DBPM system performance is determined by the design and implementation of beam position signal processing algorithm.In order to develop the system,a beam position signal processing algorithm is implemented on FPGA.The...DBPM system performance is determined by the design and implementation of beam position signal processing algorithm.In order to develop the system,a beam position signal processing algorithm is implemented on FPGA.The hardware is a PMC board ICS-1554A-002(GE Corp.)with FPGA chip XC5VSX95T.This paper adopts quadrature frequency mixing to down convert high frequency signal to base.Different from conventional method,the mixing is implemented by CORDIC algorithm.The algorithm theory and implementation details are discussed in this paper.As the board contains no front end gain controller,this paper introduces a published patent-pending technique that has been adopted to realize the function in digital logic.The whole design is implemented with VHDL language. An on-line evaluation has been carried on SSRF(Shanghai Synchrotron Radiation Facility)storage ring.Results indicate that the system turn-by-turn data can measure the real beam movement accurately,and system resolution is 1.1μm.展开更多
In this paper,in order to achieve the output signal processing of cavity beam position monitor(CBPM),we develop a digital intermediate frequency receiver architecture based signal processing system,which consists of r...In this paper,in order to achieve the output signal processing of cavity beam position monitor(CBPM),we develop a digital intermediate frequency receiver architecture based signal processing system,which consists of radio frequency(RF) front end and high speed data acquisition board.The beam position resolution in the CBPM signal processing system is superior to 1μm.Two signal processing algorithms,fast Fourier transform(FFT) and digital down converter(DDC),are evaluated offline using MATLAB platform,and both can be used to achieve,the CW input signal,position resolutions of 0.31μm and 0.10μm at -16 dBm.The DDC algorithm for its good compatibility is downloaded into the FPGA to realize online measurement,reaching the position resolution of 0.49μm due to truncation error.The whole system works well and the performance meets design target.展开更多
In recent years, the discoveries of dinosaur footprints have been successively reported from Dianshi Town, Zizhou City, Shaanxi Province. The footprints include the tracks of theropod, ornithopod and sauropod as well....In recent years, the discoveries of dinosaur footprints have been successively reported from Dianshi Town, Zizhou City, Shaanxi Province. The footprints include the tracks of theropod, ornithopod and sauropod as well. Actually, the dinosaur footprints were found by local inhabitants much earlier in history, but not for science. The slabs bearing the dinosaur footprints were collected for domestic use, such as building stones, millstones, cellar covers, sheepfold fences, windlass holders, etc. This paper is to describe the dinosaur footprints on both sides of three slabs used for cellar covers, sheepfold fences and windlass holders by the local people. 24 dinosaur footprints and 4 trackways have been recognized and all of them belong to theropod. Four kinds of dinosaur footprints are identified, including 1 new ichnogenus and 2 new ichnospecies： （1） Shanbeipus caudatus ichnogen, et ichnosp, nov.; （2） Pengxianpus yulinensis ichnosp, nov.; （3） Eubrontes ichnosp; （4） Kayentapus ichnosp. Dinosaur-footprint-bearing beds were initially identified as the Fuxian Formation of the Lower Jurassic. Multipal dinosaur footprints associated with fragment plant fossils suggest a humid fluviolacustrine environment setting in the Ordos Basin during the early period of the Jurassic.展开更多
基金Supported by Shanghai Synchrotron Radiation Facility project
文摘DBPM system performance is determined by the design and implementation of beam position signal processing algorithm.In order to develop the system,a beam position signal processing algorithm is implemented on FPGA.The hardware is a PMC board ICS-1554A-002(GE Corp.)with FPGA chip XC5VSX95T.This paper adopts quadrature frequency mixing to down convert high frequency signal to base.Different from conventional method,the mixing is implemented by CORDIC algorithm.The algorithm theory and implementation details are discussed in this paper.As the board contains no front end gain controller,this paper introduces a published patent-pending technique that has been adopted to realize the function in digital logic.The whole design is implemented with VHDL language. An on-line evaluation has been carried on SSRF(Shanghai Synchrotron Radiation Facility)storage ring.Results indicate that the system turn-by-turn data can measure the real beam movement accurately,and system resolution is 1.1μm.
基金Supported by National Natural Science Foundaion of China(No.11075198)
文摘In this paper,in order to achieve the output signal processing of cavity beam position monitor(CBPM),we develop a digital intermediate frequency receiver architecture based signal processing system,which consists of radio frequency(RF) front end and high speed data acquisition board.The beam position resolution in the CBPM signal processing system is superior to 1μm.Two signal processing algorithms,fast Fourier transform(FFT) and digital down converter(DDC),are evaluated offline using MATLAB platform,and both can be used to achieve,the CW input signal,position resolutions of 0.31μm and 0.10μm at -16 dBm.The DDC algorithm for its good compatibility is downloaded into the FPGA to realize online measurement,reaching the position resolution of 0.49μm due to truncation error.The whole system works well and the performance meets design target.
基金the BJAST Youth Backbone Training Plan(No.2014-08) for the financial support
文摘In recent years, the discoveries of dinosaur footprints have been successively reported from Dianshi Town, Zizhou City, Shaanxi Province. The footprints include the tracks of theropod, ornithopod and sauropod as well. Actually, the dinosaur footprints were found by local inhabitants much earlier in history, but not for science. The slabs bearing the dinosaur footprints were collected for domestic use, such as building stones, millstones, cellar covers, sheepfold fences, windlass holders, etc. This paper is to describe the dinosaur footprints on both sides of three slabs used for cellar covers, sheepfold fences and windlass holders by the local people. 24 dinosaur footprints and 4 trackways have been recognized and all of them belong to theropod. Four kinds of dinosaur footprints are identified, including 1 new ichnogenus and 2 new ichnospecies： （1） Shanbeipus caudatus ichnogen, et ichnosp, nov.; （2） Pengxianpus yulinensis ichnosp, nov.; （3） Eubrontes ichnosp; （4） Kayentapus ichnosp. Dinosaur-footprint-bearing beds were initially identified as the Fuxian Formation of the Lower Jurassic. Multipal dinosaur footprints associated with fragment plant fossils suggest a humid fluviolacustrine environment setting in the Ordos Basin during the early period of the Jurassic.
