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EP0685825A2
Expired / Lapsed
EP
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Electronic identification system
Assignee: ZIH Corp
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Filing: 1992-01-03
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Granted: —
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Expires: 2012-01-03
Abstract
Abstract An identification system comprises an interrogator and a number of transponders. The interrogator includes a transmitter (10) for transmitting an interrogation signal to the transponder, and a receiver (16,18,20,22) for receiving a response signal from the transponder. A micro-processor (28) identifies the transponder from data in the response signal. Each transponder comprises a receiving antenna (30) for receiving the interrogation signal, a code generator (36), a transmitting antenna (32), and a modulator (40) connected to the code generator. On receipt of the interrogation signal the transponder repeatedly transmits a response signal containing data which identifies the transponder. The interrogator detects successful identification of any transponder and briefly interrupts the interrogation signal to indicate the successful identification. Each transponder includes a logic circuit (42) responsive to a respective interruption in the interrogation signal to cease transmission of its own response signal.
Inventors
- 👤 Michael John Camille Marsh
- 👤 Andrzej Lenarcik
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 21:36
CPC Classifications
G; G07; G07B; G07B15/00; G07B15/06; G07B15/063; G01; G01S; G01S13/00; G01S13/74; G01S13/75; G01S13/751; G01S13/758; G06; G06K; G06K17/00; G06K17/0022; G06K7/00; G06K7/0008; G06K7/10; G06K7/10009; G06K7/10019; G06K7/10029; G06K7/10039; G06K7/10059; G07C; G07C9/00; G07C9/20; G07C9/28; G08; G08B; G08B13/00; G08B13/02; G08B13/14; G08B13/1427; G08B21/00; G08B21/02; G08B21/0202; G08B21/0222; G08B21/0227; G08G; G08G1/00; G08G1/01; G08G1/017; H; H04; H04L; H04L1/00; H04L1/08
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
120 words
An identification system comprising an interrogator and a set of transponders, the interrogator including transmitter means (10) for transmitting an interrogation signal to the transponder, receiver means (16,18,20,22) for receiving a response signal from the transponder, and processor means (28) for identifying the transponder from data in the response signal; each transponder comprising a receiving antenna (30) for receiving the interrogation signal, a code generator (36), a transmitting antenna (32), and a modulator (40) connected to the code generator, so that on receipt of the interrogation signal the transponder transmits a response signal containing data which identifies the transponder, characterised in that the set of transponders contains two or more transponder in which said code generator generates the same code.
Claim 2
Dependent Claim
120 words
An identification system comprising an interrogator and a set of transponders, the interrogator including transmitter means (10) for transmitting an interrogation signal to the transponder, receiver means (16,18,20,22) for receiving a response signal from the transponder, and processor means (28) for identifying the transponder from data in the response signal; each transponder comprising a receiving antenna (30) for receiving the interrogation signal, a code generator (36), a transmitting antenna (32), and a modulator (40) connected to the code generator, so that on receipt of the interrogation signal the transponder transmits a response signal containing data which identifies the transponder, characterised in that the set of transponders contains two or more transponder in which said code generator generates the same code.
Claim 3
Dependent Claim
33 words
An identification system according to claim 1 characterised in that each transponder is adapted to repeat the transmission of the response signal to increase the probability of successful reception thereof by the interrogator.
Claim 4
Dependent Claim
53 words
An identification system according to claim 2 characterised in that the interrogator is adapted to detect successful identification of any transponder and to modify the interrogation signal to indicate the successful identification, each transponder including meant (38,42) responsive to a respective modification of the interrogation signal to cease transmission of its response signal.
Claim 5
Dependent Claim
54 words
An identification system according to claim 3 characterised in that the interrogator is adapted to interrupt the interrogation signal for a predetermined period after successfully identifying a particular transponder, that transponder in turn being adapted to sense the interruption in the interrogation signal and to cease transmission of its response signal in response thereto.
Claim 6
Dependent Claim
29 words
An identification system according to claim 4 characterised in that the predetermined period for which the interrogation signal is interrupted is shorter than the response signal of the transponder.
Claim 7
Dependent Claim
45 words
An identification system according to any one of claims 1 to 5 characterised in that the transponder includes control means (42) for controlling the transmission of the response signal, the control means being adapted to cause repeated transmissions of the response signal at predetermined intervals.
Claim 8
Dependent Claim
19 words
An identification system according to claim 6 characterised in that the predetermined intervals are random or pseudo-random in length.
Claim 9
Dependent Claim
25 words
An identification system according to claim 7 characterised in that the length of the random or pseudo-random intervals is derived from data identifying the transponder.
Claim 10
Dependent Claim
48 words
An identification system according to any one of claims 1 to 8 characterised in that the interrogator is adapted to transmit a code identifying a predetermined transponder or category of transponders, each transponder including circuity (42) for enabling the transponder only on receipt of the code corresponding thereto.
Claim 11
Dependent Claim
72 words
An identification system according to any one of claims 1 to 9 characterised in that the modulator (40) of each transponder is arranged to divert a portion of the energy of the received interrogation signal to the transmitting antenna, so that on receipt of the interrogation signal, the transponder transmits a response signal comprising a carrier derived from the interrogation signal which is modulated by the output of the code generator (36).
Claim 12
Dependent Claim
55 words
An identification system according to claim 10 characterised in that the interrogator includes a mixer (20) for mixing a reference signal derived from the interrogation signal with the received response signal from the transponder, and filter means (22) for extracting a difference signal from the mixer output which contains the data from the response signal.
Claim 13
Dependent Claim
88 words
A transponder for use with the system of any one of claims 1 to 11, characterised in that the transponder comprises a receiving antenna (30) for receiving the interrogation signal, a code generator (36), a transmitting antenna 932), and a modulator (40) connected to the code generator, the transponder being adapted to transmit a response signal containing data which identifies the transponder, the transponder including control means (38,42) arranged to cause repeated transmission of the response signal to increase the probability of successful reception thereof by the interrogator.
Claim 14
Dependent Claim
30 words
A transponder according to claim 12 characterised in that the control means (42) is responsive to a respective modification of the interrogation signal to cease transmission of the response signal.
Claim 15
Dependent Claim
67 words
A transponder according to claim 11 or claim 13 characterised in that the modulator (40) is arranged to divert a portion of the energy of the received interrogation signal to the transmitting antenna (32), so that on receipt of the interrogation signal, the transponder transmits a response signal comprising a carrier derived from the interrogation signal which is modulated by the output of the code generator (36).
Claim 16
Dependent Claim
53 words
A transponder according to claim 13 or claim 14 characterised in that the control means (38,42) is arranged to monitor the received interrogation signal and to disable the modulator (40) on receipt of a predetermined confirmation signal from the interrogator which is received after successful reception of the response signal by the interrogator.
Claim 17
Dependent Claim
27 words
A transponder according to claim 15 characterised in that the control means (42) is adapted to detect an interruption of the interrogation signal of a predetermined period.
Claim 18
Dependent Claim
46 words
A transponder according to any one of claims 12 to 16 including charge storage means (c) arranged to store a portion of the energy of the interrogation signal, at least the code generator (36) being arranged to be powered by the charge storage means in operation.
Claim 19
Dependent Claim
42 words
A transponder according to any one of claims 15 to 17 characterised in that the control means (42) is adapted to monitor the received interrogation signal for a predetermined code, and to enable the modulator (40) only on receipt of that code.
Claim 20
Dependent Claim
35 words
A transponder according to any one of claims 12 to 18 characterised in that at least one of the receiving and transmitting antennas (30,32) is formed on a substrate to which the transponder is applied.
Claim 21
Dependent Claim
25 words
A transponder according to claim 19 characterised in that at least one antenna (30,32) is formed by printing on the substrate with a conductive material.
Claim 22
Dependent Claim
31 words
A transponder according to any one of claims 12 to 20 characterised in that the control means (38,42) is adapted to cause repeated transmission of the response signal at predetermined intervals.
Claim 23
Dependent Claim
18 words
A transponder according to claim 21 characterised in that the predetermined intervals are random or pseudo-random in length.
Claim 24
Dependent Claim
25 words
A transponder according to claim 22 characterised in that the length of the random or pseudo-random intervals is derived from the data identifying the transponder.
Claim 25
Dependent Claim
46 words
A transponder according to any one of claims 12 to 23 characterised in that the control means (42) is adapted to monitor the received interrogation signal and to enable transmission of the response signal only after an interruption of the interrogation signal for a predetermined duration.
Claim 26
Dependent Claim
61 words
An interrogator identifying a set of transponders comprising transmitter means (10) for transmitting an interrogation signal to the transponders, receiver means (16,18,20,22) for receiving response signals from the said plurality of transponders, and processor means (28) for identifying a transponder from data in the response signal characterised in that the interrogator determines the number of transponders responding to the interrogation signal.
Claim 27
Dependent Claim
61 words
An interrogator identifying a set of transponders comprising transmitter means (10) for transmitting an interrogation signal to the transponders, receiver means (16,18,20,22) for receiving response signals from the said plurality of transponders, and processor means (28) for identifying a transponder from data in the response signal characterised in that the interrogator determines the number of transponders responding to the interrogation signal.
Claim 28
Dependent Claim
23 words
An interrogator as claimed in claim 25 characterised in that the interrogator determines the number of transponders which reply with the same data.
Claim 29
Dependent Claim
15 words
An interrogator for use with the system of any one of claims 1 to 11.
References Cited (Backward Citations)
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