Research And Implementation Of Dynamic Signal Analysis And Processing Algorithms

Dynamic signal analyzer has always been the key tool for acoustic testing,rotating machinery testing,noise/vibration and modal analysis as well as fault diagnosis.It is widely used in aerospace,military,machinery,medical and other fields.This thesis mainly studies the processing algorithm of acoustic signal and vibration signal of rotating machinery,and realizes it in software.The acoustic signal has a wide complex frequency spectrum,it contains a variety of frequency components with different energy.Octave method is usually used for acoustic analysis.The octave method is to divide the entire frequency band into many continuous sub-bands,calculates and summarizes the spectrum in each respectively.In view of the shortcomings of the traditional method,combined with the multi-rate signal processing theory,an octave analysis method with high precision and outstanding performance for acoustic signals is realized.Octave analysis results can be displayed by power spectrum,sound pressure level diagram,waterfall diagram and other ways.The vibration signal tested from the rotating machinery,especially in the acceleration or deceleration stage,appears as a non-stationary signal with a frequency closely related to the rotatary speed.The analysis method is not traditional Fourier transform but the order analysis.Compared with the current order analysis methods,the Computed Order Tracking is employed to get the order spectrum,which reveals the relationship between the order and amplitude of the vibration signal over a period of time,and shows the overall characteristics of the signal.The rotating speed spectral map based on the short-time Fourier transform is designed to observe the trend of the order magnitude.An order tracking based on Vold-Kalman filtering is realized to observe the amplitude changes of specific order components at different rotational speeds.Finally,the octave and order analysis are tested on a built platform.The verification results show that the octave analysis method can carry out high-precision real-time analysis of acoustic signals,and the order analysis method can analyze the order spectrum,rotating speed spectral map and order tracking of rotating machinery vibration signals.