摘要
As the number of array elements and bandwidth increase,the design challenges of the Phased Array Feed(PAF)front-end and its signal processing system increase.Aiming at the ng-PAF of the 110 m radio telescope,this article introduces the concept of fully digital receivers and attempts to use Radio Frequency System-on-Chip(RFSo C)technology to digitize close to the feed array,reduce the complexity and analog components of the front-end,and improve the fidelity of the signals.The article discusses the digital beamforming topology and designs a PAF signal processing experimental system based on RFSo C+GPU hybrid architecture.The system adopts a ZCU111board to design RF-direct digitization and preprocessing front-end,which can sample eight signals up to 2.048GSPS,12 bit,channelize the signals into 1024 chunks,then reorder into four data streams and select one of the 256MHz frequency bands to output through four 10 Gb links.A GPU server is equipped with four RTX 3090 GPUs running four HRBF_HASHPIPE instances,each receiving a 64 MHz bandwidth signal for high-throughput realtime beamforming.The experimental system uses a signal generator to emulate Sa-like signals and propagates through rod antennas,which verifies the effectiveness of the beamforming algorithm.Performance tests show that after algorithm optimization,the average processing time for a given 4 ms data is less than 3 ms in the four-GPU parallel processing mode.The RFSo C integrated design shows significant advantages in power consumption and electromagnetic radiation compared with discrete circuits according to the measurement results.
基金
funded by the National Natural Science Foundation of China(NSFC,Grant No.12073066)
the National Key R&D Program of China under No.2021YFC2203502
the Youth Innovation Promotion Association of CAS under No.2020063
the NSFC(Grant Nos.61931002,12073067 and 11973077)
the Natural Science Foundation of Xinjiang Uygur Autonomous Region under No.2021D01E07
partly supported by the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF)and administrated by the Chinese Academy of Sciences(CAS)。