The RF generation of MRI spectrometer using direct digital synthesis and phase dither based on FPGA

2021 ◽  
Author(s):  
Liang Xiao ◽  
Shuai Zhou
Keyword(s):  
Direct Digital Synthesis ◽  
Digital Synthesis

An Improved Doppler Shift Simulation Method Based on Third-Order DDS

2014 ◽  
Vol 614 ◽  
pp. 356-362 ◽  
Author(s):  
Rui Li ◽  
Yuan Long Cai ◽  
Xin Bei Bai ◽  
Ming Quan Lu
Keyword(s):  
Doppler Shift ◽  
Dynamic Range ◽  
Doppler Frequency ◽  
Simulation Method ◽  
Global Navigation Satellite Systems ◽  
Direct Digital Synthesis ◽  
Third Order ◽  
Satellite Systems ◽  
Digital Synthesis ◽  
Global Navigation Satellite

A method to simulate the Doppler frequency shift of high dynamic signals of Global Navigation Satellite Systems (GNSS) is provided in this paper. The methodology of the method based on third-order Direct Digital Synthesis (DDS) is introduced and the efficient implementation architecture is proposed. The design criteria of the DDS are investigated according to the precision and dynamic range of the Doppler shift. The simulation results are also demonstrated, which indicate that the method is available for the high precision Doppler shift simulation of GNSS signals.

Simulation of Stepped-Frequency LFM Radar Echo Based on FPGA

2012 ◽  
Vol 198-199 ◽  
pp. 948-953
Author(s):  
Jian Ping Ou ◽  
Sheng Qi Liu ◽  
Wei Niu
Keyword(s):  
Moving Target ◽  
Direct Digital Synthesis ◽  
Implementation Framework ◽  
Radar Echoes ◽  
Radar Echo ◽  
Digital Synthesis ◽  
Physical Simulations ◽  
Stepped Frequency ◽  
Logic Resource

An implementation framework of stepped-frequency LFM (SF-LFM) radar echoes simulator is presented in the paper based on the decomposition and calculation of SF-LFM radar echoes of a moving target. The proposed method can be implemented conveniently with direct digital synthesis (DDS) logic resource. The feasibility of this resolution is verified with computer and semi-physical simulations experiments.

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