The Research Of Sound Absorption Coefficient System

The sound absorbing material is one of main methods the human uses to absorbe the sound and reduce the noise, so how to measure the sound absorption coefficient faster and presicer is one of the topics that the human concern. In this paper, principle, development and advantages and disadvantages of various absorption coefficient measuring method were studied. Based on the principles of two-microphone technique, this paper proposes a design of a absorption coefficient measuring system based on TMS320VC5402 and AT89S52. The system includes the power supply circuit, white noise signal generator circuit, sound intensity probe circuit, signal regulate circuit, TMS320VC5402 smallest system circuit and the communications between AT89S52 and TMS320VC5402. And for each module the working principle and key techniques are analyzed respectively. a signal disposal of circuit and DSP and MCU smallest system of PCB is made, carried on the installation and debugged.This paper also designs the software programs using C language and assembly language , mainly divided into the MCU software and DSP software. DSP software includes TMS320VC5402 initialization, data collection, A 512-point Fourier transformation and HPI interface communication ; MCU software mainly includes the HPI interface communication program design and LCD display design program. This paper gives part of the source program and the flowchart, and simulates the modules.Finally, thie paper uses 1khz, 6V sine signal to simulate signal regulate circuit, AD converter and DSP smallest system, and acquires good result.