Design And Implementation Of Multi-Mode High Speed Vector Signal Generator Based On FPGA

Vector signal generators,which are developed from analog signal generators,are a common type of equipment in wireless communication system test at the present time.Oweing to the development of wireless communication technology,especially the development of 5G technology in recent years,the communication system is developing in the direction of high speed and multi-mode,It's a great challenge for wireless communication system test,and brings higher demand on the performance of vector signal generators.With the development of technologies such as direct digital synthesizer(DDS),Software Defined Radio(SDR)and field programmable gate array(FPGA),more vector signal generators use real-time mode structure based on FPGA.This kind of vector signal generators have the advantages of convenient operation,fast response speed,wide applicability and high flexibility.However,due to the limitation of FPGA clock frequency,the vector signal generators cannot generate a higher frequency signal.Based on the analysis of the principle and method of DDS,this paper takes FPGA as the core to generate baseband signal and digital modulation signal it in real time,then converts it to analog signal through DAC,so as to determine the design idea of DDS+FPGA+DAC structure.In this paper,Vivado is used as the development platform for FPGA programming.Baseband signal generation module,carrier generation module,shaping filter module,modulation module and other modules are designed,and functional simulation of each module is carried out.At the same time,through the high-speed JESD204 B interface and the way of multi-channel parallel transmission,the problem of FPGA clock limitation is solved,and the sampling rate of the signal reaches 5 GSample/s.In the end,the construction of baseband system,modulation system,control module and interface module of vector signal generator is realized in hardware,and a real-time vector signal generator with adjustable information rate and carrier frequency is designed.After testing,the maximum frequency of the vector signal generator is 2.5 GHz,and the maximum modulation bandwidth is 625 MHz.At the same time,it can generate a variety of baseband signal waveforms and a variety of modulation modes such as ASK,FSK,BPSK,QPSK,QAM,16 QAM,64QAM and 256 QAM.