| 摘要 |
<p>The invention concerns a method and devices for checking security documents. According to this process which uses known capacitive coupling, electrical signals are transmitted by transmitting antennae via electrically conductive security features to receiving antennae and amplified. The amplitude responses and time characteristics of the electrical signals are then evaluated and compared with existing signal responses, by being converted into signal responses having easily comparable parameters. In order to enable the testing arrangement to be specifically selective, a selective amplifier is additionally coupled to the evaluation electronics. Currency-specific definition by means of the evaluation electronics according to the invention is attained in that, for a given currency, a time limit of the test signal amplitude can be determined by means of controllers, for example, this time limit differing from the duration of the amplitude response of all the other currencies.</p> |
