Real-Time High-Speed Novel Data Acquisition System Based on ZYNQ

Continuous acquisition along with streaming of analog signals at high sampling rates of order of 100 MS/s is a difficult task due to both memory and network bottlenecks. At such high sampling rates the data acquisition system follows the model of storing and forwarding the data. This needs large size on board memory. Commercially available platforms are not only quite expensive but also provide limited configuration freedom to the end developers. In order to develop a custom data acquisition device, a platform with high-speed ADCs, large onboard RAM, and embedded controller is needed. Presently, Xilinx ZYNQ offers a system on chip (SOC) based solution with strongly coupled ARM processor and FPGA. The benefit of such architecture is that the processor can handle configuration management and the FPGA can be available for handling critical time-bound tasks. The present work focuses on development of continuous high-speed acquisition system based on Zynq SOC with user-configurable options. For development of the prototype, Zynq board with two onboard ADC modules and 512 MB RAM is selected. The ADCs although support maximum sampling up to 125 MS/s, acquisition at such high rate will lead to large file sizes which will be difficult to handle and analyze. The developed system is developed for two modes, offline acquisition and live streaming over Ethernet interface. In the offline mode, the acquisition will operate at highest sampling rate of 125 Ms/s and the file will be saved locally on the Linux OS on ZYNQ. In run time streaming, the data will be transferred over the Ethernet interface to a host system. In this mode, the data is saved in chunks which are defined by the client software. In continuous streaming of data to host, the effective sampling rates were found to be of order of 30 MSps. The server program is being performed using a C program which communicates to the ARM processor. The client program is developed using Python open-source libraries with Qt-based GUI. In this paper, the details of the system design, architecture, benchmarking, software flow, and analysis of results are mentioned.