The Research Of Sound Absorption Coefficient Measuring Instrument

The rapid economic development brought about the acceleration of the process of urbanmodernization, traffic noise, construction noise is filled with people’s daily lives and have agreat influence on human physical and mental health. Therefore, modern architectural design,noise pollution control has become the focus of attention, in order to reduce the noiseabsorbing material, normally used in architectural design and the development of convenient,accurate sound absorption coefficient measuring instrument has a very good practicalsignificance.This article provides an overview of the development process, measured by theabsorption coefficient analysis and comparison of three commonly used sound absorptioncoefficient measurement method, select a two-microphone measuring oblique incidenceabsorption coefficient as a test theoretical basis. In-depth study of the measurement principleof the dual-microphone method, we designed a simple discussion based on the MCU andDSP dual-CPU architecture of the hardware circuit and software solutions, and systematicerrors. Hardware circuit modules include: control of DDS chip AD9831single-chip MSP430circuit of the sound source, acoustic-electric conversion amplifier circuit, the programmablefilter composed of MAX267, LTC6906, AD5241, AD sampling circuit constituted by theADS7862, the TMS320C5402and peripheral circuits DSP digital signal processing circuit.The article also describes the overall system software implementation, introduced the idea ofa microcontroller and DSP-side software processes and modules, the preparation of theDSP-side the main program, the AD conversion routines as well as the FFT calculationsubroutine.Finally, the design of the sound source circuit, the signal processing circuits, DSPcircuits, PCB board, and the sound source circuit and the signal processing circuit debugging,verify that the sound source can be realized as well as the filtering function of the filtercircuit.