Research Of Intelligent Detector Of Weak Signal Processing Method

Weak signal processing methods of intelligent detectors are researched from multiple angles in this paper,seperately from the inproved design of near infrared sampling circuit, electromagnetic noise suppression, simulation and analysis of weak signal processing method, and the design of digital lock-in amplifier.The intelligent multi-wavelength near-infrared sampling system has been designed. which aimed at the characteristics of weak optical signal detection.High precision numerical controlled constant current source and optical to frequency converter TSL245are used in this sampling system in order to realize high precision control of the light intensity of near infrared LED and effective detection of weak optical signal respectively.FEM was used to study the anti-electromagnetic noise design of the intelligent detector.The analysis is carried on from anti-electromagnetic interference and electromagnetic shielding, and the simulation results are beneficial to improving the electromagnetic noise suppression ability of intelligent detectors.Autocorrelation detection and adaptive noise cancellation have been used in the simulation of weak signal processing.Autocorrelation detection using a combination of self-correlation function and the digital average method to detect weak signals, meanwell, adaptive noise cancellation uses minimum mean square error algorithm and BP neural network algorithm. Simulation results show that the effect of adaptive denoising based on BP neural network algorithm is superior to the mean square error algorithm.Finally, this paper researches the method of weak signal detection based on digital lock-in amplifier.By using DSP Builder to model each sub-module of digital lock-in amplifier and then convert it to VHDL code, which is combined with the previous designed VHDL code to complete the design of DLIA.In summary, the detection of weak signals in strong noise environment can been realized using the weak signal processing methods above, thus the weak signal detection capability of intelligent detectors can be improved.