ACTIVE TRANSPONDER HAVING ELEMENT FOR MAKING MAXIMUM COMMUNICATION DISTANCE VARIABLE

摘要

PURPOSE: An active transponder is provided to operate in various applications or an operating mode for requesting a security of a different level by using a circuit for controlling the maximum communication distance. CONSTITUTION: Security is controlled by changing a maximum communication distance, in particular the distance to a reader. The active transponder comprises a battery(2) used for supplying a power to various electronic circuits. The transponder further comprises an amplifier(8), a module(4) for forming a demodulator for an arrival signal, and a data processing unit(10). The module(4) further includes a validity verifying element. The data processing unit(10) includes a circuit(12) for controlling the maximum communication distance between the transponder for transmitting the signal via a predetermined power and the reader. The circuit(12) is used to control a reference value of the validity verifying element or to change the gain of the amplifier(8) to enable an alteration of the maximum communication distance.