Accurate pitch determination of speech signals by means of a laryngograph

An algorithm is presented which is designed to yield reference pitch contours of speech signals for a comparative evaluation of pitch determination algorithms. For the task of pitch determination the question of error analysis in general and measurement accuracy in particular is discussed, It is shown that the accuracy of the algorithm must be better than 0.5% in order to render fine measurement errors inaudible. The algorithm uses the output signal of a laryngograph which measures the laryngeal vibrations via the changes of the electric impedance of the larynx. The point of inflection during the rapid rise of the laryngogram is taken as the estimate for the instant of glottal closure. Using a local interpolation filter the quantization error of the measurement is kept below 0.5%.