Research Of Acoustic Signal Testing And Analysis Technology Based On Android

In the world of Internet plus,if the traditional analog acoustic analyzer does not seek innovative breakthrough,it will be the trend of the world Science and Technology Insitute of contempt.How to combine with the high technology,realizing the reformand innovation is imminent.This thesis adopts a solution of modular,high universal and high expansibility to study and complete a test analysis technology combined with Android and ARM.In order to realize the real-time sound pressure level counting,spectrum analysis and other functions,and to ensure the results which handled with this test and analysis technology can meet the national standard,this thesis has made a research on the following aspects:The hardware of this test analysis technology mainly based on the interactive hardware platform between the high performances Cortex A9 ARM processor Exynos4412 and STM32F407 Dual processor.At the bottom layer of the signal acquisition,it completes the AD conversion of the acoustic electric signal,and accomplishes data communication between ARM platform and Android system through a USB-CDC interface which combined with JNI technology.At the layer of Android System,it mainly completes the basic hardware entity of data processing.The overall hardware includes the processor core circuit,signal conditioning circuit,AD conversion circuit,touch control circuit,USBHUB circuit,SD storage circuit and Power supply driver circuit.The part of software algorithm is the difficult point in this thesis,migrating the Android System and making full use of the corrected Hanning Window ZFFT frequency weighting algorithm,Time weighted analysis algorithm and Frequency doubling analysis algorithm to analyze the uploaded original data,guarteening spectral analysis results can be display on the liquid crystal display fast and accurately,at last storing informations about real-time SPL count and real time in the SD card,and simply transmiting data by Internet.This thesis proposed a method of realizing data interaction between Android System and ARM Platform by using USB-CDC interface technology.In the light of the architecture characteristics of Exynos4412 and the deficiency of traditional FFT algorithm,it takes advantages of the corrected Hanning Window ZFFT frequency weighting algorithm,Fragment time weighted analysis algorithm,Frequency doubling analysis algorithm to realize synchronous analysis of multi band signal.It is indicated that the results through this test analysis technology meet the requirements.