射电天文研究组知识库

云南天文台射电天文研究团组利用从美国伯克利大学CASPER天文信号与电子学研究中心购买的现场可编程门阵列(Field-Programmable Gate Array,FPGA)接收机平台ROACH2,实现了512 MHz输入带宽,512 MHz带宽分为128通道输出(每个通道4 M带宽),8比特采样和双极化输入(1024 MHz)的基带数据采集终端。海量数据传输方式通过SFP+万兆网口实现,利用编写的脚本文件调用DSPSR程序包实现数据的解码、相干消色散、偏振计算和折叠等处理。数据处理结果以PSRFITS格式存储。构建以ROACH2为基带数据采集终端和DSPSR为数据处理核心的脉冲星观测系统,相比于以VLBI观测终端为基础构建的观测系统,在观测模式、数据处理方法、运算效率和观测数据的通用性等方面具有更好的优越性。

The radio astronomy group of the Yunnan Observatories ( YNAO) has designed a data-collection terminal with digital baseband sampling by using a ROACH2 FPGA platform purchased from the CASPER of the Berkeley University.  The terminal has an input bandwidth of 512MHz evenly divided into 128 channels. It samples data in 8bit with input data collected in a dual-polarization mode. Massive amounts of collected data are transmitted to the processing unit through a 10 Gigabit SFP+ Ethernet port. The subsequent data-processing steps include ROACH2 data decoding, coherent de-dispersion，polarization calculation, and periodic folding using scripts to call the DSPSR package. The data processing results in output observation data in the PSRFITS format. Compared to previous VLBI terminal systems this system shows advantages in the observation mode, data processing methods, computing efficiency, flexibility of output data, and etc.