfy the predetermined range is detected by the setting condition. Therefore, the tracking error signal TE that does not satisfy the setting condition is filtered.

Thereafter, it is determined whether the tracking error signal TE is the rising edge of the intersection with the reference voltage VREF (103). The rising edge of the intersection with the reference voltage VREF is denoted by A, B, C, D in FIG.

When the tracking error signal TE is the rising edge of the intersection with the reference voltage VREF, the peak value + VTE _PK of the positive tracking error signal is detected 104. The peak value detection is first value larger by the comparison of the received tracking error signal (TE) and a tracking error signal (TE) that is received in the next (+ VTE _PK) is updated to the peak value (+ VTE _PK). The tracking error signal TE, which is continuously received, is continuously compared so that the largest value is detected as the peak value (+ VTE _PK ).

Next, the peak value (-VTE _PK ) of the negative tracking error signal is detected (105). The peak value (-VTE _PK ) is also detected in the same manner as the peak value (+ VTE _PK ).

Thereafter, the average value (AVTE1 = (+ VTE _PK -VTE _PK ) / 2) of the detected peak values (+ VTE _PK, -VTE _PK ) is calculated (106).

It is determined whether the set peak value measurement number (N is a natural number) of the tracking error signal is satisfied (107), and when the set measurement number N is not reached, the process returns to the step 101 and the processes are repeatedly performed. .

When the set number of measurements N is reached, the unbalanced value UBAL is calculated as the average of the average values AVTE1 to AVTEN calculated during the N measurements (108).

Thereafter, it is determined whether the unbalance value UBAL satisfies the tolerance range (109). When the unbalance value UBAL does not satisfy the tolerance range, the servo unit outputs a balance control signal BAL_CTL to adjust the gain of the tracking error signal generator 20, and waits 110 for a preset time TBwt. After that, the process returns to step 101 to repeat the processes 101 to 109. Here, the set time TBwt is a stabilization time after the gain of the tracking error signal generator 20 is adjusted as shown in FIG. 5.

When the unbalance value UBAL satisfies the allowable error range, the balance control operation is stopped (111).

Since the track balance adjustment method of the optical disk system according to the above technique detects the unbalance value UBAL only by the peak values (+ VTE _PK , -VTE _PK ) of the tracking error signal TE, the peak value is caused by noise. (+ VTE _PK , -VTE _PK ) has a problem that can cause an error.

In addition, the conventional method is inconvenient to appropriately set the range of the frequency of the tracking error signal TE, the range of the amplitude T _Length , the number of detections of the peak values (+ VTE _PK , -VTE _PK ), and the like. There is a ham.

An object of the present invention is to provide a method and apparatus for adjusting the track balance of an optical disc system which reduces the unbalance detection error of the tracking error signal by accurately detecting the unbalance value of the tracking error signal without being affected by noise. .

According to one or more embodiments of the present invention, there is provided a track balance adjusting method of an optical disk system that reduces an unbalance detection error of a tracking error signal, and detects an unbalance value of the tracking error signal to adjust a track balance. In the track balance adjustment method of the disk system,

(a) counting a tracking error signal for a predetermined period of time and accumulating the counting value to detect an unbalanced value; And

and (b) adjusting the balance of the tracking error signal according to the unbalance value.

In addition, the track balance adjusting device of the optical disk system for reducing the unbalance detection error of the tracking error signal according to an embodiment of the present invention for achieving the above technical problem, by detecting the unbalance value of the tracking error signal to adjust the track balance An apparatus for adjusting a track balance in an optical disk system, comprising a comparator, a counter, and a control unit.

The comparator compares the voltages of the one or more previous tracking error signals with the voltages of the one or more current tracking error signals and outputs a predetermined counting control signal when a voltage change is detected.

The counter counts in response to a predetermined counting control signal, accumulates the counting value, and outputs the unbalanced value.

The controller outputs a balance control signal when the unbalanced value is out of the tolerance range.

DETAILED DESCRIPTION In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

FIG. 6 is a diagram illustrating a waveform of a tracking error signal for explaining an unbalance detection process of a tracking error signal according to the present invention, and FIG. 7 illustrates an example of reducing unbalance detection error of a tracking error signal according to a first embodiment of the present invention. A flowchart 1100 illustrating a track balance adjustment process of the optical disc system.

The flowchart 1100 is performed by the following processes.

As shown in FIG. 7, first, the apparatus 1 waits for the set time WT shown in FIG. 6 before detecting an unbalanced value of the tracking error signal TE (1101). The set time WT is an initial stabilization time of the spindle motor, and a stabilization time after balance adjustment.

Here, the settling time is necessary to increase the accuracy of unbalance value detection of the tracking error signal.

Thereafter, when the tracking error signal TE is received 1102, the currently received tracking error signal TE (n) changes in voltage compared to the previously received tracking error signal TE (n-1). In operation 1103, it is determined whether or not the voltage change between the points is sequentially determined according to the slope of the tracking error signal TE, as indicated by P1 to P5.

If it is determined in step 1103 that there is no voltage change, the process returns to step 1102.

Here, the tracking error signal TE is a digital signal having a predetermined bit converted by the A / D converter. In the present embodiment, a case where the tracking error signal TE is a 16-bit digital signal will be described.

In step 1103, it is determined that the voltage change has occurred when there is a change in the data value of some bits in the digital signal of the current and previous tracking error signals TE.

The digital data is divided into a positive tracking error signal (+ TE) and a negative tracking error signal (-TE) based on the reference voltage VREF.

In more detail, when the tracking error signal TE is continuously A / D converted, the tracking error signal TE becomes '0000 to FFFF'. Here, when the most significant bit is inverted, the value becomes '8000 to 0000 to 7FFF'. Here, '0000' represents the reference voltage VREF, '8000' to '0000' represents a positive tracking error signal (+ TE), and '0000 to 7FFF' represents a negative tracking error signal (-TE). Indicates.

Thus, when the most significant bit is '1', it represents a positive tracking error signal (+ TE), and when the most significant bit is '0', it represents a negative tracking error signal (-TE). As a result, the most significant bit functions as a sign bit.

The change relationship of the digital data value according to the voltage change occurrence is shown in the following table. In the table below, only the lower 8 bits (bit7 to bit0) of the 16-bit digital data are shown.

TE (n) TE (n-1) Comparator Count flag counter From a positive tracking error signal 8'h02 0000 0010 ↘ 8'h00 0000 0000 count up One 8'h03 0000 0011 ↘ 8'h02 0000 0010 hold hold 8'h04 0000 0100 ↘ 8'h03 0000 0011 count up 2 8'h05 0000 0101 ↘ 8'h04 0000 0100 hold hold 8'h06 0000 0110 ↘ 8'h05 0000 0101 count up 3 8'h07 0000 0111 ↘ 8'h06 0000 0110 hold hold 8'h08 0000 1000 8'h07 0000 0111 count up 4 Negative tracking error signal 8'hff 1111 1111 ↘ 8'hff 1111 1111 hold hold 8'hfd 1111 1110 ↘ 8'hff 1111 1111 hold hold 8'hfc 1111 1100 ↘ 8'hfd 1111 1110 count down 3 8'hfb 1111 1011 ↘ 8'hfc 1111 1100 count down 2 8'hfa 1111 1010 ↘ 8'hfb 1111 1011 hold hold 8'hf9 1111 1001 ↘ 8'hfa 1111 1010 count down One 8'hf8 1111 1000 ↘ 8'hf9 1111 1001 hold hold 8'hf8 1111 0111 8'hf8 1111 1000 count down 0

In Table 1, only the upper 7 bits (bit 8 to bit 1) excluding bit 0 among the lower 8 bits of data are compared for the voltage change determination. This will be described in more detail as follows. For example, assume that the amplitude of the tracking error signal TE is 3V.

At this time, if the tracking error signal TE is A / D converted, it has a voltage difference of 12 mV (= 3 V / 256) per one bit unit in the case of 8 bits.

Thus, when only the upper 7 bits (bit8 to bit1) are used, when a voltage difference of 12 mV occurs, it is up or down counted.

In addition, in the above [Table 1], only the upper 7 bits (bit8 to bit1) except bit0 of the lower 8 bits of data are used for the voltage change determination, but the number of bits to be compared and the number thereof are the voltages for determining the voltage change. Depending on how you set the value, it can vary. In more detail, for example, when the voltage used as the reference for determining the voltage change is set to 12 mV, only the upper 7 bits (bit8 to bit1) are used for the voltage change determination.

In addition, when the voltage used as the reference for determining the voltage change is set to 24 mV, only the upper 6 bits (bit8 to bit2) are used for the voltage change determination.

In Table 1, TE (n) represents the current tracking error signal, and TE (n-1) represents the previous tracking error signal.

In Table 1, only the current tracking error signal and the immediately preceding tracking error signal are used as data for the voltage comparison, but a previous tracking error signal may also be used. Further, for the voltage comparison, the current plurality of tracking error signals and the previous plurality of tracking error signals may be used.

In the positive tracking error signal, when TE (n) is '0000 0010' and TE (n-1) is '0000 0000', it is considered that there is a voltage change because the value of bit1 is different.

In addition, when TE (n) is '0000 0011' and TE (n-1) is '0000 0010', even though the value of bit0 is different, the data from bit8 to bit1 are the same, and thus no voltage change is considered. .

Next, when it is determined in step 1103 that there is a voltage change, it is determined whether both the current and previous tracking error signals TE (n) and TE (n-1) are higher than the reference voltage VREF. (1104).

In step 1104, when the tracking error signals TE (n) and TE (n-1) are higher than the reference voltage VREF, that is, when the tracking error signal is a positive tracking error signal, the counter counts up (1105). .

In addition, when the tracking error signals TE (n) and TE (n-1) are lower than the reference voltage VREF, that is, a negative tracking error signal, counting down is performed (1106 and 1107).

In addition, when the signs of the tracking error signals TE (n) and TE (n-1) are different from each other, a part is transferred to + →-or − → +, and thus, the process returns to step 1102 without counting. do.

Here, as described in [Table 1], it is counted when a voltage change occurs, that is, whenever there is a change in data value in bit7 to bit1.

Meanwhile, even if a voltage change occurs between the tracking error signals TE (n) and TE (n-1), a predetermined frequency range may be set so as not to count in a low frequency region such as the 'H' section of FIG. 6. have.

In addition, when the tracking error signals TE (n) and TE (n-1) are all higher than the reference voltage VREF, they are counted up and are counted down when they are lower than the reference voltage VREF.

As a result, when the positive tracking error signal + TE and the negative tracking error signal -TE are symmetric with respect to the reference voltage VREF, the final counting value will be '0'.

Also, when the positive tracking error signal + TE is greater than the negative tracking error signal -TE, the final counting value will be '+ M (M is a natural number).

Also, when the positive tracking error signal + TE is smaller than the negative tracking error signal -TE, the final counting value will be '-M.

The final counting value (+ M, 0, -M) is an unbalanced value of the tracking error signal.

Thereafter, it is determined whether the set balance adjustment time has been reached (1108). If the set balance adjustment time has not been reached, the process returns to step 1102 and the processes 1102 to 1107 are repeatedly performed.

When the set balance adjustment time is reached, it is determined whether the unbalance value satisfies the tolerance range (1109).

If the unbalanced value does not satisfy the tolerance range, a balance control signal BAL_CTL is output (1110). The balance control signal BAL_CTL adjusts the gain of the I / V converter 24 by varying the value of the resistor Rv of the tracking error signal generator 20 (see FIG. 2). Thereafter, the process returns to step 1101.

If the unbalance value satisfies the tolerance range, the balance control operation is stopped (1111).

As described above, according to the track balance adjusting method of the optical disk system according to the first embodiment of the present invention, since the tracking error signal is not counted at the low frequency, no frequency check is necessary.

In addition, since a minute unbalance value between the tracking error signals + TE and -TE can be detected, stable track balance adjustment is possible.

FIG. 8 is a flowchart 1200 illustrating a track balance adjustment process of an optical disk system for reducing an unbalance detection error of a tracking error signal according to a second embodiment of the present invention.

The flowchart 1200 is performed in the following processes.

As shown in FIG. 8, first, the controller 120 waits for the set time WT shown in FIG. 6 before detecting the unbalanced value of the tracking error signal TE (1201). The set time WT is an initial stabilization time of the spindle motor, and a stabilization time after balance adjustment.

Thereafter, when the tracking error signal TE is received 1202, it is determined whether the tracking error signal TE has a frequency within a predetermined range (1203).

If the frequency is not within the predetermined range, the process returns to step 1202 where the next tracking error signal TE is received.

When the frequency is within the predetermined range, it is determined whether the tracking error signal TE is higher than the reference voltage VREF (1204).

In step 1204, the tracking error signal TE is up counted when the reference voltage VREF is higher (1205).

In addition, when the tracking error signal TE is lower than the reference voltage VREF, it is down counted (1206 and 1207).

As a result, when the positive tracking error signal + TE and the negative tracking error signal -TE are symmetric with respect to the reference voltage VREF, the final counting value will be '0'.

Also, when the positive tracking error signal + TE is greater than the negative tracking error signal -TE, the final counting value will be '+ M (M is a natural number).

Also, when the positive tracking error signal + TE is smaller than the negative tracking error signal -TE, the final counting value will be '-M.

The final counting value (+ M, 0, -M) is an unbalanced value of the tracking error signal.

After that, it is determined whether the set balance adjustment time has been reached (1208). If the set balance adjustment time has not been reached, the process returns to step 1202 and the processes 1202 to 1207 are repeatedly performed.

When the set balance adjustment time is reached, it is determined whether the unbalance value satisfies the tolerance range (1209).

If the unbalanced value does not satisfy the tolerance range, a balance control signal BAL_CTL is output 1210. The balance control signal BAL_CTL adjusts the gain of the I / V converter 24 by varying the value of the resistor Rv of the tracking error signal generator 20 (see FIG. 2). Thereafter, the process returns to step 1201.

In addition, if the unbalance value satisfies the tolerance range, the balance control operation is stopped 1211.

FIG. 9 is a diagram illustrating a waveform of a tracking error signal for explaining an unbalance detection process of the tracking error signal by the flowchart shown in FIG. 8.

In FIG. 9, (a) shows a case where the duty of the positive tracking error signal + TE is greater than the duty of the negative tracking error signal -TE. (b) shows the case where the duty of the positive tracking error signal (+ TE) and the duty of the negative tracking error signal (-TE) are the same, that is, the balance is achieved. Incidentally, (c) shows a case where the duty of the positive tracking error signal + TE is less than the duty of the negative tracking error signal -TE.

9 (a), (b) and (c), 'U' is an up counting period, and 'D' is a down counting period. 'H' is a low frequency region and is a holding period in which no counting is performed.

FIG. 10 is a block diagram showing an embodiment of a track balance control unit which is a part of the servo unit of the optical disc system according to the present invention, and shows a track balance control unit for performing a track balance adjustment method of the optical disc reproducing apparatus according to the first embodiment. Indicates.

In FIG. 10, the track balance control unit 30 includes an A / D converter 31, first and second buffers 32 and 33, a comparator 34, a counter 35, and a control unit 36.

The A / D converter 31 converts the tracking error signal TE from the tracking error signal generator 20 (see FIG. 2) into a digital signal. The first buffer 32 temporarily stores the current tracking error signal TE (n), and the second buffer 33 temporarily stores the previous tracking error signal TE (n-1).

The comparator 34 compares the voltage between the current and previous tracking error signals TE (n) and TE (n-1), and further, the tracking error signals TE (n) and TE (n). -1) and the reference voltage VREF are compared to output a counting control signal.

In more detail, when the voltage difference is generated between the tracking error signals TE (n) and TE (n-1), the comparator 34 generates the tracking error signals TE (n) and TE ( n-1)) to the reference voltage VREF.

The comparator 34 outputs an up counting control signal when all of the voltages of the tracking error signals TE (n) and TE (n-1) are higher than the reference voltage VREF, and outputs the reference voltage ( Outputs a down counting control signal when it is lower than VREF).

The counting control signal when a part of voltages of the tracking error signals TE (n) and TE (n-1) is higher than the reference voltage VREF and another part is lower than the reference voltage VREF. Does not output

In addition, the comparator 34 counts the count so that the comparator 34 does not count in a low frequency region such as the 'H' section of FIG. 6 even if a voltage change occurs between the tracking error signals TE (n) and TE (n-1). Control signal is not output.

The counter 35 performs an up or down counting according to the counting control signal, and outputs an unbalanced counting value.

The counter 35 counts up when the comparator 34 outputs an up counting control signal, and counts down when the comparator 34 outputs a down counting control signal.

The controller 36 adjusts the balance of the tracking error signal by outputting a balance control signal BAL_CTL when the unbalance value is out of an allowable error range.

In FIG. 10, the track balance control unit for performing the method according to the first embodiment is illustrated, but only one buffer is used, and the comparator 34 compares the tracking error signal TE and the reference voltage VREF. And outputting a counting control signal, a track balance control unit for performing the track balance adjustment method of the optical disc reproducing apparatus according to the second embodiment can be configured.

In addition, the controller 36 includes registers for setting an adjustment time of a track balance, a stabilization time of a spindle motor, and the like, and the types and functions of the registers are as follows.

register function Configuration xGcnt Set measurement cycle (total time of reference measurement cycle when balancing) 16 bit xGwt Waiting time after track balance adjustment 16 bit Gok Allowable range of unbalanced values 8bit Fcutting Low frequency component cutting value of tracking error signal 8bit Gokflagreg Flag indicating whether the unbalanced value is within the allowable range GokFlag [3]: {xPecnt [15: 8] = 0 & (xPecnt [7: 0] <Gok [7: 0])} → 1GokFlag [2]: {xPecnt [ 15: 9] = 0 → 1GokFlag [1]: {xPecnt [15: 8] = 0 → 1GokFlag [0]: {xPecnt [15: 7] = 0 → 1 16 bit xPEcnt Unbalance value check count 16 bit

According to the GokFlag value of the register (GokflagReg) in [Table 2], it is checked in which range the unbalanced value is. As GokFlag is increased from 1 to F, the error is smaller.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, according to the track balance adjusting method and apparatus of the present invention, since minute unbalance of the tracking error signal is accurately detected, the detection error of the tracking error signal is reduced, so that the track balance can be stably adjusted.

1 is a block diagram schematically showing a general optical disc player.

FIG. 2 is a circuit diagram illustrating an implementation example of a tracking error signal generator that is a part of the RF amplifier illustrated in FIG. 1.

3 is a diagram illustrating a waveform of a general tracking error signal.

4 is a flowchart showing an example of a track balance adjusting process of the optical disk reproducing apparatus according to the prior art.

FIG. 5 is a diagram showing waveforms of a tracking error signal for explaining a track balance adjustment process of the optical disc player according to the prior art. FIG.

6 is a diagram illustrating a waveform of a tracking error signal for explaining an unbalance detection process of a tracking error signal according to the present invention.

7 is a flowchart showing a track balance adjustment process of the optical disk reproducing apparatus for reducing the unbalance detection error of the tracking error signal according to the first embodiment of the present invention.

8 is a flowchart showing a track balance adjustment process of the optical disk reproducing apparatus for reducing the unbalance detection error of the tracking error signal according to the second embodiment of the present invention.

FIG. 9 is a diagram illustrating a waveform of a tracking error signal for explaining an unbalance detection process of the tracking error signal by the flowchart shown in FIG. 8.

Fig. 10 is a block diagram showing an embodiment of a track balance control unit that is part of a servo unit of the optical disk reproducing apparatus according to the present invention.

Claims (16)

A track balance adjustment method of an optical disc system that detects an unbalanced value of a tracking error signal and adjusts a track balance. (a) counting a voltage change of the tracking error signal received for a predetermined period, and accumulating the counting value to detect an unbalanced value; And (b) adjusting the balance of the tracking error signal according to the unbalance value; reducing the unbalance detection error of the tracking error signal. The method of claim 1, wherein step (a) (c) continuously receiving the tracking error signal after waiting for a set time; (d) counting when a voltage difference occurs between the plurality of continuously received tracking error signals; And (e) repeating step (d) for the set balance adjustment time to detect an unbalance value according to the final cumulative counting value. How to adjust the track balance. The method of claim 2, wherein step (d) determining whether a voltage difference between the plurality of tracking error signals occurs; (g) performing a counting operation when the voltage difference is generated in step (f); And and (h) not performing a counting operation when the voltage difference is not generated in the step (f). The method of claim 3, wherein step (g) (i) up counting when all of the plurality of tracking error signals are higher than a predetermined reference voltage; (j) down counting when all of the plurality of tracking error signals are lower than the reference voltage; And and (k) not counting when some of the plurality of tracking error signals are higher than the reference voltage and others are lower than the reference voltage. How to adjust the track balance of an optical disc system. The method of claim 4, wherein step (g) (l) when the plurality of tracking error signals have a frequency other than a predetermined range, not counting. The track balance adjusting method of the optical disc system of claim 1, further comprising the step of not counting. The method of claim 4, wherein the plurality of tracking error signals At least one tracking error signal currently received; And A method of adjusting the track balance of an optical disc system, the method comprising reducing at least one unbalanced detection error of the tracking error signal, characterized in that it comprises at least one previously received tracking error signal. The method of claim 4, wherein The step (c) further comprises the step of A / D converting the tracking error signal (m) continuously received into a predetermined bit of digital data, In step (f), when a data value of some bits of the predetermined bits of each of the plurality of digital data is changed, it is determined that a voltage difference is generated between the plurality of tracking error signals. The tracking error signal is divided into a positive signal and a negative signal based on the reference voltage. The digital data includes at least one sign bit indicating whether the tracking error signal is the positive signal or the negative signal. The track balance adjustment of the optical disc system which reduces the unbalance detection error of the tracking error signal Way. The method of claim 7, wherein step (g) and (n) determining whether the tracking error signals are higher or lower than the reference voltage according to the data value of the sign bit. How to adjust the balance. The method of claim 7, wherein The some bits are bits that are compared to determine whether a voltage difference between the plurality of tracking error signals occurs. The number of bits to be compared is changed in accordance with the voltage value set for determining the voltage change track balance adjustment method of the optical disk system to reduce the unbalance detection error of the tracking error signal. The method of claim 1, wherein step (a) (o) after waiting for a set time, receiving the tracking error signal having a frequency within a predetermined range; (p) counting the tracking error signals received continuously; (q) repeating the step (p) for the set balance adjustment time to detect an unbalance value according to the final cumulative counting value, wherein the unbalance detection error of the tracking error signal is reduced. How to adjust the track balance. The method of claim 10, wherein step (p) (r) up counting when the tracking error signal is greater than a predetermined reference voltage; And (s) down-counting when less than the reference voltage, reducing the unbalance detection error of the tracking error signal. The method of claim 10, The step (o) further includes the step of A / D converting the tracking error signal continuously received (t) into a predetermined bit of digital data, The tracking error signal is divided into a positive signal and a negative signal based on the reference voltage. The digital data includes at least one sign bit indicating whether the tracking error signal is the positive signal or the negative signal. The track balance adjustment of the optical disc system which reduces the unbalance detection error of the tracking error signal Way. The method of claim 11, wherein step (p) (u) determining whether the tracking error signals are higher or lower than the reference voltage according to the data value of the sign bit, wherein the track of the optical disc system reduces the unbalance detection error of the tracking error signal. How to adjust the balance. The method of claim 1, wherein step (b) (v) determining whether the unbalance value satisfies an allowable error range; (w) repeating steps (a) and (b) by outputting a balance control signal and returning to step (a) when the tolerance range is not satisfied; And and (x) stopping the balance control operation when the tolerance range is satisfied, wherein the unbalance detection error of the tracking error signal is reduced. A track balance adjusting device of an optical disk system that detects an unbalanced value of a tracking error signal and adjusts a track balance. A comparator for comparing a voltage of the one or more previous tracking error signals with the voltage of the one or more current tracking error signals and outputting a predetermined counting control signal when a voltage change is detected; A counter that counts in response to the predetermined counting control signal, accumulates the counting value, and outputs an unbalanced value; And And a control unit for outputting a balance control signal when the unbalanced value is out of an allowable error range. The method of claim 15, The counting control signal includes an up counting control signal; And Includes a down counting control signal, The comparator And outputting the up or down counting control signal by comparing the voltages of the tracking error signals with a predetermined reference voltage when the voltage change is detected, thereby reducing the unbalance detection error of the tracking error signal. Track balance adjustment device.