Design And Implenentation Of Digital Security Telephone

With developing of the information technology. Information security has become not to be ignored important issues. For example: Securities transactions, telephone banking account, the password was intercepted by the military command voice messages tapping, Voice communication security needs of the occasion, the confidentiality of telephone set higher requirements. Not ordinary telephone increasingly higher for the confidentiality requirements of the occasion use. That developed high-performance telephone confidentiality is very important. The issues about the based on the DSP of digital encryption telephone design and implementation.Firstly, the simulations of the speech signal acquisition, analog signals to digital conversion. And then, the acquisition of digital signal compression coding. According to the design first speech signal characteristics of the speech signal encoding method, the based on the AD73311 and AMBE2000 voice Acquisition Module. Module to achieve digital voice signals in the collection, coding, a frame structure output. Speech signals to digital encryption laid the foundation for the Acquisition Module voice signal processing delay to meet system requirements.Secondly, the hardware design of digital encryption telephone system structure. Painted drawings and PCB map through the analysis of the speech signal processing and transmission delays. The echo cancels how to use the hardware to improve the quality of voice calls. Design SI3016 chip of PSTN interface circuit. SI3016 manual recommends using circuit analysis and reliability of the circuit.Finally, the implementation of encryption algorithm based on the hardware. Focus research of representation algorithm encryption IDEA and RSA encryption algorithm. In-depth study of IDEA Encryption Algorithm the safety and hardware implementation advantages, Based on the IDEA Encryption Algorithm in the DSP realization of digital voice encryption methods. Development and using of CCS software simulate IDEA encryption algorithm. Simulator in the CCS model, by setting DSP configuration information, optimizes C code. The CCS System tool of Profiler measure procedures cycle. Algorithm running on the instructions of a few cycle analysis and the results showed: IDEA encryption algorithm time delay and system delay to meet requirements then verify the IDEA encryption algorithm in a project.