초록 ▼

An identification system comprises an interrogator and a plurality of transponders. The interrogator includes a transmitter which transmits at least two independent interrogation signals to the transponders, and a receiver for receiving response signals from the transponders. The interrogator also i

An identification system comprises an interrogator and a plurality of transponders. The interrogator includes a transmitter which transmits at least two independent interrogation signals to the transponders, and a receiver for receiving response signals from the transponders. The interrogator also includes processor means for identifying the transponders from data in the received response signals. Each transponder comprises receiving means, a code generator, and transmitter means connected to the code generator. On receipt of at least one of the transmitted interrogation signals the transponder transmits a response signal containing data which identifies it. The interrogation signals may be transmitted continuously or intermittently. In a preferred embodiment, the interrogation signals are relatively narrow bandwidth signals at different frequencies. The receiving means of each transponder has a relatively broad reception bandwidth so that the transponder is responsive to one or more of the interrogation signals.

대표청구항 ▼

[ We claim:] [1.] An identification system comprising:an interrogator; anda plurality of transponders;the interrogator comprising:transmitter means for transmitting an interrogation signal to a plurality of transponders,receiver means for receiving a respective plurality of response signals from the

[ We claim:] [1.] An identification system comprising:an interrogator; anda plurality of transponders;the interrogator comprising:transmitter means for transmitting an interrogation signal to a plurality of transponders,receiver means for receiving a respective plurality of response signals from the plurality of transponders, andmeans for identifying the plurality of transponders from the respective plurality of response signals,the interrogator being capable of disabling any of the plurality of transponders;each of the plurality of transponders comprising:receiving means, andtransmitting means,whereby, on receipt of the transmitted interrogation signal, the transponder transmits a response signal;wherein the interrogator transmits at least two intermittent interrogation signals, with an interval between successive interrogation signals which is less than a minimum period within which transponders which have been disabled reset themselves automatically.