Shortwave Spread Spectrum Radio Modem, And To Achieve

In modern war, the information's accurate and un-detective by the enemy are vital to the result. Since the last century, the spread spectrum and hopping spectrum transmitter-receiver has been used in military. After about one hundred developing and improvement, even the basic theory haven't changed much, but as the development of large scale IC there are large sum of and fast processing of digital signal processor. At the same time the theory of software radio make the spread spectrum and hopping spectrum transmitter-receiver continue develop based on the concept of software radio.This paper is to discuss how to realize the modulation and demodulation using FPGA(Field.Programmable.Gate.Array) so as to making the spread spectrum transmitter-receiver can be used. The whole transmitter-receiver framework came from the software radio idea. There are five major works in this paper.1.Proposed a solution to analog modulation and demodulation's digital realization based on software radio idea.2.Relized amalgamation of analog and digital modulation/demodulation on a chip.3.Analyzed and designed algorithm of several important modules based on Matlab and FPGA.4. Recounted design approach and result of filter such as decimation filter,interpolation Filter,low pass filer.5. Relized DS-DQPSK(Direct sequence Spread spectrum Diffrential Quarter Phase Shift Key) and DMF(Digital Matched Filter) .