With the application of automatic control in various lighting occasions and the promotion of microwave inductor increasing, different application occasions have different requirements for microwave inductor. Therefore, different applications may have different requirements for sensitivity detection. The conventional sensitivity adjustment method is to match different magnification and duration according to the amplitude of the induction signal to adjust different sensitivity requirements. In practical application, there may be the problem of self-excited triggering in some environments. The so-called self-excited triggering is an abnormal working state in which there is no moving reflector at the front of the sensor, but the sensor still has action output, and the output end still has a certain amplitude and frequency output signal.
Because the output signal of microwave Doppler effect is very weak, it is necessary to amplify the small signal, and the amplification gain is very large, the small signal change will cause the big signal change. When the working environment of the product changes (such as: placed in a large area of metal reflection environment, outdoor environment, high temperature environment, low temperature environment), it will cause the product not working and instability. Generally speaking, microwave sensors use directional microwave antennas. Ideally, there is only the main lobe, but in fact there must be side lobe and side lobe. When the installation position is surrounded by non-metallic materials, most of the energy of the side lobe and side lobe can be released well, and the reflection is generally small, so the influence on detection is small.
If it is installed in the extreme having large metal reflective environment, due to the effect of reflection of the metal its vice lobe and sidelobe microwave signals most be repeated reflection, the reflection of microwave signal will inevitably to the microwave sensor in the test of microwave signals, resulting in the absence of the actual human body moving occurs, the microwave sensor also exists certain signal output, Different environments have different output sizes, so if the sensitivity of microwave sensor is set to the same indiscriminately, it will inevitably cause the problem of misoperation in some occasions. However, microwave sensors cannot know their specific installation environment in advance before delivery, so microwave sensors with adjustable detection sensitivity in fixed gears cannot meet various application scenarios. And currently for sensitivity adjustment by microwave amplifier amplification of signal detection after or regulating the processing of the signal processing circuit threshold to achieve different sensitivity, when certain situations such as large area metal reflective environment vice lobe and sidelobe microwave signals most be repeated reflection, may cause the body to move signals submerged in the reflection, It may cause problems that do not work properly.
In order to provide a microwave sensor with matching sensitivity that can be adjusted according to the actual installation environment, the high sensitivity mode and common mode of the product can be seamlessly switched.
