Explanation of alarm terms (2)

Anti-pet technology: There are two ways: one is the physical way, which is to reduce the probability of false alarms caused by small pets by changing the division method of the Fresnel lens. This way is superficial, and the effect is also limited. The second way is to use digital processing and analysis of the detection signal, mainly to collect data on the detected signal, and then analyze the signal period, amplitude and polarity. These factors specifically reflect the characteristics of the shape, volume, speed, pyroelectric infrared energy of the moving object, and the displacement per unit time. The microprocessor of the detector analyzes and compares the collected data to determine whether the moving object is a human or a small animal.

Double-curtain technology: Curtain detectors are generally used to prevent entrances and exits such as windows and balconies. However, after installing general curtain detectors, the owner may trigger the detector alarm when entering or leaving the balcony, and the owner ’s activity space will be affected. Very restrictive. The direction identification curtain detector can solve this problem. The direction recognition curtain is generally composed of double curtains. These two curtains are divided into inner curtain A and outer curtain B. When the head of the household moves from the inside out, the inner curtain A is triggered first, and then the outer curtain B is triggered. At this time, the detector does not alarm; when the intruder breaks in from the outside, the outer curtain B is triggered first, and then the inner curtain A. At this time, the detector alarms immediately. When the head of the household returns to the room after going out, the outer curtain B is triggered first and then the inner curtain A is triggered. For this reason, it is necessary to distinguish between the return of the head of the household and the invasion of outsiders. No alarm when returning.

Four-curtain curtain technology: composed of four-curtain curtain, its working principle is the same as the above-mentioned double-curtain curtain, with direction recognition function. However, it uses a digital signal processing circuit (DSP) and the application of three vector digital orthogonal analysis technology, which can more accurately identify the moving direction of the human body, and further improve the accuracy of direction recognition.

Transmitting distance: the longest distance that the device in the alarm system transmits the wireless alarm signal after receiving the signal.

Sensitivity: Refers to the speed of the detector's response to the alarm signal. The sensitivity is high and can be detected at a long distance from the detector. The sensitivity is low and the detector can only detect a relatively short range. The ratio of the change Δy of the sensor output to the input change Δx that caused the change. Its value is the ratio between the two.

Sensitivity error: For some reason, it will cause sensitivity change and produce sensitivity error.

Zero-drift: The sensor output changes when the sensor is working for a long time, when the outside temperature changes, or when there is interference (shock, vibration, humidity, electromagnetic, etc.). The output is zero-drift at zero.

Emission frequency: The wavelength of electromagnetic wave emission is calculated by MHZ. The public wave band specified by the National Electromagnetic Wave Management Committee is 315 / 433MHZ.

Infrared technology: In nature, any object above absolute temperature (-273 degrees) will produce an infrared spectrum. The wavelength of infrared energy released by objects at different temperatures is different, so the infrared wavelength is related to the temperature. of. The infrared detector is a converter of infrared radiant energy and a key component of an infrared imaging device. It uses the difference (change) in the background temperature of the alert house from the surface temperature of the moving object as a change in far infrared energy, condensing light in the thermoelectric device Above, here, the signal from light energy to electrical energy is amplified and detected, that is, the radiant energy is converted into another form of energy that is easy to measure, and in most cases converted to electrical energy. The basic concept of infrared detection of infrared detectors is to sense the temperature difference between moving objects and background objects.