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WO1991010206A1 - Systeme de transmission - Google Patents

Systeme de transmission Download PDF

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Publication number
WO1991010206A1
WO1991010206A1 PCT/GB1990/001990 GB9001990W WO9110206A1 WO 1991010206 A1 WO1991010206 A1 WO 1991010206A1 GB 9001990 W GB9001990 W GB 9001990W WO 9110206 A1 WO9110206 A1 WO 9110206A1
Authority
WO
WIPO (PCT)
Prior art keywords
signals
signal
transducers
phase shift
tag
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB1990/001990
Other languages
English (en)
Inventor
Bernard John Regan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CRYPTAG Ltd
Original Assignee
CRYPTAG Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by CRYPTAG Ltd filed Critical CRYPTAG Ltd
Publication of WO1991010206A1 publication Critical patent/WO1991010206A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
    • H04B5/40—Near-field transmission systems, e.g. inductive or capacitive transmission systems characterised by components specially adapted for near-field transmission
    • H04B5/45—Transponders
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
    • G06K7/10316—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves using at least one antenna particularly designed for interrogating the wireless record carriers
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
    • G06K7/10316—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves using at least one antenna particularly designed for interrogating the wireless record carriers
    • G06K7/10336—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves using at least one antenna particularly designed for interrogating the wireless record carriers the antenna being of the near field type, inductive coil

Definitions

  • This invention relates to a transmission sys and more particularly to a transmitter for transmitting d signals to transponders.
  • interrogation systems wh comprise a fixed or central reader and a number of transpon tags, the system providing for two-way communication between reader and the transponder tags.
  • the system may be used access control, article tagging, animal husbandry and a vari of other applications.
  • the tags need to be low c and are subject to size limitations.
  • Communication between the reader and transpon tags may be carried by a magnetic field or an electric fie
  • the communication has hitherto been very dependent u the orientation of the tag to the reader.
  • a radio frequency magnetic field generated by injecting current into a coil. The magnetic fi at any point is given by:
  • J3c> is a linear vector.
  • the receiver coil in the responds only to one component of the magnetic field, so that signal induced in the receiver coil is given by:
  • £ is a vector defining the sensitive axis of t transponder tag.
  • the sign induced in the receiver coil will not be sufficient: if satisfactory signal corresponds to 10% or more of Ho, then in 1 of possible orientations the signal will not be satisfacto
  • it necessary for there to be very high probability that a tag will respond to the reader it is possible to increase the probability of signal detection by providing each tag with more than one receiver coil but this increases the cost and probably the size of the tag.
  • a signal transmitter which comprises two transmitting transducers transmitting corresponding signals with a phase shift between them.
  • the two transmitted signals are in quadrature (i.e. with a 90° phase shift between them).
  • the magnetic field at the position of a transponder tag is the superposition of the two fields produced by the respective coils, and is given by:
  • the probability of the magnetic field at the transponder tag exceeding the required level is now much higher than with a single coil transmitter.
  • the two transmitted fields J3A and HE. are substantially orthogonal.
  • the two fields IIA and IIB are substantially equal in magnitude.
  • a signal receiver which comprises two receiving transducers and means for combining their output signals together after one said output signal has been subjected to a phase shift.
  • This receiver improves the reception of signals emitted by the transponder tag.
  • the two receiving transducers are mounted with their sensitive axes orthogonal to each other.
  • an interrogation system comprising a reader 1-4, 6-8 and a transponder tag 5.
  • the reader comprises a processing circuit 1 which generates a signal for transmission, this signal being at radio frequency and with data modulated thereon.
  • the signal is applied to a frame coil 3, and via a 90° phase shift circuit 2 to a coil 4 wound on a ferrite rod and arranged so that its field is generally orthogonal to the field produced by the frame coil 3.
  • the two aerials 3, 4 transmit their signals to the tag 5, which detects the signals and generates and transmits a response (at the same or a different frequency) which is picked up by one or more aerials 6, 6 of the reader.
  • the picked-up signals are amplified at 7,7 and fed to a multiplexer 8 where they are added together, the combined signal being passed to a processing circuit 1.
  • the multiplexer 8 may employ a phase shift (preferably 90° at the frequency concerned) at one of its inputs, to ensure that it will provide an output signal if either input has a significant signal present and without risk of them cancelling each other out.
  • a phase shift preferably 90° at the frequency concerned
  • the same effect may be achieved for example as follows.
  • the signals from the two receiver aerials 6,6 are demodulated for both in-phase components (SP1 and SP2 respectively) and quadrature components (SQ1 and SQ2 respectively), and then combined to give:
  • the transmitter aerials 3, 4 may be both frame coils or both ferrite rod coils, but the arrangement of one frame coil and one ferrite rod has the advantage of fitting well into a transmitter unit.
  • the two receiver coils are also mounted orthogenal to each other.
  • the principles of the invention are equally applicable to a transmitter generating electric fields.
  • the signals are near-field radio frequency (i.e. the distances involved are shorter than the wavelength).

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Electromagnetism (AREA)
  • General Health & Medical Sciences (AREA)
  • Artificial Intelligence (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Signal Processing (AREA)
  • Near-Field Transmission Systems (AREA)

Abstract

Un transmetteur de signaux comprend deux transducteurs (3, 4) transmettant des signaux correspondants avec de préférence un décalage de phase mutuel de 90°. Les champs transmis par les deux transducteurs sont de préférence sensiblement mutuellement orthogonaux. Cette disposition améliore considérablement la probabilité que le signal transmis soit détectée par une étiquette répondeuse (5). Un récepteur des signaux provenant de l'étiquette répondeuse comprend des transducteurs de réception (6, 6), dont les sorties sont combinées lorsque l'un des signaux a subi un décalage de phase de préférence de 90°. Les transducteurs de réception (6, 6) sont de préférence montés de manière mutuellement orthogonale.
PCT/GB1990/001990 1989-12-20 1990-12-20 Systeme de transmission Ceased WO1991010206A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB898928693A GB8928693D0 (en) 1989-12-20 1989-12-20 Transmission system
GB8928693.4 1989-12-20

Publications (1)

Publication Number Publication Date
WO1991010206A1 true WO1991010206A1 (fr) 1991-07-11

Family

ID=10668201

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1990/001990 Ceased WO1991010206A1 (fr) 1989-12-20 1990-12-20 Systeme de transmission

Country Status (2)

Country Link
GB (1) GB8928693D0 (fr)
WO (1) WO1991010206A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0704814A3 (fr) * 1994-09-30 1997-06-04 Toshiba Kk Système d'excitation de circuits à couplage magnétique
NL1002807C2 (nl) * 1996-04-05 1997-10-07 Nedap Nv Twee responders tegelijk herkennen door PACE (Phase Alternating Code Extension).
FR2797123A1 (fr) * 1999-07-28 2001-02-02 Gemplus Card Int Systeme d'identification d'objets sur un convoyeur en mouvement
NL1028330C2 (nl) * 2005-02-18 2006-08-21 Nedap Nv Smart Shelf.

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3849633A (en) * 1972-01-04 1974-11-19 Westinghouse Electric Corp Object identifying apparatus
FR2494059A1 (fr) * 1980-11-07 1982-05-14 Motorola Inc Procede et dispositif de demodulation de porteuse a acquisition rapide
EP0185610A2 (fr) * 1984-12-21 1986-06-25 Angewandte Digital Elektronik GmbH Dispositif pour la transmission sans contact de signal et d'énergie
DE3603098A1 (de) * 1985-02-03 1987-01-08 Svaetopluk Radakovic Eine einrichtung mit mehreren empfangsspulen zur vermeidung eines empfangsverlustes durch die richtcharakteristiken der sende- und empfangsspule bei einer signaluebertragung mit magnetischem feld
DE3622010A1 (de) * 1985-07-05 1987-06-04 Svaetopluk Radakovic Einrichtung zur signaluebertragung mit magnetischem feld, einer ausschliessung der richtwirkungen der sende- und empfangsspule verwendbar bei ununterbrochenem informationsfluss
WO1989005549A1 (fr) * 1987-12-04 1989-06-15 Magellan Corporation (Australia) Pty. Ltd. Appareil et procedes d'identification

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3849633A (en) * 1972-01-04 1974-11-19 Westinghouse Electric Corp Object identifying apparatus
FR2494059A1 (fr) * 1980-11-07 1982-05-14 Motorola Inc Procede et dispositif de demodulation de porteuse a acquisition rapide
EP0185610A2 (fr) * 1984-12-21 1986-06-25 Angewandte Digital Elektronik GmbH Dispositif pour la transmission sans contact de signal et d'énergie
DE3603098A1 (de) * 1985-02-03 1987-01-08 Svaetopluk Radakovic Eine einrichtung mit mehreren empfangsspulen zur vermeidung eines empfangsverlustes durch die richtcharakteristiken der sende- und empfangsspule bei einer signaluebertragung mit magnetischem feld
DE3622010A1 (de) * 1985-07-05 1987-06-04 Svaetopluk Radakovic Einrichtung zur signaluebertragung mit magnetischem feld, einer ausschliessung der richtwirkungen der sende- und empfangsspule verwendbar bei ununterbrochenem informationsfluss
WO1989005549A1 (fr) * 1987-12-04 1989-06-15 Magellan Corporation (Australia) Pty. Ltd. Appareil et procedes d'identification

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0704814A3 (fr) * 1994-09-30 1997-06-04 Toshiba Kk Système d'excitation de circuits à couplage magnétique
NL1002807C2 (nl) * 1996-04-05 1997-10-07 Nedap Nv Twee responders tegelijk herkennen door PACE (Phase Alternating Code Extension).
FR2797123A1 (fr) * 1999-07-28 2001-02-02 Gemplus Card Int Systeme d'identification d'objets sur un convoyeur en mouvement
WO2001008080A3 (fr) * 1999-07-28 2001-08-16 Gemplus Card Int Systeme d'identification d'objets sur un convoyeur en mouvement
NL1028330C2 (nl) * 2005-02-18 2006-08-21 Nedap Nv Smart Shelf.
EP1693778A1 (fr) * 2005-02-18 2006-08-23 N.V. Nederlandsche Apparatenfabriek NEDAP Système d'étagères munis d'une système de détection d'étiquettes pour lire des étiquettes RFID

Also Published As

Publication number Publication date
GB8928693D0 (en) 1990-02-28

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