GB1290097A - - Google Patents

Info

Publication number
GB1290097A
GB1290097A GB1290097DA GB1290097A GB 1290097 A GB1290097 A GB 1290097A GB 1290097D A GB1290097D A GB 1290097DA GB 1290097 A GB1290097 A GB 1290097A
Authority
GB
United Kingdom
Prior art keywords
mhz
transmitter
label
frequency
receiver
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.)
Expired
Application number
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
Priority to AU5297069 priority Critical
Application filed filed Critical
Publication of GB1290097A publication Critical patent/GB1290097A/en
Application status is Expired legal-status Critical

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • G01S13/75Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors
    • G01S13/751Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors wherein the responder or reflector radiates a coded signal
    • G01S13/755Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors wherein the responder or reflector radiates a coded signal using delay lines, e.g. acoustic delay lines
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • G01S13/75Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors
    • G01S13/751Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors wherein the responder or reflector radiates a coded signal
    • G01S13/753Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors wherein the responder or reflector radiates a coded signal using frequency selective elements, e.g. resonator
    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00Burglar, theft or intruder alarms
    • G08B13/22Electrical actuation
    • G08B13/24Electrical actuation by interference with electromagnetic field distribution

Abstract

1290097 Radio signalling UNISEARCH Ltd 24 March 1970 [2 April 1969] 14100/70 Heading H4L [Also in Division G4] In an electronic surveillance system, two signals are transmitted simultaneously which have different and widely spaced frequencies, and which when picked up by a passive label located within the near field region of the lower frequency signal are mixed to produce a reply signal which is distinctive in frequency from said transmitted signals. The reply signal is processed in equipment which is also responsive to at least one of the transmitted signals, and which verifies the presence of a label by reference thereto. As described, a main transmitter 1, Fig. 2, has a frequency of 915 MHz and emits pulses of length 10 micro-seconds and of repetition frequency 5000/sec. An auxiliary transmitter 2 has a frequency of 100 kHz and emits pulses of length 1 milli-second and of repetition frequency 93/sec. A label 3 comprises a stripline microwave aerial A, Fig. 3, which is operable at frequencies of 915 and 1830 MHz, and which has two sections separated by a thin dielectric film where they overlap, a semi-conductor diode B, capable of frequency doubling and frequency mixing, and a loop aerial C, operable at a frequency of 100 kHz. When the transmitter 2 is off, the signal from the label 3 comprises the 1830 MHz second ha monic, and when the transmitter 2 is on, the signal from the label 3 also contains 1830Œ0.1 MHz sidebands. Said signals are received by a receiver 4 which is tuned to 1830 MHz, and has a 300 kHz pass band. An AGC system 5 controls the gain of the receiver 4 and acts only on signals received while the main transmitter 1 is on and the auxiliary transmitter 2 is off, so that the 1830 MHz received signal is brought to a standard level, and propagation path losses are compensated. The output from the receiver 4 is processed in an analyser 6, during periods when the transmitter 2 is on, and responses are accepted as genuine when the sidebands are present in sufficient proportions. In a second embodiment, a main transmitter (15), Fig. 4 (not shown), operating at 915 MHz, an auxiliary transmitter (16), operating at 100 kHz, and a label (17), similar to the label shown in Fig. 3, are used but a receiver system (18) is tuned to receive the 915À1 MHz sideband generated by mixing the two transmitted signals in the label, and to reject 915 MHz signals. Synchronous detection is used, and direct connections from the transmitters to the receiver carry the necessary phase information. Time gating may be used to ensure that only responses within a pre-determined distance from the receiver are accepted. In a third embodiment (Fig. 5, not shown), in which main and auxiliary transmitters operating respectively at 915 MHz and 100 kHz are also used, a label 21, Fig. 6, comprises a single turn loop aerial 24, which receives microwave pulses from the main transmitter, a surface acoustic wave delay line 25, which produces after a time of approximately 500 nanoseconds an electro-acoustic echo of each transmitter pulse, which is re-radiated by the aerial 24, a modulation diode 26, and a multi-turn loop aerial 27, which receives from the auxiliary transmitter. The output from the label 21 comprises pulses of frequencies 914.9 MHz, 915 MHz and 915À1 MHz, the first and third resulting from intermodulation of the received 100 kHz and 915 MHz signals by the diode 26. All three pulses are delayed by 500 nano-seconds from the originating pulse from the main transmitter, and they are separated therefrom in a time gated receiver, and are processed.
GB1290097D 1969-04-02 1970-03-24 Expired GB1290097A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU5297069 1969-04-02

Publications (1)

Publication Number Publication Date
GB1290097A true GB1290097A (en) 1972-09-20

Family

ID=3739082

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1290097D Expired GB1290097A (en) 1969-04-02 1970-03-24

Country Status (12)

Country Link
JP (1) JPS5122797B1 (en)
AR (1) AR211833A1 (en)
BE (1) BE748053A (en)
BR (1) BR7017853D0 (en)
CH (1) CH522259A (en)
DE (1) DE2015319C3 (en)
FR (1) FR2038186A1 (en)
GB (1) GB1290097A (en)
IL (1) IL34201D0 (en)
LU (1) LU60651A1 (en)
NL (1) NL172893C (en)
SE (1) SE341363B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4481428A (en) * 1981-05-19 1984-11-06 Security Tag Systems, Inc. Batteryless, portable, frequency divider useful as a transponder of electromagnetic radiation

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4413254A (en) * 1981-09-04 1983-11-01 Sensormatic Electronics Corporation Combined radio and magnetic energy responsive surveillance marker and system
US4642640A (en) * 1983-04-25 1987-02-10 Sensormatic Electronics Corporation Signal receptor-reradiator and surveillance tag using the same
US4736207A (en) * 1986-01-31 1988-04-05 Sensormatic Electronics Corporation Tag device and method for electronic article surveillance
US5095240A (en) * 1989-11-13 1992-03-10 X-Cyte, Inc. Inductively coupled saw device and method for making the same
US4951057A (en) * 1989-11-13 1990-08-21 X-Cyte, Inc. Inductive input/output coupling for a surface acoustic wave device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4481428A (en) * 1981-05-19 1984-11-06 Security Tag Systems, Inc. Batteryless, portable, frequency divider useful as a transponder of electromagnetic radiation

Also Published As

Publication number Publication date
SE341363B (en) 1971-12-20
NL172893C (en) 1983-11-01
IL34201D0 (en) 1970-05-21
BE748053A1 (en)
DE2015319C3 (en) 1980-02-21
BR7017853D0 (en) 1973-04-17
DE2015319A1 (en) 1970-10-15
LU60651A1 (en) 1971-06-14
JPS5122797B1 (en) 1976-07-12
DE2015319B2 (en) 1979-06-28
FR2038186A1 (en) 1971-01-08
NL172893B (en) 1983-06-01
AR211833A1 (en) 1978-03-31
CH522259A (en) 1972-06-15
BE748053A (en) 1970-09-28
NL7004749A (en) 1970-10-06

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Legal Events

Date Code Title Description
414F Notice of opposition given (sect. 14/1949)
414B Case decided by the comptroller ** grants allowed (sect. 14/1949)
PS Patent sealed
429A Application made for amendment of specification (sect. 29/1949)
429H Application (made) for amendment of specification now open to opposition (sect. 29/1949)
429D Case decided by the comptroller ** specification amended (sect. 29/1949)
PE20 Patent expired after termination of 20 years