Measurement of airflow in speech

It has been shown previously that a mask-type wire screen pneumotachograph can be constructed with a time resolution of 1/2 msec. In this paper it is shown that with careful design a resolution of about 1/4 msec can be achieved. The various factors involved in optimizing such a mask are described. A major practical limitation in the design has been the need for a fast-responding differential pressure transducer to measure mask pressure; however, a simple electrical compensating network is described that allows the use of a nondifferential transducer. Also determined are the conditions under which breath moisture condensing on the wire screen affects the performance of the mask. An example is given of how a high-speed pneumotachograph can be used, with a measure of the pressure across a constriction in the vocal tract, to derive the time variation of the flow conductance and resistance at that constriction. The advantages of a high-speed pneumotachograph in laryngeal frequency extraction are also considered.