Electronic indentification system with transponder muting

A transponder comprising

• means for receiving an interrogation signal;
• means for repeatedly transmitting transponder response signals including data which identifies the transponder;
• means for inserting a random or pseudo-random interval between transponder response signals;
• and
• control means for muting the transponder in response to an indication of successful identification occurring a predetermined period after a corresponding one of the transponder response signals is transmitted, wherein
• in a set of transponders, two or more transponders having a same transponder identity are arranged to transmit the transponder response signals including a same data in response to the interrogation signal.

An interrogator for identifying a set of transponders, the interrogator comprising:

• a transmitter arranged to transmit an interrogation signal to the set of transponders;
• a receiver arranged to receive transponder response signals from the transponders;
• means for identifying the transponder response signals and for determining a number of transponders;
• and
• means for indicating a successful identification to the identified transponder a predetermined period after a corresponding one of the transponder response signals from the identified transponder is received, wherein
• the identified transponder is arranged to be muted in response to the successful identification, and
• the set of transponders include at least two transponders having a same transponder identity and transmitting the transponder response signals having a same data in response to the interrogation signal.

An integrated circuit for use in a transponder, the integrated circuit comprising:

• means for repeatedly generating second signals including data which identifies the integrated circuit in response to a first signal;
• means for inserting one of a random and pseudo-random interval between the second signals;
• means, responsive to an indication of successful identification from an interrogator, for disabling the means for repeatedly generating second signals, wherein:
• in a set of integrated circuits, allowing at least two of the integrated circuits to generate the second signals including identical data indicating identical identities for respective ones of the at least two integrated circuits in response to an interrogation signal.

A transponder comprising:

• an integrated circuit;
• and
• a receiving antenna formed on a substrate, the integrated circuit comprising:
• means for repeatedly generating second signals including data which identifies the integrated circuit in response to a first signal;
• means for inserting one of a random and pseudo-random interval between the second signals;
• means, responsive to an indication of successful identification from an interrogator, for disabling the means for repeatedly generating second signals, wherein:
• in a set of transponders having integrated circuits, allowing at least two of the transponders to generate the second signals including identical data indicating identical identities for respective ones of the at least two transponders in response to an interrogation signal.

A transponder comprising:

• an integrated circuit;
• and
• a transmitting antenna formed on a substrate, the integrated circuit comprising:
• means for repeatedly generating second signals including data which identifies the integrated circuit in response to a first signal;
• means for inserting one of a random and pseudo-random interval between the second signals;
• means, responsive to an indication of successful identification from an interrogator, for disabling the means for repeatedly generating second signals, wherein:
• in a set of transponders having integrated circuits, allowing at least two of the transponders to generate the second signals including identical data indicating identical identities for respective ones of the at least two transponders in response to an interrogation signal.

A method for identifying a transponder in an identification system, the method comprising:

• transmitting an interrogation signal to a plurality of transponders from an interrogator;
• transmitting a transponder response signal from a transponder in response to the interrogation signal, the transponder response signal including data which identifies the transponder;
• receiving the transponder response signal at the interrogator;
• identifying the transponder from the data in the transponder response signal;
• indicating a successful identification of the transponder response signal to the identified transponder a predetermined period after the transponder response signal from the identified transponder is received at the interrogator;
• and
• muting the transponder in response to receiving the successful identification indication from the interrogator, wherein
• at least two transponders of the plurality of transponders have a same transponder identity and transmit transponder response signals including the same transponder identity in response to the interrogator signal, and
• when the transponder fails to sense a successful indication of the transponder response signal, retransmitting the transponder response signal a random or pseudo-random interval of time after a previous transmission of the transponder response signal.