Research On Sound Level Detection Technology Based On Linux Operation System

Acoustics is to study the production, spread, reception and interaction within materials. Sound is produced by the vibration of objects, including solid, liquid and gas. When an object vibrates, it will motivate the surrounding elastic medium to spread outward with a certain speed in the form of density alternate. The dilatational wave is defined as acoustic wave. Acoustic wave can exert pressure on objects which it contacts. Sound level meter is used to detect the pressure of acoustic wave and transform it into electrical signal. The signal can be used to figure out the sound level. As a basic measuring instrument, sound level meter is widely used in industrial production to detect the status of machine and evaluate the environmental noise. Research on sound level detection instrument is of practical value.The research focuses on constructing real-time detecting system of sound level. The system is designed on the basis of embedded Linux OS. Hardware system mainly includes sound pressure sensor, digital signal processor and ARM core chip The gathered sound pressure signal is transferred into digital signal. DSP ship processes the digital signal to figure out time weighing sound pressure level and frequency spectrum. ARM chip with Linux OS receives the calculating result from DSP and show it as images. The system makes full use of the powerful digital signal processing capacity of DSP and performs well in sound pressure level detection. Experimental result shows that the system can detect sound pressure level in real time and meets the requirement of the state standard as Ⅰ-level sound level meter.This paper studies on sound pressure level detection on the basis of embedded technology. An algorithm for calculating time weighing sound pressure level is established and optimized based on DSP. The algorithm speeds up the calculating of time weighing sound pressure level and enhances the real-time capability of the detecting system.Experimental result shows that the system meets the requirement of the state standard in every aspect.