EP0837432A1 - Device for monitoring a security element in an interrogation area - Google Patents

Device for monitoring a security element in an interrogation area Download PDF

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Publication number
EP0837432A1
EP0837432A1 EP97117104A EP97117104A EP0837432A1 EP 0837432 A1 EP0837432 A1 EP 0837432A1 EP 97117104 A EP97117104 A EP 97117104A EP 97117104 A EP97117104 A EP 97117104A EP 0837432 A1 EP0837432 A1 EP 0837432A1
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Prior art keywords
signal
direct signal
received
direct
computing
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EP97117104A
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German (de)
French (fr)
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EP0837432B1 (en
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David Stocks
Terry Clancy
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Meto International GmbH
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Meto International GmbH
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    • 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
    • G08B13/2482—EAS methods, e.g. description of flow chart of the detection procedure
    • 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

Definitions

  • the invention relates to a device for monitoring of an electronic security element in one Interrogation zone, consisting of a transmission device, the at least one periodic interrogation signal in the interrogation zone sends out, the interrogation signal the security element stimulates to send a detection signal, one Receiving device which receives the detection signal, and a computing / control unit that the by the Received device evaluates signals and at Identification of the security element an alarm triggers.
  • EP 123 586 B proposes to send a field with a frequency F3 in the Hz range to the query zone in addition to two query fields with the frequencies F1 and F2 in the kHz range.
  • the low-frequency interrogation field causes the securing element to be driven from saturation in one direction to saturation in the other direction in time with this field.
  • the characteristic signal therefore occurs periodically with the frequency of the low-frequency field.
  • the invention has for its object a device propose the recognition of articles related to electronically detectable security elements are improved within a query zone.
  • the object is achieved in that the computing / control device the received signal in terms of amplitude and phase (I component and Q component) evaluates that an interference signal occurring in the received signal recognizes and approximates and that it received signal freed from the interference signal.
  • the base signal b (s) corresponds to the signal generated by the Analog to Digital Converters (ADC) appears when the Transmitter is turned off and no external Noise sources are present.
  • the basic signal b (s) therefore corresponds to that of the electronics of the receiving device resulting signal.
  • the transmission device When the transmission device is switched on, one becomes smaller Share of the transmitted signal directly from the receiving device receive.
  • This signal component corresponds to that direct signal d (s).
  • the direct signal varies both in Amplitude as well as in phase if for example a person is near the receiving device.
  • a security element As soon as a security element passes the query zone, it generates a signal proportional to the transmission signal Detection signal. This signal is consequently also proportional to the direct signal d (s).
  • External noise signals from the receiving device received are reflected in the signal component n (s).
  • the direct signal d * (s) is the same k ⁇ e j ⁇ ⁇ D (s) and the response signal of the security element t * (s) is set equal to t (s), where k in turn describes the change in amplitude and ⁇ the change in phase of the direct signal d (s).
  • every non-linear material in the interrogation zone generates electromagnetic signals with the frequency F1 + F2 or their harmonics, including shopping trolleys or metal packaging.
  • metal plates are often provided on the side facing away from the interrogation zone. If the interference were static, it would be sufficient to always subtract a constant value from the received signal.
  • the interference signals change, for example as a result of fluctuations in the energy supply - this causes amplitude changes -, the frequencies F1, F2, F3 used in the system - these cause phase changes - or a mechanical movement - this affects Amplitude and phase. Since the amplitudes of these interference signals are up to 20 times larger than the detection signals from fuse elements, slight fluctuations already have a serious effect on the detection probability of fuse elements if a simple subtraction algorithm is used. It is therefore extremely important that changes in amplitude and phase of the direct signal can be compensated for in accordance with the invention.
  • the computing / regulating device outputs the direct signal d (s) the difference in long-term averages of received signals r (s) and base signals b (s) are determined. This allows increase the measuring accuracy of the device.
  • the rotation is obtained by multiplying d (s) by the complex number Re_Energie - j ⁇ Im_Energie Re_Energy 2nd + Im_Energy 2nd simulated, where Re_Energie characterizes the energy of the real part and Im_Energie the energy of the imaginary part of the direct signal d (s).
  • the rotated direct signal rd (s) with the complex number rc - j ⁇ ic multiplies, resulting in the final direct signal fd (s) fd (s) rd (s) ⁇ (rc - j ⁇ ic) results.
  • the computing / control device then subtracts the calculated (simulated) value for fd (s) from that received signal r (s).
  • Fig. 1 shows a schematic representation of the Device 1 according to the invention for detecting a a securing element 2 provided Article 6 in one Query zone 3.
  • Query zone 3 is composed of two in essentially parallel detector gates formed, the transmitter 4 and the Receiving device 5 included. Of course you can both devices 4, 5 also in a detector gate be housed.
  • the control of the monitoring device 1 and the evaluation of the measured values takes place by means of the computing / regulating device 7.
  • the transmission device 4 transmits cyclically Scan signals of a predetermined bandwidth in the Query zone 3 off.
  • the bandwidth is such that it is ensured that all for article security resonant circuits used despite production-related Tolerances in their resonance frequency are detected will.
  • the receiving device 5 receives a signal r (s) that in addition to the detection signal t * (s) also a signal component d (s), which is sent directly from the transmitting device 4 originates, as well as signals from external noises n (s).
  • the received signals r (s) are in the amplifier 10 amplified and demodulated in the demodulator 11.
  • the Analog-digital converter 12 subsequently provide measured values for the I component, which is the amplitude of a received Signal r (s) reflects, and the Q component that Contains phase information of the received signal r (s), to the computing / control device 7.
  • FIG. 3 shows an analog block diagram of a monitoring device 1 for electromagnetic safety elements 2.
  • Send the two transmission antennas of the transmission device 4 Signals of frequencies F1, F2 and F3 in interrogation zone 3.
  • the interrogation signals make the electromagnetic Securing element 2, which is essentially made of a metal with non-linear magnetic properties Transmission of detection signals t * (s) stimulated by the receiving device 5 can be received.
  • the received signals r (s) also contain signals n (s) which come from external noise sources.
  • Program items 14 to 18 include a so-called initialization program, which is connected upstream of the actual control program. This initialization program is preferably run through at a fixed time interval in order to ensure that the device 1 according to the invention is always available with the latest possible output values.
  • the receiving device is activated under program point 15.
  • the received signals r (s) are averaged over m cycles, the duration of a cycle corresponding to the duration of a periodic interrogation signal.
  • the averaged value is stored as base signal b (s).
  • this basic signal corresponds to the signal component of the receiving device 5 when the transmitting device 4 is switched off. Subsequently, the transmission device 4 is switched on in accordance with program point 17. At point 18, the corresponding averaged base signal b (s) is subtracted from the received signal averaged over several cycles. The result of this calculation is the direct signal d (s).
  • the improved rotated direct signal ard (s) is then correlated at 24 with the received signal r '(s).
  • the I component and the Q component of the received signal r '(s) r (s) - b (s) correlated with the I component of the improved rotated direct signal ard (s).
  • rc corr (Re (ard (s)), Re (r '(s))) the proportion of ard (s) contained in the I component of the received signal r (s) -b (s)
  • ic corr (Re (ard (s)), Im (r '(s))) the proportion of the improved signal ard (s) which is contained in the Q component of the received signal r (s) - b (s).
  • the rotated direct signal rd (s) is multiplied by the coefficients calculated under point 24.
  • the final direct signal fd (s) then results in fd (s) ⁇ rd (s) ⁇ (rc-j ⁇ ic).
  • the detection signal of the security element 2 is calculated under program item 26 using the following formula: t (s) ⁇ r '(s) - fd (s).
  • the detection signal t (s) of the security element is normalized to the final direct signal fd (s) at program point 27; t (s) ⁇ t (s) / fd (s).

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Signal Processing (AREA)
  • Automation & Control Theory (AREA)
  • Computer Security & Cryptography (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Burglar Alarm Systems (AREA)

Abstract

The device (1) consists of a transmitter (4) which transmits at least one periodic interrogation signal into an interrogation zone (3). The interrogation signal stimulates a security element (2) to transmit an identity signal which is received by a receiver (5). A computer/control unit (7) evaluates the received identity signal and triggers an alarm if the security element is identified. The computer/control unit evaluates the received identity signal wrt. its amplitude and phase, detects a noise signal contained in the received signal and frees the received signal from the noise signal.

Description

Die Erfindung betrifft eine Vorrichtung zur Überwachung eines elektronischen Sicherungselementes in einer Abfragezone, bestehend aus einer Sendeeinrichtung, die zumindest ein periodisches Abfragesignal in die Abfragezone aussendet, wobei das Abfragesignal das Sicherungselement zur Aussendung eines Erkennungssignals anregt, einer Empfangseinrichtung, die das Erkennungssignal empfängt, und einer Rechen-/Regeleinheit, die die von der Empfangseinrichtung empfangenen Signale auswertet und bei Identifizierung des Sicherungselementes einen Alarm auslöst.The invention relates to a device for monitoring of an electronic security element in one Interrogation zone, consisting of a transmission device, the at least one periodic interrogation signal in the interrogation zone sends out, the interrogation signal the security element stimulates to send a detection signal, one Receiving device which receives the detection signal, and a computing / control unit that the by the Received device evaluates signals and at Identification of the security element an alarm triggers.

Aus der DE 44 36 977.8 ist bereits eine Anlage zur elektronischen Überwachung von Artikeln, die mit Resonanzschwingkreisen gesichert sind, bekannt geworden. Um einerseits die Empfindlichkeit gegenüber Störsignalen zu erhöhen und andererseits eine hohe Nachweiswahrscheinlichkeit zu erreichen, werden sowohl die Amplituden der empfangenen Signale als auch der Phasenunterschiede zwischen dem Feld des Senders und den empfangenen Signalen ausgewertet. Die Resonanzfrequenz der Sicherungselemente variiert infolge von Fertigungstoleranzen. Um sicherzustellen, daß alle Sicherungselemente innerhalb vorgegebener Toleranzen detektiert werden, strahlt die Sendevorrichtung zyklisch ein Abfragesignal mit einer auf die Toleranzvorgaben bei der Fertigung der Sicherungselemente abgestimmten Bandbreite in die Abfragezone ab. Als Vergleichswerte kommen fest vorgegebene Schwellenwerte bzw. zuvor abgespeicherte Kurvenverläufe zur Anwendung. Hieraus resultiert der Nachteil dieser bekannt gewordenen Vorrichtung: die tatsächlichen, die Empfangssignale beeinflussenden Störquellen in der Abfragezone bzw. in Nähe der Abfragezone werden nicht oder nur unzureichend berücksichtigt.From DE 44 36 977.8 a system for electronic monitoring of articles related to Resonance resonant circuits are secured, become known. Around on the one hand, the sensitivity to interference signals increase and on the other hand a high probability of detection to achieve both the amplitudes of the received signals as well as the phase differences between the field of the transmitter and the received signals evaluated. The resonance frequency of the fuse elements varies due to manufacturing tolerances. Around ensure that all security elements are within predetermined tolerances are detected, the radiates Transmitting device cyclically with an interrogation signal the tolerance specifications in the manufacture of the Security elements matched bandwidth in the Query zone. Fixed comparison values come as comparison values Threshold values or previously saved curves for Application. This results in the disadvantage of this known become device: the actual ones Interference sources influencing reception signals in the Query zone or in the vicinity of the query zone are not or insufficiently considered.

Zur Detektierung von elektromagnetischen Sicherungselementen in einer Abfragezone wird in der EP 123 586 B vorgeschlagen, zusätzlich zu zwei Abfragefelder mit den Frequenzen F1 und F2 im kHz-Bereich ein Feld mit einer im Hz-Bereich liegenden Frequenz F3 in die Abfragezone zu senden. Die beiden Abfragefelder mit den Frequenzen F1 und F2 regen ein in der Abfragezone befindliches Sicherungselement zur Aussendung eines charakteristischen Signals mit den Intermodulationsfrequenzen n·F1 ± m·F2 (n, m = 0, 1, 2,...) an. Das niederfrequente Abfragefeld bewirkt, daß das Sicherungselement im Takt dieses Feldes von der Sättigung in eine Richtung zur Sättigung in die andere Richtung getrieben wird. Das charakteristische Signal tritt daher periodisch mit der Frequenz des niederfrequenten Feldes auf. Als alternative Lösung ist auch bekannt geworden, lediglich ein im kHz-Bereich liegendes Abfragefeld zur Erregung des Sicherungselementes zu verwenden, wobei das Erkennungssignal des Sicherungselementes wiederum im Takte eines niederfrequenten Feldes, das das weichmagnetische, nicht-lineare Material zwischen den beiden Sättigungen hin- und hertreibt, auftritt.In order to detect electromagnetic security elements in a query zone, EP 123 586 B proposes to send a field with a frequency F3 in the Hz range to the query zone in addition to two query fields with the frequencies F1 and F2 in the kHz range. The two query fields with the frequencies F1 and F2 excite a security element located in the query zone for the transmission of a characteristic signal with the intermodulation frequencies n · F1 ± m · F2 (n, m = 0, 1, 2, ...). The low-frequency interrogation field causes the securing element to be driven from saturation in one direction to saturation in the other direction in time with this field. The characteristic signal therefore occurs periodically with the frequency of the low-frequency field. As an alternative solution, it has also become known to use only an interrogation field in the kHz range to excite the fuse element, the detection signal of the fuse element again in the cycle of a low-frequency field, which moves the soft magnetic, non-linear material between the two saturations drifts, occurs.

Der Erfindung liegt die Aufgabe zugrunde, eine Vorrichtung vorzuschlagen, die das Erkennen von Artikeln, die mit elektronisch detektierbaren Sicherungselementen ausgestattet sind, innerhalb einer Abfragezone verbessert.The invention has for its object a device propose the recognition of articles related to electronically detectable security elements are improved within a query zone.

Die Aufgabe wird dadurch gelöst, daß die Rechen-/Regeleinrichtung das empfangene Signal bezüglich Amplitude und Phase (I-Komponente und Q-Komponente) auswertet, daß sie ein in dem empfangenen Signal auftretendes Störsignal erkennt und näherungsweise ermittelt und daß sie das empfangene Signal von dem Störsignal befreit.The object is achieved in that the computing / control device the received signal in terms of amplitude and phase (I component and Q component) evaluates that an interference signal occurring in the received signal recognizes and approximates and that it received signal freed from the interference signal.

Gemäß einer vorteilhaften Weiterbildung der erfindungsgemäßen Vorrichtung wird vorgeschlagen, daß die Rechen-/Regeleinrichtung das empfangene Signal r(s), wobei s = 1, 2, 3,....n den jeweiligen Meßwert charakterisiert, in die folgenden Teilsignale zerlegt: ein Basissignal b(s), ein direktes Signal d*(s), das Antwortsignal des Sicherungselementes t*(s) und ein Rauschsignal n(s).According to an advantageous development of the The device according to the invention proposes that the Computing / control device, the received signal r (s), wherein s = 1, 2, 3, .... n characterizes the respective measured value, broken down into the following sub-signals: a base signal b (s), a direct signal d * (s), the response signal of the Fuse element t * (s) and a noise signal n (s).

Im Falle eines RF-Sicherungselemente überwachenden Systems entspricht das Basissignal b(s) dem Signal, das von den Analog-Digital-Wandlern (ADC) angezeigt wird, wenn die Sendevorrichtung ausgeschaltet ist und keine externe Rauschquellen vorhanden sind. Das Basissignal b(s) entspricht daher dem von der Elektronik der Empfangsvorrichtung herrührenden Signal.In the case of a system monitoring RF security elements the base signal b (s) corresponds to the signal generated by the Analog to Digital Converters (ADC) appears when the Transmitter is turned off and no external Noise sources are present. The basic signal b (s) therefore corresponds to that of the electronics of the receiving device resulting signal.

Bei eingeschalteter Sendevorrichtung wird ein geringer Anteil des gesendeten Signals direkt von der Empfangsvorrichtung empfangen. Dieser Signalanteil entspricht dem direkten Signal d(s). Das direkte Signal variiert sowohl in Amplitude als auch in der Phase, wenn sich beispielsweise eine Person in der Nähe der Empfangsvorrichtung aufhält. Sobald ein Sicherungselement die Abfragezone passiert, erzeugt es ein zu dem Sendesignal proportionales Erkennungssignal. Dieses Signal ist folglich auch proportional zu dem direkten Signal d(s). Externe Rauschsignale, die von der Empfangsvorrichtung empfangen werden, spiegeln sich in dem Signalanteil n(s). When the transmission device is switched on, one becomes smaller Share of the transmitted signal directly from the receiving device receive. This signal component corresponds to that direct signal d (s). The direct signal varies both in Amplitude as well as in phase if for example a person is near the receiving device. As soon as a security element passes the query zone, it generates a signal proportional to the transmission signal Detection signal. This signal is consequently also proportional to the direct signal d (s). External noise signals from the receiving device received are reflected in the signal component n (s).

Aufgrund des Zuvorgesagten hat es sich als besonders vorteilhaft erwiesen, bei Vorrichtungen zur Überwachung von Resonanzfrequenz(RF)-Sicherungselementen das direkte Signal d*(s) gleich k·ejΘ ·d(s) und das Antwortsignal des Sicherungselementes t*(s) gleich k·ejΘ ·d(s)·t(s) zu setzen. Hierbei kennzeichnet k die Amplitudenänderung und Θ die Phasenänderung des direkten Signals d(s).Based on what has been said, it has proven to be particularly advantageous for devices for monitoring resonance frequency (RF) security elements to be the same as the direct signal d * (s) k · e jΘ · D (s) and the response signal of the security element t * (s) is the same k · e jΘ D (s) t (s) to put. Here, k denotes the change in amplitude and Θ the change in phase of the direct signal d (s).

Im Falle einer Vorrichtung zur Überwachung von elektromagnetischen(EM) Sicherungselementen ist gemäß einer vorteilhaften Weiterbildung der erfindungsgemäßen Vorrichtung vorgesehen, daß das direkte Signal d*(s) gleich k·ejΘ ·d(s) und das Antwortsignal des Sicherungselementes t*(s) gleich t(s) gesetzt wird, wobei k wiederum die Amplitudenänderung und Θ die Phasenänderung des direkten Signals d(s) beschreibt.In the case of a device for monitoring electromagnetic (EM) security elements, it is provided according to an advantageous development of the device according to the invention that the direct signal d * (s) is the same k · e jΘ · D (s) and the response signal of the security element t * (s) is set equal to t (s), where k in turn describes the change in amplitude and Θ the change in phase of the direct signal d (s).

Im folgenden wird auf das in der Beschreibungseinleitung beschriebene Überwachungssystem mit den drei Frequenzen F1, F2 und F3 Bezug genommen. Bei einem elektromagnetischen Überwachungssystem erzeugt jedes nicht-lineare Material in der Abfragezone elektromagnetische Signale mit der Frequenz F1 + F2 oder deren Harmonischen, also auch Einkaufswagen oder Metallverpackungen.
Um die Sende-/Empfangsvorrichtungen gegen derartige Störeinflüsse nach außen zu schützen, sind auf der der Abfragezone abgewandten Seite oftmals Metallplatten vorgesehen. Wären die Störeinflüsse statisch, wäre es ausreichend, von dem empfangenen Signal stets einen konstanten Wert abzuziehen. Dies ist jedoch oftmals nicht der Fall: die Störsignale ändern sich beispielsweise infolge von Schwankungen der Energieversorgung -hierdurch werden Amplitudenänderungen verursacht -, der in dem System verwendeten Frequenzen F1, F2, F3 - diese bedingen Phasenänderungen - oder einer mechanische Bewegung - diese wirkt sich auf Amplitude und Phase aus. Da die Amplituden dieser Störsignale bis zu 20mal größer sind als die Erkennungssignale von Sicherungselementen, wirken sich geringfügige Schwankungen bereits gravierend auf die Detektionswahrscheinlichkeit von Sicherungselementen aus, wenn ein einfacher Subtraktionsalgorithmus verwendet wird. Es ist daher von herausragender Bedeutung, daß Amplituden- und Phasenänderungen des direkten Signals erfindungsgemäß kompensiert werden können.In the following, reference is made to the monitoring system with the three frequencies F1, F2 and F3 described in the introduction to the description. In an electromagnetic surveillance system, every non-linear material in the interrogation zone generates electromagnetic signals with the frequency F1 + F2 or their harmonics, including shopping trolleys or metal packaging.
In order to protect the transmitting / receiving devices against such interference from the outside, metal plates are often provided on the side facing away from the interrogation zone. If the interference were static, it would be sufficient to always subtract a constant value from the received signal. However, this is often not the case: the interference signals change, for example as a result of fluctuations in the energy supply - this causes amplitude changes -, the frequencies F1, F2, F3 used in the system - these cause phase changes - or a mechanical movement - this affects Amplitude and phase. Since the amplitudes of these interference signals are up to 20 times larger than the detection signals from fuse elements, slight fluctuations already have a serious effect on the detection probability of fuse elements if a simple subtraction algorithm is used. It is therefore extremely important that changes in amplitude and phase of the direct signal can be compensated for in accordance with the invention.

Als besonders vorteilhaft hat es sich herausgestellt, wenn die Rechen-/Regeleinrichtung das direkte Signal d(s) aus der Differenz der Langzeitmittel von empfangenen Signalen r(s) und Basissignalen b(s) bestimmt. Hierdurch läßt sich die Meßgenauigkeit der Vorrichtung erhöhen.It has proven to be particularly advantageous if the computing / regulating device outputs the direct signal d (s) the difference in long-term averages of received signals r (s) and base signals b (s) are determined. This allows increase the measuring accuracy of the device.

Eine vorteilhaften Weiterbildung der erfindungsgemäßen Vorrichtung sieht vor, daß die Rechen-/Regeleinrichtung folgende Näherung macht: das direkte Signal d(s) wird in der IQ-Ebene derart gedreht, daß seine Hauptkomponente mit der Richtung der I-Komponente zusammenfällt, wobei rd(s) das direkte Signal nach der Drehung (= gedrehtes direktes Signal) beschreibt.An advantageous development of the invention The device provides that the computing / control device makes the following approximation: the direct signal d (s) is in the IQ plane rotated so that its main component with the direction of the I component coincides with rd (s) the direct signal after the rotation (= rotated direct Signal) describes.

Insbesondere wird die Rotation durch Multiplikation von d(s) mit der komplexen Zahl Re_Energie - j·Im_Energie Re_Energie2 + Im_Energie2 simuliert, wobei Re_Energie die Energie des Realteils und Im_Energie die Energie des Imaginärteils des direkten Signals d(s) kennzeichnet.In particular, the rotation is obtained by multiplying d (s) by the complex number Re_Energie - j · Im_Energie Re_Energy 2nd + Im_Energy 2nd simulated, where Re_Energie characterizes the energy of the real part and Im_Energie the energy of the imaginary part of the direct signal d (s).

Gemäß einer vorteilhaften Ausgestaltung ist vorgesehen, daß die Rechen-/Regeleinrichtung von dem gedrehten direkten Signal rd(s) einen eventuell vorhandenen Anteil des Imaginärteils des gedrehten direkten Signals subtrahiert und dadurch das verbesserte direkte Signal ard(s) = rd(s) - Im(rd(s))·corr(Im(rd(s)),Re(rd(s))) erhält, wobei corr(Im(rd(s)),Re(rd(s))) = ΣIm(rd(s))·Re(rd(s))ΣIm(rd(s))2 den Anteil des Imaginärteils des gedrehten direkten Signals Im(rd(s)) in dem Realteil des gedrehten direkten Signals Re(rd(s)) beschreibt.According to an advantageous embodiment, it is provided that the computing / regulating device subtracts from the rotated direct signal rd (s) a possibly present portion of the imaginary part of the rotated direct signal and thereby the improved direct signal ard (s) = rd (s) - Im (rd (s)) corr (Im (rd (s)), Re (rd (s))) receives, whereby corr (Im (rd (s)), Re (rd (s))) = ΣIm (rd (s)) · Re (rd (s)) ΣIm (rd (s)) 2nd describes the portion of the imaginary part of the rotated direct signal Im (rd (s)) in the real part of the rotated direct signal Re (rd (s)).

Gemäß einer vorteilhaften Weiterbildung der erfindungsgemäßen Vorrichtung korreliert die Rechen-/Regeleinrichtung das verbesserte direkte Signal ard(s) mit dem empfangenen Signal r(s), wobei die Korrelationen vorteilhafterweise folgendermaßen lauten:

  • rc = corr(Re(ard(s)),Re(r(s) - b(s))) - hier wird der Anteil des verbesserten direkten Signals ard(s) in der I-Komponente des empfangenen Signals r(s) bestimmt - und
  • ic = corr(Re(ard(s)),Im(r(s) - b(s))) - hier wird der Anteil des verbesserten Signals ard(s) in der Q-Komponente des empfangenen Signals r(s) ermittelt.
    • According to an advantageous development of the device according to the invention, the computing / control device correlates the improved direct signal ard (s) with the received signal r (s), the correlations advantageously being as follows:
  • rc = corr (Re (ard (s)), Re (r (s) - b (s))) - Here the proportion of the improved direct signal ard (s) in the I component of the received signal r (s) is determined - and
  • ic = corr (Re (ard (s)), Im (r (s) - b (s))) - Here the proportion of the improved signal ard (s) in the Q component of the received signal r (s) is determined.

    • Anschließend wird gemäß einer vorteilhaften Ausgestaltung der erfindungsgemäßen Vorrichtung das gedrehte direkte Signal rd(s) mit der komplexen Zahl rc - j·ic multipliziert, wodurch sich das endgültige direkte Signal fd(s) zu fd(s) = rd(s)·(rc - j·ic) ergibt. Then, according to an advantageous embodiment of the device according to the invention, the rotated direct signal rd (s) with the complex number rc - j · ic multiplies, resulting in the final direct signal fd (s) fd (s) = rd (s) · (rc - j · ic) results.

    Die Rechen-/Regeleinrichtung subtrahiert dann den errechneten (simulierten) Wert für fd(s) von dem empfangenen Signal r(s). The computing / control device then subtracts the calculated (simulated) value for fd (s) from that received signal r (s).

    Die Erfindung wird anhand der nachfolgenden Figuren näher erläutert. Es zeigt:

  • Fig. 1: eine schematische Darstellung einer Überwachungszone für elektronisch gesicherte Artikel,
  • Fig. 2: ein Blockdiagramm einer Überwachungsvorrichtung für Sicherungselemente mit Resonanzschwingkreisen,
  • Fig. 3: ein Blockdiagramm einer Überwachungsvorrichtung für elektromagnetische Sicherungselemente und
  • Fig. 4: ein Flußdiagramm eines bevorzugt zur Anwendung kommenden Steuerprogramms für die Rechen-/Regeleinrichtung.
    • The invention is explained in more detail with reference to the following figures. It shows:
  • 1: a schematic representation of a surveillance zone for electronically secured articles,
  • 2: a block diagram of a monitoring device for fuse elements with resonant resonant circuits,
  • 3 shows a block diagram of a monitoring device for electromagnetic security elements and
  • 4: a flow diagram of a control program for the computing / regulating device, which is preferably used.

    • Fig. 1 zeigt eine schematische Darstellung der erfindungsgemäßen Vorrichtung 1 zur Detektierung eines mit einem Sicherungselement 2 versehenen Artikels 6 in einer Abfragezone 3. Die Abfragezone 3 wird von zwei im wesentlichen parallel aufgestellten Detektorgattern gebildet, die die Sendevorrichtung 4 und die Empfangsvorrichtung 5 enthalten. Selbstverständlich können beide Vorrichtungen 4, 5 auch in einem Detektorgatter untergebracht sein. Die Steuerung der Überwachungsvorrichtung 1 sowie die Auswertung der Meßwerte erfolgt mittels der Rechen-/Regeleinrichtung 7.Fig. 1 shows a schematic representation of the Device 1 according to the invention for detecting a a securing element 2 provided Article 6 in one Query zone 3. Query zone 3 is composed of two in essentially parallel detector gates formed, the transmitter 4 and the Receiving device 5 included. Of course you can both devices 4, 5 also in a detector gate be housed. The control of the monitoring device 1 and the evaluation of the measured values takes place by means of the computing / regulating device 7.

    In Fig. 2 ist ein Blockdiagramm einer Überwachungsvorrichtung 1 für Sicherungselemente 2 mit Resonanzschwingkreisen dargestellt. Die Sendevorrichtung 4 sendet zyklisch Abtastsignale einer vorgegebenen Bandbreite in die Abfragezone 3 aus. Die Bandbreite ist so bemessen, daß sichergestellt ist, daß alle zur Artikelsicherung eingesetzten Resonanzschwingkreise trotz fertigungsbedingter Toleranzen in ihrer Resonanzfrequenz detektiert werden. 2 is a block diagram of a monitoring device 1 for fuse elements 2 with resonant circuits shown. The transmission device 4 transmits cyclically Scan signals of a predetermined bandwidth in the Query zone 3 off. The bandwidth is such that it is ensured that all for article security resonant circuits used despite production-related Tolerances in their resonance frequency are detected will.

    Die Empfangsvorrichtung 5 empfängt ein Signal r(s), das neben dem Erkennungssignal t*(s) auch einen Signalanteil d(s) enthält, der direkt von der Sendevorrichtung 4 herrührt, sowie Signale von externen Geräuschen n(s). Die empfangenen Signale r(s) werden in dem Verstärker 10 verstärkt und in dem Demodulator 11 demoduliert. Die Analog-Digital-Wandler 12 liefern nachfolgend Meßwerte für die I-Komponente, die die Amplitude eines empfangenen Signals r(s) widerspiegelt, und die Q-Komponente, die Phaseninformation des empfangenen Signals r(s) beinhaltet, an die Rechen-/Regeleinrichtung 7.The receiving device 5 receives a signal r (s) that in addition to the detection signal t * (s) also a signal component d (s), which is sent directly from the transmitting device 4 originates, as well as signals from external noises n (s). The received signals r (s) are in the amplifier 10 amplified and demodulated in the demodulator 11. The Analog-digital converter 12 subsequently provide measured values for the I component, which is the amplitude of a received Signal r (s) reflects, and the Q component that Contains phase information of the received signal r (s), to the computing / control device 7.

    Fig. 3 zeigt ein analoges Blockdiagramm einer Überwachungsvorrichtung 1 für elektromagnetische Sicherungselemente 2. Die beiden Sendeantennen der Sendevorrichtung 4 senden Signale der Frequenzen F1, F2 und F3 in die Abfragezone 3. Durch die Abfragesignale wird das elektromagnetische Sicherungselement 2, das im wesentlichen aus einem Metall mit nicht-linearen magnetischen Eigenschaften besteht, zur Aussendung von Erkennungssignalen t*(s) angeregt, die von der Empfangsvorrichtung 5 empfangen werden. Neben den Erkennungssignalen t*(s) und den direkten Signalen d(s) enthalten die Empfangssignale r(s)auch Signale n(s), die von externen Geräuschquellen herrühren. Wie im Falle der Überwachung von Sicherungselementen 2 mit Resonanzschwingkreisen werden auch hier der Rechen-/Regeleinrichtung 7 die I- und die Q-Komponente der empfangenen Signale r(s) zwecks erfindungsgemäßer Auswertung zur Verfügung gestellt.3 shows an analog block diagram of a monitoring device 1 for electromagnetic safety elements 2. Send the two transmission antennas of the transmission device 4 Signals of frequencies F1, F2 and F3 in interrogation zone 3. The interrogation signals make the electromagnetic Securing element 2, which is essentially made of a metal with non-linear magnetic properties Transmission of detection signals t * (s) stimulated by the receiving device 5 can be received. In addition to the Detection signals t * (s) and the direct signals d (s) the received signals r (s) also contain signals n (s) which come from external noise sources. As in the case of Monitoring of security elements 2 with resonant circuits are also the computing / control device 7 I and the Q component of the received signals r (s) purpose provided evaluation according to the invention.

    Fig. 4 zeigt ein Flußdiagramm eines Steuerprogramms, das besonders gut für die erfindungsgemäße Auswertung der Empfangssignale r(s) geeignet ist. Die Programmpunkte 14 bis 18 umfassen ein sogenanntes Initialisierungsprogramm, welches dem eigentlichen Steuerprogramm vorgeschaltet ist. Dieses Initialisierungsprogramm wird vorzugsweise in einem festen zeitlichen Abstand durchlaufen, um sicherzustellen, daß der erfindungsgemäßen Vorrichtung 1 stets möglichst aktuelle Ausgangswerte zur Verfügung stehen. Nach dem Start des Programms bei 14, wird unter dem Programmpunkt 15 die Empfangsvorrichtung aktiviert. Die empfangenen Signale r(s) werden über m Zyklen gemittelt, wobei die Dauer eines Zyklus' jeweils der Dauer eines periodischen Abfragesignals entspricht. Der gemittelte Wert wird als Basissignal b(s) gespeichert. Dieses Basissignal entspricht, wie an vorhergehender Stelle bereits definiert, dem Signalanteil der Empfangsvorrichtung 5 bei ausgeschalteter Sendevorrichtung 4.
    Nachfolgend wird entsprechend dem Programmpunkt 17 die Sendevorrichtung 4 eingeschaltet. Bei Punkt 18 wird von dem über mehrere Zyklen gemittelten, empfangenen Signal das entsprechend gemittelte Basissignal b(s) subtrahiert. Das Ergebnis dieser Berechnung ist das direkte Signal d(s).    4 shows a flow chart of a control program which is particularly well suited for the evaluation of the received signals r (s) according to the invention. Program items 14 to 18 include a so-called initialization program, which is connected upstream of the actual control program. This initialization program is preferably run through at a fixed time interval in order to ensure that the device 1 according to the invention is always available with the latest possible output values. After starting the program at 14, the receiving device is activated under program point 15. The received signals r (s) are averaged over m cycles, the duration of a cycle corresponding to the duration of a periodic interrogation signal. The averaged value is stored as base signal b (s). As already defined at the previous point, this basic signal corresponds to the signal component of the receiving device 5 when the transmitting device 4 is switched off.
    Subsequently, the transmission device 4 is switched on in accordance with program point 17. At point 18, the corresponding averaged base signal b (s) is subtracted from the received signal averaged over several cycles. The result of this calculation is the direct signal d (s).

    Dieser Initialisierungsphase schließt sich das eigentliche Steuer-und Überwachungsprogramm zwecks Detektierung sich innerhalb der Überwachungszone befindlicher Sicherungselemente an. Bei Programmpunkt 19 werden die während eines Zyklus empfangenen Signale aufgezeichnet. Bezogen auf die in der Einleitung beschriebenen, zum Stand der Technik gehörenden Überwachungssysteme läßt sich ein Zyklus folgendermaßen definieren: Im Falle des RF-Systems entspricht er der Zeitdauer, während der die Aussendung eines Frequenzbereiches vorgegebener Bandbreite erfolgt. Im Falle des EM-Systems wird der Zyklus durch die Niederfrequenz F3 bestimmt. Anschließend wird bei 20 das Basissignal b(s) von dem empfangenen Signal r(s) subtrahiert. Das Ergebnis dieser Subtraktion ist das korrigierte empfangene Signal r'(s). Unter Punkt 21 wird das laufende Mittel des direkten Signals d(s) aktualisiert. Die Aktualisierung erfolgt nach folgender Berechnung: d(s) ← (d(s)*·x + r'(s))/(x + 1) mit x = const. This initialization phase is followed by the actual control and monitoring program for the purpose of detecting security elements located within the monitoring zone. At program point 19, the signals received during a cycle are recorded. In relation to the monitoring systems belonging to the state of the art described in the introduction, a cycle can be defined as follows: In the case of the RF system, it corresponds to the time period during which the transmission of a frequency range of predetermined bandwidth takes place. In the case of the EM system, the cycle is determined by the low frequency F3. Subsequently, the base signal b (s) is subtracted from the received signal r (s) at 20. The result of this subtraction is the corrected received signal r '(s). At point 21 the running average of the direct signal d (s) is updated. The update is based on the following calculation: d (s) ← (d (s) * x + r '(s)) / (x + 1) with x = const.

    Dies ist die formelmäßige Darstellung eines über einen längeren Zeitraum laufenden, einen Mittelwert bildenden Filters. x ist die Zeitkonstante des Filters.This is the formulaic representation of one over one longer period, averaging Filters. x is the time constant of the filter.

    Unter Programmpunkt 22 erfolgt eine Drehung des direkten Signals d(s), die so ausgelegt ist, daß das Maximum des direkten Signals d(s) in Richtung der I-Komponente zu liegen kommt. Vorzugsweise erfolgt die Rotation dadurch, daß das direkte Signal d(s)* mit der komplexen Zahl Re_Energie - j·Im_Energie Re_Energie2 + Im_Energie2 multipliziert wird. Hierbei charakterisiert Re_Energie die Energie des Realteils von d(s) und Im_Energie die Energie des Imaginärteils von d(s). (Re_Energie2 + Im_Energie2) entspricht der Gesamtenergie. Das gedrehte direkte Signal rd(s) ist das Ergebnis dieser Rotation.Under program point 22 there is a rotation of the direct signal d (s) which is designed such that the maximum of the direct signal d (s) comes to lie in the direction of the I component. The rotation preferably takes place in that the direct signal d (s) * with the complex number Re_Energie - j · Im_Energie Re_Energy 2nd + Im_Energy 2nd is multiplied. Here, Re_Energie characterizes the energy of the real part of d (s) and Im_Energie the energy of the imaginary part of d (s). (Re_Energie 2 + Im_Energie 2 ) corresponds to the total energy. The rotated direct signal rd (s) is the result of this rotation.

    Es ist durchaus möglich, daß nach der Drehung eine Korrelation zwischen dem Realteil Re(rd(s)) und dem Imaginärteil Im(rd(s)) des gedrehten direkten Signals rd(s) vorhanden ist. Dieser verbleibende Anteil wird unter Programmpunkt 23 von dem gedrehten direkten Signal rd(s) subtrahiert. Das Ergebnis dieser Subtraktion ist das verbesserte gedrehte direkte Signal ard(s) ← rd(s) - Im(rd(s))·corr(Im(rd(s)),Re(rd(s))) wobei corr(Im(rd(s)),Re(rd(s))) = ΣIm(rd(s))·Re(rd(s))ΣIm(rd(s))2 den Anteil des Imaginärteils des gedrehten direkten Signals Im(rd(s)) in dem Realteil des gedrehten direkten Signals Re(rd(s)) beschreibt. Allgemein mit den Größen a und b ausgedrückt gilt: corr(a,b) = (Σ a · b)/(Σ a2). It is quite possible that after the rotation there is a correlation between the real part Re (rd (s)) and the imaginary part Im (rd (s)) of the rotated direct signal rd (s). This remaining portion is subtracted from the rotated direct signal rd (s) under program point 23. The result of this subtraction is the improved rotated direct signal ard (s) ← rd (s) - Im (rd (s)) corr (Im (rd (s)), Re (rd (s))) in which corr (Im (rd (s)), Re (rd (s))) = ΣIm (rd (s)) · Re (rd (s)) ΣIm (rd (s)) 2nd describes the portion of the imaginary part of the rotated direct signal Im (rd (s)) in the real part of the rotated direct signal Re (rd (s)). Generally expressed with the sizes a and b: corr (a, b) = (Σ a · b) / (Σ a 2nd ).

    Anschließend wird bei 24 das verbesserte gedrehte direkte Signal ard(s) mit dem empfangenen Signal r'(s) korreliert. Insbesondere werden die I-Komponente und die Q-Komponente des empfangenen Signals r'(s) = r(s) - b(s) mit der I-Komponente des verbesserten gedrehten direkten Signals ard(s) korreliert.The improved rotated direct signal ard (s) is then correlated at 24 with the received signal r '(s). In particular, the I component and the Q component of the received signal r '(s) = r (s) - b (s) correlated with the I component of the improved rotated direct signal ard (s).

    Hierbei ist rc = corr(Re(ard(s)),Re(r'(s))) der Anteil von ard(s), der in der I-Komponente des empfangenen Signals r(s)-b(s) enthalten ist, und ic = corr(Re(ard(s)),Im(r'(s))) der Anteil des verbesserten Signals ard(s), der in der Q-Komponente des empfangenen Signals r(s) - b(s) enthalten ist.Here is rc = corr (Re (ard (s)), Re (r '(s))) the proportion of ard (s) contained in the I component of the received signal r (s) -b (s), and ic = corr (Re (ard (s)), Im (r '(s))) the proportion of the improved signal ard (s) which is contained in the Q component of the received signal r (s) - b (s).

    Bei 25 wird das gedrehte direkte Signal rd(s) mit den unter Punkt 24 berechneten Koeffizienten multipliziert. Das endgültige direkte Signal fd(s)ergibt sich dann zu fd(s) ← rd(s)·(rc-j·ic). At 25, the rotated direct signal rd (s) is multiplied by the coefficients calculated under point 24. The final direct signal fd (s) then results in fd (s) ← rd (s) · (rc-j · ic).

    Das Erkennungssignal des Sicherungselementes 2 wird unter Programmpunkt 26 nach folgender Formel berechnet: t(s) ← r'(s) - fd(s). The detection signal of the security element 2 is calculated under program item 26 using the following formula: t (s) ← r '(s) - fd (s).

    Falls es sich bei der erfindungsgemäßen Vorrichtung 1 um ein Überwachungssystem für Resonanzfrequenz-Sicherungelemente handelt, wird bei Programmpunkt 27 das Erkennungssignal t(s) des Sicherungselementes auf das endgültige direkte Signal fd(s) normiert; t (s) ← t(s)/fd(s). If the device 1 according to the invention is a monitoring system for resonance frequency security elements, the detection signal t (s) of the security element is normalized to the final direct signal fd (s) at program point 27; t (s) ← t (s) / fd (s).

    Nunmehr wird bei Punkt 28 geprüft, ob es sich bei dem Signal t*(s) um ein Erkennungssignal eines Sicherungselementes 2 handelt. Falls diese Überprüfung ergibt, daß es sich um das Erkennungssignal t*(s) eines Sicherungselementes 2 handelt, wird bei 29 ein Alarm ausgelöst. Nach der bei Punkt 29 erfolgten Überprüfung kehrt das Programm auf den Punkt 19 zurück und startet den nächsten Überwachungszyklus. It is now checked at point 28 whether the Signal t * (s) around a detection signal of a Securing element 2 is. If this review shows that it is the detection signal t * (s) one Security element 2 is, an alarm at 29 triggered. After the check at point 29 the program returns to point 19 and starts the next monitoring cycle.

    BezugszeichenlisteReference list

    11
    erfindungsgemäße Vorrichtungdevice according to the invention
    22nd
    SicherungselementSecuring element
    33rd
    AbfragezoneQuery zone
    44th
    SendevorrichtungTransmitter
    55
    EmpfangsvorrichtungReceiving device
    66
    Artikelitems
    77
    Rechen-/SteuereinheitComputing / control unit
    88th
    SägezahngeneratorSawtooth generator
    99
    spannungsgesteuerter Oszillator (VCO)voltage controlled oscillator (VCO)
    1010th
    Verstärkeramplifier
    1111
    DemodulatorDemodulator
    1313
    FrequenzerzeugerFrequency generator
    ss
    Anzahl der MessungenNumber of measurements
    b(s)b (s)
    BasissignalBase signal
    r(s)r (s)
    empfangenes Signalreceived signal
    d(s)d (s)
    direktes Signaldirect signal
    d*(s)d * (s)
    direktes Signaldirect signal
    n(s)n (s)
    RauschsignalNoise signal
    t(s)t (s)
    Signal erzeugt durch SicherungselementSignal generated by fuse element
    t*(s)t * (s)
    Signal erzeugt durch SicherungselementSignal generated by fuse element
    rd(s)rd (s)
    gedrehtes direktes Signalrotated direct signal
    ard(s)ard (s)
    korrigiertes gedrehtes direktes Signalcorrected rotated direct signal
    fd(s)fd (s)
    endgültiges direktes Signalfinal direct signal
    kk
    AmplitudenänderungChange in amplitude
    ΘΘ
    PhasenänderungPhase change
    jj
    imaginäre Zahl (j = -1 )imaginary number ( j = -1 )

    Claims (12)

    Vorrichtung zur Überwachung eines elektronischen Sicherungselementes in einer Abfragezone, bestehend aus einer Sendeeinrichtung, die zumindest ein periodisches Abfragesignal in die Abfragezone aussendet, wobei das Abfragesignal das Sicherungselement zur Aussendung eines Erkennungssignals anregt, einer Empfangseinrichtung, die das Erkennungssignal empfängt, und einer Rechen-/Regeleinheit, die die von der Empfangseinrichtung empfangenen Signale auswertet und bei Identifizierung des Sicherungselementes einen Alarm auslöst,
    dadurch gekennzeichnet,
    daß die Rechen-/Regeleinrichtung (7) das empfangene Signal bezüglich Amplitude und Phase (I-Komponente und Q-Komponente) auswertet, daß sie ein in dem empfangenen Signal auftretendes Störsignal (fd(s)) erkennt und näherungsweise ermittelt und daß sie das empfangene Signal (r(s)) von dem Störsignal (fd(s)) befreit.    Device for monitoring an electronic security element in an interrogation zone, consisting of a transmission device that emits at least one periodic interrogation signal into the interrogation zone, the interrogation signal stimulating the security element to emit a detection signal, a receiving device that receives the detection signal, and a computing / control unit , which evaluates the signals received by the receiving device and triggers an alarm when the security element is identified,
    characterized,
    that the computing / control device (7) evaluates the received signal with respect to amplitude and phase (I component and Q component), that it detects and approximately detects an interference signal (fd (s)) occurring in the received signal and that it does so received signal (r (s)) freed from the interference signal (fd (s)).         Vorrichtung nach Anspruch 1,
    dadurch gekennzeichnet,
    daß die Rechen-/Regeleinrichtung (7) das empfangene Signal r(s), wobei S = 1, 2, 3,....N ist, in die folgenden Teilsignale zerlegt: ein Basissignal b(s), ein direktes Signal d*(s), das Antwortsignal des Sicherungselementes t*(s) und ein Rauschsignal n(s).    Device according to claim 1,
    characterized,
    that the computing / control device (7) breaks down the received signal r (s), where S = 1, 2, 3, .... N, into the following partial signals: a basic signal b (s), a direct signal d * (s), the response signal of the security element t * (s) and a noise signal n (s).         Vorrichtung nach Anspruch 1 oder 2,
    dadurch gekennzeichnet,
    daß im Falle einer Vorrichtung zur Überwachung von Resonanzfrequenz(RF)-Sicherungselementen das direkte Signal d*(s) gleich k·ejΘ ·d(s) und das Antwortsignal des Sicherungselementes t*(s) gleich k·ejΘ ·d(s)·t(s) gesetzt wird, wobei k die Amplitudenänderung und Θ die Phasenänderung des direkten Signals d(s) beschreibt.     Device according to claim 1 or 2,
    characterized,
    that in the case of a device for monitoring resonance frequency (RF) security elements, the direct signal d * (s) is the same k · e jΘ · D (s) and the response signal of the security element t * (s) is the same k · e jΘ D (s) t (s) is set, where k describes the change in amplitude and Θ the change in phase of the direct signal d (s).         Vorrichtung nach Anspruch 1 oder 2,
    dadurch gekennzeichnet,
    daß im Falle einer Vorrichtung zur Überwachung von elektromagnetischen (EM) Sicherungselementen das direkte Signal d*(s) gleich k·ejΘ ·d(s) und das Antwortsignal des Sicherungselementes t*(s) gleich t(s) gesetzt wird, wobei k die Amplitudenänderung und Θ die Phasenänderung des direkten Signals d*(s)beschreibt.    Device according to claim 1 or 2,
    characterized,
    that in the case of a device for monitoring electromagnetic (EM) security elements, the direct signal d * (s) is the same k · e jΘ · D (s) and the response signal of the security element t * (s) is set equal to t (s), where k describes the change in amplitude and Θ the change in phase of the direct signal d * (s).         Vorrichtung nach Anspruch 2, 3 oder 4,
    dadurch gekennzeichnet,
    daß die Rechen-/Regeleinrichtung (7) das direkte Signal d(s) aus der Differenz der Langzeitmittel von empfangenen Signalen r(s) und Basissignalen b(s) bestimmt.    Device according to claim 2, 3 or 4,
    characterized,
    that the computing / regulating device (7) determines the direct signal d (s) from the difference between the long-term mean of received signals r (s) and basic signals b (s).         Vorrichtung nach Anspruch 5,
    dadurch gekennzeichnet,
    daß die Rechen-/Regeleinrichtung (7) folgende Näherung macht: das direkte Signal d(s) wird in der IQ-Ebene derart gedreht, daß seine Hauptkomponente mit der Richtung der I-Komponente zusammenfällt, wobei rd(s) das direkte Signal nach der Drehung (= gedrehtes direktes Signal) beschreibt.    Device according to claim 5,
    characterized,
    that the computing / control device (7) makes the following approximation: the direct signal d (s) is rotated in the IQ plane in such a way that its main component coincides with the direction of the I component, with rd (s) following the direct signal which describes rotation (= rotated direct signal).         Vorrichtung nach Anspruch 6,
    dadurch gekennzeichnet,
    daß die Rotation durch Multiplikation von d(s) mit der komplexen Zahl Re_Energie - j·Im_Energie Re_Energie2 + Im_Energie2 erfolgt, wobei Re_Energie die Energie des Realteils und Im-Energie die Energie des Imaginärteils des direkten Signals d*(s) kennzeichnet.     Apparatus according to claim 6,
    characterized,
    that the rotation by multiplying d (s) by the complex number Re_Energie - j · Im_Energie Re_Energy 2nd + Im_Energy 2nd takes place, where Re_Energie characterizes the energy of the real part and Im-energy the energy of the imaginary part of the direct signal d * (s).         Vorrichtung nach Anspruch 7,
    dadurch gekennzeichnet,
    daß die Rechen-/Regeleinrichtung (7) von dem gedrehten direkten Signal rd(s) einen eventuell vorhandenen Anteil des Imaginärteils des gedrehten direkten Signals subtrahiert und dadurch das verbesserte direkte Signal ard(s) = rd(s) - Im(rd(s))·corr(Im(rd(s)),Re(rd(s))) erhält, wobei corr(Im(rd(s)),Re(rd(s))) = ΣIm(rd(s))·Re(rd(s))ΣIm(rd(s))2 den Anteil des Imaginärteils des gedrehten direkten Signals Im(rd(s)) in dem Realteil des gedrehten direkten Signals Re(rd(s)) angibt.    Device according to claim 7,
    characterized,
    that the computing / regulating device (7) subtracts from the rotated direct signal rd (s) a possibly present portion of the imaginary part of the rotated direct signal and thereby the improved direct signal ard (s) = rd (s) - Im (rd (s)) corr (Im (rd (s)), Re (rd (s))) receives, whereby corr (Im (rd (s)), Re (rd (s))) = ΣIm (rd (s)) · Re (rd (s)) ΣIm (rd (s)) 2nd indicates the proportion of the imaginary part of the rotated direct signal Im (rd (s)) in the real part of the rotated direct signal Re (rd (s)).         Vorrichtung nach Anspruch 5 und 8,
    dadurch gekennzeichnet,
    daß die Rechen-/Regeleinrichtung (7) das verbesserte direkte Signal ard(s) mit dem empfangenen Signal r(s) korreliert.    Device according to claims 5 and 8,
    characterized,
    that the computing / control device (7) correlates the improved direct signal ard (s) with the received signal r (s).         Vorrichtung nach Anspruch 9,
    dadurch gekennzeichnet,
    daß die Korrelationen folgendermaßen lauten: rc = corr(Re(ard(s)),Re(r(s) - b(s))), wodurch der Anteil des verbesserten direkten Signals ard(s) in der I-Komponente des empfangenen Signals r(s) bestimmbar wird, und ic = corr(Re(ard(s)),Im(r(s) - b(s))), wodurch der Anteil des verbesserten Signals ard(s) in der Q-Komponente des empfangenen Signals r(s) bestimmbar wird.     Device according to claim 9,
    characterized,
    that the correlations are as follows: rc = corr (Re (ard (s)), Re (r (s) - b (s))) , whereby the proportion of the improved direct signal ard (s) in the I component of the received signal r (s) can be determined, and ic = corr (Re (ard (s)), Im (r (s) - b (s))) , whereby the proportion of the improved signal ard (s) in the Q component of the received signal r (s) can be determined.     Vorrichtung nach Anspruch 10,
    dadurch gekennzeichnet,
    daß das gedrehte direkte Signal rd(s) mit der komplexen Zahl rc - j·ic multipliziert wird, wodurch sich das endgültige direkte Signal fd(s) zu fd(s) = rd(s)·(rc - j·ic) ergibt.     Apparatus according to claim 10,
    characterized,
    that the rotated direct signal rd (s) with the complex number rc - j · ic is multiplied, resulting in the final direct signal fd (s) fd (s) = rd (s) · (rc - j · ic) results.     Vorrichtung nach Anspruch 11,
    dadurch gekennzeichnet,
    daß die Rechen-/Regeleinrichtung (7) den errechneten Wert für fd(s) von dem empfangenen Signal r(s) subtrahiert.    Device according to claim 11,
    characterized,
    that the computing / regulating device (7) subtracts the calculated value for fd (s) from the received signal r (s).
    EP97117104A 1996-10-18 1997-10-02 Device for monitoring a security element in an interrogation area Expired - Lifetime EP0837432B1 (en)

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    DE19642985 1996-10-18
    DE19642985A DE19642985A1 (en) 1996-10-18 1996-10-18 Device for monitoring an electronic security element in an interrogation zone

    Publications (2)

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    EP0837432A1 true EP0837432A1 (en) 1998-04-22
    EP0837432B1 EP0837432B1 (en) 2002-07-03

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    EP (1) EP0837432B1 (en)
    DE (2) DE19642985A1 (en)
    ES (1) ES2177874T3 (en)

    Families Citing this family (3)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    DE19809433C1 (en) * 1998-03-05 1999-06-24 Siemens Ag Initialisation method for motor vehicle anti-theft protection system
    NL1026690C2 (en) * 2004-07-20 2006-01-23 Nedap Nv Electronic detection system for detecting anti-theft and / or identification labels.
    KR100814002B1 (en) * 2006-06-29 2008-03-14 삼성전자주식회사 Data recovery method and apparatus for radio frequency identification

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    EP0707296A1 (en) * 1994-10-15 1996-04-17 Esselte Meto International GmbH Electronic article surveillance system

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    US4531117A (en) * 1983-07-05 1985-07-23 Minnesota Mining And Manufacturing Company Variable frequency RF electronic surveillance system
    CA1234892A (en) * 1984-02-16 1988-04-05 Pierre Taillefer Security tag detection system
    US4668942A (en) * 1984-11-19 1987-05-26 Progressive Dynamics, Inc. Signal analysis apparatus including recursive filter for electromagnetic surveillance system
    SE9203479L (en) * 1992-01-20 1993-07-21 Rso Corp SET UP AND DEVICE FOR ELECTRONIC IDENTIFICATION

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    Publication number Priority date Publication date Assignee Title
    EP0565481A1 (en) * 1992-04-07 1993-10-13 Actron Entwicklungs AG Label detection apparatus
    EP0707296A1 (en) * 1994-10-15 1996-04-17 Esselte Meto International GmbH Electronic article surveillance system

    Also Published As

    Publication number Publication date
    EP0837432B1 (en) 2002-07-03
    DE19642985A1 (en) 1998-04-23
    ES2177874T3 (en) 2002-12-16
    US6064296A (en) 2000-05-16
    DE59707635D1 (en) 2002-08-08

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