Multi-institutional Communication Baseband Signal Generation Module Design And Implementation

Vector signal source plays an important role in the test instrument of today’s communication system, which is usually used in the testing and inspection of a digital communication receiving device. The development of science and technology and process improvement, then the system performance is greatly improved, the resulting problems is the need for more accurate, more equipment to test. However, the property of the original signal generator cannot meet the demand of industrial measurement apparently. In this context, it needs the re-depth research for digital baseband signal generator technology and design baseband digital generator which can provide multi-institutional and high-bandwidth digital. It is used to meet the needs of industrial development and the requirements of the new generation of vector signal source in the future.The research of this paper is based on the project “PXI vector signal source”. It focuses on the theory and design methods of the multi-institutional communication baseband signal generation and processing. The overall program is based on the idea of software radio. It constructs theoretical framework baseband signal generation module and takes DSP+FPGA as the hardware platform. Then it will generate multi-institutional communication baseband signal which can meet requirements through design and simulation. The main contents of this paper are followed:1, The design of shaping filter unit. It reduces the complexity of the design through optimizing design program and implementing optional types and controllable parameters of shaping filter. It uses the design scheme based on a combination of DSP and FPGA. DSP is responsible for the calculation and distribution of coefficient, and the FPGA is used to import filter coefficient correctly. Then it completes the online reload design of shaping filter coefficients and achieves a shaping filter of pulse signal;2, The design of variable-rate signal processing unit. It Is based on the theory of multi-rate signal processing, Using the program of FIR+CIC interpolation filter, editing programme and simulating, it achieves process of variable rate baseband signal,inhibits distortion of the mirror caused by the sampling clock;3, The simulation unit design of Doppler shift. The research content of this part is to meet the demand for high dynamic target signal simulation of a new generation ofsignal generator. It is based on the signal generator and direct digital frequency synthesis(DDS), and generating Doppler shift signal, then realize the dynamic simulation of moving targets.These are the main contents of the dissertation, through the analysis and derivation of relevant theory, then based on the technology of vector signal modulation, and according to the theory of software radio thinking, then it use programmable logic device(FPGA) to build a open, standardized, modular universal hardware platform to do program research and design.Eventually produce multi-institutional communication baseband signal indicators meet the requirements.