Study And Implement On Pivotal Craft Of Reducing Noise In Wireless Speech Communication

For speech communication, noise and interference will make listener fatigued and affect intelligibility and articulation of speech. As a result, it is necessary to design corresponding device to reduce noise in wireless speech communication.This thesis focus on the basic theory of speech processing, the key technologies to reduce noise in speech and the design and implementation of corresponding noise reduce devices. Based on those studies, a prototype of noise in speech reducing device for wireless communication is designed and implemented, with its effects evaluated. Specifically, this thesis includes the following work:the basic theory of speech processing and noise in speech reduce. We study the short interval character of speech signal and short interval process technology, and classify the noise and disturbance in wireless receiver terminal into 3 categories and present corresponding schemes. Because of uncertainty of the noise and jam's character, we also introduce adaptive signal process to deal with the problem.studies on the approaches for speech enhancement. We put emphasis on the approaches based on short interval estimation and analysis the application of those approaches for reducing the noise in speech.DSP technologies for reducing noise in speech. We study the character of DSP and discuss the procedure to design noise reducing system, and discuss some issues for system architecture, design and debug.Design and implementation of the prototype of a wireless speech noise reducing device. We design hardware circuit to reduce noise and disturbance. Directed by simulation, we also programme the codes for DSP and three improved approaches for speech enhancement are designed and adopted in the prototype. Evaluations show that it works well in practice.