The system updates an autocorrelation function of the audio signal from samples in the audio signal, estimates an autocorrelation function of the speech signal from the updated autocorrelation function of the audio signal, and calculates {HEAD ~ a power spectral density} of the speech signal using {TAIL ~ the estimated autocorrelation function} 
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The system updates an autocorrelation function of the audio signal from samples in the audio signal , estimates an autocorrelation function of the speech signal from the updated autocorrelation function of the audio signal , and calculates { HEAD ~ a power spectral density } of the speech signal using { TAIL ~ the estimated autocorrelation function }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL