Voice Based On Bone Conduction Signal Reconstruction Technology

With the development of mobile communication, speech in telecommunication under the environment of high background noise has been a problem which is an urgent demand to be meet. Since the signal and noise have the same band, it is very difficult to separate speech signal from background noise, which is concerned by more and more researchers.This dissertation is different from traditional speech enhancement methods which are based on noise characteristic such as adaptive noise cancellation or spectral subtraction processing. In this dissertation the speech signal conducted by bone was taken as the object to be studied and the exploitive study on the acoustical characteristic of speech signal conducted by bone was performed by the method of theory combined with experiment. Then a proposition about speech reconstruction based on speech signal conducted by bone was presented, and the design of software and hardware was completed. The thesis mainly includes the following three aspects: 1. analyzing the characteristics of speech signal conducted by bone; 2. reconstructing speech signal based on speech signal conducted by bone theoretically; 3. designing a prototype.The first aspect was contributed to analyze characteristic of speech signal conducted by bone. In this part, an analysis to several kinds of character of speech signal conducted by bone based on its acoustical principle was firstly given. Secondly, the relativity of the speech signal and that conducted by bone and the relation between the spectrum and timbre were analyzed, so some regulations were discovered. Based on correction of spectrum, a method for speech reconstruction was proposed. Thirdly, the power constant was obtained by large quantity statistic experiments.The second aspect was to design the speech reconstruction based on speech signal conducted by bone and its implementation. Focused on the sine model of the speech signal creation, and finished the reconstruction by using it. At the same time, based on the knowledge of digital signal processing, reconstruction by harmonic correction and time variant digital filter was proposed.The last aspect was devoted to compare and analyze the above three types of reconstruction. In this dissertation, two reconstruction methods suitable for communication in flight and general terrestrial mobile communication separately were chosen. Based on analog electronic technology theory, a prototype was designed, which was small, cheap and applicable for terrestrial mobile communication.