Research And Exploit The Noise Analyse System Based On Acoustic Holography Theory

Noise pollution is one of the main entironment pollution, it had been paid more attention to controll.In order to controll noise,it is very important to find out the source of noise.There are different frequency characteristic and sound pressure grade of a mulriple noise object.Finding out the location and magnitude of noise source,then analysing the characteristic and diffusing approach,which is very important to decrease the total noise. Acoustic holography is introduced in the thesis,it has many advantages in noise analyse.It not only can recognise noise source,it also can analyse the process of space diffusing approach of sound source.This thesis introduces the basic theory of acoustic holography,the reconstruction formula and forecast formula.Consider of the disadvantages of common arithmetic, a new holography reconstruction method based on Neural Network (NN) is proposed.Under the existing technical condition, from the angle of actual application, this research developed a set of noise analyse system which based on Windows.Using it,we can recognize and locate noise source and forecast sound field.The part of hardware is composed of micophones, amplifier, DAQ card and computer.The part of software is composed of the data acquisition module,the data processing module,the module of reconstruction of sound field, spectrum analyse module,the figure drawing module.Visual Basic and MATLAB are the main development tools.VB is an important tool in Windows.It is very popular because of its strong function and convenience character.The research chooses USB-7822 DAQ card for data acquisition.Because the card has a DLL,so we must program for it.In the...