DEVICE FOR DECODING DIGITAL SIGNAL MULTIPLEXED TO VIDEO SIGNAL, AND METHOD FOR ACQUIRING THE DIGITAL SIGNAL

摘要

PROBLEM TO BE SOLVED: To accurately acquire a digital signal multiplexed to a video signal by thresholding acquired video digital data by a determined threshold estimated as a suitable value and reproducing a digital signal. SOLUTION: An allowable range determination part 811 determines an allowable range to be a reference for discriminating whether the inherent threshold of each effective data determined by a 3rd threshold determination part 810 is suitable or not. An effective data judging threshold determination part 812 determines a threshold (effective data judging threshold) to be used for judging the '0'/'1' level of each effective data based on the threshold inherent in each effective data, the allowable range and a threshold determined by a 1st threshold determination part 807. A code generation part 804 judges the '0'/'1' level of each effective data extracted by an effective data extraction part 803 based on the threshold determined by the determination part 812 and generates a character code or a control code for two characters.