Haze detection device and method based on digital phase locking and photoacoustic spectrometry technologies

Abstract

The invention discloses a haze detection device and method based on digital phase locking and photoacoustic spectrometry technologies. The device comprises an excitation light source, a photoacousticcell and a microphone; the photoacoustic cell is connected with the excitation light source and provided with a microphone, and gas in the photoacoustic cell resonates under the action of the excitation light source; the microphone is used for detecting resonance signals in the photoacoustic cell, the microphone is connected with an analog-digital converter, the analog-digital converter is connected with a DSP, and the DSP sends out signals to drive the drive circuit. According to the invention, the phase-locked amplifier is developed by combining wavelength modulation and second harmonic extraction technologies, so the gas absorption coefficient is inverted by detecting a weak current signal, and the defects of large volume, high cost, easiness in being influenced by external noise and the like of the existing photoacoustic spectrometry gas detection system are overcome.

Description

Technical field [0001] The present invention relates to the field of detection technology, in particular to a haze detection device and method based on digital phase lock and photoacoustic spectroscopy technology. Background technique [0002] The existence of haze will bring harm to human society and seriously affect human health. It is necessary to detect these hazardous gases. In recent years, as scholars have used photoacoustic spectroscopy technology to carry out a large number of detections of polluting gases, photoacoustic spectroscopy technology has been increasingly used in energy, electricity, industrial gas emissions, atmospheric environment monitoring, and life and health. Diagnosis and other research in the field of gas detection. The existing photoacoustic spectroscopy technology generally uses a lock-in amplifier to extract the second harmonic. Because the amplitude of the second harmonic signal is positively related to the gas concentration, the second harmonic e...

AI Technical Summary

Problems solved by technology

However, the lock-in amplifiers on the market are bulky and expensive, and are not suitable for popularization.

[0003] The Chinese patent with the publication number CN110208195A discloses a photoacoustic spectrum single-channel lock-in amplification device for gas detection. When performing phase compensation, only when the phase difference between the reference signal and the signal to be measured is 0, the amplitude It will reach the maximum. The process of adjusting the phase is tentatively adjusted by changing the resistance value of the resistor. There will always be errors in the adjustment process, so that the phase difference between the signals is not zero.

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