The Research Of Digital Communication Technology Over HF

Digital communication is a new technology in radio communication, by digitizing the signal and using DSP technology, we can improve not only the performance of the radio system but also its agility and compatibility. This paper deals with some research and practice of digital communication in HF communication, we use the technology of multi-rate signal process to digitize the channel from IF 500KHz, to base band in HF system. Through designing and demonstrating the project we utilize TMS320C549 DSP chip as hardware plat, Harris corporation's Programmable Downconverter and Upconverter to design the circuit. Then we debug the circuit and complete some modulation/de-modulation,such as SSB, FM, AM. We also do some signal processes including Digital Squelch of analog speech and Speech Compression.