Internetbaserade insamling och behandling av data

Sammanfattning

Abstract

Aim of this project was to analyse signals and try to localize the position of source of sound. It is done

with three microphones which have 90 degrees angle to each other. Each microphone detects one part

of the sound wave. The microphones are connected toan ADC which turns signals from analogue to

digital shape. After that the three signals are transformed to a computer. As known a computer

receives only digital signals which are the main reason to use the ADC. The signals are analysed by

computer with help of special softwares. These softwares are LabVIEW and MATLAB which are used

in this work. This analysis of the signals is divided in two parts. The first part is the FFT-analyse (Fast

Fourier Transform) of the signal from the microphones. It means that the signals frequency’s domain

is showed, in other word it shows which frequency components a signal has. Then the result is showed

online by a function belonging to LabVIEW which is called Web Publish.

In second part the position of the signal source is determined by cross correlation. The position is

determined by the difference of time between two signals from same source which are measured by

cross correlation and you can determine angle by triangulating which is described in report.