Abstract: An apparatus for the protection of signal copy for preventing unauthorized copying of music software such as records, compact discs and music tape by recording is arranged such that when recording audio signals on a medium, certain supplemental information is added to the audio signal to be recorded, and in the process of copying by reproducing this medium, when the supplemental signal is detected in the reproduced signal, the copying action is stopped to protect it from being copied.

Abstract: An apparatus for the protection of signal copy for prevention unauthorized copying of music software such as records, compact discs and music tape by recording is arranged such that when recording audio signals on a medium, certain supplemental information is added to the audio signal to be recorded, and in the process of copying by reproducing this medium, when the supplemental signal is detected in the reproduced signal, the copying action is stopped to protect it from being copied.

Abstract: A high speed method for formant extraction includes the steps of calculating linear prediction coefficients by executing linear prediction analysis of an input speech signal, extracting a coarse formant frequency by making a linear combination of multiple regression coefficients obtained through multiple regression analysis executed with speech feature parameters taken as predictor variables and with formant frequencies taken as criterion variables and speech feature parameters, and solving a root of an inverse filter formed of the linear prediction coefficients by an approximation method in which the coarse formant frequency is set up as an initial value of the root of the inverse filter and an approximation of root is recursively calculated until it converges to the root.