Implementation of VLBI Digital Baseband Converter with CUDA

Author(s):  
Yongqiang Chen ◽  
Hong Ma ◽  
Yiwen Jiao ◽  
Yandu Liu
Keyword(s):  
2021 ◽  
Vol 21 (10) ◽  
pp. 248
Author(s):  
Xin Pei ◽  
Jian Li ◽  
Na Wang ◽  
Toktonur Ergesh ◽  
Xue-Feng Duan ◽  
...  

Abstract A multi-function digital baseband data acquisition system is designed for the sampling, distribution and recording of wide-band multi-channel astronomical signals. The system hires a SNAP2 board as a digital baseband converter to digitize, channelize and packetize the received signal. It can be configured dynamically from a single channel to eight channels with a maximum bandwidth of 4096 MHz. Eight parallel HASHPIPE instances run on four servers, each carrying two NVMe SSD cards, achieving a total continuous write rate of 8 GB s−1. Data are recorded in the standard VDIF file format. The system is deployed on a 25-meter radio telescope to verify its functionality based on pulsar observations. Our results indicate that during the 30-minute observation period, the system achieved zero data loss at a data recording rate of 1 GB s−1 on a single server. The system will serve as a verification platform for testing the functions of the QTT (QiTai radio Telescope) digital backend system. In addition, it can be used as a baseband/VLBI (Very Long Baseline Interferometry) recorder or D-F-engine of correlator/beamformer as well.


Author(s):  
Xin-Kai Chen ◽  
Guolin Li ◽  
Xiang Xie ◽  
XiaoWen Li ◽  
Zhihua Wang ◽  
...  
Keyword(s):  

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Chai Jianwen

This paper mainly studies the basic concept of baseband transmission of digital signal and the transmission processof digital signal baseband transmission and how to design digital baseband transmission system with MATLABsoftware simulation. This paper fi rst introduces the theoretical basis of this subject, including digital communication,the composition of digital baseband transmission system and digital baseband signal transmission process. Then thepaper introduced the characteristics of digital baseband transmission system, including digital PAM signal powerdensity and common line pattern, and by comparing choosing the fi nal bipolar zero return code. Then we introducedthe MATLAB simulation software. The conditions of the best reception of the digital baseband signal are describedand how the waveform of the baseband signal is observed by an oscilloscope. Finally, according to the basic stepsof simulation process, the simulation process of digital baseband transmission system is realized by MATLABsimulation tool, and the system is analyzed.


Author(s):  
Houcine Chougrani ◽  
Jean Schwoerer ◽  
Pierre-Henri Horren ◽  
Amer Baghdadi ◽  
Francois Dehmas

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2060
Author(s):  
Na Bai ◽  
Liang Wang ◽  
Yaohua Xu ◽  
Yi Wang

In this paper, we present a new digital baseband processor for UHF tags. It is a low-power and low-voltage digital circuit and adopts the Chinese military standard protocol GJB7377.1. The processor receives data or commands from the RF front-end and carries out various functions, such as receiving and writing data to memory, reading and sending memory data to the RF front-end and killing tags. The processor consists of thirteen main sub-modules: TPP decoding, clock management, random number generator, power management, memory controller, cyclic redundancy check, FM0 encoding, input data processing, output data processing, command detection module, initialization module, state machine module and controller. We use ModelSim for the TPP decoding simulation and communication simulation between tag and reader, and the simulation results meet the design requirements. The processor can be applied to UHF tags and has been taped out using a TSMC 0.18 um CMOS process.


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