Laser dust monitor with digital modulation and demodulation and its monitoring method

Abstract

The invention provides a laser dust monitor with digital modulation and demodulation and a monitoring method. The said monitor includes: a digital processing unit, which generates digital modulation signals and sends them to a digital-to-analog conversion drive circuit; a digital-to-analog conversion drive circuit, which converts digital modulation signals into analog signals to drive laser diodes; a laser diode, which generates a modulated laser driven by a digital-to-analog conversion drive circuit; a light source collimator, which filters the modulated laser, the filtered lasers first irradiating dust particulate matters and then falling on a detector; a detector, which generates photoelectric signals and sends them to an amplifier circuit; an amplifier circuit, which amplifies photoelectric signals and sends them to an analog-to-digital conversion circuit; an analog-to-digital conversion circuit, which converts the amplified photoelectric signals into digital quantity and sends itto the digital processing unit, which conducts demodulation and wave-filtering to the digital quantity of photoelectric signals to get the intensity of the photoelectric signals. The dust concentration value is obtained by multiplying the intensity of the photoelectric signals and the scattering coefficient of dust particles.

Description

technical field [0001] The invention relates to the technical field of laser dust monitoring, in particular to a digital modulation and demodulation laser dust monitor and a monitoring method. Background technique [0002] The dust monitor is based on the principle of laser forward scattering method. Dust particles are proportional to the intensity of scattered light under the irradiation of measured modulated light, so the more dust, the stronger the scattered light. Since the scattered light of the dust in the laser dust meter is very weak, in order to amplify the weak signal with high precision, to suppress the interference of ambient light and the drift of the photoelectric sensor, it is necessary to modulate the photoelectric signal to suppress the interference of ambient light, the drift of the photoelectric sensor, and the laser light source. Drift and drift of the system itself. Laser dust detectors generally use analog circuits to realize signal modulation and dem...

AI Technical Summary

Problems solved by technology

[0004] Moreover, the inventors found that the structure of the analog circuit is complicated, and the precision of the electronic components is very high, it is easy to introduce noise, there are many drift links, and it is difficult to debug and maintain the circuit.

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