A Novel SAR Signal Reconstruction Method from Non-uniform Sampling Associated with Fractional Fourier Transform

Author(s):  
Shi Ruofan ◽  
Zhao Juan ◽  
Tao Ran
Geophysics ◽  
2019 ◽  
Vol 84 (6) ◽  
pp. G83-G92
Author(s):  
Ya Xu ◽  
Fangzhou Nan ◽  
Weiping Cao ◽  
Song Huang ◽  
Tianyao Hao

Irregular sampled gravity data are often interpolated into regular grid data for convenience of data processing and interpretation. The compressed sensing theory provides a signal reconstruction method that can recover a sparse signal from far fewer samples. We have introduced a gravity data reconstruction method based on the nonequispaced Fourier transform (NFT) in the framework of compressed sensing theory. We have developed a sparsity analysis and a reconstruction algorithm with an iterative cooling thresholding method and applied to the gravity data of the Bishop model. For 2D data reconstruction, we use two methods to build the weighting factors: the Gaussian function and the Voronoi method. Both have good reconstruction results from the 2D data tests. The 2D reconstruction tests from different sampling rates and comparison with the minimum curvature and the kriging methods indicate that the reconstruction method based on the NFT has a good reconstruction result even with few sampling data.


2021 ◽  
Vol 12 (1) ◽  
pp. 37-44
Author(s):  
Ryszard Golański ◽  
Juliusz Godek

Adaptive Delta Modulation with Non-uniform Sampling (ANS-DM) is one of the waveform coding techniques, where a sampling instant and a quantization step size are adapted to the signal. The ANS-DM modulator produces an output binary stream, that carries information about the signal and includes necessary data of coder parameters (sampling instant and quantization step). In the demodulator, these values are recovered for proper signal reconstruction. The paper reports the problem of synchronizing clocks (transmitting and receiving) in the (ANS-DM) delta codecs systems. The original synchronization method, valuable in systems dedicated to the transmission of the bits with variable time duration was projected and experimentally verified. Performed measurements and observations have shown the elimination of the synchronization loss phenomenon.


2014 ◽  
Vol 989-994 ◽  
pp. 3993-3996 ◽  
Author(s):  
Yan Jun Wu ◽  
Gang Fu ◽  
Fei Liu

The fractional Fourier transform (FRFT) is a generalization of the Fourier transform. The article first introduces the definition of FRFT transformation; then analyzed FRFT Chirp signal based on this humble proposed restoration Chirp signal in a noisy background in two ways: one is based on parameter estimation, and the other is based on the scores Fourier domain filtering to achieve signal reconstruction; Finally, simulation verify the feasibility of the above analysis.


2015 ◽  
Vol 6 (2) ◽  
pp. 106-115 ◽  
Author(s):  
Lei Guo ◽  
Robert Wang ◽  
Yunkai Deng ◽  
Mingjiang Wang ◽  
Xiulian Luo

2011 ◽  
Vol 403-408 ◽  
pp. 1596-1600
Author(s):  
Shou Qiang Chen ◽  
Hua Sun ◽  
Yu Ke Wang

Based on the character that many channels should be used in the periodic non uniform sampling, this paper has transferred sampling to a matrix vector operation by the theory in confederate subspace. By adopting periodic non uniform sampling and reconstruction method basing L1 algorithm, this paper analyzed the reconstruction requirements of the Minimal L1 Norm in periodic non uniform sampling and perfectly reconstructed signals via interpolator. Last, take the multiband sinusoidal Signal as an example, a simulation has been conducted.


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