Research on a Coherent Dedispersion Algorithm for Pulsar Baseband Data  

作　　者：Hai-Long Zhang Ya-Zhou Zhang Meng Zhang Jie Wang Ting Zhang Shuang-Qiang Wang Jian-ping Yuan Xin-Chen Ye Jian Li 

机构地区：[1]Xinjiang Astronomical Observatory,Chinese Academy of Sciences,Urumqi 830011,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Key Laboratory of Radio Astronomy,Chinese Academy of Sciences,Nanjing 210008,China [4]National Astronomical Data Center,Beijing 100101,China [5]College of Physics and Astronomy,China West Normal University,Nanchong 637002,China

出　　处：《Research in Astronomy and Astrophysics》2023年第1期285-295,共11页天文和天体物理学研究（英文版）

基　　金：supported by National Key R&D Program of China Nos.2021YFC2203502 and 2022YFF0711502;the National Natural Science Foundation of China(NSFC)(12173077 and 12003062);the Tianshan Innovation Team Plan of Xinjiang Uygur Autonomous Region(2022D14020);the Scientific Instrument Developing Project of the Chinese Academy of Sciences,Grant No.PTYQ2022YZZD01;the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF);administrated by the Chinese Academy of Sciences(CAS);Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01A360);supported by China National Astronomical Data Center(NADC);supported by Astronomical Big Data Joint Research Center。

摘　　要：When the pulsar signal propagates in the interstellar medium(ISM),the high frequency and low frequency components of the signal reach the radio telescope with a certain delay.Therefore,the pulsar signal will appear energy dispersion,which will broaden the pulse profile,decrease the signal to noise ratio,and even lead to the disappearance of the pulse signal.In this paper,we analyze the sampling,polarization and arrangement of baseband data based on the coherent dedispersion algorithm for the problem of pulsar baseband data dedispersion.We systematically study the coherent dedispersion data processing procedure,and test the pulse profile changes under different FFT block sizes.An optimal selection strategy of FFT block sizes is proposed for reducing the operation time and obtaining a better pulse profile.We propose two methods,one is the generation of ISM transfer function,the other is the pulsar period and phase prediction method at a certain time,and discuss integral and folding strategies.We test the algorithm based on the baseband data of CASPSR and Medusa terminals observed by the Parkes 64 m radio telescope,and analyze the reading and processing methods of baseband data of different terminals.The experimental results show that the phase and amplitude information of the pulse profile processed by our algorithm is basically consistent with the results obtained by DSPSR.

关 键 词：pulsar -coherent dedispersion -baseband data -pulse profile 

分 类 号：P145.6[天文地球—天体物理]