SNR Improvement of an Optical Wave Microphone Using a Wavelet Network

Abstract

In this paper, we discuss an approach of S/N ratio improvement for an optical wave microphone. With the optical wave microphone, ultra-weak diffraction light; which is resulting from phase modulation from a sound wave, is converted to an electrical signal using a light detector. In this way the optical wave microphone can detect the sound without making any contact with others. Signal intensity could be increased or S/N ratio could be improved with (1) optical method, (2) method using electrical circuit, or (3) method using information processing. In this study, we adopted wavelet network as one of the methods using information processing. As a result we succeeded noise reduction at low frequency using only proposed algorithm, not by using combination of various filters.