The Research And Implementation Of Voice Transmission And Encryption System

Along with the rapidly developing of the communication technology, the mobile and the intelligent equipment, all kinds of wireless transmission applications are gradually expanding. Many new words such as The Internet of things, Intelligent Household, Wireless Observe and Control appeared. So the development of many voice applications towards intelligent, mobile and secure. People not only confine to pay attention to the voice transmission quality, but also notice the compositive, convenience and the voice transmission process safety of the phonic acquisition. Therefore, how to gather and transmit the voice information effectively and safely has become a hot problem.Based on the study of the theory of speech collection coding, encryption and wireless transmission, this paper realize a voice collection, transmission and encryption system on a singlechip, achieves translating the theoretical knowledge into actual application. Based on the deep research of ADPCM coding and multimedia encryption, this paper choose an ADPCM encoding chip MC145540 as the hardware to realize the analog voice signal collection and coding, and realize the voice encryption by programming on the AVR singlechip, then use a integrated wireless modules to achieve the speech wireless transmission. Receiver uses this software and hardware system to decrypt and unzip the speech data, then recover the voice in the end. The whole system can realize a short-range wireless voice transmission, and the module of the voice acquisition coding and encryption could be applied into The Internet of things system as a security speech sensor node, so it has great practical value.In this paper the research contents and innovative points mainly include:(1) Based on a detailed study and simulation analysis to the ADPCM algorithm, the paper do not achieve this algorithm by software, but emulate the whole coding and decoding process by the research of ADPCM algorithm. It's easy to use software to realize the algorithm directly in the future.(2) On the analysis of the original MHT encryption algorithm, this paper puts forward an improved MHT encryption scheme. It not only provides theory basis for this system of encryption system, but also can be applied to various other multimedia coding schemes including Huffman coding steps. It plays a positive role on the multimedia encryption research and development. Then based on the improved MHT encryption scheme and combined with the system's speech coding bit stream of probability and statistics characteristics, the paper realize an diographic encrypt scheme which is fit for the hardware platform of this system to complete the encrypt process.(3) The hardware platform of the speech transmission and encryption system is composed by the singlechip, voice encoding chip and wireless module. It has many advantages such an small volume, low power consumption and high portability etc, so it can be widely used in nowadays popular systems, such as The Internet of things and Intelligent Household etc. It will have great practical value.