KR20070082504A - Input signal quality estimation apparatus and method, and optical disc drive thereof - Google Patents

Abstract

A signal quality evaluation apparatus, a method therefor, and an optical disc driver are provided to accurately evaluate the quality of an input signal irrespective of recording density. A level value detecting unit(300) detects a level value of an input signal on the basis of a binary signal of the input signal. An input signal configuring unit(310) configures a plurality of ideal input signals by using the detected level value and a plurality of binary signals previously defined. A quality operating unit(320) obtains the quality of the input signal on the basis of an operation among a plurality of the ideal input signals.

Description

Input signal quality estimation apparatus and method, and optical disc drive

1 is a functional block diagram illustrating a general binarization process.

2A-2C show examples of jitter generated between the offset and the removed RF signal and the system clock.

3 is a functional block diagram of an input signal quality estimation apparatus according to an embodiment of the present invention.

4 is a detailed view of the level value detection unit shown in FIG. 3.

FIG. 5 is a detailed view of the input signal construction unit and the quality calculation unit shown in FIG. 3.

6 is an exemplary hardware configuration of a PR (1, 2, 1) channel.

7 is an output graph when a binary signal of an input signal changes from -1 to 1;

FIG. 8 is a diagram showing the variation of the output waveform when one waveform has a one-bit shifted relationship with respect to the other waveform.

9 is an exemplary diagram illustrating a distance graph between two waveforms according to a change.

Fig. 10A is an illustration of the distance between two waveforms when the 3-tap PR channel is PR (1, 2, 1).

FIG. 10B is a diagram illustrating the distance between two waveforms when the 3-tap PR channel is PR (1, 8, 1).

FIG. 11A is a diagram illustrating physical meanings in the case of FIG. 10A.

FIG. 11B is a diagram illustrating the physical meaning in the case of FIG. 10B.

12 is a detailed view of an input signal quality estimation apparatus based on LSNR operation according to another embodiment of the present invention.

13A to 13C are correlation diagrams according to signal quality.

14 is an example of a functional block diagram of an optical disk driver according to an embodiment of the present invention.

15 is another example of a functional block diagram of an optical disk driver according to another embodiment of the present invention.

16 is another example of a functional block diagram of an optical disk driver according to another embodiment of the present invention.

17 is another example of a functional block diagram of an optical disk driver according to another embodiment of the present invention.

18 is a flowchart illustrating an input signal quality estimation method according to an exemplary embodiment of the present invention.

The present invention relates to a signal quality evaluating apparatus and method for evaluating the quality of an input signal and an optical disk driver having a signal quality evaluating apparatus.

The input signal is an analog signal and may be an RF signal reproduced from a storage medium such as a disk. A disc is a storage medium on which binary signals are recorded. However, the RF (Radio Frequency) signal read from the disc has the characteristics of an analog signal due to the disc characteristics and the optical characteristics of the optical disc driver. Therefore, the optical disk driver requires a binarization process of converting an RF signal into a binary signal. The binarization process may be performed using the comparator 100 as shown in FIG.

1 is a functional block diagram illustrating a general binarization process. Referring to FIG. 1, the binarization process is performed using the comparator 100 and the low pass filter 110. The comparator 100 compares the input RF signal with a slicing level and outputs the result. The input RF signal is an RF signal read from a disk. The output of the comparator 100 is sent to the low pass filter 110 while being sent to the next processing block. The low pass filter 110 low pass filters the output of the comparator 100. The output of the low pass filter 110 is transmitted as a slicing level of the comparator 100.

The conventional optical disk driver converts an RF signal read from the disk into a binary signal through a binarization process shown in FIG. 1, and applies a signal converted into a binary signal to a phase lock loop to create a system clock. The binary signal and the system clock are used to play the data read from the disk. There is a slight phase difference between the RF signal and the system clock. This is called jitter.

2A through 2C illustrate jitter between the RF signal and the system clock with the offset removed, based on the falling edge of the system clock. Ideally, the edge of the system clock exactly matches the zero crossing of the RF signal. In practice, however, the intersection of the edges of the system clock and the zero crossing of the RF signal does not exactly coincide, and a slight difference occurs in time. This car is called jitter.

Traditionally, the jitter value, which is the difference between the RF signal and the system clock, is used to evaluate the quality of the RF signal. That is, in the ideal case, the zero crossing of the RF signal is precisely located at the edge of the system clock, so little jitter is measured. However, in the event of noise or anomalies in the RF signal, the zero crossing of the RF signal is not accurately located at the edge of the system clock, thus measuring jitter. Therefore, the quality of the RF signal can be ascertained based on the measured jitter value.

However, as the recording density of a disc increases, the size of the RF signal corresponding to a short T (where T is an interval of 1 foot) is gradually smaller. As a result, in the case of an RF signal corresponding to a short T binary signal, even if a little noise is added, the distortion of the signal may be relatively large or may be located near zero and an incorrect jitter value may be measured. Therefore, in the case of high density disks, the jitter value measured based on the difference between the RF signal and the system clock cannot be used to accurately evaluate the quality of the RF signal.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an optical disk drive having a signal quality evaluation device and method and a signal quality evaluation device capable of accurately evaluating the quality of an input signal (or a reproduction signal or an RF signal) regardless of recording density. have.

Another object of the present invention is to evaluate the quality of an input signal using an ideal input signal according to a predefined binary signal and a level value of the input signal based on the relationship between the input signal and the binary signal of the input signal. An optical disk driver having a signal quality evaluating apparatus and method and a signal quality evaluating apparatus are provided.

In order to achieve the above technical problem, the present invention includes a level value detection unit for detecting a level value of the input signal based on a binary signal of the input signal; An input signal construction unit configured to construct a plurality of ideal input signals using the detected level values and a plurality of predefined binary signals; And a quality calculating unit for obtaining the quality of the input signal based on the calculation between the plurality of ideal input signals.

The quality calculating unit further calculates a level signal to noise ratio (LSNR) calculation result using the input signal and a binary signal, and calculates a calculation result between the LSNR calculation result and the plurality of ideal input signals to calculate the quality of the input signal. It is desirable to obtain.

In order to achieve the above technical problem, the present invention provides a signal quality evaluation apparatus for evaluating the quality of the reproduction signal using a signal reproduced from a disc, a binary signal of the reproduction signal, and a plurality of predefined binary signals; And a system controller for correcting a focusing position while finely adjusting a focus offset based on the evaluation result of the signal quality evaluation apparatus.

In order to achieve the above technical problem, the present invention provides a signal quality evaluation apparatus for evaluating the quality of the reproduction signal by using a signal reproduced from a disc, a binary signal of the reproduction signal, and a plurality of predefined binary signals. A disk driver including a system controller for fine-adjusting the tilt correction based on the evaluation result of the signal quality evaluation apparatus.

According to an aspect of the present invention, there is provided an apparatus, comprising: an input signal quality evaluation apparatus for evaluating the quality of a reproduction signal using a signal reproduced from a disc, a binary signal of the reproduction signal, and a plurality of predefined binary signals; And a system control unit for adjusting the detrack offset in detail while changing the detrack offset based on the evaluation result of the signal quality evaluating apparatus.

According to an aspect of the present invention, there is provided an apparatus, comprising: an input signal quality evaluation apparatus for evaluating the quality of a reproduction signal using a signal reproduced from a disc, a binary signal of the reproduction signal, and a plurality of predefined binary signals; And a system controller for fine-tuning the recording conditions while changing the recording conditions for the disc based on the evaluation result of the signal quality evaluation apparatus.

According to an aspect of the present invention, there is provided a method including detecting a level value of an input signal based on a binary signal of an input signal; Constructing a plurality of ideal input signals using the detected level values and a plurality of predefined binary signals; And obtaining a quality of the input signal based on a calculation between the plurality of ideal input signals.

The method for evaluating signal quality further includes calculating a level signal-to-noise ratio (LSNR) using the input signal and the binary signal, and obtaining the quality of the input signal comprises the LSNR operation result and the plurality of ideals. It is preferable to calculate the quality of the input signal by calculating the operation result between the input signals.

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

3 is a functional block diagram of an input signal quality estimation apparatus according to the present invention. Referring to FIG. 3, the input signal quality evaluation apparatus includes a level value detection unit 300, an input signal configuration unit 310, and a quality calculation unit 320.

The level value detection unit 300 detects the level value of the input signal using a binary signal (hereinafter referred to as a binary signal) of the input signal. In this case, the detected level value may be defined as a level value indicating a current channel state.

The level value detection unit 300 classifies the input signal into a plurality of levels based on the binary signal, and detects the level value of the input signal by obtaining an average value for each level. To this end, the level value detection unit 300 may be configured as shown in FIG. 4. 4 is a detailed view of the level value detection unit 300 shown in FIG. Referring to FIG. 4, the level value detection unit 300 includes an input signal separator 400 and a level value detector 440.

The input signal separator 400 separates an input signal into a plurality of levels using a binary signal. To this end, the input signal separator 400 includes an input signal processor 410, a binary signal processor 420, and a selection unit 430.

The input signal processor 410 includes n delayers 410_1410_n. The n delays 410_1410_n are for synchronizing the input signal with the binary signal.

The binary signal processor 420 outputs a selection signal combined with the input binary signal. To this end, the binary signal processor 420 includes j delayers 421_1421_j and a selection signal generator 422. That is, in the case of FIG. 4, since the binary signal processor 420 includes j delayers 421_1421_j, the selection signal generator 422 may generate 2 ^{j + 1} selection signals. For example, if a binary signal processor 420 comprises a two delays, the selection signal generator 422 may generate a second ^three selection signals. The two ^three select signals that can be generated are 000, 001, 010, 011, 100, 101, 110, 111.

The selection unit 430 selectively transmits the signal output from the input signal processor 410 according to the signal output from the binary signal processor 420. For example, when the 000 value is output from the binary signal processor 420, the selection unit 430 outputs level 0 with respect to the signal output from the input signal processor 410. In addition, when the 111 value is output from the binary signal processor 420, the selection unit 430 outputs the level m with respect to the signal output from the input signal processor 410. At this time, level m corresponds to level 7.

In this way, the level (one of the level 0 level m) of the input signal corresponding to the binary signal is output from the input signal separation unit 400. In this case, the level output from the input signal separator 400 may be regarded as an estimate of an ideal signal. The level output from the input signal separator 400 is transmitted to the level value detector 440.

The level value detector 440 obtains an average value for each level (level value 0 level value m), and detects the average value as the level value of the input signal. To this end, the level value detector 440 includes m + 1 average value filters 440_0440_m. Therefore, the level value detector 440 may be defined as a filter unit. The average filter 440_1440_m may obtain an average value for a long period with respect to the input level. For example, the average value filter 440_1440_m may calculate an average value for each level by using Equation 1.

Updated level value = previous level value + (delayed input signal-previous level value) / constant

The updated level value in Equation 1 is an average value obtained by each average filter 440_1440_m. In Equation 1, the previous level value is an average value previously obtained by each average filter 440_1440_m, and may be retained by each average filter 440_1440_m. The delayed input signal in Equation 1 is a level output from the input signal separator 400.

In Equation 1, the constant may be determined experimentally in consideration of the processing speed of the signal quality estimation apparatus. In other words, as the constant is set to a large value in Equation 1, the updated level value is smaller, and the processing speed of the signal quality evaluation apparatus is generally slowed down. The constant may be set to 256, for example. When the average value is calculated as in Equation 1, if the delayed input signal is equal to the previous level value, the updated level value is equal to the previous level value.

In addition, the average filter 440_1440_m may be configured to obtain an average value using a low pass filter.

The input signal constructing unit 310 configures a plurality of ideal input signals using the level value detected from the level value detecting unit 300 and a predefined binary signal. The quality calculating unit 320 calculates the quality of the input signal based on the calculation between the plurality of ideal input signals.

To this end, the input signal configuration unit 310 and the quality calculation unit 320 may be configured as shown in FIG. FIG. 5 is a detailed view of the input signal configuration unit 310 and the quality calculation unit 320 shown in FIG. 3.

Referring to FIG. 5, the input signal constructing unit 310 includes two binary tables 510 and 530 and two selectors 520 and 540, and the quality calculating unit 320 includes a distance calculator ( 550).

Binary tables 510 and 530 have preset binary signals. The selector 520 selects one of the level values transmitted from the level value detection unit 300 based on the binary signal provided from the binary table 510, and selects the selected signal as the ideal input signal as the quality calculation unit 320. To send. The selector 540 selects one of the level values transmitted from the level value detection unit 300 based on the binary signal provided from the binary table 530, and selects the selected signal as the other ideal input signal as the quality calculating unit 320. To send). Accordingly, the input signal configuration unit 310 constitutes a plurality of ideal input signals.

The binary signals provided from the binary table 510 and the binary table 530 have different binary signals. This is to configure a plurality of different input signals in order to measure the error occurring in the input signal. That is, the binary signal provided in the binary table 530 may be a binary signal shifted by one bit with respect to the binary signal provided in the binary table 510. For example, when the binary signal provided by the binary table 510 is 0000111, the binary signal provided by the binary table 530 may be 0001111. In addition, the binary signal provided in the binary table 530 may be a binary signal shifted by 2T with respect to the binary signal provided in the binary table 510. For example, when the binary signal provided by the binary table 510 is 00011000, the binary signal provided by the binary table 530 may be 00001100. In addition, the binary signal provided in the binary table 530 may be a binary signal subjected to 2T successive shifts with respect to the binary signal provided in the binary table 510. For example, when the binary signal provided in the binary table 510 is 00011001100, the binary signal provided in the binary table 530 may be 00001100110.

When the binary signal provided by the binary table 510 is 0000111 and the binary signal provided by the binary table 530 is 0001111, the selector 520 selects and transmits the level value 2, and the selector 540 selects the level value. 3 can be selected for transmission.

The quality computing unit 320 includes a distance calculator 550 as shown in FIG. 5. The distance calculator 550 calculates the sum of squares of differences between the selector 520 included in the input signal construction unit 301 and the level values transmitted from the selector 540, and calculates the sum of the squares of the input signal. quality). In addition, the distance calculator 550 may obtain a square root of the sum of squares of the differences between the level values transmitted from the selector 520 and the selector 540, and output the obtained square root as the quality of the input signal. In addition, the distance calculator 550 obtains a value obtained by dividing the square root of the sum of squares of the differences between the level values transmitted from the selector 520 and the selector 540 by the amplitude of the input signal, and calculating the obtained value as the quality of the input signal. You can print

That is, the principle of how to obtain the signal quality from the ideal input signal is as follows. As a simple example, let's look at how an input signal is generated. Referring to the PR (partial response) channel, the PR (1,2,1) channel means that a signal passed through a digital filter having a filter coefficient of 1,2,1 can be obtained when a binary signal is input. Looking at the hardware configuration as shown in FIG. 6 is an exemplary hardware configuration of a PR (1, 2, 1) channel. In this case, it is assumed that the input binary signal is -1 or 1 so that the DC value becomes 0 for convenience. Since three binary signals constitute one output, the number of cases of 2 ³ is generated in consideration of the number of all cases. The output signal at this time is shown in Table 1.

In Table 1, the third and sixth cases show 1T. In the case of BD (Bluray Disc) or HD-DVD (High Definition-DVD), 0T cannot be output because 1T does not exist in the binary signal itself. For example, when the binary signal of the input signal is as follows, the signal output from the digital filter of FIG. 6 is as follows.

Binary data: -1 -1 -1 -1 +1 +1 -1 -1 -1 +1 +1 +1 +1 +1 +1 +1

Output data: -4 -4 -2 +2 +2 -2 -4 -2 +2 +4 +4 +4 +4

A graph of the output signal when the binary signal changes from -1 to 1 is shown in FIG. 7 is a graph of the output signal when the binary signal changes from -1 to 1. FIG. In FIG. 7, the signal indicated by the dotted line is the binary signal, and the signal indicated by the solid line is the output signal. The response characteristic when a binary signal goes from -1 to 1 is commonly called a step response. As the binary signal changes, the output signal does not change immediately, but has a response characteristic of length 3 (because it is 3 taps). And shape characteristics determined by the coefficient of the tap.

Generally speaking, inter symbol interference (ISI) is an inter-symbol interference in a dictionary meaning, but the specific meaning thereof is that the output signal does not come out when the step input is input as shown in FIG. This means that the deformation occurs as much as the corresponding shape. Since the ISI is a variable according to the laser spot shape and the pit length in the case of an optical disc, the length of the ISI is exactly proportional to the storage capacity of the disc in the same spot shape. Then, from the point of view of obtaining an ideal binary signal in the presence of ISI, it is necessary to analyze what distribution the ideal input signal should have.

To analyze this, the waveform of the output signal is checked when a binary signal shifted by one bit in PR (1, 2, 1) is input. In particular, when the input binary signal is shifted by 1 bit, the output signal of FIG. 6 is also shifted by 1 bit. In this case, the input signal (output signal of FIG. 6) obtained by the actual circuit is positioned between the signal composed of the solid line of FIG. 7 and the signal composed of the dotted line. In the case of using the recently used Partial Response Maximum Likelyhood (PRML), it is possible to determine whether the input signal is closer to the dotted line or the solid line.

At this time, the probability that an error occurs in the distribution that the ideal input signal should have becomes smaller as the distance between the solid line waveform and the dotted line waveform of FIG. 7 increases. The reason for this is to determine whether the input signal is close to the solid line or the dotted line of FIG. 7. The basic principle of PRML is that the farther the distance between the solid line and the dotted line waveform of FIG. This can be clearly determined.

In general, the distance of two waveforms is the Euclidean distance, and the Euclidean distance is the sum of all squares obtained by subtracting two incoming signals per unit time.

For example, as shown in FIG. 8, when the distance between two waveforms is obtained, 0.5 ² + 1 ² + 0.5 ² = 1.5 mm. The larger the distance of 1.5mm, the easier it is to discriminate the signal. Fig. 8 is a diagram showing a change in output waveform when one waveform is shifted 1 bit with respect to another waveform. In the case of 3 taps, the ideal waveform distribution (that is, the distribution of levels) can be obtained in the form of PR (a, b, a) in the case of a general 3Tap PR model, and a and b require the following conditions: Do.

1.a <b (spot distribution condition of the optical disc, distribution in which the center of the spot is larger than the other parts of the spot)

2.a + b + a = 1 (typical FIR filter conditions)

3.a> 0, b> 0

By specifically solving this condition, the conditions of b = 1-2a and 0 <a <0.5 can be obtained. In this case, Table 1 should be modified as shown in Table 2 below.

In the case of FIG. 8, the distance between two waveforms can be obtained as (-2a) ² + (2b) ² + (2a) ² . If b is eliminated, the equation can be simplified to 24a ² -16a + 4.

9, it can be seen that a value of 4 is obtained when the maximum value is a = 0 for a condition of 0 <a <0.5, and a value of 4/3 is obtained when the minimum value is a = 1/3. 9 is a distance graph of two waveforms according to a change in a, where the horizontal axis is a value and the vertical axis is distance.

Therefore, the detection performance for the input signal is best when the 3-tap PR channel is PR (0,1,0), and the detection performance for the input signal when PR (1/3, 1/3, 1/3) is I can see the worst. Analyzing this with the level distribution, in the case of PR (0,1,0), the level distribution of the input signal is exactly the same as the ideal square wave, and the closer the three-tap PR channel is to PR (0,1,0), the input signal. The detection rate for is meant to be excellent.

In another example, if PR (1,2,1) is compared with PR (1,8,1), a PRIC (1,8, 1) has a better detection rate with respect to the input signal in PR (1,8,1) because of the 1.76mm Wickly distance. It can be seen that the larger the modulation size of 2T, the better the performance of the PRML.

Therefore, through the circuits of Figs. 4 and 5, the level values of the input signals are detected from the binary signals and the input signals, and two ideal input signals are constructed according to the detected level values and the predefined binary signals, and then the two ideal inputs. The distance between the signals is obtained and the quality of the input signal is evaluated.

In this case, a value called distance may be defined as an example of signal quality. That is, as shown in FIGS. 10A and 10B, an equation for obtaining a distance between two signals having a difference may be defined as in Equation 2. FIG. 10A shows a case of PR (1, 2, 1), and FIG. 10B shows a case of PR (1, 8, 1).

In Equation 2, RF _true is a waveform shown by solid lines in FIGS. 10A and 10B, and RF _false is a waveform shown by dotted lines in FIGS. 10A and 10B. The physical meaning of Equation 2 is the same as in FIGS. 11A and 11B. FIG. 11A shows a case of PR (1, 2, 1), and FIG. 11B shows a case of PR (1, 8, 1). In Equation 2, NRZI _difference is a number representing how many bits are different among two binary signal strings constituting the input signal.

Meanwhile, another signal quality evaluation method for obtaining a signal noise rate (SNR) using the level value detection unit 300, an input signal, and a binary signal may be defined as in Equation 3.

Since Equation 3 is a signal obtained from a level, it is expressed as LSNR (Level SNR) for convenience. An input signal quality estimation apparatus based on the LSNR operation may be configured as shown in FIG. 12. 12 is a detailed diagram of an input signal quality estimation apparatus based on LSNR operation, and includes an input signal separator 1200, a level value detector 1240, a selector 1250, and a quality calculator 1260.

The input signal separator 1200 is configured in the same manner as the input signal separator 400 illustrated in FIG. 4. Accordingly, the input signal separator 1200 may include an input signal processor 1210 including n delayers 1210_11210_n, a binary signal processor 1220 including j delayers 1221_1421_j, and a selection signal generator 1222. And a selection unit 1230 for selectively transmitting a signal output from the input signal processor 1210 according to the signal output from the binary signal processor 1220.

The level value detector 1240 is configured and operates in the same manner as the level value detector 440 illustrated in FIG. 4. The selector 1250 selects and transmits one of the level values output from the level value detector 1240 according to the signal output from the binary signal processor 1220.

The quality calculator 1260 calculates the quality of the input signal based on the LSNR operation and outputs the result of the calculation.

When the signal quality evaluating apparatus of FIG. 3 and the signal quality evaluating apparatus of FIG. 12 are combined, highly accurate signal quality measurement is possible. That is, when the distance obtained from the quality calculating unit 320 of FIG. 3 and the result calculated by the quality calculating unit 1260 of FIG. 12 are calculated as in Equation 4, accurate signal quality can be measured. Therefore, in Equation 4, an embodiment in which the quality calculating unit 320 and the quality calculating unit 1260 of FIG. 12 are combined may be presented. In Equation 4, New parameter may be defined as the measured signal quality.

New parameter = sqrt (distance) * LSNR

In general, LSNR is an indicator of how much noise component appears in the input signal. The larger the value, the better the quality of the input signal, and the distance represents the output characteristic according to the frequency of the input signal from which the noise component is removed. Therefore, the larger the value, the better the quality of the input signal. Thus, when these two parameters are combined, the quality of the input signal can be measured accurately. FIG. 13A illustrates a relationship between signal quality and bit error rate by LSNR operation, FIG. 13B illustrates a relationship between signal quality and bit error rate by distance, and FIG. 13C illustrates signal quality when LSNR operation and distance operation are combined. A diagram of the relationship between bit error rates. FIG. 13C can measure accurate signal quality compared to FIGS. 13A and 13B.

Therefore, the quality calculation unit 320 of FIG. 3 may be modified to obtain the quality of the input signal based on the distance and LSNR obtained based on the two ideal signals. Since the distance defined by Equation 2 is the sum of the squares of the differences between the two signals, the square root must be taken to calculate the geometric distance mean, so Equation 4 is the sqrt operation on the distance.

In some cases, it may be necessary to normalize the quality of the signal obtained by Equation 4 with the maximum amplitude of the input signal to compensate for the magnitude of the input signal. In this case, Equation 4 may be redefined as in Equation 5. Therefore, in Equation 5, New parameter may be defined as the quality of the measured signal.

New parameter = sqrt (distance) * LSNR / Amplitude of Input Signal

In addition, a signal quality evaluation such as Equation 4 may be defined as defined in Equation 6.

Equation 6 is a case where the signal quality is obtained in consideration of the distance. That is, the quality of the signal is obtained by calculating the sum of the squares of the noise signal and the sum of the distances between the two waveforms as shown in Equation 6. In Equation 6, log is a concept used to express the dB in dB. If there is no ₁₀ log ₁₀ in Equation 6 may be omitted. In Equation 6, New parameter may be defined as the quality of a signal measured according to the present invention.

Since the signal quality evaluation unit proposed in the present invention has the advantage that the signal quality can be accurately evaluated even in the case of a high density disk, the quality evaluation value is, for example, the focus correction, the tilt correction, It can be utilized for track correction, recording signal optimization, and the like.

Focus correction in the optical disk driver measures the signal quality reproduced from the disk by changing the focus portion to be corrected, and then finds the focus portion having the best performance. To this end, the optical disk driver may be configured as shown in FIG. 14. That is, the optical disk driver 1400 is based on the present invention based on the relationship between the reproduction signal picked up from the disk 1401 and the binary signal of the reproduction signal and the plurality of ideal reproduction signals according to the present invention. The focus driver 1404 focuses on the focusing part having optimal performance by finely adjusting the focus offset of the focus driver 1404 based on the evaluation results of the signal quality evaluating apparatus 1403 and the signal quality evaluating apparatus 1403 that evaluate the The system controller 1405 may be included. The focusing part having the optimal performance may be a point at which the new parameter of Equation 4 or Equation 5 becomes maximum. The optical disk driver of FIG. 14 may be reconfigured to include the signal quality evaluation device 1403 in the system control unit 1405.

The tilt correction in the optical disk drive measures the signal quality to be reproduced by changing the tilt portion to be corrected, and then searches for the tilt portion having the best performance. For this purpose, the optical disc driver may be configured as shown in FIG. That is, the optical disk driver 1500 is adapted to reproduce the reproduction signal based on the relationship between the reproduction signal picked up from the disc 1501 and the binary signal of the reproduction signal and the plurality of ideal reproduction signals according to the present invention. A system control unit for controlling the tilt adjusting unit 1504 to fine tune the tilt based on the evaluation results of the signal quality evaluating apparatus 1503 and the signal quality evaluating apparatus 1503 for evaluating the quality to search for a tilt portion having an optimal performance. 1505). The portion having the optimal performance may be a point at which the New parameter of Equation 4 or Equation 5 becomes maximum. The optical disk driver of FIG. 15 may be reconfigured to include the signal quality evaluating apparatus 1503 in the system control unit 1505.

Detrack correction in an optical disk drive measures the signal quality by changing the detrack portion to be corrected, and then searches for the detrack portion with optimum performance. To this end, the optical disk driver may be configured as shown in FIG. That is, the optical disc driver 1600 is based on the present invention based on the relationship between the reproduction signal picked up from the disc 1601 and the binary signal of the reproduction signal and the plurality of ideal reproduction signals according to the present invention. Based on the evaluation results of the signal quality evaluator 1603 and the signal quality evaluator 1603, the detrack adjusting unit 1604 is controlled to fine tune the detrack offset to search for a detrack portion having optimal performance. It may include a system control unit 1605. The portion having the optimal performance may be a point at which the New parameter of Equation 4 or Equation 5 becomes maximum. The optical disk driver of FIG. 16 may be reconfigured to include the signal quality evaluation apparatus 1603 in the system controller 1605.

In order to optimize the recording signal in the optical disk drive, the recording conditions are changed by changing the recording conditions, the recorded signals are read, the signal quality is measured, and the recording conditions are adjusted to the parts having optimum performance. To this end, the optical disk driver may be configured as shown in FIG. That is, the optical disk driver 1700 is based on the present invention based on the relationship between the reproduction signal picked up from the disk 1701 through the pickup unit 1702 and the binary signal of the reproduction signal and the plurality of ideal reproduction signals. Based on the evaluation results of the signal quality evaluating apparatus 1703 and the signal quality evaluating apparatus 1703, the light streaks are recorded with the recording conditions corresponding to the signals having the best quality among the signals reproduced from the disc 1701, while changing the recording conditions. The write strategy waveform generator 1704 may include a system controller 1705 for generating a write waveform. The recording condition corresponding to the signal having the highest quality may be a condition in which the New parameter of Equation 4 or 5 is maximized. The optical disk driver of FIG. 17 may be reconfigured to include the signal quality evaluation device 1703 in the system control unit 1705.

18 is a flowchart illustrating an input signal quality estimation method according to another exemplary embodiment.

Referring to FIG. 18, the method according to the present invention detects a level value of an input signal similarly to the level value detecting unit 300 of FIG. 3 using a binary signal and an input signal (1801). That is, in operation 1801, the input signal is divided into a plurality of levels using a binary signal, an average value for each level of each of the input signals divided into the plurality of levels is obtained, and the average value is detected as a level value of the input signal. .

Next, a plurality of ideal input signals are configured based on the detected level value of the input signal and a plurality of predefined binary signals (1802). Constructing a plurality of ideal input signals is configured similarly to that described in the input signal construction unit 310 of FIG. That is, the plurality of ideal input signals are configured by selecting a level value of the input signal detected in operation 1801 based on the plurality of predefined binary signals.

The quality of the input signal is obtained by calculating a plurality of ideal input signals (1803). The operation between the plurality of ideal input signals is similar to that described in the quality computation unit 320 of FIG. Alternatively, the operation between the plurality of ideal input signals may be performed in a manner similar to the combination of the quality calculating unit 320 of FIG. 3 and the quality calculating unit 1260 of FIG. 12.

That is, in operation 1803, the square root of the sum of the squares of the differences between the plurality of ideal input signals may be obtained, and the obtained square root may be obtained as the quality of the input signal. Alternatively, in operation 1803, a value obtained by dividing the square root of the sum of squares of the differences between the plurality of ideal input signals by the amplitude of the input signal may be obtained, and the obtained value may be obtained as the quality of the input signal. Or step 1803, further comprising calculating a level signal-to-noise ratio (LSNR) using the input signal and the binary signal, and calculating a calculation result between the LSNR calculation result and a plurality of ideal input signals to determine the quality of the input signal. Can be obtained.

Alternatively, operation 1803 may further include calculating a level signal-to-noise ratio (LSNR) using the input signal and the binary signal, and calculating the LSNR calculation result based on the amplitude of the input signal and the plurality of ideal input signals. The result can be calculated to find the quality of the input signal. Alternatively, in operation 1803, the quality of the input signal may be obtained by using Equation 6.

The program for performing the signal quality estimation method according to the present invention can be embodied as computer readable codes on a computer readable recording medium. Computer-readable recording media include all kinds of storage devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

As described above, the present invention can accurately evaluate the quality of the input signal (or the reproduction signal or the RF signal) regardless of the recording density.

Further, using the signal quality obtained according to the present invention, the present invention provides an optical disk driver capable of accurately following a focus offset, or an optical disk driver capable of accurately following a tilt, or an optical disk capable of accurately following a detrack. A driver or an optical disk driver capable of knowing accurate recording conditions can be provided.

Claims (25)

A level value detection unit detecting a level value of the input signal based on the binary signal of the input signal; An input signal construction unit configured to construct a plurality of ideal input signals using the detected level values and a plurality of predefined binary signals; And And a quality calculating unit for obtaining a quality of the input signal based on the calculation between the plurality of ideal input signals. The method of claim 1, wherein the level value detection unit, An input signal separator configured to separate the input signal into a plurality of levels using the binary signal; And a level value detector which obtains an average value for each level of each of the input signals separated into the plurality of levels, and detects the average value as a level value of the input signal. 3. The apparatus of claim 2, wherein the input signal separator comprises a delayer for delaying the input signal to synchronize the input signal with the binary signal before separating the input signal into the plurality of levels. The apparatus of claim 2, wherein the level value detector obtains the average value using a low pass filter. The method of claim 2, wherein the level value detector, characterized in that for obtaining the average value based on the following equation, Updated level value = previous level value + (delayed input signal-previous level value) / constant Wherein the updated level value is the average value, and the previous level value is a previously obtained average value. The method of claim 1, wherein the input signal configuration unit, A plurality of binary tables having said predefined binary signal; And A plurality of selectors for selecting one of the level values output from the level value detection unit by the binary signals provided from the plurality of binary tables and transmitting as the plurality of ideal input signals, And a binary signal provided from the plurality of binary tables has a different value. The signal quality evaluation according to claim 6, wherein the quality calculating unit obtains a sum of squares of differences between a plurality of level values transmitted from the plurality of selectors, and outputs the obtained sum as the quality of the input signal. Device. 7. The signal quality of claim 6, wherein the quality calculating unit obtains a square root of a sum of squares of differences between a plurality of level values transmitted from the plurality of selectors, and outputs the obtained square root as the quality of the input signal. Evaluation device. 7. The apparatus of claim 6, wherein the quality calculating unit obtains a value obtained by dividing a square root of a sum of squares of differences between a plurality of level values transmitted from the plurality of selectors by the amplitude of the input signal, and obtaining the obtained value by the quality of the input signal. And a signal quality evaluation device. The method of claim 1, wherein the quality calculation unit further calculates a level signal to noise ratio (LSNR) calculation result using the input signal and a binary signal, and calculates a calculation result between the LSNR calculation result and the plurality of ideal input signals. Obtaining the quality of the input signal, the signal quality evaluation apparatus. The method of claim 1, wherein the quality calculating unit calculates a result of shaping a level signal-to-noise ratio (LSNR) calculation result using the input signal and a binary signal to the amplitude of the input signal and the plurality of ideal input signals. Obtaining the quality of the input signal, the signal quality evaluation apparatus. 2. The apparatus of claim 1, wherein the quality calculating unit obtains the quality of an input signal based on the following equation.

A signal quality evaluation device for evaluating the quality of the reproduced signal using a signal reproduced from a disc, a binary signal of the reproduced signal, and a plurality of predefined binary signals; And And a system controller for correcting a focusing position while finely adjusting a focus offset based on an evaluation result of the signal quality evaluating apparatus. A signal quality evaluating apparatus for evaluating the quality of the reproduced signal using a signal reproduced from a disc, a binary signal of the reproduced signal, and a plurality of predefined binary signals; And a system controller for fine-adjusting the tilt correction based on the evaluation result of the signal quality evaluation apparatus. An input signal quality evaluation apparatus for evaluating the quality of the playback signal using a signal reproduced from a disc, a binary signal of the playback signal, and a plurality of predefined binary signals; And And a system controller for fine-tuning the detrack offset while changing the detrack offset based on the evaluation result of the signal quality evaluating apparatus. An input signal quality evaluation apparatus for evaluating the quality of the playback signal using a signal reproduced from a disc, a binary signal of the playback signal, and a plurality of predefined binary signals; And And a system controller for fine-tuning the recording conditions while changing the recording conditions for the disc based on the evaluation result of the signal quality evaluation apparatus. Detecting a level value of the input signal based on a binary signal of the input signal; Constructing a plurality of ideal input signals using the detected level values and a plurality of predefined binary signals; And Obtaining a quality of the input signal based on a calculation between the plurality of ideal input signals. The method of claim 17, wherein the detecting of the level value comprises: Dividing the input signal into a plurality of levels using the binary signal; Obtaining a mean value for each level of each of the input signals separated into the plurality of levels, and detecting the mean value as a level value of the input signal. 18. The method of claim 17, wherein the input signal construction step comprises selecting the level values of the input signals based on the predefined binary signals to configure the plurality of ideal input signals. . 18. The method of claim 17, wherein the obtaining of the quality of the input signal comprises: obtaining a sum of squares of differences between the plurality of ideal input signals, and obtaining the obtained sum as the quality of the input signal. . 18. The method of claim 17, wherein the obtaining of the quality of the input signal comprises: calculating a square root of a sum of squares of differences between the plurality of ideal input signals, and calculating the obtained square root as the quality of the input signal. Way. 18. The method of claim 17, wherein the obtaining of the quality of the input signal comprises: obtaining a value obtained by dividing a square root of the sum of squares of the differences between the plurality of ideal input signals by the amplitude of the input signal, and obtaining the obtained value by the quality of the input signal. The signal quality evaluation method characterized by the above-mentioned. The method of claim 17, wherein the signal quality evaluation method comprises: Calculating a level signal to noise ratio (LSNR) using the input signal and the binary signal; The calculating of the quality of the input signal may include calculating a quality of the input signal by calculating a calculation result between the LSNR calculation result and the plurality of ideal input signals. The method of claim 17, wherein Calculating a level signal to noise ratio (LSNR) using the input signal and the binary signal; The obtaining of the quality of the input signal may include calculating a quality of the input signal by calculating a result of shaping the LSNR operation result into an amplitude of the input signal and calculating a calculation result between the plurality of ideal input signals. Assessment Methods. The method of claim 17, wherein the signal quality evaluation method comprises: Calculating a level signal to noise ratio (LSNR) using the input signal and the binary signal; The determining of the quality of the input signal may include obtaining a quality of the input signal based on the following equation.

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