Method of reading the data stored in a passive responder by means of an interrogation device comprising a receiving section

摘要

A method is described for reading the data stored in a passive responder (20) by means of an interrogation device (10) including a receiving section (14). To initiate a read cycle the interrogation device (10) transmits an HF interrogation pulse which on reception in the responder (20) is used to generate a supply voltage and initiates the transmission of an HF signal coded with the stored data. The frequency of the HF interrogation pulse is varied during its transmission over a predetermined range containing the nominal frequency of the responder (20). The receiving section (14) of the interrogation device (10) includes a tuning circuit (15) which adjusts the receiving frequency of the receiving section (14) to the frequency of the HF signal transmitted by the responder (20).