ADDITIONAL INFORMATION IDENTIFICATION METHOD AND ADDITIONAL INFORMATION IDENTIFICATION PROCESSING UNIT

摘要

PROBLEM TO BE SOLVED: To provide an additional information identification processing unit that detects additional information, superimposed on an information signal with spread spectrum processing at a small spread gain in a short time which high detection accuracy and properly processes the information signal, based on the result of detection. SOLUTION: A additional information signal detection section 11 uses inverse spread spectrum processing to detect four times additional information f2a which is superimposed on a information signal f1a repetitively four times in a period shorter than a decoding period of spread information through spread spectrum processing, based on a PN signal f5a of spread spectrum processing from a PN-generating section 13. A coincidence detection section 12 confirms the coincidence of four times detection results and confirms superimposition of the additional information f2a, then the additional information f2a is detected in a short time because the period of spread spectrum processing is short, the additional information f2a is detected with high detection accuracy by a small spread gain through the confirmation of coincidence of four times detection, and based on the detection of the additional information f2a, write inhibit by a write section 2A is conducted properly.