Double-frequency detecting channel type antitheft system

Abstract

The invention relates to a double-frequency detecting channel type antitheft system which is provided with a host computer, a detection door as well as an alarm and a display which are controlled by the host computer, wherein the detection door is internally provided with an antenna; the host computer is internally provided with a synchronous modulator-demodulator for modulating low-frequency electromagnetic wave and ultrahigh-frequency electromagnetic wave into a composite signal and a synchronous digital signal processing device, wherein the synchronous modulator-demodulator is controlled by the synchronous digital signal processing device. The double-frequency detecting channel type antitheft system provided by the invention combines the advantages of an ultrahigh-frequency band and a low-frequency band when detecting by adopting ultrahigh frequency and low frequency and has strong capacity of resisting disturbance, and when goods are hidden in clothes and packsacks, an alarm system can still accurately alarm; the data transmission speed is high, and the detecting efficiency is increased; the reading distance is longer and is generally up to 4-6m; whether lending or putting in storage is marked or not is judged, and compared with the traditional magnetizing and demagnetizing, the judgment error is reduced, the judgment is more precise, and information error can not appear.

Description

technical field [0001] The invention relates to an anti-theft system, in particular to a dual-frequency detection channel type anti-theft system. Background technique [0002] The existing commodity anti-theft system is an important anti-loss means for shopping malls, supermarkets, clothing stores, etc., and can be equipped with commodity electronic detectors, decoders or unlockers, hand-held detectors, and supporting materials. There are transmitters and receivers in the commodity electronic detector, which are respectively placed on both sides of the exit of the shopping mall or supermarket. There are soft labels or hard signs on the goods. The soft labels are pasted in the form of self-adhesive, and the hard signs are fixed with steel pins or locks. . After the customer pays, the cashier uses the decoder to remove the soft label or the unlocker to remove the hard label from the product. After the payment is delivered, the product will be taken away by the customer throug...

AI Technical Summary

Problems solved by technology

At present, the tags used in the society can usually carry item information, which brings convenience to item statistics and storage, so the existing anti-theft alarm system is generally designed for high-frequency bands, which has the following shortcomings: the anti-interference ability is not strong, when the item is hidden When it is in clothes or backpacks, the accuracy of the alarm system is not high, and there will be false alarms, which will cause economic losses to shopping malls, supermarkets, bookstores, etc.

However, compared with RFID products in other frequency bands, the data transmission rate of low-frequency is relatively slow, and it cannot store a large amount of information; the anti-theft tags used are long in size, generally above 8cm, which is not conducive to concealment; The tag needs to be located in the near-field area radiated by the reader antenna, and the reading distance is generally less than 1 meter

[0004] There is a composite tag consisting of low-frequency tags and UHF radio frequency identification tags in the existing market. The anti-theft door for this tag has some design difficulties. For example, the transmission of low-frequency electromagnetic waves requires a large Cannot be fired while affected

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