Method of sampling color signal
AssigneeContec, LLC
InventorsShiro Hayano, Masamitsu Toda, Kazuyoshi Nishiyama
Life of this patent
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Abstract
Receiving an instruction designating a frequency f by an MPU (1), a programmable clock generator (2) generates a dot clock D which has the frequency f. The dot clock D and a horizontal synchronizing signal H having a cycle T.sub.H are supplied to a counter (3). The counter (3) counts the number N of activations of the dot clock D during the cycle T.sub.H. The activation number N is supplied to a comparator (4), together with a predetermined number K which is designated by the MPU (1). The comparator (4) compares these numbers and supplies a comparison result C to the MPU (1). The MPU (1) updates the frequency f, in accordance with the comparison result C.
Claims7
A color signal sampling method for sampling a color signal of an analog form, using a sampling clock having a frequency f, said color signal sampling method comprising the steps of:
- (a) inputting a horizontal synchronizing signal which is activated during a predetermined cycle T.sub.H and inputting said color signal;
- (b) counting the number N of activations of said sampling clock per said cycle T.sub.H ;
- (c) comparing said number N of activations with a predetermined number K;
- (d) setting said frequency f to a specific frequency by performing:
- (d-1) first processing for decreasing said frequency f when N>K, and
- (d-2) second processing for increasing said frequency f when N<K;
- (d-3) third processing for first increasing said frequency f and then decreasing said frequency f when N=K;
- and
- (e) sampling said color signal using said sampling clock at said specific frequency.
A color signal sampling method for sampling a color signal of an analog form, using a sampling clock having a frequency f, said color signal sampling method comprising the steps of:
- (a) inputting a horizontal synchronizing signal which is activated during a predetermined cycle T.sub.H and inputting said color signal;
- (b) counting the number N of activations of said sampling clock per said cycle T.sub.H ;
- (c) comparing said number N of activations with a predetermined number K;
- (d) setting said frequency f to a specific frequency;
- and
- (e) sampling said color signal using said sampling clock at said specific frequency;
- wherein said frequency f is controlled in a unit which is finer than 1/T.sub.H ;
- and
- said step (d) includes the steps of:
- when N=K,
- (d-1) increasing said frequency f by said unit and setting said frequency f which sets N=K+1 for a first time as a first frequency,
- (d-2) decreasing said frequency f by said unit and setting said frequency f which sets N=K+1 for a first time as a second frequency, and
- (d-3) calculating said specific frequency by dividing a sum of said first and second frequencies by 2.
A color signal sampling method for sampling a color signal of an analog form, using a sampling clock having a frequency f, said color signal sampling method comprising the steps of:
- (a) inputting a horizontal synchronizing signal which is activated during a predetermined cycle T.sub.H and inputting said color signal;
- (b) counting the number N of activations of said sampling clock per said cycle T.sub.H ;
- (c) comparing said number N of activations with a predetermined number K;
- (d) setting said frequency f to a specific frequency by performing a processing for decreasing said frequency f when N>K;
- and
- (e) sampling said color signal using said sampling clock at said specific frequency;
- wherein said frequency f is controlled in a unit which is finer than 1/T.sub.H ;
- and said processing step includes the steps of:
- (d-1) decreasing said frequency f by said unit and setting said frequency f to a frequency immediately before N=K as a first frequency,
- (d-2) decreasing said frequency f by said unit and setting said frequency f which sets N=K-1 for a first time as a second frequency, and
- (d-3) calculating said specific frequency by dividing a sum of said first and second frequencies by 2.
A color signal sampling method for sampling a color signal of an analog form, using a sampling clock having a frequency f, said color signal sampling method comprising the steps of:
- (a) inputting a horizontal synchronizing signal which is activated during a predetermined cycle T.sub.H and inputting said color signal;
- (b) counting the number N of activations of said sampling clock per said cycle T.sub.H ;
- (c) comparing said number N of activations with a predetermined number K;
- (d) setting said frequency f to a specific frequency by performing a processing for increasing said frequency f when N<K;
- and
- (e) sampling said color signal using said sampling clock at said specific frequency;
- wherein said frequency f is controlled in a unit which is finer than 1/T.sub.H ;
- and said processing step includes the steps of:
- (d-1) increasing said frequency f by said unit and setting said frequency f to a frequency immediately before N=K as a first frequency,
- (d-2) increasing said frequency f by said unit and setting said frequency f which sets N=K+1 for a first time as a second frequency, and
- (d-3) calculating said specific frequency by dividing a sum of said first:
- and second frequencies by 2.
Dependencies are inferred from the claim text.