Patent ID: 7315623
Filing Date: 2008-01-01
Classification: G10L

Abstract:
1. A method of suppressing ambient noise in a hands-free device having two microphones spaced a predetermined distance apart, each of which supplies a microphone signal, comprising: generating a sum signal and a difference signal of the two microphone signals; computing a first Fourier transform R(f) of the sum signal (S) and a second Fourier transform of the difference signal; detecting speech pauses from the first and second Fourier transforms R(f) and D(f); determining first spectral power density S determining second spectral power density S calculating the transfer function H generating the interference power density S calculating the transfer function H filtering the first Fourier transform R(f) with the spectral subtraction filter; and transforming the output signal of the spectral subtraction filter back to the time domain.