Design Of Multi-channel And High Speed Signal Acquisition Module Based On VPX Bus

With the development of radar technology,requirements of signal acquisition rate, resolution, conversion speed and processing speed for radar signal processing system have become more and more sophisticated, so that low-rate and low-resolution acquisition system have been unable to meet the radar imaging algorithm demands for large-capacity and high-precision data at this stage. With the appearance of higher speed ADC and higher performance FPGA, we have made it feasible to design the high speed signal acquisition module.Starting from the function of signal acquisition, this article implemented a multi-channel high-speed signal acquisition module based on VPX bus standard. This module realized that two pieces of synchronous could sample, process data and transmit at the same time, with a resolution of 12 bits and the highest sampling rate can reach to 3.6GSPS. First, this article starts from the requirements and indexes of SAR imaging real-time signal processor,and describes the overall structure of the module in detail, including the selection of the chips and the design of the interface circuit, and as well as introduces how PCB is designed according to the requirements of the signal integrity and power integrity. Then, this article introduces the logic design of FPGA.It starts from the SPI configuration of ADC, and completes the design of the ADC's acquisition mode control, data acquisition, serial to parallel conversion, reduction of speed transmission and others step by step. Finally, on the basics of the Rapid IO data exchange based on VPX bus standard, We can achieve data communication between the acquisition board and the other processing boards through VPX bus, and the real-time display of the acquisition signal could be also realized. This collecting module based on multi-channel ADC and FPGA combination mode has been proved valuable in engineering application.