CA1180788A - System for registrating a passing article - Google Patents
System for registrating a passing articleInfo
- Publication number
- CA1180788A CA1180788A CA000387303A CA387303A CA1180788A CA 1180788 A CA1180788 A CA 1180788A CA 000387303 A CA000387303 A CA 000387303A CA 387303 A CA387303 A CA 387303A CA 1180788 A CA1180788 A CA 1180788A
- Authority
- CA
- Canada
- Prior art keywords
- marker
- period
- receiving
- transmitting
- area
- 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
Links
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B13/00—Burglar, theft or intruder alarms
- G08B13/22—Electrical actuation
- G08B13/24—Electrical actuation by interference with electromagnetic field distribution
- G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
- G08B13/2405—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used
- G08B13/2414—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used using inductive tags
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B13/00—Burglar, theft or intruder alarms
- G08B13/22—Electrical actuation
- G08B13/24—Electrical actuation by interference with electromagnetic field distribution
- G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
- G08B13/2465—Aspects related to the EAS system, e.g. system components other than tags
- G08B13/2468—Antenna in system and the related signal processing
- G08B13/2471—Antenna signal processing by receiver or emitter
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B13/00—Burglar, theft or intruder alarms
- G08B13/22—Electrical actuation
- G08B13/24—Electrical actuation by interference with electromagnetic field distribution
- G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
- G08B13/2465—Aspects related to the EAS system, e.g. system components other than tags
- G08B13/2468—Antenna in system and the related signal processing
- G08B13/2474—Antenna or antenna activator geometry, arrangement or layout
Abstract
A b s t r a c t A system for registrating an article passing a prede-termined area, and comprising a transmitter and a receiver with a common aerial alternately transmitting and receiving electromagnetic signals. A marker is attached to each article and receives said signals and transmits in turn other signals at passage of the area. The common transmitting and receiving aerial is formed as a multipole loop, preferably looped as a figure-of-eight dipole loop located in one plane. The known systems are encumbered with the problem that the marker with some orientations can pass without being detected.
According to the invention the transmitting period is followed by a first receiving period in which the number of wave peaks is counted, and at least one additional receiving period in which the number of peaks is counted too. If the number of peaks during the first receiving period is suffi-ciently high, and the following period does not include too many peaks, the presence of a marker in the area is indicated.
This system is so sensitive that the weaker side areas of another orientation than the main area may be utilized too.
As a result, the marker cannot pass the area without being detected irrespective of its orientation.
According to the invention the transmitting period is followed by a first receiving period in which the number of wave peaks is counted, and at least one additional receiving period in which the number of peaks is counted too. If the number of peaks during the first receiving period is suffi-ciently high, and the following period does not include too many peaks, the presence of a marker in the area is indicated.
This system is so sensitive that the weaker side areas of another orientation than the main area may be utilized too.
As a result, the marker cannot pass the area without being detected irrespective of its orientation.
Description
7 ~ ~
The invention relates to a system for registrating an article passing through a predetermined area, and comprising a transmitter and a receiver with a common aerial alternately transmitting and receiving electromagnetic signals~ as well as a marker attached ~o each article and receiving said signals and transmitting other signals at passage through said area3 whereby the transmitting and receiving period changes as the signals transmitted have a constant signal frequency through the entire transmitting period, and as a signal processor counts a predetermined number of signals received uninter~
ruptedly from the marker comprising a tuned circuit and com-pares the frequency thereof to the frequency of the signals transmitted by the transmitter during a transmitting period, whereby the transmitting and receiving aerial is formed by a multipole loop, preferably looped like an eight and positioned in one plane.
Such a system is for instance known from Danish Patent ll~5,169 issued to Security Products International A/S. This known system is, however, encumbered with the draw-back that the marker in some orientations may pass without being detected by the main area.
The system according to the invention is characterised in that the transmitting period is followed by a first re-receiving period in which the number of for instance wave peaks is counted, and at least one additional receiving period in which the number of peaks is counted too. When the number of peaks during the first period is sufficiently high, and the following period does not include too many peaks, it is in-dicated that a marker is present in the area.
According to a particularly advantageous embodiment of ~ .~
, ) 7 ~ ~t the s~7stem alarm is only produced when the difference in num ber of wave peaks during the first receiving period and the number of wave peaks during the second period is sufficiently great. In this manner the system may be made so sensitive that the weaker side areas of another orientation may be uti-lized. As a result, the marker cannot pass the area without being detected irrespective of its orientation.
Furthermore, the system no longer depends on the shape and orientation of the aerial.
The invention will be described below with reference to the accompanying drawing, in which Fig~ 1 is a diagrammatic view of the system according to the invention, Fig. 2 illustrates the use of the system, Fig. 3 illustrates another possibility of using the system, whereby the construction of the aerial is indicated, and Fig. 4 illustrates both the transmitted and the received signals.
Fig. 1 illustrates how an aerial 1 is connected to a transmitter 2 or a receiver 3, 4 through a change-over switch 5. This change-over switch is controlled by a synchronizing unit 6 having an appropriately high frequency. At the trans-mission of a short signal from the transmitter 2 at the fre-quency of ~or instance 1 MHz, an alternating current is in-duced in an oscillatory circuit in a marker 18, cf. Fig. 2, when said marker is present within the electromagnetic area ; created by the transmitting aerial. When this transmission of signals ceases, i.e. when the aerial 1 is connected to the ~\
t ~l~O7~
receiver 3, 4 through the change-over switch 5, the oscilla-tory circuit of the marker 18 emits a signal at the same fre-quency until -the oscillations are quenched. This signal is received by the aerial 1 and transmitted to a signal proces-sor 7 through the receiver 3, 4. At th0 same time this signalprocessor 7 receives pulses from the synchronizing unit 6 and is thereby permitted to count the signals received uninter-ruptedly from a marker 18. This procedure is obtained by the counter in question being zeroed when no signal is received during the receiving period following immediately upon a transmitting period. The signal processor 7 furthermore con-trols whether the frequency of the signals received corre-sponds to the frequency of the signals transmitted. As a re-sult an additional security against false alarms is pro~ided.
Fig. 2 illustrates how a plurality of figure-of-eight aerials 8 may be located in such a manner that a broad pas-sage can be controlled. The system is built into a frame stand, and the frame members 9, 10, 11, 12, 13, 14, 15, and 16 form the figure-of-eight aerial. The transmitter 2, the receiver 3, 4, and the processor 7 have been built into a box 17.
The figure~of-eight aerial, which preferably is located in one plane, generates a toroidal area, which for the sake of clarity only appears at one of the aerials. This procedure implies within a predetermined range that the passing marker is detectable almost irrespective of its orientation.
According to the invention it is, however, also shown how the weaker side areas also may be utilized, said areas only being indicated at one of the aerials too for the sake 3 ~ 7~
of clarity. They may be utilized in such a manner that a mar-ker cannot pass therethrough either when itis parallel to the direction (two directions) of the main area. This is accord-ing to the invention obtained by the transmitting period last-ing for instance 60 ~sec. and the following first receivingperiod lasting 20 ~sec. During this period, the number of peaks is counted, and when the transmitter frequency is 1 MHz, it corresponds to about 20 peaks or periods (or more when noice signals are present too). Subsequently, a blank period of for instance 40 ~sec. follows, and then a second receiving period, cf. Fig. 4, in which the number of peaks is counted.
When a predetermined number of peaks is counted during a re-ceiving period, a signal is transmitted. When another prede-termined number of signals is uninterruptedly counted from the first receiving perioa at the same time as the number of signals from the second receiving period does not exceed a predetermined number, the alarm is produced. In this manner the system is so sensitive that the weaker side areas can be utilized too. The side areas may thereby detect the marker 18 20 when said marker has not been detected by the main area, then utilizing that the orientation of these weaker side areas differs from the orientation of the main area, cf. Fig. 2.
An additional advantage of the system according to the invention is that it does not depend on the form and location ~5 of the aerial. Furthermore, it is possible to use a multipole aerial. In all cases it is, however, an advantage to shape the aerial in such a manner that remote areas from the outside are automatically compensated for, e.g. by the loops having the same area.
78~
The system furthermore possesses the advantage that it is not sensitive to shakings and is easy to mount.
The marker is preferably formed by a coil in connection with a capacitor, the coil functioning as a receiving and transmitting aerlal for the marker. The Q-value is preferably greater than 50.
The system according to the invention may be varied in many ways without thereby deviating from the scope of the invention. According to an alterna-tive embodiment of the di-gital high-pass filter, the signal to be filtrated is carried through an A/D converter and subsequently to a digital com-puter in the form of a microprocessor automatically perform-ing the filtration.
: .,,
The invention relates to a system for registrating an article passing through a predetermined area, and comprising a transmitter and a receiver with a common aerial alternately transmitting and receiving electromagnetic signals~ as well as a marker attached ~o each article and receiving said signals and transmitting other signals at passage through said area3 whereby the transmitting and receiving period changes as the signals transmitted have a constant signal frequency through the entire transmitting period, and as a signal processor counts a predetermined number of signals received uninter~
ruptedly from the marker comprising a tuned circuit and com-pares the frequency thereof to the frequency of the signals transmitted by the transmitter during a transmitting period, whereby the transmitting and receiving aerial is formed by a multipole loop, preferably looped like an eight and positioned in one plane.
Such a system is for instance known from Danish Patent ll~5,169 issued to Security Products International A/S. This known system is, however, encumbered with the draw-back that the marker in some orientations may pass without being detected by the main area.
The system according to the invention is characterised in that the transmitting period is followed by a first re-receiving period in which the number of for instance wave peaks is counted, and at least one additional receiving period in which the number of peaks is counted too. When the number of peaks during the first period is sufficiently high, and the following period does not include too many peaks, it is in-dicated that a marker is present in the area.
According to a particularly advantageous embodiment of ~ .~
, ) 7 ~ ~t the s~7stem alarm is only produced when the difference in num ber of wave peaks during the first receiving period and the number of wave peaks during the second period is sufficiently great. In this manner the system may be made so sensitive that the weaker side areas of another orientation may be uti-lized. As a result, the marker cannot pass the area without being detected irrespective of its orientation.
Furthermore, the system no longer depends on the shape and orientation of the aerial.
The invention will be described below with reference to the accompanying drawing, in which Fig~ 1 is a diagrammatic view of the system according to the invention, Fig. 2 illustrates the use of the system, Fig. 3 illustrates another possibility of using the system, whereby the construction of the aerial is indicated, and Fig. 4 illustrates both the transmitted and the received signals.
Fig. 1 illustrates how an aerial 1 is connected to a transmitter 2 or a receiver 3, 4 through a change-over switch 5. This change-over switch is controlled by a synchronizing unit 6 having an appropriately high frequency. At the trans-mission of a short signal from the transmitter 2 at the fre-quency of ~or instance 1 MHz, an alternating current is in-duced in an oscillatory circuit in a marker 18, cf. Fig. 2, when said marker is present within the electromagnetic area ; created by the transmitting aerial. When this transmission of signals ceases, i.e. when the aerial 1 is connected to the ~\
t ~l~O7~
receiver 3, 4 through the change-over switch 5, the oscilla-tory circuit of the marker 18 emits a signal at the same fre-quency until -the oscillations are quenched. This signal is received by the aerial 1 and transmitted to a signal proces-sor 7 through the receiver 3, 4. At th0 same time this signalprocessor 7 receives pulses from the synchronizing unit 6 and is thereby permitted to count the signals received uninter-ruptedly from a marker 18. This procedure is obtained by the counter in question being zeroed when no signal is received during the receiving period following immediately upon a transmitting period. The signal processor 7 furthermore con-trols whether the frequency of the signals received corre-sponds to the frequency of the signals transmitted. As a re-sult an additional security against false alarms is pro~ided.
Fig. 2 illustrates how a plurality of figure-of-eight aerials 8 may be located in such a manner that a broad pas-sage can be controlled. The system is built into a frame stand, and the frame members 9, 10, 11, 12, 13, 14, 15, and 16 form the figure-of-eight aerial. The transmitter 2, the receiver 3, 4, and the processor 7 have been built into a box 17.
The figure~of-eight aerial, which preferably is located in one plane, generates a toroidal area, which for the sake of clarity only appears at one of the aerials. This procedure implies within a predetermined range that the passing marker is detectable almost irrespective of its orientation.
According to the invention it is, however, also shown how the weaker side areas also may be utilized, said areas only being indicated at one of the aerials too for the sake 3 ~ 7~
of clarity. They may be utilized in such a manner that a mar-ker cannot pass therethrough either when itis parallel to the direction (two directions) of the main area. This is accord-ing to the invention obtained by the transmitting period last-ing for instance 60 ~sec. and the following first receivingperiod lasting 20 ~sec. During this period, the number of peaks is counted, and when the transmitter frequency is 1 MHz, it corresponds to about 20 peaks or periods (or more when noice signals are present too). Subsequently, a blank period of for instance 40 ~sec. follows, and then a second receiving period, cf. Fig. 4, in which the number of peaks is counted.
When a predetermined number of peaks is counted during a re-ceiving period, a signal is transmitted. When another prede-termined number of signals is uninterruptedly counted from the first receiving perioa at the same time as the number of signals from the second receiving period does not exceed a predetermined number, the alarm is produced. In this manner the system is so sensitive that the weaker side areas can be utilized too. The side areas may thereby detect the marker 18 20 when said marker has not been detected by the main area, then utilizing that the orientation of these weaker side areas differs from the orientation of the main area, cf. Fig. 2.
An additional advantage of the system according to the invention is that it does not depend on the form and location ~5 of the aerial. Furthermore, it is possible to use a multipole aerial. In all cases it is, however, an advantage to shape the aerial in such a manner that remote areas from the outside are automatically compensated for, e.g. by the loops having the same area.
78~
The system furthermore possesses the advantage that it is not sensitive to shakings and is easy to mount.
The marker is preferably formed by a coil in connection with a capacitor, the coil functioning as a receiving and transmitting aerlal for the marker. The Q-value is preferably greater than 50.
The system according to the invention may be varied in many ways without thereby deviating from the scope of the invention. According to an alterna-tive embodiment of the di-gital high-pass filter, the signal to be filtrated is carried through an A/D converter and subsequently to a digital com-puter in the form of a microprocessor automatically perform-ing the filtration.
: .,,
Claims (4)
1. A system for detecting the presence of a marker in a predetermined area, said marker including a tuned circuit, said system comprising a transmitter and a receiver having a common aerial, means for alternately transmitting and receiving electromagnetic signals through said common aerial, said transmitted signals having a predetermined frequency which, when received by the tuned circuit of said marker, causes said circuit to transmit signals at one of said frequency, and another predetermined frequency, and signal processing means associated with said receiver adapted to detect and compare signals of said tuned circuit received during at least two spaced receiving periods between transmitting periods to thereby detect the presence of said marker within said area.
2. A system as claimed in claim 1, characterized in that the transmitting period is followed by a first receiving period in which the number of for instance wave peaks (periods) is counted, and at least one additional receiving period in which the number of peaks is counted too, an alarm only being produced when the counting during the first receiving period is sufficiently great and the counting during the second receiving period is not too great.
3. A system as claimed in claim 2, characterized by the alarm only being produced when the difference in countings is sufficiently great.
4. A system as claimed in claim 2 or 3, characterized by the transmitting period lasting 60 µsec., and by each following receiving period lasting 20 µsec.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000387303A CA1180788A (en) | 1981-10-05 | 1981-10-05 | System for registrating a passing article |
| ZA826195A ZA826195B (en) | 1981-10-05 | 1982-08-25 | A system for registrating a passing article |
| NO823180A NO156349C (en) | 1981-10-05 | 1982-09-20 | INSTALLATION FOR REGISTRATION OF A PASSAGE OF AN OBJECT THROUGH A PRESERVED AREA. |
| JP57163282A JPS58121495A (en) | 1981-10-05 | 1982-09-21 | Detector for article passing |
| ES515888A ES8306264A1 (en) | 1981-10-05 | 1982-09-22 | Detector for article passing |
| AU88670/82A AU535114B2 (en) | 1981-10-05 | 1982-09-24 | A system for registering a passing article |
| NL8203849A NL8203849A (en) | 1981-10-05 | 1982-10-04 | DEVICE FOR RECORDING AN OBJECT THROUGH A PARTICULAR AREA. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000387303A CA1180788A (en) | 1981-10-05 | 1981-10-05 | System for registrating a passing article |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1180788A true CA1180788A (en) | 1985-01-08 |
Family
ID=4121088
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000387303A Expired CA1180788A (en) | 1981-10-05 | 1981-10-05 | System for registrating a passing article |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS58121495A (en) |
| AU (1) | AU535114B2 (en) |
| CA (1) | CA1180788A (en) |
| ES (1) | ES8306264A1 (en) |
| NL (1) | NL8203849A (en) |
| NO (1) | NO156349C (en) |
| ZA (1) | ZA826195B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4509039A (en) * | 1983-07-05 | 1985-04-02 | Minnesota Mining And Manufacturing Company | Shielded, closely spaced transmit-receiver antennas for electronic article surveillance system |
| NL8803170A (en) * | 1988-12-27 | 1990-07-16 | Nedap Nv | IDENTIFICATION SYSTEM. |
| US5382780A (en) * | 1993-10-01 | 1995-01-17 | Duncan Industries Parking Control Systems Corp. | Portable time metering device |
| JPH07263935A (en) * | 1994-03-24 | 1995-10-13 | Hochiki Corp | Antenna equipment |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5645200B2 (en) * | 1973-03-10 | 1981-10-24 | ||
| US4243980A (en) * | 1978-02-17 | 1981-01-06 | Lichtblau G J | Antenna system for electronic security installations |
-
1981
- 1981-10-05 CA CA000387303A patent/CA1180788A/en not_active Expired
-
1982
- 1982-08-25 ZA ZA826195A patent/ZA826195B/en unknown
- 1982-09-20 NO NO823180A patent/NO156349C/en unknown
- 1982-09-21 JP JP57163282A patent/JPS58121495A/en active Granted
- 1982-09-22 ES ES515888A patent/ES8306264A1/en not_active Expired
- 1982-09-24 AU AU88670/82A patent/AU535114B2/en not_active Ceased
- 1982-10-04 NL NL8203849A patent/NL8203849A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0354392B2 (en) | 1991-08-20 |
| NO823180L (en) | 1983-04-06 |
| AU8867082A (en) | 1983-04-14 |
| ES515888A0 (en) | 1983-06-01 |
| AU535114B2 (en) | 1984-03-01 |
| NO156349C (en) | 1987-09-02 |
| ZA826195B (en) | 1983-07-27 |
| NL8203849A (en) | 1983-05-02 |
| ES8306264A1 (en) | 1983-06-01 |
| NO156349B (en) | 1987-05-25 |
| JPS58121495A (en) | 1983-07-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |