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Issue #207 October 2007
Embedded Speech
Speech Synthesis for Small Applications
by Nicusor Birsan & Ionut Tarsa
Start | Embedding Speech | Speech Synthesis Techniques | Open-Source Project | System Building Blocks | Sound From Luminary Micro | First Big Porting Problem | Synthesizer | Translator | The LM3S811 Speaks | More Speech Applications | Sources & PDF
SPEECH SYNTHESIS TECHNIQUES
Before starting an embedded project, it’s a good idea to look at the application domain to find the appropriate algorithms for embedding. Several different techniques can help you generate embedded speech. The methods are usually classified into three groups, each of which has its own benefits and drawbacks.
The first method, articulatory synthesis, involves modeling the human speech production system. In the second method, formant synthesis, synthesized speech output is created using an acoustic model. Parameters such as fundamental frequency, voicing, and noise levels are varied over time to create a waveform of artificial speech. The third method, concatenative synthesis, involves prerecorded audio samples derived from natural speech.
The articulatory method is still too complicated for high-quality implementations, but it may turn out to be a useful technique in the future. The formant and concatenative methods are the most commonly used in current synthesis systems. Formant synthesis was dominant for a long time, but the concatenative method is becoming more and more popular.
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