Design And Implementation Of Multi-Channel RF Synchronous Acquisition System

As an application branch of high-speed data acquisition,the acquisition and digital processing of radio frequency signals often need to be completed in the digital receivers carried by radar,microwave detectors and satellites.RF direct band-pass acquisition can directly perform analog-to-digital conversion after signal filtering and low noise amplification,which is conducive to improving the system integration.In order to meet the requirement of high-speed data acquisition and storage system development project,a multi-channel RF synchronous acquisition system based on FPGA device is designed and implemented in this paper.The multi-channel RF synchronous acquisition system designed in this paper is composed of two sets of acquisition boards,which are modularized by FMC interface standard.This RF acquisition system uses XC7K325 T FPGA as the control device and AD9680,which supports JESD204 B encoded serial output,which can realize 8-channel RF synchronous acquisition with sampling rate up to 500 MSPS and quantization digit up to 14 bits.Each acquisition board is equipped with DDR3 onboard buffer up to 8GB,which can achieve data acquisition cache up to 10 s,and the acquisition time and data storage can be configured by the upper computer.At the same time,the acquisition board achieves high-speed communication with the host computer by integrating the PCI interface with theoretical data transmission rate of 1GB/s.The main work of this paper includes basic theory and interface protocol research,system hardware circuit design,logic design of FPGA and system test and performance analysis.Through the analysis of project requirements,the scheme design and device selection of the acquisition system are completed,and the schematic diagram and PCB design of the acquisition board are carried out.Then on the Vivado platform,the logic design and Simulation of each functional module are completed by using Verilog language.Finally,the system test platform is built,and the functional verification and performance test of the functional module and the system as a whole are carried out.The system test results show that under the condition of sampling rate of 370 MSPS and input signal frequency of 1401~1425 MHz,the effective bits of eight acquisition channels are greater than 9.1 bits,the spurious-free dynamic range is greater than 65.6dBFS,and the synchronization error between channels does not exceed one sampling point before and after,which meets the design requirements.The RF acquisition system is based on JESD204 B protocol,FMC interface and PCIe bus.It has the characteristics of miniaturization,modularization,good scalability and strong compatibility.