Detection method of electronic article surveillance equipment

Abstract

The invention discloses a detection method of electronic article surveillance (EAS) equipment, which is characterized by comprising the following steps: (A) external electromagnetic environment information is acquired through a receiving unit of the equipment, and the external electromagnetic environment information is analyzed to get a phase point disturbing the clean environment, wherein the phase point is a work point A; (B) the one or more work points A are locked through a DSP LOCK digital signal processing technology, and the work points are locked so that during normal work, a transmitting unit of the equipment works in a time period t1 in front of the work point A, and the receiving unit is just in the work point A, namely, a time period t3; and (C) the equipment works normally: when that there is an electronic goods tag is determined, the tag is locked using an EAS LOCK system, a display unit displays information in a blink way, and the alarm is raised. Through the method, phase locking is carried out through passive inspection and active inspection to eliminate the interference of objects at other resonant frequencies in the environment, and the anti-interference abilityand sensitivity of electronic goods tag detection are improved.

Description

technical field [0001] The invention relates to the field of electronic tags, in particular to a detection method of a commodity electronic detector. Background technique [0002] Commodity electronic detectors are referred to as EAS, which mainly work in acousto-magnetic, radio frequency and other ways. As the name suggests, the acousto-magnetic system emits an ultrasonic 58KHz signal (or other frequencies such as 66KHz). If there is a tag nearby, resonance will occur. After the transmission ends, the resonance gradually decays. Whether there is a tag can be judged by detecting the attenuation signal. Such as figure 2 Shown is a schematic diagram of the existing tag resonance phenomenon, and a 58KHz pulse is emitted within the time period t1. During time period t3, the receive window is opened. In order to avoid overlapping, there is a delay of hundreds of uS between these two periods, and the delay can be adjusted. This period of time is t2. The tag response frequenc...

AI Technical Summary

Problems solved by technology

[0003] First, when the system is working, it is necessary to adjust the phase, that is, the time point of transmission and reception, to ensure that the environment for receiving static electromagnetic waves during the t3 period is relatively clean, otherwise the influence of clutter may cause false alarms; the phase adjustment is generally based on the AC power supply. Operation, however, needs to be reset if the environment changes;

[0004] Second, the 58KHz transmission signal has an excitation effect on the surrounding objects, but the resonance frequency is different, and the excitation effect is not obvious. Conversely, if there is an object with a related resonance frequency nearby, it can also generate an attenuation signal similar to the label in the t3 period , which is an important reason for false alarms, such as LED lamps, using switching power supplies, which have inductive components, which are very easy to couple around the frequency of 58KHz

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