Research And Implementation Of High-Speed Facsimile Technology

By strong functions, simple operations and multi-uses, the facsimile becomes an important communication manner in daily work and lives. It is widely spread and popularly used. With the progress of the communication and the digital signal processing, the facsimile is developing towards high-speed, networking, secrecy and multimedia directions. Presently, the widely used G3 facsimile comes into contact with image processing, computer communications, digital signal processing and so on, becoming a digital processing device which has strong power. The facsimile technique combining with PC forms PC-FAX communication system. It will have much wide application foreground.The facsimile markets of our country develop fast, but there are mainly introduced whole machines. There is less self-research, and the technology draggles. The systemic research is rare. The researches have done are almost based on hardware or DSP platforms which have bad compatibility and transplantation. So, doing research on the facsimile, and developing a software facsimile system which has good transplantation and could work without hardware modem have important application values.In this thesis, deeply research on document G3 facsimile which is prescribed by ITU-T is done. The main work is as follows:(1) The development, actuality and future developing trend of the facsimile are introduced simply. The facsimile system and its modules' functions are presented and analyzed.(2) Researches on ITU-T T.30 recommendation and V series recommendations related with document G3 facsimile are done. The software facsimile system is designed.(3) The facsimile transmission procedure is researched particularly. The five phases-call establishment, pre-message procedure, in-message procedure, post-message procedure, call release-of the receiver are realized.(4) The principles of source code and channel code are expatiated. The presentations of HDLC procedure, CRC, ARQ are given. The ECM transmission of the facsimile document is implemented on Visual C++ 6.0 platform.(5) The principle of V.29 modem is researched carefully, and the algorithms of the scrambler, the 16QAM codec, the raise cosine roll-off filter, the descrambler and other modules are realized in C language.