After clarifying the problem of infrared radiation, some companies in the industry have carried out targeted improvements and modifications to active infrared intrusion detectors, and have made certain progress. In view of the shortcomings in the signal characteristics of the product detection medium, first of all, the transformation is aimed at it, and the following types of typical technologies for authorized invention patents have been formed.
1. Code modulation. To encode and modulate the infrared pulse beam, in layman's terms, is to digitally transform the infrared beam to give each infrared beam a different code, so that each receiver on the receiving end can identify its corresponding beam, so that the single product can be used Multiple infrared beams form a high and tight detection interface.
One of the technical characteristics of code modulation is synchronous communication. One of its advantages is to take advantage of the limitation of synchronization conditions to ensure that multiple pairs of the same product will not cause "alternative" missed alarms due to the same signal characteristics.
There are currently two forms of products using this technology, one is the through-beam type, that is, the transmitter and receiver are separately configured on both sides; the other is the cross-beam type, that is, the spacing/corresponding configuration of the transmitting and receiving devices on both sides. For the working principle of such products, the industry also uses "time division scanning circuit" to describe. In fact, time-divided pulses can be classified as special cases of coded pulses. Therefore, the author believes that "coding and modulation" is a more rigorous "superior" expression.
2. Adaptive adjustment of emission intensity. The maximum emission intensity is still in accordance with national standards, but the emission intensity can be automatically adjusted according to the degree of attenuation of the beam intensity by the environment, so that the emission energy is maintained within 2 times the actual use distance. This not only ensures that the product has the ability to resist the attenuation caused by bad weather conditions, but also greatly reduces the intensity and opportunities of similar signal interference in the environment.
3. Adaptive conversion of modulation frequency. When another signal with the same modulation frequency is detected, it will automatically switch to a new modulation frequency to work, further reducing the chance of interference from similar signals in the environment.
4. The shortest trigger response time of the new active infrared intrusion detector has reached 20ms, which can ensure that the alarm is reliably triggered when an intruder runs through the detection interface at a speed of 10m/s.
Missing industry norms
Active infrared intrusion detectors are products listed in the national compulsory certification catalog. At present, many manufacturers produce coded and modulated infrared beams that have obtained compulsory certification (the certificate catalog includes infrared screens, infrared guardrails, infrared gratings, etc.). However, only one of the products covered by the certificate has a use distance of more than 60 meters.
The current national standard GB10408.4-2000 active infrared intrusion detector has a standard age of 11 years. Due to multi-faceted reasons such as the popularity of market applications and changes in the application environment, it is in urgent need of revision or re-enactment. There are many manufacturers in the market that use false labels for the use distance of their products; a small number of models of products are certified, and then certified, and most of the products that have not been certified are sold. Manufacturers in the industry have plagiarism at different levels from appearance to principle. Due to the lack of relevant management regulations and law enforcement bodies, the above violations cannot be dealt with at any level.
Management regulations and law enforcement entities are missing, technical regulations and product standards are seriously lagging behind; market and industry management is not in place; vicious price wars, violations of compulsory certification regulations, product plagiarism in business operations; engineering designers and product users have special comments on product evaluation rules It is the ambiguity of legal evaluation elements/application evaluation elements, etc.; this leads to the obstruction of technological innovation and severely hinders the application and popularization.
