Research And Design Of The Spreading Spectrum Signal Generator Based On FPGA

Signal generator is very important in modern electronic instruments.It is widely applied in many fields such as communication ,navigation,radar,measure and control.The paper mainly focuses on the design and realization of direct frequency and false random yard , and proposes the model design of the hardware based on the analysis and study of the questions, such as the theory of spread spectrum communication, the whole structure of signal source, design of the carrier wave is modulated and the filter.The paper introduces the development and the application of the technique of FPGA, including the basic VHDL language grammar, develop process and so on. The signal source with low phase noise , high resolution , high-accuracy and high stability is proposed, which adopts the direct digital synthesizer (DDS), based on the analysis of different frequency synthesizers.The choice of false distance measurement random yard is studied, the shifted array is decided to be the expanded frequency code array of the system and shifted array, which is fit for the system , is chosen, based on the analysis of the distance measurement random yard. And the paper analyzes each FPGA hardware circuit.Binary system phase-shift keying phase trial-and-error method is chosen and the hardware is realized as to the key technique of the modulate carrier wave.Transmission characteristic of the radio frequency broadband filter is studied and analyzed and the radio frequency broadband filter is designed based analysis of the frequency spectrum characteristic the Butterworth filter, the Chebyshev filter, the ellipse filter and the Bessel filter. Finally output waves of the design are shown in the paper.