Design Of High Speed Data Acquisition Card Based On FPGA

In BeiDou Navigation Satellite System,a software navigation receiver based on Software Defined Radio is composed of hardware front-end,IF data processing and baseband signal processing chip.Navigation satellite signal is down converted to digital baseband by mixer and band pass filter,A high-speed data acquisition card is needed for IF signal acquisition purposes,to provide testing data for baseband study and research.In this thesis,we use serial to parallel conversion to slow down the data rate for parallel branches,and then use the low-speed storage device to complete data storage.The whole process is divided into two modules,data dispatch module and data collection module.Data dispatch module reduces the speed of data and storage ping-pong operation.The data collection module re-orders data that was chopped during data storageConsidering the high cost of the SSD,the invention chose SD card as the data storage media.SD cards are semiconductor memory devices based on flash memory,and is widely used in portable devices.Nevertheless,storage speed of SD card is not able to meet the requirements of the project.We designed a new storage scheme to complete the data storage,i.e.,a storage scheme for high speed data storage by low speed device with serial-in parallel-out controller.First of all,reduce the speed of a high speed digital signal by means of ping-pong operation.And then,store the data in SD card.In this thesis,we choose the 4bit-SD mode to achieve the process of storing data to SD card.After the process of the data storage,we need to re-order the data back to the original order.Data was read from a number of cards in sequence,and the parallel to serial conversion is realized.Finally,data is stored in a card to complete the high speed data sampling process.In this thesis,all modules were implemented using Verilog HDL,and Mentor Graphics's Modelsim was chosen as the simulation software for functional verification.All compilation work were done with Altera's Quartus ? 11.0.Verification platform is Altera's Cyclone ? development board and FPGA model is EP2C35F672C6N.Hardware testing results show that the data store rate can reach 49Mb/s using single card and 200Mb/s can be achieved by using 4 SD card.