A pitch follower for speech signals

Oscillograms of a speech signal show, during the voiced parts, a distinct periodicity, which is a measure for the fundamental. The shape of this fundamental is an important datum in phonetic research. The present article describes the result of an investigation on the possibility of deriving this periodicity pitch from the speech signal on the basis of a time measurement. The instrument designed for the purpose can be divided into 3 parts: 1. A pulse generator, which fires at the highest tops of the speech signal. 2. A periodicity finder, also called an interval screen, which determines on the basis of the criterion that the mutual equality of two adjacent intervals between the highest tops must lie within +/- 10%, that a signal is periodic (voiced). 3. Some error-correcting circuits, which are necessary to cancel the consequences of jumps in the periodicity greater than +/- 10%.