RINGUP/ RINGDOWN INTERROGATION OF RFID TAGS

摘要

The method of interrogating an RFID memory device (14) including one or more vibrating members (16-34) each being able to resonate at a different known resonant frequency uses a ring-up/down interrogation technique which exploits a property of the resonance increments in relation to the background that is not exploited in steady-state interrogation techniques. This ring-up/down interrogation technique operates by application of an electrical stimulus of appropriate band width to which one or more of the resonances can respond and absorb some amount of energy, holding it in (ultimately) mechanical form ("ring-up")(228). This stimulus is then reduced to zero, and the electrical response appearing across the terminals of the device then recorded ("ring-down")(230).