A real-time formant tracker based on the inverse filter control method

Formant frequencies are very important speech features in the area of speech perception and practical application. Although some formant estimation methods have been proposed previously, those have been inferior in real-time operation. Previously, we have proposed a new type of formant estimation based on IFC (Inverse Filter Control) method and applied into speech analysis and application systems in our study. Since the IFC method is based on speech waveform processing, the realization of a real-time system has been expected. On the other hand, recently the cheap electric boards which mounted a very high-speed DSP (Digital Signal Processor) have been marketed. We have applied such a DSP board into developing a real-time formant tracker based on the IFC method. By correcting the original C-language program for DSP operation, we have confirmed the real-time operation, which have estimated four formant frequencies from F1 to F4. Moreover, those estimates were almost the same as those by the original PC simulation. In this paper, we describe system modification for DSP realization and discuss effects of software modifications from C-language into DSP program.