Water quality detection system based on AC detection

Abstract

The invention discloses a water quality detection system based on AC detection. The water quality detection system is characterized by comprising a light source controller, a light source, a sample cell, a photoelectric converter, an AC detector and an MCU, wherein the light source controller outputs an alternating voltage or current driving signal to drive the light source to work, the light source emits an initial AC optical signal with an amplitude consistent with the driving signal under the driving of the light source controller, the photoelectric converter can convert a residual optical signal absorbed by the sample cell into an electric signal consistent with residual light intensity, the AC detector is used for filtering an interference signal, detecting a useful electric signal and outputting detection results to the MCU, and the MCU calculates the concentration of a target substance in the sample cell through operation. The water quality detection system is not influenced by backlight, the dark current of the photoelectric converter and bias of a circuit, can effectively improve signal detection capability and has detection accuracy far higher than that of a common DC detection system.

Description

technical field [0001] The invention belongs to the field of water quality detection and relates to a signal processing method for water quality detection, in particular to a system for realizing water quality detection by detecting light intensity changes through AC detection. Background technique [0002] Under different conditions, the wavelength, intensity, and polarization state of the absorption or emission spectra of material molecules are different, which has an inherent relationship with the structural characteristics of the material. The molecular structures of different substances are different, and the intensities corresponding to the absorption and emission spectra are different; when the concentration of the same substance is different, the absorption intensity at the same absorption peak position will also be different. Therefore, by detecting the absorption degree of a certain substance in water to light of a specific wavelength, the composition and concentra...

AI Technical Summary

Problems solved by technology

In the prior art, the light source generally adopts a DC drive mode, and the light intensity detector is mostly a simple filter. This method of measuring the concentration of the target substance in water by detecting the change of the DC signal is easily affected by the background light and the dark current of the photoelectric converter. The influence of DC and low-frequency interference signals such as the bias signal of the circuit itself and the bias signal of the circuit itself, the accuracy of the detection results is poor

Images