Patent ID: 6385548
Filing Date: 2002-05-07
Classification: G10L

Abstract:
A computer-implemented method for characterizing a signal over a detection cycle having a plurality of time intervals, each time interval having a predetermined number of input samples, the method comprising the steps of:determining a local Average Magnitude Difference Function (AMDF) value over a predetermined range of pitch frequencies for each of the plurality of time intervals; determining an average difference AMDF value over the plurality of time intervals from said local AMDF values; determining a minimum AMDF value over the plurality of time intervals; determining a sum of the AMDF values over the plurality of time intervals; computing a first metric equal to the minimum AMDF value over the plurality of time intervals divided by the sum of the AMDF values over the plurality of time intervals; computing a second metric equal to the average difference AMDF value over the plurality of time intervals divided by the sum of the AMDF values over the plurality of time intervals; determining from said first metric whether the signal is a noise signal or not a noise signal; determining from said second metric whether the signal is a voice signal or a tone signal; and providing an output of the determination of signal type.