FPGA-based Baseband Signal Research And Implementation Of Storage And Reconstruction

A technique for baseband signal storage and reconstruction is widely used in electronic surveillance, spectrum monitoring, satellite monitoring, electromagnetic compatibility, mobile communications and other fields. It solves the problem of intercept and measure of complex signals due to the current rapidly development of radio communication and satellite technology. Meanwhile, it meets the demands of information warfare and electronic warfare in military fields.The thesis is based on the vector signal source project. It focuses on the real-time storage and signal reconstruction of digital baseband signal. It also introduces a variety of related theories and design methods. In this paper, the whole scheme is based on the software ratio idea and the FPGA hardware platform. After the design, simulation and validation, the real-time storage of multi-type baseband signal is successfully realized with a rate as high as 12800 MB/s and the signal reconstruction can be as many as 200 interpolation.The thesis contains two parts. One is the storage control of digital baseband signal, and the other one is the reconstruction of digital baseband signal. The storage control unit of baseband signal includes three aspects. The first aspect is the design and implementation of baseband signal generating and receiving units. This unit provides two kinds of alternative baseband data sources that is multi-standard data externally received or internally generated. The second aspect is the parameter setting, simulation and verification of DDR3 memory controller. This process guarantees the proper operation of IP core and seamless connection between FPGA and DDR3 memory. And the last aspect is the design, simulation and verification of user logic based on DDR3 memory controller, including operation of read or write command and baseband data, control of user logic state transition and continuous processing of baseband signal. The baseband signal reconstruction unit includes the following two aspects. The first one is the design, simulation and verification of FIR compensation filter and CIC interpolation filter, and the calculation of filter coefficients and online overload of the FIR IP core. The second one is the design and realization of baseband signal reconstruction units. Based on the frequency response characteristics of the CIC and FIR filter, variable interpolation filter is applied to the baseband signal with cascade method. In this way, the frequency domain image component can be effectively removed with further improved harmonic components and high speed, and smooth baseband signal waveform can be obtained.A set of baseband signal storage and reconstruction technique is provided in this paper and so is an efficient technique for the user storage interface and multi-rate filtering of baseband signal. The high speed storage of baseband signal and large multiples interpolation filtering reconstruction are realized based on the FPGA. It largely reduces the period of research and development with excellent transportability and extendibility. It also meets all the demands of the project.