Group-addressable transponder arrangement
First Claim
1. A method of communicating between an interrogator unit and at least two responder units, said method comprising the steps of:
- transmitting from said interrogator unit to each of said responder units at least one interrogation pulse of a selected frequency and having a transmitted Group Address modulated thereon;
receiving by each of said responder units said interrogation pulse;
demodulating said interrogation pulse within each of said responder units;
comparing said transmitted Group Address to a responder group address stored within a memory within each of said responder units;
activating within each of said responder units a threshold signal upon detection of a decreasing power level of said interrogation pulse;
exciting a carrier wave within each of said responder units, said carrier wave having substantially said selected frequency;
transmitting an response from each of said responder units, said response generated upon activation of said threshold signal and upon comparison of said transmitted Group Address to said responder group address;
detecting the presence of more than one responder unit by receiving an unintelligible response at said interogator unit.
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Accused Products
Abstract
A responder unit (12) located in spaced relation with respect to an interrogator unit (10) is described. The responder unit (12) has a responder unit receiver (130) for receiving at least one RF interrogation pulse, a responder unit memory (168) containing a potentially unique responder unit group address, a responder unit controller (202) operably connected to the memory (168) for comparing the potentially unique responder unit group address to the Group Address, and a responder unit transmitter (130) for transmitting a RF response when the potentially unique responder unit group address matches the Group Address.
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Citations
11 Claims
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1. A method of communicating between an interrogator unit and at least two responder units, said method comprising the steps of:
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transmitting from said interrogator unit to each of said responder units at least one interrogation pulse of a selected frequency and having a transmitted Group Address modulated thereon; receiving by each of said responder units said interrogation pulse; demodulating said interrogation pulse within each of said responder units; comparing said transmitted Group Address to a responder group address stored within a memory within each of said responder units; activating within each of said responder units a threshold signal upon detection of a decreasing power level of said interrogation pulse; exciting a carrier wave within each of said responder units, said carrier wave having substantially said selected frequency; transmitting an response from each of said responder units, said response generated upon activation of said threshold signal and upon comparison of said transmitted Group Address to said responder group address; detecting the presence of more than one responder unit by receiving an unintelligible response at said interogator unit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of detecting the presence of a number of responder units which are identifiable by a selected group address code, said method comprising the steps of:
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transmitting at least one interrogation pulse having said selected group address code modulated thereon; determining whether any of said plurality of responder units are within range of said interrogator unit, said determining step accomplished by; i) determining that none of said responder units are within range by not receiving a response signal; ii) determining that one of said responder units is within range by receiving an intelligible response signal;
oriii) determining that more than one of said responder units are within range by receiving an unintelligible response signal. - View Dependent Claims (9, 10, 11)
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Specification