Research Of Adaptive LMS Algorithm And The Application Of The Noise Filtering

LMS adaptive filter's structure is simple, easy to implement and can automatically adjust the filter parameters to achieve optimal filtering through an adaptive LMS algorithm without knowing a priori signal and noise statistical properties. In view of the above advantages, the article will state using adaptive LMS filter to filter the chromatographic signal. By analyzing the characteristics of the signal output by chromatographic detector and noise mixed with it, comparing the various advantages and disadvantages of adaptive LMS filtering algorithm, we improve the adaptive LMS algorithm to make it suitable for chromatographic signal filtering.In chromatographic signal processing, chromatographic signal filtering is the most important one. The common method is to detect the analog signal output by the detector and converted into digital signal through A/D converter. And then transfer the data to the computer through the serial port or USB interface, using chromatography data processing software for noise filtering, signal peak detection and overlapping peaks cutting and so on. However, the chromatographic signal is so weak that little noise will have a huge impact, and it is susceptible to external environmental. If chromatographic signal mixed with large noise, it will affect the qualitative and quantitative of chromatographic analysis. Therefore, the requirements of the filter are relatively high. The main idea of this article's is:filter the noise before the data transfer to the computer to avoid the superimposing of the noise of circuit and the noise during the transmission and the pollution to the chromatographic signals. While improving the accuracy of spectral peaks, and also laid a good foundation for software data processing.To verify the feasibility of the method, we analyze the convergence of the algorithm, anti-interference ability and tracking ability in theory, and compare them by Matlab software simulation, confirming the superiority of the improved LMS algorithm. Finally, write adaptive LMS algorithm procedures in the QuartusⅡsoftware development platform with Verilog HDL language to achieve the chromatographic signal noise filtering with the cyclone series FPGA's EP1C6Q240C8 chips, and this has achieves good results.