| Software radio technology breaks through the core hardware technology of traditional receiver which has single function and poor expansibility in antenna test system, radar system and communication system. The open software module is used by software radio technology which has reusability and easy reconstruction in standardization platform. The software radio digital IF receiver in this paper is realized by using of MATLAB and Lab VIEW mixed programming. The main contents are as follows:1) The background of the project is introduced, then the influence factors and implementation methods of Resolution Bandwidth(RBW) are analyzed. According to the relationship between RBW, sampling points and analysis precision, the application conditions of FFT analysis method and digital intermediate frequency filter method are presented.2) The overall implementation scheme of Software Radio IF receiver is proposed. The realization method, spectrum analysis structure and the realization scheme of the quadrature demodulation are described. The implementation scheme of IF signal down conversion image rejection, spectrum analysis and quadrature demodulation is discussed.3) The software radio intermediate frequency receiver is developed and tested. It includes control and simulation data module, digital down conversion module, window and FFT module, digital filter in the frequency domain analysis module and baseband signal demodulation module. Noise signal, tone signal, dual tone signal and modulation signal waveform of the verification results show that function and performance of the software radio receiver achieves the predetermined requirements. In the range from lOHz to 3MHz RBW is optional, bandwidth is 10MHz and SPAN is adjustable.This paper implements the software radio IF receiver which is applied to antenna measurement system with reusability and flexibility. Frequency domain analysis, modulation and demodulation functions of the receiver can be used in a variety of different systems. |
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