The Design And Implementation Of Key Technologies In SSB Shortwave Adaptive Antenna Anti-interference System

This paper researches the integrating application of adaptive antenna array technology, spread-spectrum communication technology and transform-domain filter technology in shortwave communication area, basing on the background of improving on the shortwave communication equipments being used in Chinese Army, and all the key techniques mentioned above are implemented in a single FPGA chip.The primary contents and innovations of this article are introduced below.In order to take advantage of the high speed of calculation, and at the same time, improve the accuracy and dynamic-range of the algorithm, three kinds of multi-input floating point adder algorithm (FPA) are summarized and a high-performance multi-input FPA structure is put forward with a self-defined floating point format. The performance of the high-performance structure on calculation speed and logic resource consuming is better than the normal structure.Adaptive antenna array technology based on LMS (Least Mean Square) algorithm is discussed. And LMS algorithm based on floating point format in implemented successfully using the high-performance structure and the new floating point format. Simulation and test results show that the requirments of calculation speed and logic resource consuming can be satisfied.PN code synchronization algorithm based on serial-search acquisition scheme and delay-looked loop tracking is discussed in detail.The design and implementation of transform-domain filter algorithm based on FFT/IFFT transform is discussed. We propose a new method of calculating the best threshold according to the characteristic of PN (Pseudo Noise) code. Logic resource can be reduced efficiently by re-using implementation models.Finally, we summarize this thesis and give a prospect of the future work.