US5489908A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for identifying multiple transponders
Assignee: Texas Instruments Inc
•
Filing: 1994-07-27
•
Granted: 1996-02-06
•
Expires: 2014-07-27
Abstract
Abstract Apparatus and method for identifying a plurality of transponders (10-16) located within an inquiry field (18) of an interrogation unit (20) are provided. Each transponder (10-16) is assigned an unique identification code, and the interrogation unit (20) dynamically constructs and modifies a bit string used to solicit responses from selected transponder(s) until each transponder (10-16) in the inquiry field (18) is identified. The bit string is transmitted to the transponders, which compares it with the least significant bits of their respective identification codes. A mismatch between the identification code and the bit string results in suppressing the response from the transponder.
Inventors
- 👤 Kurt Orthmann
- 👤 Andreas Hagl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:45
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/10009; G06K7/10019; G06K7/10029; G06K7/10039; G06K7/0008
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
122 words
A method for identifying a plurality of transponders comprising the steps of: assigning an unique identification code to each one of said plurality of transponders; dynamically building and modifying a bit string and transmitting said bit string to said transponders; permitting responses from those transponders having identification code endings equal to said transmitting bit string; suppressing responses from those transponders having identification code endings different from said transmitted bit string; repeating said bit string building, modifying and transmitting step and response permitting and suppressing step until only one transponder response is received and said transponder identified thereby; and repeating said bit string building, modifying and transmitting step and response permitting and suppressing step until all of said plurality of transponders are identified.
Claim 2
Independent Claim
122 words
A method for identifying a plurality of transponders comprising the steps of: assigning an unique identification code to each one of said plurality of transponders; dynamically building and modifying a bit string and transmitting said bit string to said transponders; permitting responses from those transponders having identification code endings equal to said transmitting bit string; suppressing responses from those transponders having identification code endings different from said transmitted bit string; repeating said bit string building, modifying and transmitting step and response permitting and suppressing step until only one transponder response is received and said transponder identified thereby; and repeating said bit string building, modifying and transmitting step and response permitting and suppressing step until all of said plurality of transponders are identified.
Claim 3
Dependent Claim
105 words
The method, as set forth in claim 1, wherein said bit string building and modifying step comprises the steps of: increasing the number of bits in said bit string by adding a bit of a predetermined logic value to a most significant bit position when more than one transponder responds to said transmitted bit string; inverting the logic value of a most significant bit after successfully identifying a transponder; and decreasing the number of bits in said bit string by deleting a bit from a least significant bit position when no more than one transponder responds to said transmitted bit string more than once successively.
Claim 4
Dependent Claim
41 words
The method, as set forth in claim 1, further comprising the step of transmitting a bit string ending of those successfully identified transponders, and suppressing said responses from those transponders having identification code endings equal to said transmitted bit string ending.
Claim 5
Dependent Claim
29 words
The method, as set forth in claim 1, further comprising the step of comparing said transmitted bit string and least significant bits of each of said transponder identification codes.
Claim 6
Dependent Claim
21 words
The method, as set forth in claim 1, further comprising the step of storing said identification codes of successfully identified transponders.
Claim 7
Dependent Claim
23 words
The method, as set forth in claim 5, further comprising the step of deleting said stored identification codes after a predetermined time period.
Claim 8
Dependent Claim
22 words
The method, as set forth in claim 1, further comprising the step of reckoning a shifted resonance frequency of said transponder responses.
Claim 9
Dependent Claim
18 words
The method, as set forth in claim 1, further comprising the step of storing said transmitted bit strings.
Claim 10
Independent Claim
118 words
A method for identifying a plurality of transponders located in close proximity with one another within an inquiry field of an interrogation unit, comprising the steps of: assigning an unique identification code to each of said plurality of transponders; constructing a bit string; transmitting said bit string in an interrogation pulse; silencing those transponders having an identification code ending unequal to said bit string; receiving responses to said interrogation pulse from those transponders having an identification code ending equal to said bit string; modifying said bit string and transmitting said bit string until only one transponder responds and is identified; and repeating said modifying and transmitting bit string step until all of said plurality of transponders are identified.
Claim 11
Independent Claim
118 words
A method for identifying a plurality of transponders located in close proximity with one another within an inquiry field of an interrogation unit, comprising the steps of: assigning an unique identification code to each of said plurality of transponders; constructing a bit string; transmitting said bit string in an interrogation pulse; silencing those transponders having an identification code ending unequal to said bit string; receiving responses to said interrogation pulse from those transponders having an identification code ending equal to said bit string; modifying said bit string and transmitting said bit string until only one transponder responds and is identified; and repeating said modifying and transmitting bit string step until all of said plurality of transponders are identified.
Claim 12
Dependent Claim
43 words
The method, as set forth in claim 9, wherein said bit string constructing and modifying step comprises the step of adding a bit value to a predetermined bit position of said bit string after more than one transponder responds to said interrogation pulse.
Claim 13
Dependent Claim
42 words
The method, as set forth in claim 9, wherein said bit string constructing and modifying steps comprise the step of inverting the bit value of a predetermined bit position of said bit string after only one transponder responds to said interrogation pulse.
Claim 14
Dependent Claim
46 words
The method, as set forth in claim 9, wherein said bit string constructing and modifying steps comprise the step of deleting a bit value at a predetermined bit position in said bit string after only one transponder responds to said interrogation pulse more than once successively.
Claim 15
Dependent Claim
103 words
The method, as set forth in claim 9, wherein said bit string constructing and modifying steps comprise the steps of: increasing the number of bits in said bit string by adding a bit of a predetermined logic value to a most significant bit position when more than one transponder responds to said interrogation pulse; inverting the logic value of a most significant bit after successfully identifying a transponder; and decreasing the number of bits in said bit string by deleting a bit from a least significant bit position when no more than one transponder responds to said interrogation pulse more than once successively.
Claim 16
Dependent Claim
41 words
The method, as set forth in claim 9, further comprising the step of transmitting a bit string ending of those successfully identified transponders, and suppressing said responses from those transponders having identification code endings equal to said transmitted bit string ending.
Claim 17
Dependent Claim
29 words
The method, as set forth in claim 9, further comprising the step of comparing said transmitted bit string and least significant bits of each of said transponder identification codes.
Claim 18
Dependent Claim
21 words
The method, as set forth in claim 9, further comprising the step of storing said identification codes of successfully identified transponders.
Claim 19
Dependent Claim
23 words
The method, as set forth in claim 16, further comprising the step of deleting said stored identification codes after a predetermined time period.
Claim 20
Dependent Claim
22 words
The method, as set forth in claim 9, further comprising the step of reckoning a shifted resonance frequency of said transponder responses.
Claim 21
Dependent Claim
18 words
The method, as set forth in claim 9, further comprising the step of storing said transmitted bit strings.
Claim 22
Dependent Claim
116 words
A transponder system comprising: an interrogation unit comprising: a processor dynamically building and modifying a bit string; a transmitter transmitting an interrogation pulse including said bit string receivable within an inquiry field; and a plurality of transponders located in close proximity with one another within said inquiry field, each transponder comprising: a memory storing an unique identification code; a resonant circuit receiving said interrogation pulse, said interrogation pulse including said bit string; a controller comparing said received bit string with least significant bits of said stored identification code; and a de-energizer circuit suppressing said resonant-circuit from transmitting a response in response to said least significant bits of said identification code being unequal to said bit string.
Claim 23
Dependent Claim
116 words
A transponder system comprising: an interrogation unit comprising: a processor dynamically building and modifying a bit string; a transmitter transmitting an interrogation pulse including said bit string receivable within an inquiry field; and a plurality of transponders located in close proximity with one another within said inquiry field, each transponder comprising: a memory storing an unique identification code; a resonant circuit receiving said interrogation pulse, said interrogation pulse including said bit string; a controller comparing said received bit string with least significant bits of said stored identification code; and a de-energizer circuit suppressing said resonant-circuit from transmitting a response in response to said least significant bits of said identification code being unequal to said bit string.
Claim 24
Dependent Claim
33 words
The system, as set forth in claim 20, wherein said transponder resonant circuit transmits a response in response to said least significant bits of said identification code being equal to said bit string.
Claim 25
Dependent Claim
32 words
The system, as set forth in claim 21, wherein said interrogation unit further comprises: a receiver receiving said transponder response; and a memory storing bit strings eliciting response from only one transponder.
References Cited (Backward Citations)
US4333072A
Cited
US5041826A
Cited
US5053774A
Cited
US5438335A
Cited
NL8802718A
Cited
US5430447A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-02-05 | 1999-08-07 | 2000-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-02-05 | 2003-08-07 | 2004-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-02-05 | 2007-08-07 | 2008-02-06 | $7700.00 | Window Closed / Lapsed |