Based On Spread Spectrum Technology, Non-line-of-sight Wireless Image Transmission System

With the rapid development of wireless communications, recently, the demand of video transmission becomes more and more urgent. Traditional microwave transmission requires rigid line-of-sigh (LOS) condition, which means that the road between the transmitter and receiver can not be blocked by other items. However, in city and suburb scenarios, the blockage caused by various kinds of buildings and landforms are extremely severe. The aim of this work is to tackle the problem of video transmission at non-line-of-sigh (NLOS) environment , which is of great value for practical application.The paper mainly introduces the implementation of a NLOS Wireless Video Transmission Equipment based on Spread Spectrum technology. In the phase of feasible analysis, wireless channel in NLOS environment is analyzed at first and several kinds of technology, which can handle the challenging task of wireless video transmission in NLOS environment , are proposed for discussion and selection. After the comprehensive analysis and comparison of technology features, cost budget, development period and practical requirements, Spread Spectrum technology is chosen to implement the target system. In the design phase, a whole Top-Down analysis and module design was done, and finally the circuit of The Baseband Module was realized and tested.The first chapter introduces the basic requirements of aim product and the feasibility analysis;second chapter introduces the basic theory of DSSS technology which is the basis of the target product;third chapter introduces the Top-Down design of the whole system;in the following two chapters, the realization of baseband module circuit is introduced in detail;Finally, sixth chapter gives the conclusion and expectation.