Shortwave Data Radio For Development,

This paper is devoted to designing a Software Radio (SR)-based civil short-wave transceiver with higher performance and lower cost, which can transmit and receive analog AM/FM voice as well as low-speed data. Further more, all the functions mentioned above are implemented with software algorithms, instead of hardware components.Due to the speed restriction of the DSP platform, the system, for the time being, does not have the ability of high-speed data communication. However, the algorithms proposed in this paper can be applied to high-speed data transmission. For this reason, the work we conducted in this paper is also a sub-theme of the projects in the field of SR undertaken by our department, such as "A study on the critical techniques for SR implementation" and "The interception of the Burst Satellites' Signals ".In this paper, the system design scheme and test results are discussed and presented in detail. Futher more, a data transfer protocol is designed for improving the reliablility of data transmission on short-wave channel. This protocol is based on Stop-and-Wait protocol and it is suitable for half-duplex communication.The preliminary tests prove the feasibility of the proposed scheme and show that the product designed in this paper meets the assumed requirements well.