Research And Application Of Weak Signal Filtering

In the fields of medical diagnosis,sports research,aerospace and integrated industrial control,more and more attention is paid to high-precision intelligent technology.Especially in the face of today's increasingly integrated electronic devices and complex electromagnetic interference environments,the collection and processing of small signals is even more important.The main research content of this paper is to filter and denoise the small signal of myoelectric signal.In order to extract clear and complete EMG signals,the denoising of EMG signals is imperative.The extraction and analysis of many human electrical signals can also be used to refer to the processing methods of myoelectric signals.Therefore,the research is of great significance and value.In the small signal detection system and the high-sensitivity automatic instrument,the sensor output electrical signal is small and extremely susceptible to interference from external noise signals.In this paper,the surface electromyography signal is taken as an example for analysis and research.According to the characteristics of weak signal,low frequency and high vulnerability,the design requirements of the system are proposed.The overall design plan is determined based on the source and characteristics of the main disturbances.In order to make a more scientific and effective design,the following two points need to be observed: one is to analyze the characteristics of the target signal and the environmental interference factors in a targeted manner,so as to propose corresponding specific measures;the second is to join from the source of signal acquisition.Noise reduction,filtering processing,and further digital filtering of the collected electrical signals to improve acquisition accuracy.The acquisition module of the small signal is designed.This can reduce the noise interference from the source as much as possible from the source.If the large-scale filtering algorithm is used directly to implement signal filtering,it will not only increase the complexity but also reduce the flexibility.Therefore,the small signal acquisition and processing front-end module was first designed.It has a high common mode rejection ratio,flexible gain adjustment,and good noise immunity.And it includes a preamplifier circuit,a band pass filter circuit,and a trap circuit.And do simulation experiments in Multisim software.This verifies the correctness and feasibility of each module.Hardware filtering is implemented from the front-end acquisition stage of the signal.Finally,the signal data is collected and processed based on STM32.Its main interference includes baseline drift,power frequency interference and motion interference.This paper introduces and studies the noise reduction processing of algorithms such as adaptive filtering and wavelet transform.Compare and analyze the two.Through simulation verification,the design basically meets the requirements.And it can achieve filtering processing of small signals.