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 arti...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.展开更多
A digital correlator is a crucial element in a modern radio telescope.In this paper,we describe a scalable design for the correlator system of the Tianlai pathfinder array,which is an experiment dedicated to testing k...A digital correlator is a crucial element in a modern radio telescope.In this paper,we describe a scalable design for the correlator system of the Tianlai pathfinder array,which is an experiment dedicated to testing key technologies for conducting a 21cm intensity mapping survey.The correlator implements the FX design,which firstly performs a fast Fourier transform(FFT) including polyphase filter bank(PFB) computation using a Collaboration for Astronomy Signal Processing and Electronics Research(CASPER) Reconfigurable Open Architecture Computing Hardware-2(ROACH2) board,then computes cross-correlations by employing Graphics Processing Units(GPUs).The design has been tested both in laboratory and in actual observation.展开更多
The discovery of ubiquitous habitable extrasolar planets,combined with revolutionary advances in instrumentation and observational capabilities,has ushered in a renaissance in the search for extraterrestrial intellige...The discovery of ubiquitous habitable extrasolar planets,combined with revolutionary advances in instrumentation and observational capabilities,has ushered in a renaissance in the search for extraterrestrial intelligence(SETI).Large scale SETI activities are now underway at numerous international facilities.The Five-hundred-meter Aperture Spherical radio Telescope(FAST)is the largest single-aperture radio telescope in the world,and is well positioned to conduct sensitive searches for radio emission indicative of exo-intelligence.SETI is one of the five key science goals specified in the original FAST project plan.A collaboration with the Breakthrough Listen Initiative was initiated in 2016 with a joint statement signed both by Dr.Jun Yan,the then director of National Astronomical Observatories,Chinese Academy of Sciences(NAOC),and Dr.Peter Worden,Chairman of the Breakthrough Prize Foundation.In this paper,we highlight some of the unique features of FAST that will allow for novel SETI observations.We identify and describe three different signal types indicative of a technological source,namely,narrow band,wide-band artificially dispersed and modulated signals.Here,we propose observations with FAST to achieve sensitivities never before explored.For nearby exoplanets,such as TESS targets,FAST will be sensitive to an EIRP of 1.9×1011 W,well within the reach of current human technology.For the Andromeda Galaxy,FAST will be able to detect any Kardashev type II or more advanced civilization there.展开更多
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+3 种基金the Youth Innovation Promotion Association of CAS under No.2020063the NSFC(Grant Nos.61931002,12073067 and 11973077)the Natural Science Foundation of Xinjiang Uygur Autonomous Region under No.2021D01E07partly 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)。
文摘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supported by the Repair and Procurement Program of the Chinese Academy of Sciences (CAS)the National Natural Science Foundation of China (Grant Nos. 11473044, 11633004, 11773011 and 11761141012)+1 种基金Mo ST Grants (2016YFE0100300 and 2012AA121701)the CAS Frontier Science Key Project (QYZDJ-SSWSLH017)
文摘A digital correlator is a crucial element in a modern radio telescope.In this paper,we describe a scalable design for the correlator system of the Tianlai pathfinder array,which is an experiment dedicated to testing key technologies for conducting a 21cm intensity mapping survey.The correlator implements the FX design,which firstly performs a fast Fourier transform(FFT) including polyphase filter bank(PFB) computation using a Collaboration for Astronomy Signal Processing and Electronics Research(CASPER) Reconfigurable Open Architecture Computing Hardware-2(ROACH2) board,then computes cross-correlations by employing Graphics Processing Units(GPUs).The design has been tested both in laboratory and in actual observation.
文摘The discovery of ubiquitous habitable extrasolar planets,combined with revolutionary advances in instrumentation and observational capabilities,has ushered in a renaissance in the search for extraterrestrial intelligence(SETI).Large scale SETI activities are now underway at numerous international facilities.The Five-hundred-meter Aperture Spherical radio Telescope(FAST)is the largest single-aperture radio telescope in the world,and is well positioned to conduct sensitive searches for radio emission indicative of exo-intelligence.SETI is one of the five key science goals specified in the original FAST project plan.A collaboration with the Breakthrough Listen Initiative was initiated in 2016 with a joint statement signed both by Dr.Jun Yan,the then director of National Astronomical Observatories,Chinese Academy of Sciences(NAOC),and Dr.Peter Worden,Chairman of the Breakthrough Prize Foundation.In this paper,we highlight some of the unique features of FAST that will allow for novel SETI observations.We identify and describe three different signal types indicative of a technological source,namely,narrow band,wide-band artificially dispersed and modulated signals.Here,we propose observations with FAST to achieve sensitivities never before explored.For nearby exoplanets,such as TESS targets,FAST will be sensitive to an EIRP of 1.9×1011 W,well within the reach of current human technology.For the Andromeda Galaxy,FAST will be able to detect any Kardashev type II or more advanced civilization there.