Research And Implementation On Adaptive Equalization In HF Data Transmission System

On the basis of the MIL-STD-188-141B protocol of the 3th generation HF communication, this paper studies the key technologies of high speed data transmission in HF channel, with focuses on the research of adaptive equalization of receiver.Inter-Symbol Interference (ISI) is the main factor that degrades the performance of the HF communications, which is caused by the multi-path effect. And the adaptive equalization is an important component to suppress ISI in receivers. Accordingly, the related algorithms and structures of this technology are studied in this paper, and the simulation results show that the Decision Feedback Equalizer (DFE) of square root Kalman algorithm is competent in HF Communications because of its good performance in convergence and stability. However, it also has a disadvantage of Error Propagation which affects the judge of the information. To solve this problem, a new DFE scheme is proposed which use an Error-detecting processor to classify the outputs of the decision device and to restrict the feedback filter weights by a norm constraint. And the scheme is tested in the Watterson channel model with a performance improved effectively.Finally, an analysis is made on the implementation schemes of the transmitter and receiver on TMS320C5509 DSP supplied by TI Company, and a scheme based on adaptive equalizer is given.