ELECTRONIC VALIDATION MACHINE FOR DOCUMENTS

摘要

Information can be obtained from a document having printed electronic circuits (82-96) by using an electronic verification machine (108, 224) that determines the electrical characteristics or signatures of the circuits printed on the document. The electronic verification machine ( 108,224) electronically couples with the circuit applies an excitation signal such as an AC signal (242) having a predetermined frequency to the circuit. A detection circuit (226A-226H) in the electronic verification machine then generates a detection signal in response to the excitation signal which represents the characteristics of the circuit printed on the document. The electrnic verification machine (108, 224) can also be used to stigmatize the document by applying a signal to the electronic circuits having sufficient strength to alter the electronic circuit.