Method and apparatus for detecting specific signal pattern in a signal read from an optical disc
View Patent ↗A signal pattern detecting apparatus, which is capable of detecting a physical mark in a read back signal being read from an optical disc, includes a matching signal generator, a signal comparing device, and a decision circuit. The matching signal generator is utilized for generating a matching signal, capable of being utilized to identify the physical mark, according to a reference clock and a wobble clock. The signal comparing device is electrically connected to the matching signal generator, and utilized for comparing the matching signal with a wobble data signal to generate a comparison signal. The decision circuit is electrically connected to the signal comparing device, and utilized for generating an indication signal according to the comparison signal and a threshold value. Both the wobble data signal and the wobble clock are derived from 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 generating an indication signal according to the comparison signal and a threshold value;
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) generating an indication signal according to the comparison signal and a 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 , further comprising:
toggling the indication signal if the operating value exceeds the threshold value.
33. The method of claim 31 , wherein the predetermined period corresponds to a specific number of periods of the wobble clock.
34. The method of claim 33 , 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.