Patent ID: 6070803
Filing Date: 2000-06-06
Classification: G01S,G06K,H03J

Abstract:
A reading device for interacting with at least one transponder having a transponder resonant circuit exhibiting a transponder resonance frequency (fo), said reading device comprising:a reading device resonant circuit which is designed as a reading device antenna and a reading device resonant circuit capacitor, said reading device resonant circuit being tuned to said resonance frequency (fo); andan automatic tuning unit connected to said reading device resonant circuit for automatically tuning said reading device resonant circuit to said resonance frequency (fo) of said reading device by adjusting said reading device resonant circuit to compensate said reading device resonant circuit for external influences on said reading device resonant circuit;at least one adjustment element for altering the operating characteristics of said reading device resonant circuit; andwherein said automatic tuning unit includes means for selectively connecting and disconnecting said at least one adjustment element to said reading device resonant circuit based on a state of said reading device resonant circuit;wherein said automatic tuning unit defines a value such that said operating characteristics of said reading device resonant circuit are changed by incrementing or decrementing said value to tune said reading device resonant circuit to said resonance frequency (fo);wherein said at least one adjustment element includes at least one inductor or at least one capacitor.