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Design of FIR vocal tract models with linear and nonlinear phase
Vondra, Martin ; Vích, Robert
Experiences with the IIR cepstral model based on Padé approximation of the exponential function indicate some problems with stability. An experiment in designing a FIR cepstral vocal tract model has been made. The computation of the impulse response of the FIR filter that realizes the vocal tract model can be accomplished either using the window method of digital filter design or by a recursive computation directly from real cepstrum using the minimum-phase approximation.
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Multi-function Realization of the TTS System
Přibil, Jiří
The research report describes the TTS system realized in the form of the DLL library for Windows 95/98//NT/2k/XP platform and also in the form of the MS ISAPI/NSAPI script for Internet applications. This TTS system works with the synthesis based on LPC, cepstral, and harmonic speech models and on the impulse response of the cepstrum.
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Czech-speaking artificial face
Chaloupka, J. ; Nouza, J. ; Přibil, Jiří
This paper describes an artificial face that can speak and articulate Czech. It employs the computer-controlled 3D model of virtual head, know as Baldi, which was developed in USA for communication in English. Here we present methods and algorithms that allowed us to use Baldi with Czech spoken language, both synthesised as well as natural. The methods are based on speech synthesis and speech recognition techniques.
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Microstructure optical fibres
Kaňka, Jiří ; Honzátko, Pavel ; Matějec, Vlastimil ; Kašík, Ivan ; Martan, Tomáš
A review of microstructure optical fibers, their use and methods of preparation is presented. Two classes of microstructure optical fibers in accordance with wave guiding mechanism are introduced. Unique dispersion properties and their structure dependence are discussed. Highly nonliner fibers, large mode area fibers and highly birefringent fibers are reported. Finally, the research carried out IREE Prague is summarized.
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Preparation and characterisation of chalcogenide glasses
Ležal, Dimitrij ; Zavadil, Jiří ; Poulain, M.
Chalcogenide glasses systems AS-S, As-Se, As-S-Se and Ge-Se-Te have been prepared and characterised by absorption spectroscopy, scanning electron microscopy and photoluminescence. Photoluminescence spectra have been measured in wide temperature range and the role of multiphonon transitions in mediating the inner 4f-4f electronic transitions was demonstrated. Peculiar Pr related band at 1600 nm has been found in some samples.
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Pump-controlled gain-locked Raman fibre amplifier
Karásek, Miroslav
Preliminary results of numerical simulation of pump-controlled, gain-locked Raman fibre amplifier have been presented. Numerical model of the gain-locked amplifier is based on interative solution of propagation equations for pumps, signals and spectral components of amplified spontaneous emission. Proportional-derivative feedback loop which controls the pump power has been implemented. Suppression of surviving channel power fluctuations due to channel addition/removal has been investigated.
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