Method and apparatus for detecting specific signal pattern in a signal read from an optical disc
View Patent ↗A method utilized for detecting a physical mark in a signal read from an optical disc, including: generating a matching signal capable of being utilized to identify the physical mark according to a reference clock and a wobble clock; generating a comparison signal by comparing the matching signal and a wobble data signal; determining whether a period of which the level of the comparison signal surpass a predetermined level within a predetermined period is greater than a threshold or not; and if the period greater than the threshold, generating an indication signal corresponding to the location of the physical mark. Wherein the wobble data signal and the wobble clock is generated according to the read back signal.
1. A signal pattern detecting apparatus for detecting a physical mark in a read back signal being read from an optical disc, the signal pattern detecting apparatus comprising:
a matching signal generator for generating a matching signal, capable of being utilized to identify the physical mark, according to a reference clock and a wobble clock;
a signal comparing device electrically connected to the matching signal generator for comparing the matching signal with a wobble data signal to generate a comparison signal; and
a decision circuit electrically connected to the signal comparing device for determining if a period reaches a threshold value, the period corresponding to how long the comparison signal reaches a predetermined level within a predetermined period, and if the period reaches the threshold value then decision circuit toggles an indication signal corresponding to a location of the specific signal pattern;
wherein both the wobble data signal and the wobble clock are derived from the read back signal.
2. The signal pattern detecting apparatus of claim 1 , wherein the matching signal comprises the physical mark.
3. The signal pattern detecting apparatus of claim 1 , wherein the matching signal comprises a reversed waveform of the physical mark.
4. The signal pattern detecting apparatus of claim 1 , wherein the matching signal comprises a waveform corresponding to the wobble clock.
5. The signal pattern detecting apparatus of claim 1 , wherein the matching signal comprises a waveform corresponding to a reversed waveform of the wobble clock.
6. The signal pattern detecting apparatus of claim 1 , wherein the physical mark corresponds to a minimum shift keying mark (MSK mark).
7. The signal pattern detecting apparatus of claim 1 , wherein the physical mark corresponds to a bi-phase shift keying mark (BPSK mark) specified in the DVD+R/+RW or HD-DVD standard.
8. The signal pattern detecting apparatus of claim 1 , wherein the reference clock is a channel bit clock derived from the read back signal and the reference clock is multiple times the frequency of the wobble clock.
9. The signal pattern detecting apparatus of claim 1 , wherein the matching signal generator comprises:
a counting unit for counting according to the reference clock to generate a plurality of count values; and
a toggle circuit electrically connected to the counting unit for generating the matching signal according to the count values;
wherein the counting unit is reset according to the wobble clock.
10. The signal pattern detecting apparatus of claim 1 , wherein the decision circuit comprises:
an integrating circuit electrically connected to the signal comparing device for generating an operating value according to the level of the comparison signal within the predetermined period or by calculating a moving sum of the level of the comparison signal; and
a comparator electrically connected to the integrating circuit for comparing the operating value with the threshold value to generate the indication signal.
11. The signal pattern detecting apparatus of claim 10 , wherein the integrating circuit is an accumulator.
12. The signal pattern detecting apparatus of claim 10 , wherein the predetermined period corresponds to a specific number of periods of the wobble clock.
13. The signal pattern detecting apparatus of claim 12 , wherein the integrating circuit respectively generates a plurality of operating values in a plurality of predetermined periods, and the comparator compares a sum of the operating values with the threshold value.
14. The signal pattern detecting apparatus of claim 1 , wherein both the wobble data signal and the matching signal are binary signals.
15. The signal pattern detecting apparatus of claim 14 , wherein the signal comparing device is a XOR logic or a XNOR logic.
16. The signal pattern detecting apparatus of claim 1 , wherein both the wobble data signal and the matching signal are digital signals having more than two levels.
17. The signal pattern detecting apparatus of claim 16 , wherein the signal comparing device is a digital multiplier.
18. The signal pattern detecting apparatus of claim 1 , wherein the wobble data signal is binary or a digital signal of more than two levels and the matching signal is the converse of the wobble data signal.
19. The signal pattern detecting apparatus of claim 18 , wherein the signal comparing device is an adder.
20. A method for detecting a physical mark in a read back signal being read from an optical disc, the method comprising:
(a) generating a matching signal, capable of being utilized to identify the physical mark, according to a reference clock and a wobble clock;
(b) comparing the matching signal with a wobble data signal to generate a comparison signal; and
(c) determining if a period reaches a threshold value, the period corresponding to how long the comparison signal reaches a predetermined level within a predetermined period, and generating an indication signal corresponding to a location of the specific signal pattern if the period reaches the threshold value;
wherein both the wobble data signal and the wobble clock are derived from the read back signal.
21. The method of claim 20 , wherein the matching signal comprises the physical mark.
22. The method of claim 20 , wherein the matching signal comprises a reversed waveform of the physical mark.
23. The method of claim 20 , wherein the matching signal comprises a waveform corresponding to the wobble clock.
24. The method of claim 20 , wherein the matching signal comprises a waveform corresponding to a reversed waveform of the wobble clock.
25. The method of claim 20 , wherein the physical mark corresponds to a bi-phase shift keying mark (BPSK mark) specified in the DVD+R/+RW or HD-DVD standard.
26. The method of claim 20 , wherein the physical mark corresponds to a minimum shift keying mark (MSK mark).
27. The method of claim 20 , wherein the reference clock is a channel bit clock derived from the read back signal and the reference clock is multiple times the frequency of the wobble clock.
28. The method of claim 20 , wherein both the wobble data signal and the matching signal are binary signals.
29. The method of claim 20 , wherein both the wobble data signal and the matching signal are digital signals having more than two levels.
30. The method of claim 20 , wherein one of the wobble data signal and the matching signal is a binary signal while the other signal is a digital signal having more than two levels.
31. The method of claim 20 , wherein step (c) further comprises:
generating an operating value according to the level of the comparison signal within the predetermined period; and
generating the indication signal according to the operating value and the threshold value.
32. The method of claim 31 , wherein the predetermined period corresponds to a specific number of periods of the wobble clock.
33. The method of claim 32 , further comprising:
respectively generating a plurality of operating values in a plurality of predetermined periods; and
toggling the indication signal if a sum of the operating values exceeds the threshold value.
34. The method of claim 31 , further comprising:
toggling the indication signal if the operating value exceeds the threshold value.