Patent ID: 7016507
Filing Date: 2006-03-21
Classification: H03G,H04R

Abstract:
1. A method of reducing noise in an input signal, said input signal containing speech and noise related to each other by a signal to noise ratio, the method comprising the steps: (1) detecting the presence and absence of speech; (2) in the absence of speech, determining a noise magnitude spectral estimate (|{circumflex over (N)}(f)|); (3) in the presence of speech, comparing the magnitude spectrum of the input signal (|X(f)|) to the noise magnitude spectral estimate (|{circumflex over (N)}(f)|); (4) calculating an attenuation function (H(f)) from the magnitude spectrum of the input signal (|X(f)|) and the noise magnitude spectral estimate (|{circumflex over (N)}(f)|), the attenuation function (H(f)) being dependent on the signal to noise ratio; and, (5) modifying the input signal by the attenuation function (H(f)) to generate a noise reduced signal wherein there is no substantial modification to the input signal for very low and for very high signal to noise ratios.