Infrared anti-theft device and method thereof for automatically transforming modulating frequency

Abstract

The invention provides an infrared anti-theft device, which comprises a transmitting terminal and a receiving terminal. In the technical scheme, the transmitting terminal and the receiving terminal both comprise a list predefined with a plurality of fundamental frequencies; and each fundamental frequency is arrayed in the list according to a predefined procedure. The method for automatically transforming modulating frequency for the infrared anti-theft device, provided by the invention, comprises the following steps: defining the working frequency and the encoding rule of the infrared beam by the transmitting terminal or the receiving terminal; and performing the two-way synchronous communication between the transmitting terminal and the receiving terminal, and judging the operation environment and determining whether the modulating frequency is to be automatically changed by the receiving terminal. The invention can automatically choose the appropriate fundamental frequency with the receiving of the same fundamental-frequency disturbing signal, thereby ensuring the normal operation of the system under the condition of concentrated installation of the device and improving the reliability and practicality of the device or even the system.

Description

technical field [0001] The invention relates to the field of alarm devices, and specifically provides an infrared anti-theft device and a method for automatically changing modulation frequencies in the infrared anti-theft device. Background technique [0002] Traditional active infrared intrusion detectors account for 80% of the perimeter anti-intrusion detectors. They use infrared rays as the anti-intrusion medium, which has the advantage of being invisible to human vision, but has weaknesses. First of all, traditional active infrared intrusion detectors use fundamental frequency modulation technology, and the signal characteristics of each infrared pulse beam are the same. Due to the characteristics of infrared pulse beam scattering (calculated based on the current best lens scattering angle of 1.5°, the theoretical value of the spot diameter when the beam reaches 100 meters is about 5 meters), the infrared receiver at the receiving end receives multiple beams at the same ...

AI Technical Summary

Problems solved by technology

As long as one of the pair of devices has the above problems, it is necessary to adjust the adjacent pairs of devices, that is, to re-adjust all the devices; in addition, due to environmental changes such as window openings, there are randomness and uncertainty in time, configuration, etc. However, even if the debugging can be completed, there is still a possibility in the application that the receiving end receives other infrared beams with the same fundamental frequency and may cause false alarms due to changes in environmental factors, requiring re-debugging; the more serious problem is that the When factors change and the receiving end receives other infrared beams with the same basic frequency, which causes a missing alarm, the device itself and the system cannot reflect in time, and the problem can only be found in the post-theft verification; even due to random changes in environmental factors, and uncertainty without checking the source of the problem

It can be seen that under dense installation conditions, the method of manually setting the fundamental frequency is almost impossible to operate

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