Method and device for dynamically adjusting sync-on-green (SOG) signal of video signal

1. A method for dynamically adjusting a sync-on-green (SOG) signal of a video signal, said method comprising steps of:

receiving a video signal comprising an SOG signal;

outputting a clamped signal by clamping said video signal according to a clamp level;

determining a triggering level so as to output a triggering signal according to a first sampling value and a second sampling value of said SOG signal;

comparing said clamped signal and said triggering signal so as to output a compared signal; and

performing a control operation according to said compared signal so as to generate a feedback control signal for dynamically adjusting said clamp level and said triggering level.

2. The method as recited in claim 1 , wherein said triggering level is determined by using a weighting process.

3. The method as recited in claim 2 , wherein said first sampling value is a bottom voltage value of said SOG signal.

4. The method as recited in claim 3 , wherein said second sampling value is a top voltage value of said SOG signal.

5. The method as recited in claim 4 , wherein said triggering level is expressed as:

said triggering level=said first sampling value+K*Delta;

where K is a default setting value and Delta is a difference value between said first sampling value and said second sampling value.

6. The method as recited in claim 4 , wherein said triggering level is expressed as:

said triggering level=said second sampling value−K*Delta;

where K is a default setting value and Delta is a difference value between said first sampling value and said second sampling value.

7. The method as recited in claim 4 , wherein said triggering level is expressed as:

said triggering level=said first sampling value±C;

where C is a manual setting value.

8. The method as recited in claim 4 , wherein said triggering level is expressed as:

said triggering level=said second sampling value±C;

where C is a manual setting value.

9. The method as recited in claim 4 , wherein said triggering level is a manual setting value.

10. The method as recited in claim 2 , wherein said weighting process comprises steps of:

providing a weighting value; and

performing a weighting operation according to said first sampling value and said second sampling value so as to determine said triggering level.

11. The method as recited in claim 10 , wherein said weighting value is a default setting value.

12. The method as recited in claim 10 , wherein said weighting value is a manual setting value.

13. A method for dynamically adjusting a sync-on-green (SOG) signal of a video signal, said method comprising steps of:

receiving a video signal comprising an SOG signal;

outputting a clamped signal by clamping said video signal according to a clamp level;

determining a triggering level so as to output a triggering signal by using a weighting process according to a first sampling value and a second sampling value of said SOG signal;

comparing said clamped signal and said triggering signal so as to output a compared signal;

performing a control operation according to said compared signal and at least an input voltage signal; and

generating a feedback control signal for dynamically adjusting said clamp level and said triggering level.

14. The method as recited in claim 13 , wherein said input voltage signal is an output level signal from a window comparator.

15. The method as recited in claim 13 , wherein said input voltage signal is an output digital signal from an analog-to-digital converter.

16. The method as recited in claim 13 , wherein said weighting process comprises steps of:

providing a weighting value; and

performing a weighting operation according to said first sampling value and said second sampling value so as to determine said triggering level.

17. The method as recited in claim 16 , wherein said weighting value is a default setting value.

18. The method as recited in claim 16 , wherein said weighting value is a manual setting value.

19. A device for dynamically adjusting a sync-on-green (SOG) signal of a video signal, said device comprising:

a clamp circuit for clamping a video signal so as to output a clamped signal;

a triggering level circuit for determining a triggering level according to a first sampling value and a second sampling value of said SOG signal so as to output a triggering signal;

a comparator for receiving said clamped signal and said triggering signal so as to output a compared signal; and

a control unit coupled to said triggering level circuit and said comparator for receiving said compared signal so as to provide said triggering level circuit with a feedback control signal.

20. The device as recited in claim 19 , further comprising:

a window comparator for receiving said clamped signal so as to provide an output level signal.

21. The device as recited in claim 19 , further comprising:

an analog-to-digital converter for receiving said clamped signal so as to provide an output digital signal.

22. The device as recited in claim 19 , wherein said control unit receives said compared signal and at least an input voltage signal and performs a control operation on said compared signal, said output digital signal and said output level signal.

23. The device as recited in claim 21 , wherein said analog-to-digital converter comprises a successive approximation register.