Apparatus and method of estimating the quality of input signal, and optical disc driver

Abstract

An apparatus and method of estimating the quality of an input signal, and an optical disc driver including the apparatus for estimating the quality of the input signal, the signal quality estimating apparatus including a level value detection unit that detects level values of an input signal according to a binary signal of the input signal, an input signal composing unit that composes a plurality of ideal input signals by using the level values and a plurality of pre-defined binary signals, and a quality calculation unit that obtains a quality of the input signal according to a calculation between the plurality of ideal input signals.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

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

FIGS. 2A through 2C illustrate a jitter generated between an offset-removed RF signal and a system clock;

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

FIG. 4 is a detailed block diagram of a level value detection unit shown in FIG. 3;

FIG. 5 is a detailed block diagram of an input signal composing unit and a quality calculation unit shown in FIG. 3;

FIG. 6 illustrates a hardware structure of a PR(1, 2, 1) channel;

FIG. 7 is an output graph when the binary signal of an input signal varies from −1 to 1;

FIG. 8 is a graph showing a variation of an output waveform when one waveform is shifted one bit from the other waveform;

FIG. 9 is a graph showing a distance between two waveforms versus a value “a”;

FIG. 10A is a graph showing a distance between two waveforms when a three tap PR channel is PR(1, 2, 1);

FIG. 10B is a graph showing a distance between two waveforms when a three tap PR channel is PR(1, 8, 1);

FIG. 11A is a graph showing FIG. 10A in a physical sense;

FIG. 11B is a graph showing FIG. 10B in a physical sense;

FIG. 12 is a detailed block diagram of an input signal quality estimating apparatus based on a level signal noise rate (LSNR) calculation, according to another embodiment of the present invention;

FIGS. 13A through 13C are correlation diagrams with respect to a signal quality;

FIG. 14 is a functional block diagram of an optical disc driver according to an embodiment of the present invention;

FIG. 15 is a functional block diagram of an optical disc driver according to another embodiment of the present invention;

FIG. 16 is a functional block diagram of an optical disc driver according to another embodiment of the present invention;

FIG. 17 is a functional block diagram of an optical disc driver according to another embodiment of the present invention; and

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

Claims

1. A signal quality estimating apparatus comprising: a level value detection unit to detect level values of an input signal according to a binary signal of the input signal;an input signal composing unit to compose a plurality of ideal input signals by using the level values and a plurality of pre-defined binary signals; anda quality calculation unit to obtain a quality of the input signal according to a calculation between the plurality of ideal input signals.

2. The signal quality estimating apparatus as claimed in claim 1, wherein the level value detection unit comprises: an input signal separator to separate the input signal into a plurality of levels using the binary signal; anda level value detector to obtain averages of each of the levels of the input signal such that the averages are the level values of the input signal.

3. The signal quality estimating apparatus as claimed in claim 2, wherein the input signal separator comprises one or more delays that delay the input signal before separating the input signal into the plurality of levels in order to synchronize the input signal with the binary signal.

4. The signal quality estimating apparatus as claimed in claim 2, wherein the level value detector obtains the averages using low-pass filters.

5. The signal quality estimating apparatus as claimed in claim 2, wherein the level value detector obtains the averages using an equation:

6. The signal quality estimating apparatus as claimed in claim 1, wherein the input signal composing unit comprises: a plurality of binary tables comprising the pre-defined binary signals.

7. The signal quality estimating apparatus as claimed in claim 6, wherein the input signal composing unit further comprises: a plurality of selectors to select a plurality of level values from among the level values detected by the level value detection unit according to the pre-defined binary signals of the plurality of binary tables, and to transmit the selected level values as the plurality of ideal input signals.

8. The signal quality estimating apparatus as claimed in claim 7, wherein the plurality of binary tables comprises a first binary table outputting a first binary signal, of the pre-defined binary signals, and a second binary table outputting a second binary signal, of the pre-defined binary signals, different from the first binary signal.

9. The signal quality estimating apparatus as claimed in claim 7, wherein the quality calculation unit calculates a sum of squares of differences between the plurality of level values received from the plurality of selectors, and outputs the sum as the quality of the input signal.

10. The signal quality estimating apparatus as claimed in claim 7, wherein the quality calculation unit calculates a square root of a sum of squares of differences between the plurality of level values received from the plurality of selectors, and outputs the square root as the quality of the input signal.

11. The signal quality estimating apparatus as claimed in claim 7, wherein the quality calculation unit calculates a division, by an amplitude of the input signal, of a square root of a sum of squares of differences between the plurality of level values received from the plurality of selectors, and outputs a result of the division as the quality of the input signal.

12. The signal quality estimating apparatus as claimed in claim 1, wherein the quality calculation unit calculates a level signal to noise ratio (LSNR) using the input signal and the binary signal, such that a higher a value of the LSNR corresponds to a better signal quality.

13. The signal quality estimating apparatus as claimed in claim 12, wherein the quality calculation unit calculates the LSNR by performing an equation: LSNR=10 log10(Σideal signal2)/(Σnoise signal2).

14. The signal quality estimating apparatus as claimed in claim 12, wherein the quality calculation unit obtains the quality of the input signal by performing an arithmetic operation on the calculated LSNR and the calculation between the plurality of ideal input signals.

15. The signal quality estimating apparatus as claimed in claim 14, wherein the quality calculation unit obtains the quality of the input signal by performing an equation: New parameter=sqrt(distance)*LSNR, where the New parameter corresponds to the quality of the input signal and the distance corresponds to a distance between two ideal input signals.

16. The signal quality estimating apparatus as claimed in claim 12, wherein the quality calculation unit obtains the quality of the input signal by performing an arithmetic operation on a result of a normalization of the LSNR to an amplitude of the input signal with the calculation between the plurality of ideal input signals.

17. The signal quality estimating apparatus as claimed in claim 16, wherein the quality calculation unit obtains the quality of the input signal by performing an equation:

18. The signal quality estimating apparatus as claimed in claim 1, wherein the quality calculation unit obtains the quality of the input signal by performing an equation:

19. A signal quality estimating method comprising: detecting level values of an input signal according to a binary signal of the input signal;composing a plurality of ideal input signals by using the level values and a plurality of pre-defined binary signals; andobtaining a quality of the input signal according to a calculation between the plurality of ideal input signals.

20. The signal quality estimating method as claimed in claim 19, wherein the detecting of the level values comprises: separating the input signal into a plurality of levels using the binary signal; andobtaining averages of each of the levels of the input signal such that the averages are the level values of the input signal.

21. The signal quality estimating method as claimed in claim 19, wherein the composing of the plurality of ideal input signals comprises: selecting the level values according to the pre-defined binary signals so as to compose the plurality of ideal input signals.

22. The signal quality estimating method as claimed in claim 19, wherein the obtaining of the quality of the input signal comprises: summing squares of differences between the plurality of ideal input signals; andoutputting the sum as the quality of the input signal.

23. The signal quality estimating method as claimed in claim 19, 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; andoutputting the square root as the quality of the input signal.

24. The signal quality estimating method as claimed in claim 19, wherein the obtaining of the quality of the input signal comprises: dividing, by an amplitude of the input signal, a square root of a sum of squares of differences between the plurality of ideal input signals; andoutputting a result of the dividing as the quality of the input signal.

25. The signal quality estimating method as claimed in claim 19, wherein the obtaining of the quality of the input signal comprises calculating an LSNR using the input signal and the binary signal such that a higher value of the LSNR corresponds to a better signal quality.

26. The signal quality estimating method as claimed in claim 25, wherein the obtaining of the quality of the input signal further comprises: performing an arithmetic operation on the calculated LSNR and the calculation between the plurality of ideal input signals.

27. The signal quality estimating method as claimed in claim 25, wherein the obtaining of the quality of the input signal further comprises: performing an arithmetic operation on a result of a normalization of the LSNR to an amplitude of the input signal with the calculation between the plurality of ideal input signals.

28. The signal quality estimating method as claimed in claim 19, wherein the obtaining of the quality of the input signal comprises: performing an equation:

29. A computer-readable recording medium encoded with the method of claim 19 and implemented by a computer.

30. An optical disc driver comprising: a signal quality estimating apparatus to estimate a quality of an input signal reproduced from an optical disc regardless of a recording density of the optical disc; anda system control unit to adjust conditions for recording and/or reproducing data to/from the optical disc while varying the conditions according to the quality of the input signal.

31. The optical disc driver as claimed in claim 30, wherein the signal quality estimating apparatus comprises: a level value detection unit to detect level values of the input signal according to a binary signal of the input signal;an input signal composing unit to compose a plurality of ideal input signals by using the level values and a plurality of pre-defined binary signals; anda quality calculation unit to obtain the quality of the input signal according to a calculation between the plurality of ideal input signals,

32. The optical disc driver as claimed in claim 30, wherein the system control unit corrects a focusing location by finely adjusting a focus offset according to the quality of the input signal.

33. The optical disc driver as claimed in claim 30, wherein the system control unit finely adjusts a tilting correction according to the quality of the input signal.

34. The optical disc driver as claimed in claim 30, wherein the system control unit finely adjusts a detracking offset according to the quality of the input signal.