| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 99 === Speech Interface of human-machine interactive system provides not only friendly interface but also a directly feedback mechanism for user. In this thesis, an embedded system is designed and implemented with using the pitch-based single-words speech verification to promote the functionality for speech interactive interface. The proposed system is especially designed for the hardware resource limitation environment, and it has the following features: small size, low cost, low power consumption, real-time operation, and can be widely applied to speech interactive applications.
In pitch detection, the average magnitude difference function (AMDF) is adopted to predict the pitch period feature for speaker independent utterance verification. We propose an upper bound strategy to reduce the iteration times of SAA (subtraction absolute operation and accumulation), and this new manner can reduce the computations power with high AMDF accuracy. The proposed pitch period feature extraction manner is implemented on an embedded system with 8051 MCU, preamplifier circuit, AGC and filtering circuit. For single command of 2 seconds duration speech data, the average speech verification accuracy rate is about 95% under difference distances from speaker to microphone. From experimental results, we found that the detected pitch period from the modified AMDF is still reliable.
The proposed prototype can be widely applied to human-machine interactive system, such as alarm clock, intelligent toys, real-time feedback system, and hand-free remote controller, etc.
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