The Study On Key Technologies Of Short Wave Direct Sequence Spread Spectrum Communication System

This paper aims to create a shortwave direct sequence spread spectrum communication platform, the main key to the short-wave direct sequence spread spectrum communication technology research. Taking into account the systemic and integrity of the paper, the first basic principles of direct sequence spread spectrum technology are introduced briefly, then the two key technologies affecting system performance are studied.Examines the impact of frequency difference on synchronous and demodulation, and gives the solutions to it. Especially in the great frequency difference, low signal-to-noise ratio conditions, with the use of the pseudo-code acquisition based on FFT algorithm, Frequency offset will be reduced rapidly to the capture scope of the loop. The method can significantly reduce the acquisition time.The possibility of further increasing the anti-jamming capability of spreading systems is studied, an improved algorithm for narrowband interference suppression is discussed. Several of the generic algorithms for frequency domain narrowband interference suppression are analyzed and simulated, its performance are evaluated. On this basis, Adaptive Multi-threshold detection algorithm is improved in the paper. Simulation results show that the algorithm greatly enhances the ability of anti intermittent narrowband interference.A intermediate frequency digital shortwave spread spectrum communication hardware platform is built on the basis of TMS320C6416. Validity of algorithms above mentioned is validated.