METHOD OF ACOUSTIC MEASUREMENTS AND MICROPHONE FOR ITS REALIZATION Russian patent published in 2004 - IPC

FIELD: acoustic measurements. SUBSTANCE: method of acoustic measurements is based on recording of sound pressure with the help of membrane. Membrane comes in the form of thin transparent plane-parallel plate carrying thin layer that is positioned with inclination between light radiation source and reflecting mirror. Sound pressure is recorded by means of interference bands of standing light wave in the form of signal of spatial frequency. For realization of this method there is proposed microphone comprising membrane and optically coupled light radiation source, reflecting mirror that partially transmits light radiation, periodic system including photocells placed behind mentioned reflecting mirror and spectrum analyzer. Membrane comes in the form of thin transparent plane-parallel plate carrying thin layer and placed between light radiation source and reflecting mirror at angle of θ, found from relation sinθ = k/2d, where θ is angle between thin partially transmitting layer and wave front of light wave; λ is length of light wave; d is period of interference bands. Proposed method and microphone make it feasible to measure volume acoustic signals with high sensitivity and can find use in generation of various color-musical effects. EFFECT: high-sensitivity measurement of volume acoustic signals. 4 cl, 2 dwg