| 摘要 |
PROBLEM TO BE SOLVED: To make decoding of signal contents impossible and to make fabrication/alteration of a magnetic card, etc., difficult by recording an irrewritable analog random signal that a pulse height value of a regenerative pulse voltage is changed irregularly on at least another upper part magnetic layer. SOLUTION: A first magnetic layer 2 and a second magnetic layer 3 are laminated on a substrate 1, and an irrewritable analog random fixed signal 5 is formed on the second magnetic layer 3. The second magnetic layer 3 is formed by soft magnetic material of coercive force 400 Oe or below. When a variable signal is regenerated while applying a bias, a composite signal between the analog random fixed signal 5 and the variable signal is regenerated. Thus, in addition to a variable information signal to be recorded on the first magnetic layer 2 and the analog random fixed signal to be formed on the second magnetic layer 3, the composite signal of those signals is used as a third information signal. By using the variable information signal, the fixed signal and the composite signal, the encoding is performed. |
