Speech analysing circuit starting from harmonics of frequencies - works back to fundamental frequency, using mathematical relationship of hypothetical values

摘要

The circuit is used to analyse speech signals to determine the pitch. It starts from the frequencies of a number of top notes in the energy spectrum and works back to find the fundamental frequency. A scale with hypothetical values is assumed for the unknown frequency of the fundamental. It starts off from a function of x defined for positive real values of x with real values of w, where w indicates the max. of the whole value of x. A relationship is established with a function of g for a positive real value of g, where g represents the hypothetical value of the fundamental frequency. The true value is obtained by estimation.