Patent ID: 6640208
Filing Date: 2003-10-28
Classification: G10L

Abstract:
A voiced/unvoiced speech classifier comprising:an input terminal for receiving a digitized speech signal; a feature extractor having an input coupled to the input terminal and an output providing feature vectors of the input speech signal; a correlator having an input coupled to the output of the feature extractor and an output providing an autocorrelation value of the feature vectors of the input speech signal; a decision maker having a first input coupled to the output of a combiner, a second input for receiving a threshold value and an output providing a signal indicative of whether a measure of the input speech signal partly based on the autocorrelation value of the feature vectors of the input speech signal is above or below the threshold value; a Signal to Noise Ratio (SNR) calculator having an input coupled to the input terminal and an output providing a SNR signal; a threshold value adjuster having an input coupled to the output of the SNR calculator and an output coupled to the second input of the comparator to provide thereto the threshold value adjusted according to the SNR signal; a signal energy calculator having an input coupled to the input terminal and an output providing an indication of the energy of the input speech signal; and a combiner having a first Input coupled to the output of the correlator, an output coupled to the first input of the comparator and a second input coupled to the output of the signal energy calculator providing the measure of the input speech signal.