Acoustomagnetic anti-theft system capable of resisting electromagnetic interference

Abstract

The invention discloses an acoustomagnetic anti-theft system capable of resisting electromagnetic interference. The system comprises an antenna body and at least two wave absorption layers used for absorbing electromagnetic wave signals within a first frequency range; the antenna body is provided with a first surface used for transmitting an electromagnetic wave signal to an acoustomagnetic sensorand / or receiving the electromagnetic wave signal transmitted by the acoustomagnetic sensor, and at least two second surfaces used for corresponding to at least two electromagnetic interference sources one to one; the second surfaces and the first surface are located on different sides of the antenna body; the wave absorption layers are used for being correspondingly arranged between the second surfaces and the electromagnetic interference sources, facing the corresponding second surfaces or covering the electromagnetic interference sources; the first frequency range is consistent with the work frequency range of the antenna body and electromagnetic interference frequency ranges of the electromagnetic interference sources. The detection distance between the acoustomagnetic anti-theft system and an acoustomagnetic soft label cannot be greatly reduced, and therefore the acoustomagnetic anti-theft system is beneficial for being matched with acoustomagnetic soft labels for using.

Description

technical field [0001] The invention relates to the field of acoustomagnetic technology, in particular to an acoustomagnetic anti-theft system resistant to electromagnetic interference. Background technique [0002] Acoustomagnetic anti-theft system, as one of the electronic commodity anti-theft systems, is widely used in various shopping malls due to its superior performance, to protect the commodities on sale from being stolen. The acoustomagnetic anti-theft system mainly includes three parts: the transmitting antenna, the receiving antenna and the control device. Its working principle is: the transmitting antenna regularly transmits 58kHz electromagnetic wave signals to form an alternating magnetic field. Since the resonant frequency of the magnetic sensor is consistent with the carrier frequency in the alternating magnetic field, a resonant signal with a frequency of about 58kHz is generated. During the timing silence time of the transmitting antenna (that is, when the t...

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Problems solved by technology

[0006] For example, for a vertical acoustic magnetic anti-theft system, when the transmitting antenna of the vertical acoustic magnetic anti-theft system is close to a metal object (such as a metal counter, a metal shelf or a steel bar in a wall, etc.), or the vertical acoustic magnetic anti-theft system When the receiving antenna is close to the electromagnetic interference source that continuously emits electromagnetic interference signals, the method of reducing the transmitting sensitivity of the transmitting antenna or the receiving sensitivity of the receiving antenna will make the width of the effective anti-theft channel of the vertical acoustic and magnetic anti-theft system within 50cm. The effective anti-theft channel can only pass through one person at the same time, which is not conducive to the use of shopping malls with a large flow of people, thus greatly limiting the use of acoustic and magnetic soft labels

For the buried acoustic and magnetic anti-theft system, since the transmitting antenna is installed under the ground, the transmitting antenna will be close to many steel bars under the ground, and the method of reducing the transmitting sensitivity of the transmitting antenna or the receiving sensitivity of the receiving antenna will be The effective anti-theft height of the buried acoustic and magnetic anti-theft system is within 50cm, while the waist height of most people in the world is about 1.2, and the height of most of the hand-held goods is slightly lower than the waist height (generally above 50cm). Buried anti-theft systems are almost useless for acoustomagnetic soft tags

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