Single chip transponder device

An electronic identification system for identifying a plurality of objects comprising:

• a controller/interrogator unit for interrogating the objects to be identified and processing the responses received, said controller interrogator unit including:
• means for generating an RF carrier signal, said RF carrier signal comprising an interrogation signal,
• means for transmitting said interrogation signal towards an object to be identified,
• means for receiving a responsive signal generated in response to said interrogation signal, and
• means for decoding, storing, and displaying the response received;
• and
• a transponder unit, carried by each object to be identified, comprising:
• a single monolithic semiconductor chip;
• receiving means on said semiconductor chip for receiving the interrogation signal from said controller-interrogator unit,
• diode means on said semiconductor chip for rectifying the received interrogation signal in order to generate operating power for the transponder device, and for mixing an encoded data word with a digital carrier signal in order to generate sum and difference signals, said sum and difference signals comprising said responsive signal,
• digital circuit means on said semiconductor chip for deriving a clock signal and said digital carrier signal from said interrogation signal,
• data generating means on said semiconductor chip responsive to said clock signal for generating the encoded data word that is mixed with the digital carrier signal in said diode means, and
• transmitting means on said semiconductor chip for transmitting the responsive signal to said controller/interrogator unit.

A transponder device consisting of:

• a single semiconductor chip;
• receiving means placed on said semiconductor chip for receiving a carrier signal from an external source;
• diode means for rectifying the received carrier signal in order to generate operating power for the transponder device, and for mixing an encoded data word with the carrier signal in order to generate sum and difference signals, said diode means comprising an electrical circuit that is fabricated on said semiconductor chip;
• digital circuit means for deriving a clock signal from said carrier signal, said digital circuit means comprising electrical circuits that are fabricated on said semiconductor chip;
• data generating means responsive to said clock signal for generating the encoded data word that is mixed with the carrier signal in said diode means, said data generating means comprising an electrical circuit that is fabricated on said semiconductor chip;
• and
• transmitting means placed on said semiconductor chip for transmitting the sum and difference signals to a location external from said transponder device.