VIDEO SIGNAL TRANSMISSION METHOD, SUPERIMPOSED INFORMATION EXTRACTION METHOD, VIDEO SIGNAL OUTPUT DEVICE, VIDEO SIGNAL RECORDING DEVICE, AND VIDEO SIGNAL RECORDING MEDIUM

A circuit to extract spectrally spread additional information superimposed on the video signal rapidly and correctly. The output device 10 generates the PN code string every second vertical interval with reference to the video sync signal, and spectrally spreads the additional information using this PN code string. The spectrally spread additional information is superimposed on the video signal every second vertical interval and outputted. Upon receiving the video signal, in the recording device for recording the video signal on a recording medium, the video signal component cancel each other between the video signal component in the vertical interval on which the additional information is superimposed and the video signal component in the vertical interval on which the additional information is not superimposed because of the field correlation of the video signal, and only the additional information is extracted.