Object identification system
First Claim
1. An object identification system comprising:
- an interrogation circuit including a sweep frequency signal generator for generating a sweep frequency signal;
a transmitting/receiving duplex circuit connected to said interrogation circuit;
transmitting/receiving antenna means which is connected to said transmitting/receiving duplex circuit and transmits said sweep frequency signal as an interrogation signal;
an answer device which includes a plurality of resonators with different resonance frequencies connected in parallel one another and an answer antenna means connected in parallel with said resonators, and which is fixed on an object to be identified and transmits resonance answer signals corresponding to the resonances of said resonators in response to said interrogation signal toward said transmitting/receiving antenna means;
phase adjusting means which is connected to said transmitting/receiving duplex circuit and said interrogation circuit and adjusts the phases of the sweep frequency signal from said sweep frequency signal generating circuit and said resonance answer signal to have a phase difference of substantially 0 or 180 degrees;
a detector for detecting a ringing answer signal included in said resonance answer signal from the output of said phase adjusting means;
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Accused Products
Abstract
A transmitting/receiving antenna radiates a sweep frequency signal as an interrogation signal to an answer device. The answer device includes a plurality of resonators which are connected in parallel and have different resonance frequencies and answer antenna means connected in parallel with these resonators and transmits resonance answer signals including ringing answer signals corresponding to the resonators, in response to the interrogation signal. A phase adjusting means is provided which receives at the inputs the sweep frequency signal and the resonance answer signal and adjusts the phases of these signals to have the phase difference therebetween 0° or 180°. The output of the phase adjusting means is applied to a detector where the ringing answer signals are detected to form binary answer signals corresponding to the ringing answer signals, respectively. An object with the answer device fixed thereat is identified from these binary answer signals.
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Citations
11 Claims
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1. An object identification system comprising:
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an interrogation circuit including a sweep frequency signal generator for generating a sweep frequency signal; a transmitting/receiving duplex circuit connected to said interrogation circuit; transmitting/receiving antenna means which is connected to said transmitting/receiving duplex circuit and transmits said sweep frequency signal as an interrogation signal; an answer device which includes a plurality of resonators with different resonance frequencies connected in parallel one another and an answer antenna means connected in parallel with said resonators, and which is fixed on an object to be identified and transmits resonance answer signals corresponding to the resonances of said resonators in response to said interrogation signal toward said transmitting/receiving antenna means; phase adjusting means which is connected to said transmitting/receiving duplex circuit and said interrogation circuit and adjusts the phases of the sweep frequency signal from said sweep frequency signal generating circuit and said resonance answer signal to have a phase difference of substantially 0 or 180 degrees; a detector for detecting a ringing answer signal included in said resonance answer signal from the output of said phase adjusting means; - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11)
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2. a separation circuit for separating the ringing answer signals included in the output of said detector;
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a signal extracting circuit for extracting binary answer signals corresponding to said separated ringing answer signals; and a memory circuit for storing said binary answer signals.
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Specification