Patent ID: 8564722

Claim:
A horizontal synchronization signal detection system, comprising: a coarse period estimator for receiving a CVBS signal and estimating a minimum value and corresponding position of each period of the CVBS signal to calculate a coarse period of a horizontal synchronization signal; and a fine period time estimator for receiving the coarse period of the horizontal synchronization signal and dividing the horizontal synchronization signal into first signals in a first part and second signals in a second part so as to add the first signals to generate a first sum and to add the second signals to generate a second sum, wherein a signal accumulation time of each part is half of a time length of the horizontal synchronization signal; the fine period time estimator detects a middle point of the horizontal synchronization signal when the first sum is equal to the second sum; when the first sum minus the second sum is not equal to zero, the steps of fine-tuning the coarse period to generate a fine-tuned coarse period, extracting the horizontal synchronization signal according to the fine-tuned coarse period, and determining whether the first sum is equal to the second sum are repeatedly executed until the first sum is equal to the second sum for indicating that the middle point of the horizontal synchronization signal is detected.