An optical microphone with echo cancellation

摘要

An echo-cancelling system for an optical microphone, for eliminating acoustical echoes from a source of acoustical signals to which the microphone is connected, the system comprising: 739 כ" א באייר התשס" ד - May 12, 2004 a source of light for illuminating the acoustical membrane; a photodetector for receiving light reflected from said membrane and for producing output signals; means for supplying power to said source of light; a preamplifier for amplifying said output signals; an input terminal for receiving electrical signals from said source of acoustical signals; a time delay circuit for receiving signals from said source of acoustical signals; a time delay circuit for receiving signals from said source of acoustical signals, and a circuit for regulating the amplitude of the delayed electrical signals, connected between said delay circuit and said source of light, for changing the current supplied to said source of light by said light source power means.