Testing system and method for acoustic-magnetic anti-theft soft tag resonator

Abstract

The invention provides a test system for an acoustic magnetic anti-theft soft label resonator, and relates to the field of resonator detection, and the system comprises an excitation mechanism which is configured to emit an excitation signal to the resonator; the direct current bias magnetic field mechanism is configured to generate a static bias magnetic field, and the resonator is located in the influence range of the static bias magnetic field; the measuring mechanism is configured to output an induced voltage signal according to the magnetic flux change of the resonator; according to the invention, superposition of a direct current bias magnetic field and a pulse excitation signal is accurately controlled, and high-speed data acquisition and analysis are combined, so that high-precision automatic testing of parameters such as resonant frequency, amplitude, quality factor, frequency deviation and the like is realized; the problems of sensitive environmental interference, insufficient data acquisition speed, low DC bias control precision and the like in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the field of resonator detection, and particularly to a test system and method for a resonator of an acousto-magnetic anti-theft soft label. Background Art

[0002] Electronic Article Surveillance (EAS) is widely used in the retail industry. The core component of the acousto-magnetic label consists of a cobalt-nickel-based amorphous resonator, a semi-hard magnetic polarizer, and a cavity. Under the excitation of an external pulsed magnetic field, the resonator generates mechanical vibrations due to the magnetostrictive effect, and its resonance signal is captured by the detection system to trigger an alarm.

[0003] Currently, there are the following problems in the testing of resonators of acousto-magnetic anti-theft soft labels in the industry: lack of a unified standard, existing testing devices and systems have not formed a standardized solution, resulting in poor comparability of test results among different manufacturers; sensitive to environmental interference, the testing accuracy is easily affected by environmental magnetic field interference, especially with significant errors in complex electromagnetic environments; insufficient control of the DC bias, the linearity and stability of the DC bias magnetic field directly affect the testing accuracy, and it is difficult to achieve precise regulation with existing technologies; low data acquisition speed, transient resonance signals (such as attenuation characteristics) require a high-speed acquisition system, and traditional equipment is difficult to capture the complete response; low degree of automation, relying on manual operation, with low efficiency and prone to introducing human errors. Summary of the Invention

[0004] The purpose of the present invention is to provide a test system and method for a resonator of an acousto-magnetic anti-theft soft label, which improve the detection efficiency and accuracy of the resonator.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A test system for a resonator of an acousto-magnetic anti-theft soft label, comprising: an excitation mechanism configured to send an excitation signal to the resonator; a DC bias magnetic field mechanism configured to generate a static bias magnetic field, and the resonator is located within the influence range of the static bias magnetic field; a measurement mechanism configured to output an induced voltage signal according to the magnetic flux change of the resonator; and an acquisition and processing mechanism configured to acquire and process the induced voltage signal output by the measurement mechanism.

[0006] Further, the test system further includes a sample fixing groove, and the resonator is disposed on the sample fixing groove.

[0007] Further, the excitation mechanism includes a waveform generator, a power amplifier, and an excitation coil, and the output signal of the waveform generator is transmitted to the excitation coil through the power amplifier.

[0008] Further, the DC bias magnetic field mechanism includes a DC power supply and a magnetic field coil. The DC power supply can supply power to the magnetic field coil, and the magnetic field coil can generate a static bias magnetic field after being supplied with power by the DC power supply.

[0009] Further, the measuring mechanism includes a measuring coil, and the acquisition and processing mechanism includes an acquisition card and a computer. The measuring coil is nested inside the magnetic field coil. The measuring coil can detect the magnetic flux change caused by the vibration of the resonance piece, and the computer obtains the detection data of the measuring coil through the acquisition card.

[0010] Further, the test system further includes a communication port. The computer is connected to the waveform generator and the DC power supply through the communication port, and the computer can control the working states of the DC power supply and the waveform generator.

[0011] Further, the number of turns of the excitation coil is 1000 - 1500, the number of turns of the magnetic field coil is 300 - 900, and the number of turns of the measuring coil is 50 - 200.

[0012] Further, the center line of the resonance piece is parallel to the axis of the excitation coil, the axis of the magnetic field coil, and the axis of the measuring coil.

[0013] Further, the amplification factor of the power amplifier is 0 - 50 times.

[0014] On the other hand, a test method for a resonance piece of an acoustic - magnetic anti - theft soft label is provided. The test method is based on the above - mentioned test system, and the test method includes the following steps: placing the resonance piece in the test area; confirming the working frequency and working timing of the excitation signal; sending the excitation signal to the resonance piece at the working frequency and the working timing through the excitation mechanism; generating a static bias magnetic field through the DC bias magnetic field mechanism; obtaining the magnetic flux change of the resonance piece under the influence of the static bias magnetic field and the excitation signal through the measuring mechanism; and judging the state of the resonance piece according to the excitation signal, the static bias magnetic field, and the magnetic flux change of the resonance piece.

[0015] Analysis shows that the present invention discloses a test system and method for a resonance piece of an acoustic - magnetic anti - theft soft label. By precisely controlling the superposition of the DC bias magnetic field and the pulsed excitation signal, combined with high - speed data acquisition and analysis, high - precision automatic testing of parameters such as resonance frequency, amplitude, quality factor, and frequency offset is realized, solving problems such as environmental interference sensitivity, insufficient data acquisition speed, and low DC bias control accuracy in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. Among them: Figure 1 The structural block diagram of an embodiment of the present invention.

[0017] Figure 2 It is a graph showing the strength relationship between a DC power supply and a static bias magnetic field. Detailed implementation manners

[0018] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present invention rather than a limitation to the present invention. In fact, those skilled in the art will clearly understand that modifications and variations can be made to the present invention without departing from the scope or spirit of the present invention. For example, features shown or described as part of one embodiment can be used in another embodiment to yield yet another embodiment. Therefore, it is desirable that the present invention includes such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0019] In the description of the present invention, the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. The terms "connected", "connected to", and "disposed" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component; it can be a wired electrical connection, a radio connection, or a wireless communication signal connection. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0020] One or more examples of the present invention are shown in the accompanying drawings. The detailed description uses numerical and alphabetical labels to refer to features in the drawings. Similar or like labels in the drawings and the description have been used to refer to similar or like parts of the present invention. As used herein, terms such as "first", "second", "third", and "fourth" etc. can be used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of individual components.

[0021] Specifically, an acousto-magnetic tag generally consists of a cobalt-nickel-based amorphous resonance sheet with a length of 40 mm, a width of 8 mm to 14 mm, and a thickness of 20 μm to 30 μm, a semi-hard magnetic polarizer, and a cavity. Under the excitation of an external pulsed magnetic field, due to the unique magnetostriction and inverse magnetostriction effects of the cobalt-nickel-based amorphous soft magnetic material, the resonance sheet can vibrate freely in the cavity. The semi-hard magnetic polarizer is located at the lower end of the resonance sheet, and its function is to reduce the sensitivity of the resonance sheet.

[0022] The acousto-magnetic anti-theft tag detection system in a supermarket mainly consists of a transmitting circuit, a transmitting antenna, a receiving circuit, a receiving antenna, a synchronization circuit, and an alarm system. The excitation signal frequency of the detection system is 58 kHz, and the repetition period is 60 Hz. To reduce the false alarm rate, signals are usually detected in 4 consecutive time intervals, and at least in 2 consecutive time intervals. At the same time, the receiver uses two receiving detection windows of the supermarket security door for reception. The two windows integrate the 58 kHz signal respectively. When an item with an acousto-magnetic anti-theft soft tag is placed in the detection window, the magnetic signal provided by the polarizer in the tag to the resonance sheet will resonate with the excitation signal. If the 58 kHz signal comes from the tag, the resonance signal will decay due to the damped motion similar to the tuning fork phenomenon. The results of integrating the 58 kHz signal by the two windows show a decaying trend. If the 58 kHz signal comes from other signal sources, such as RF or other noises, the detected signal does not decay, and the results of integrating the 58 kHz signal by the two windows are the same, so as to judge the ownership of the item. The detection time of the first window is 1.6 ms after the excitation signal stops, and the detection time of the second window is 6 ms after the excitation signal stops. The sensitivity of the detection system depends on the difference in the signals detected by two consecutive windows.

[0023] As Figure 1 shown, according to an embodiment of the present invention, a test system for an acousto-magnetic anti-theft soft tag resonance sheet is provided, including: A specimen stage. The test system further includes a sample fixing groove. The resonance sheet is arranged on the sample fixing groove. Generally, the sample fixing groove is located inside the excitation coil, the magnetic field coil, and the measurement coil, and needs to be located at the middle position of the measurement coil. The measurement coil is located inside the excitation coil, and the excitation coil is located inside the magnetic field coil.

[0024] Specifically, the center line of the resonance sheet is parallel to the axes of the excitation coil, the magnetic field coil, and the measurement coil. The parallel arrangement of the excitation coil, the magnetic field coil, and the measurement coil ensures the uniformity of the magnetic field at the position of the resonance sheet to be measured.

[0025] Specifically, the test system is set on the specimen stage. The specimen stage is made of non-magnetic material (such as polyimide). An excitation coil, a magnetic field coil and a measurement coil are coaxially installed on the specimen stage. The resonance piece is specifically installed in the sample fixing groove on the specimen stage: the sample fixing groove can accurately position the resonance piece. Usually, the size of the sample fixing groove is the same as that of the resonance piece. After the resonance piece is placed in the sample fixing groove, the position of the resonance piece can be fixed to ensure the axial alignment of the resonance piece with each coil and reduce the position error.

[0026] An excitation mechanism, the excitation mechanism is configured to send an excitation signal to the resonance piece; The above-mentioned excitation mechanism includes a waveform generator, a power amplifier and an excitation coil. The output signal of the waveform generator is sent to the excitation coil through the power amplifier.

[0027] Specifically, the waveform generator usually outputs a pulsed excitation signal of 55 kHz - 62 kHz, and the pulse width is 1 ms - 50 ms. The pulse width and the interval time are specifically adjusted according to the usage requirements.

[0028] Specifically, the number of turns of the excitation coil is 1000 - 1500. The amplification factor of the power amplifier is 0 - 50 times, and it can amplify the excitation signal to 0.1 Vpp - 50 Vpp, so as to drive the excitation coil to generate an alternating magnetic field. The waveform generator makes the excitation coil generate an alternating magnetic field by outputting a pulsed excitation signal, thereby exciting the resonance piece to vibrate.

[0029] A DC bias magnetic field mechanism, the DC bias magnetic field mechanism is configured to generate a static bias magnetic field, and the resonance piece is within the influence range of the static bias magnetic field.

[0030] The DC bias magnetic field mechanism includes a DC power supply and a magnetic field coil. The DC power supply can supply power to the magnetic field coil, and the magnetic field coil can generate a static bias magnetic field after being supplied with power by the DC power supply.

[0031] Specifically, the number of turns of the magnetic field coil is 300 - 900, and the specific number of turns is selected according to actual requirements.

[0032] Specifically, the DC power supply is usually a programmable digital power supply, such as a programmable digital power supply of model IT6863A. The voltage output range of the DC power supply is usually 0 V - 72 V, and the specific voltage value is adjusted according to the user's requirements. The DC power supply can generate a static bias magnetic field of 0 Oe - 100 Oe through the magnetic field coil. The actual current output range of the DC power supply is usually 0 mA - 3000 mA. In order to make the magnetic field coil generate a static bias magnetic field of 0 Oe - 100 Oe, the output current range of the DC power supply is usually controlled at 1 mA - 300 mA.

[0033] A measuring mechanism configured to output an induced voltage signal according to the magnetic flux change of the resonance sheet; An acquisition and processing mechanism configured to acquire and process the induced voltage signal output by the measuring mechanism.

[0034] The measuring mechanism includes a measuring coil, and the acquisition and processing mechanism includes an acquisition card and a computer. The measuring coil is nested inside the magnetic field coil. The measuring coil can detect the magnetic flux change caused by the vibration of the resonance sheet, and the computer obtains the detection data of the measuring coil through the acquisition card.

[0035] Specifically, the measuring coil is nested inside the bias magnetic field coil and can detect the magnetic flux change caused by the vibration of the resonance sheet, thereby outputting an induced voltage signal.

[0036] Specifically, the computer can control device parameters, acquire voltage / current signals in real time, analyze the resonance frequency and amplitude through FFT (Fast Fourier Transform), and perform data operations on the quality factor and frequency offset at the same time.

[0037] Furthermore, after receiving the signal acquired by the acquisition card, the computer can identify the resonance peak and calculate parameters such as the quality factor, vibration frequency, vibration amplitude, and frequency offset of the resonance sheet, and determine whether the resonance sheet is qualified according to the above parameters.

[0038] It can be understood that as Figure 2 shown, the present invention simulates the actual working state of the tag by the method of superimposing a DC bias magnetic field. The DC current has a high linearity with the induced static bias magnetic field, which improves the test accuracy. Figure 2 In it, the expression of the solid line is: y = 0.284x, R 2 = 0.9999, x represents the current of the DC power supply, y represents the magnetic field of the static bias magnetic field, and R 2 represents the fitting correlation degree between x and y. The larger the value, the better the linearity between the two. Among the Figure 2 two line segments, the dashed line represents a perfect linear curve with a correlation coefficient of 1, similar to a baseline, and the solid line represents the magnetic field relationship curve obtained according to the current. Since the two coincide very well, the coefficient relationship between the magnetic field intensity of the static bias magnetic field and the current of the DC power supply is obtained.

[0039] Specifically, the number of turns of the measuring coil is 50 - 200.

[0040] Specifically, the sampling rate of the acquisition card ≥ 1MS / s. Usually, an acquisition card with a sampling rate ≥ 1MS / s can meet the sampling requirements for the resonance sheet.

[0041] The test system further includes a communication port. The computer is connected to the waveform generator and the DC power supply through the communication port, and the computer can control the working states of the DC power supply and the waveform generator.

[0042] It can be understood that the switches and specific operating states of the DC power supply and the waveform generator are uniformly controlled by the computer, and the user can control the entire test system through the computer.

[0043] In an embodiment, the waveform generator is a waveform generator of model 2 series mixed signal oscilloscope produced by Tektronix; the DC power supply is a digital programmable DC power supply, such as a digital programmable DC power supply of model IT 6863A produced by ITECH DC Power Supply; the power amplifier is a power amplifier of model ATA-031 High Voltage Amplifier produced by Aigtek.

[0044] The specific test can be set as follows: Place the resonance chip at the center of the sample test bench, set the static bias magnetic field strength to 8 Oe, start the excitation signal frequency from 55 kHz, and step-scan to 67 kHz at a step of 150 Hz; set the amplification factor of the power amplifier to 5 times gain.

[0045] The present invention also discloses a test method for the resonance chip of an acoustic-magnetic anti-theft soft label. The test method is based on the above test system, and the test method includes the following steps: Place the resonance chip in the test area; confirm the working frequency and working timing of the excitation signal; send the excitation signal to the resonance chip through the excitation mechanism at the working frequency and working timing; generate a static bias magnetic field through the DC bias magnetic field mechanism; obtain the magnetic flux change of the resonance chip under the influence of the static bias magnetic field and the excitation signal through the measurement mechanism; judge the state of the resonance chip according to the excitation signal, the static bias magnetic field and the magnetic flux change of the resonance chip.

[0046] It can be seen from the above description that the above embodiments of the present invention achieve the following technical effects: By precisely controlling the superposition of the DC bias magnetic field and the pulsed excitation signal, combined with high-speed data acquisition and analysis, high-precision automated testing of parameters such as resonance frequency, amplitude, quality factor, and frequency offset is achieved, solving the problems of environmental interference sensitivity, insufficient data acquisition speed, and low DC bias control accuracy existing in the prior art.

[0047] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A test system for a resonance sheet of an acousto-magnetic anti-theft soft label, characterized in that Comprising: An excitation mechanism configured to send an excitation signal to a resonance piece; A DC bias magnetic field mechanism configured to generate a static bias magnetic field, and the resonance piece is within the influence range of the static bias magnetic field; A measurement mechanism configured to output an induced voltage signal according to the magnetic flux change of the resonance piece; An acquisition and processing mechanism configured to acquire and process the induced voltage signal output by the measurement mechanism.

2. The test system for the resonance sheet of the acousto-magnetic anti-theft soft label according to claim 1, wherein The test system further includes a sample fixing groove, and the resonance piece is disposed on the sample fixing groove.

3. The test system for the resonance sheet of the acousto-magnetic anti-theft soft label according to claim 1, characterized in that The excitation mechanism includes a waveform generator, a power amplifier, and an excitation coil, and the output signal of the waveform generator is sent to the excitation coil through the power amplifier.

4. The test system for a resonance sheet of an acousto-magnetic anti-theft soft label according to claim 3, characterized in that, The DC bias magnetic field mechanism includes a DC power supply and a magnetic field coil, the DC power supply can supply power to the magnetic field coil, and the magnetic field coil can generate a static bias magnetic field after being powered by the DC power supply.

5. The test system for the resonance sheet of the acousto-magnetic anti-theft soft label according to claim 4, characterized in that, The measurement mechanism includes a measurement coil, the acquisition and processing mechanism includes an acquisition card and a computer, the measurement coil is nested within the magnetic field coil, the measurement coil can detect the magnetic flux change caused by the vibration of the resonance piece, and the computer obtains the detection data of the measurement coil through the acquisition card.

6. The test system for a resonance sheet of an acousto-magnetic anti-theft soft label according to claim 5, characterized in that, The test system further includes a communication port, the computer is connected to the waveform generator and the DC power supply through the communication port, and the computer can control the working states of the DC power supply and the waveform generator.

7. The test system for the resonance sheet of the acousto-magnetic anti-theft soft label according to claim 5, characterized in that, The number of turns of winding of the excitation coil is 1000 - 1500, the number of turns of winding of the magnetic field coil is 300 - 900, and the number of turns of winding of the measurement coil is 50 - 200.

8. The test system for the resonance piece of the acousto-magnetic anti-theft soft label according to claim 5, characterized in that, The central axis of the resonance piece is parallel to the axes of the excitation coil, the magnetic field coil, and the measurement coil.

9. The test system for the resonance sheet of the acousto-magnetic anti-theft soft label according to claim 4, characterized in that, The amplification factor of the power amplifier is 0 - 50 times.

10. A testing method for a resonance sheet of an acousto-magnetic anti-theft soft tag, characterized in that, The test method is based on the test system according to any one of claims 1 - 9, and the test method includes the following steps: Place the resonance piece in the test area; Confirm the working frequency and working timing of the excitation signal; Send an excitation signal to the resonance piece through the excitation mechanism at the working frequency and the working timing; Generate a static bias magnetic field through the DC bias magnetic field mechanism; Obtain the magnetic flux change of the resonance piece under the influence of the static bias magnetic field and the excitation signal through the measurement mechanism; Judge the state of the resonance piece according to the excitation signal, the static bias magnetic field, and the magnetic flux change of the resonance piece.

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