Additional information signal superposition and detection method, additional information signal detection method, additional information signal detection device and information signal recording device

摘要

The additional information f2a, which is repeated four times in a shorter period than the decoding period of the spread information by the spread spectrum information and is superimposed on the information signal f1a in advance, is added to the spread spectrum PN signal f5a from the PN generating unit by the additional information signal detecting unit The coincidence detecting unit confirms the coincidence of the four detection results and thus the superposition of the additional information f2a is determined, whereby the additional information f2a is detected within a short period of time due to a short spread spectrum period And the additional information f2a is detected with a small spreading gain and a high detection accuracy by the coincidence detection of the four detection, and the writing unit appropriately prohibits the writing in accordance with the detection of the additional information f2a.