Study On Implementation Of Facsimile Digital Demodulation/Remodulation

The abundance of information communication resources stimulate the rapid development of communication, while the usage of effective bandwidth becomes very important. Fax is one of the primary traffic of modern communication, but its usage of bandwidth is low.The main purpose of this paper is to improve the usage of bandwidth fax signal occupy, the method of demodulation and remodulation is given. First, the features of fax communication and the mode of modulation and demodulation are described. Then some design schemes and applied techniques are proposed to achieve software modulation and demodulation, with emphasis on the 2FSK and 8DPSK modulated signal. At the same time, the identification arithmetic of the control and data signal, as well as the software implementation of carrying recovery and timing recovery, is offered. Finally, the hardware experimental panel based on DSP and the software programming flow is presented, and the analysis of feasibility is made.