Design Of Sound Intensity Measurement And Analysis System Based On LabVIEW

Sound intensity measurement is an integral part of noise control technology.Sound intensity is a vector, which can fully describe the characteristics of the acousticfield, determine the orientation and position of the sound source. Sound intensitymeasurement technology has a broad application prospect in the field of noisemeasurement.This thesis researched the algorithm of sound intensity measurement based ontwo-microphone cross-spectral method, and designed a real-time sound intensitymeasurement and analysis system, using LabVIEW as the development platform. Thissystem has realized the functions of calculating sound intensity and sound pressurelevel, frequency weighting and octave analysis. It can also manage the measurementand analysis data, including graphical display, storage and delete. This thesis isdivided into five parts. First of all, it expounded the domestic and internationalresearch status and development trend of sound intensity measurement, and pointedout the significance of sound intensity measurement and analysis system based on twomicrophone method. Secondly, it researched the relevant algorithms of soundintensity measurement, introduced the principle of it and its related technology,focusing on the principle of two microphone method, and given the derivation processof the cross-power spectral method. Thirdly, it realized the algorithms the twomicrophone cross-spectral method on the LabVIEW platform, verified the accuracyand frequency characteristics of the algorithm, and given the correspondingexperimental results and analysis. Fourthly, it introduced the structure of the system,analyzed the hardware and software architecture of the system based on dataacquisition card, described the working principles of it, given the software designrequirements of the system through the requirement analysis. Finally, designed eachfunctional modules of the software, expounded the concrete implementation of themon LabVIEW, including data acquisition module, system calibration module,measurement and analysis module, data browsing module and data managementmodule.The design of sound intensity measurement and analysis system in this thesis hasa friendly interactive interface, simple operation, strong commonality, and goodreal-time performance. It’s easy to implement function extension and modificationand maintenance of late. The experimental results show that the sound intensity level and sound pressure level measured by the system are approximately equal;conform tothe characteristics of the plane acoustic field;fully meet the requirements of GB/T17561-1998standards on the1st level of sound intensity measurement system;C-weighted and A-weighted filter;octave filter designed by digital filter method canalso meet the verification requirements of national standard on the1st class of soundlevel meter.