The Research On The System Of Multi-channel Noise Measurement And The TDE Algorithm

With the rapid development of science&technology and modern industry,noise control has become widespread issue which the human has concerned.To effectively control noise and solve the problem of noise pollution,the requirement of instruments on noise measurement and analysis is also increasing.To solving these problems,the thesis has designed and developed a multi-channel noise measurement and analysis system,and has made a study on estimation algorithm of time delay between the two signals.The main work is as follows:Firstly,the thesis has made an in-depth study of the theoretical basics of noise measurement and analysis,elaborated the physical measurement and the subjective evaluation of noise,and understood the functions of noise measurement and analysis system and the theoretical methods to achieve noise analysis clearly.Then,the thesis has made a research on estimation algorithm of the relative time delay between any two signals of the system:introducing the basic concepts and models TDE;descripting and using LabVIEW simulated two delay estimation algorithm:correlation delay estimation algorithm and adaptive LMS delay estimation algorithm;simulating the two algorithms under different categories,different amplitude and different SNR,and analyzing and comparing the performance of the two algorithms.Finally,the thesis has designed and developed a system of noise measurement analysis based on virtual instrumentation and data acquisition card using the LabVIEW graphical programming language.The system can read signal of the multiple sound pressure from the data acquisition card at the same time and analysis the noise multiplexed signal.During the design of the multi-channel noise measurement and analysis system,using the multithreading producer/consumer program structure which is often used in software development process to solve the contradiction between the real-time data acquisition and real-time data processing,has the reliability.The system modules include four parts:parameter settings,noise measurement and analysis,data browsing and result output.The module of noise measurement and analysis is the main module of multi-channel noise measurement and analysis system,in this module the key technologies are software implementation of weighting network and software implementation methods of octave and 1/3 octave and overall sound level.