CCD CZT Spectral analysis applied to real time homomorphics speech analysis-synthesis
Thomas F. Quatieri · 2005
In this paper we discuss real time spectral analysis using charge-coupled device (CCD) nonrecursive filters with an application to homomorphic speech analysis-synthesis. We consider the conventional chirp-z-transform (CZT) realization of the discrete Fourier transform (DFT) and an analogous CZT realization of a sliding transform, a modified DFT, better suited to CCD technology than the DFT. Novel CCD configurations based on both transforms are proposed for improved spectral resolution and frame rate; such schemes utilize parallel spectral processing and interpolation. Stationarity conditions and windowing techniques required by these CCD structures are discussed within the context of short-time spectral analysis. A number of homomorphic schemes and experimental results are presented which illustrate the trade-offs that CCD technology imposes between implementational complexity and synthetic speech quality.