Interrogator-responder identification system

• US 3,299,424 A
• Filed: 05/07/1965
• Issued: 01/17/1967
• Est. Priority Date: 05/07/1965
• Status: Expired due to Term

• Current Assignee: Jorgen P. Vinding
• Original Assignee: Jorgen P. Vinding
• Inventors: Vinding, Jorgen P.
• Application Number:
  US04/453,939
• Time in Patent Office: 620 Days
• US Class Current: 340/10.3
• CPC Class Codes: B61L 25/043 using inductive tags
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence

Claims

1. AN IDENTIFICATION SYSTEM FOR IDENTIFYING RESPONDERS WHEN BROUGHT WITHIN INDUCTIVE COUPLING PROXIMITY OF AN INTERROGATOR, SAID IDENTIFICATION SYSTEM COMPRISING:

AN INTERROGATOR INCLUDING, A SUBSTANTIALLY NONRADIATIVE COUPLING CIRCUIT TUNED TO AN INTERROGATOR FREQUENCY, SIGNAL SOURCE MEANS CONNECTED TO SAID TURNED COUPLING CIRCUIT TO EXCITE SAID TUNED CIRCUIT TO OSCILLATE AT SAID INTERROGATOR FREQUENCY, SENSING MEANS RESPONSIVE TO SAID TUNED COUPLING CIRCUIT TO PROVIDE A SENSED SIGNAL COMMENSURATE WITH A SELECTED CHARACTERISTIC OF THE OSCILLATIONS IN SAID TUNED COUPLING CIRCUIT, AND UTILIZATION MEANS RESPONSIVE TO SAID SENSED SIGNAL AND OPERATIVE TO PROVIDE AN INDICATION WHEN THE SELECTED CHARACTERISTIC OF SAID SENSED SIGNAL VARIES IN ACCORDANCE WITH A PRESELECTED PROGRAM;

AND AT LEAST ONE RESPONDER, EACH RESPONDER INCLUDING, A SUBSTANTIALLY NONRADIATIVE COUPLING CIRCUIT TUNED TO SAID INTERROGATOR FREQUENCY, IMPEDANCE CIRCUIT MEANS FOR CHANGING THE IMPEDANCE OF THE TUNED COUPLING CIRCUIT OF SAID RESPONDER, AND SWITCHING MEANS FOR CONNECTING SAID IMPEDANCE CIRCUIT MEANS TO THE TUNED COUPLING CIRCUIT OF SAID RESPONDER, SAID SWITCHING MEANS BEING OPERATIVE TO CONNECT AND DISCONNECT SAID IMPEDANCE CIRCUIT MEANS INTO THE TUNED COUPLING CIRCUIT OF SAID RESPONDER IN ACCORDANCE WITH SAID PRESELECTED PROGRAM.