Development Of Multi-channel Signal Generator Based On FPGA

With the rapid development of electronics and communication technology,the test systems are increasingly demanding than ever before,and the test requirements for signal types tend to be much more diversified.Therefore,it is of great significance in developing high performance signal generator.In order to meet the testing requirements of complex systems,the research on the sampling rate,stability,and bandwidth performance of arbitrary wave signal generators needs to be improved.According to the aforementioned problem,this paper proposes a design scheme for multi-channel signal generator based on "FPGA + high speed DAC + conditioning circuit".The basic method of waveform synthesis is studied firstly,and the direct digital frequency synthesis(DDS)technology with high accuracy and fast frequency conversion is studied,which lays a theoretical foundation for subsequent research.The method of waveform synthesis and digital conditioning based on FPGA as the core chip is proposed subsequently,which takes full advantage of high-speed parallel operation and reconfigurable features of FPGA.The synthesis and modulation of waveforms are accomplished by parallel structure DDS technology,which includes the design of standard wave,arbitrary wave and modulation wave(AM,FM,2FSK and SWEEP),and the output of wideband signals are also achieved.Both the compression storage technology and jitter technology are also used to effectively improve the output waveforms,spurious and quality.Then designs the adjustments for digital signals' amplitude and offset,and designs FIR filter for high frequency waveforms.The high-speed digital circuit and analog conditioning circuit are isolated by designing the parent board.The peripheral circuit of FPGA,DA conversion circuit,AXIe bus interface,and conditioning circuits are developed accordingly.The PCIe communication interface,instruction parsing,DA conversion interface,memory interface and other FPGA internal logic design and the upper computer interface are designed,and the hardware and software design of the signal generator is realized.At the last body of this research debugging and verification of multi-channel signal generator are completed,and various waveforms and performanceindicators output from the system are tested subsequently.The test results show that the developed arbitrary signal generation system is working properly with multi-channel,high sampling rate and wideband signal output.The arbitrary waveform generation and modulation functions are also achieved under the proposed scheme,and the requirements for test index are attained in terms of the frequency range,accuracy,amplitude and harmonic index.