综合孔径辐射计的分布式高速数采设计

Design of Distributed High Speed Data Acquisition System in Synthetic Aperture Radiometer

随着综合孔径辐射计对高分辨率的需求提高,信号采集通道规模迅速上升,达到数十路甚至数百路。由此提出一种分布式信号采样及处理系统,同时设计了基于分布式相关系统的高速数据采集传输网络,通道数24路,采样率60 Msps。硬件上基于分布式多级分发的思路设计了时钟链路以实现数字同步采样,经测试通道间相位延迟小于1.5°;以FPGA内置的Rocket I/O收发器为物理层,实现多数字采样阵面与后端相关单元间的高速光纤链路,结果显示误码率低于10-7。该系统稳定性高、可靠性强,能满足大规模综合孔径辐射计的需求。

With the increasing demand of synthetic aperture radiometer for high resolution,the scale of signal acquisition channels has risen rapidly,reaching tens or even hundreds of channels. In this paper,a distributed signal sampling and processing system is proposed. At the same time,a high-speed data acquisition and transmission network based on distributed correlation system is designed,with 24 channels and 60 Msps sampling rate.On the hardware,a clock link is designed based on Distributed Multi-level distribution to realize digital synchronous sampling,and the test results show that the phase delay between channels is less than 1.5 degrees. In order to realize the high-speed optical fiber link between the multi-digital sampling array and the back-end correlation units,the Racket I/O transceiver built in the FPGA is used as the physical layer,and the test results show that the bit error rate is lower than 10-7.The system has high stability and reliability,and is suitable for requirements of large-scale synthetic aperture radiometers.