Cardinal MK-spline signal processing: Spatial interpolation and frequency domain filtering

2019 ◽  
Vol 495 ◽  
pp. 116-135 ◽  
Author(s):  
Juanjuan Chen ◽  
Zhanchuan Cai
Keyword(s):  
Signal Processing ◽  
Frequency Domain ◽  
Spatial Interpolation ◽  
Frequency Domain Filtering

A High Efficient Baseband GNSS Signal Narrow Band Anti-Jamming Approach in Frequency Domain

2014 ◽  
Vol 926-930 ◽  
pp. 1857-1860
Author(s):  
Zhou Zheng ◽  
Meng Yuan Li ◽  
Wei Jiang Wang
Keyword(s):  
Signal Processing ◽  
Frequency Domain ◽  
Narrow Band ◽  
Low Frequency ◽  
Frequency Resolution ◽  
Interference Rejection ◽  
High Efficient ◽  
Digital Down Conversion ◽  
Down Conversion ◽  
Low Rate

In order to reduce the burden of the calculation and the low frequency resolution of the tradition GNSS signal intermediate narrow band anti-jamming method, it introduces a high efficient approach of narrow band interference rejection based on baseband GNSS signal processing. After digital down conversion to baseband and down sampling to a low rate, the interference is removed in frequency domain. According to the theoretical analysis and simulation, it claims that the method can reduce the calculation and increase the detection resolution in frequency domain which will realize a high efficient interference rejection.

scholarly journals The effect of temperature and frequency on magnetic properties of the Fe81B13Si4C2 amorphous alloy

2011 ◽  
Vol 43 (2) ◽  
pp. 175-182 ◽  
Author(s):  
S. Djukic ◽  
V. Maricic ◽  
A. Kalezic-Glisovic ◽  
L. Ribic-Zelenovic ◽  
S. Randjic ◽  
...  
Keyword(s):  
Signal Processing ◽  
Magnetic Properties ◽  
Amorphous Alloy ◽  
Frequency Domain ◽  
Magnetic Permeability ◽  
Structural Relaxation ◽  
Substantial Reduction ◽  
Effect Of Temperature ◽  
Influence Of Temperature ◽  
Mean Frequency

In this study it was investigated influence of temperature and frequency on permeability, coercivity and power loses of Fe81B13Si4C2 amorphous alloy. Magnetic permeability measurements performed in nonisothermal and isothermal conditions was confirmed that efficient structural relaxation was occurred at temperature of 663 K. This process was performed in two steps, the first one is kinetic and the second one is diffuse. Activation energies of these processes are: Ea1 = 52.02 kJ/mol for kinetic and Ea2 = 106.9 kJ/mol for diffuse. It was shown that after annealing at 663 K coercivity decrease about 30% and therefore substantial reduction in power loses was attained. Investigated amorphous alloy satisfied the criteria for signal processing devices that work in mean frequency domain.

Global Image Dehazing via Frequency Perception Filtering

2019 ◽  
Vol 28 (09) ◽  
pp. 1950142
Author(s):  
Linli Xu ◽  
Jing Han ◽  
Tian Wang ◽  
Lianfa Bai
Keyword(s):  
Frequency Domain ◽  
Adaptive Filtering ◽  
Low Frequency ◽  
Intermediate Frequency ◽  
Human Visual Perception ◽  
Image Dehazing ◽  
Weighting Factors ◽  
Outdoor Scenes ◽  
Frequency Domain Filtering ◽  
Three Components

In outdoor scenes, haze limits the visibility of images, and degrades people’s judgement of the objects. In this paper, based on an assumption of human visual perception in frequency domain, a novel image haze removal filtering is proposed. Combining this assumption with the theory of frequency domain filtering, we first estimate the cut-off frequency to divide the frequency domain of the hazy image into three components — low-frequency domain, intermediate-frequency domain and high-frequency domain. Then, by introducing the weighting factors, the three components are recombined together. After the theoretical deduction of frequency domain, the establishment of the actual model and adjusting the cut-off frequency and weighting factors, we finally acquire a global and adaptive filtering. This filtering can restore the details and the contours of the images, which have less noise, and improve the visibility of the objects in hazy images. Moreover, our method is simple in structure and strongly applicable, and rarely affected by parameters. Our algorithm is stable and performs well in heavy fog and the scene changes.

scholarly journals Signal-Processing Framework for Ultrasound Compressed Sensing Data: Envelope Detection and Spectral Analysis

2020 ◽  
Vol 10 (19) ◽  
pp. 6956
Author(s):  
Yisak Kim ◽  
Juyoung Park ◽  
Hyungsuk Kim
Keyword(s):  
Signal Processing ◽  
Compressed Sensing ◽  
Frequency Domain ◽  
Time Domain ◽  
Sampling Rate ◽  
Processing Technique ◽  
Original Form ◽  
Basis Matrix ◽  
Full Reconstruction ◽  
Processing Framework

Acquisition times and storage requirements have become increasingly important in signal-processing applications, as the sizes of datasets have increased. Hence, compressed sensing (CS) has emerged as an alternative processing technique, as original signals can be reconstructed using fewer data samples collected at frequencies below the Nyquist sampling rate. However, further analysis of CS data in both time and frequency domains requires the reconstruction of the original form of the time-domain data, as traditional signal-processing techniques are designed for uncompressed data. In this paper, we propose a signal-processing framework that extracts spectral properties for frequency-domain analysis directly from under-sampled ultrasound CS data, using an appropriate basis matrix, and efficiently converts this into the envelope of a time-domain signal, avoiding full reconstruction. The technique generates more accurate results than the traditional framework in both time- and frequency-domain analyses, and is simpler and faster in execution than full reconstruction, without any loss of information. Hence, the proposed framework offers a new standard for signal processing using ultrasound CS data, especially for small and portable systems handling large datasets.

scholarly journals Frequency Domain based Digital Down Conversion Architecture for Software Defined Radio and Cognitive Radio

2018 ◽  
Vol 7 (2.16) ◽  
pp. 88 ◽  
Author(s):  
Latha Sahukar ◽  
Dr M. Madhavi Latha
Keyword(s):  
Cognitive Radio ◽  
Frequency Domain ◽  
Software Defined Radio ◽  
Sampling Rate ◽  
Complex Multiplication ◽  
Clock Rate ◽  
Direct Rotation ◽  
Digital Down Conversion ◽  
Frequency Domain Filtering ◽  
Down Conversion

This paper presents a sampling rate digital down converter that is totally based on frequency domain processing. The proposed DDC is targeted for Software Defined Radio and Cognitive Radio architectures. The proposed architecture is based on replacement of the complex multiplication with direct rotation of the spectrum. Different aspects of frequency domain filtering are also discussed. The Xilinx Virtex-6 family FPGA, XC6VLX240T is used for the implementation and synthesis of the proposed FFT-IFFT based architecture. The overlapping in time domain at the output of the IFFT block is avoided using overlap and add method. In terms area, highly optimized implementation is observed in the proposed architecture when compared to the conventional DDC. The synthesis results have shown that the developed core works at a maximum clock rate of 250 MHz and at the same time  occupies  only 10% of the slices of  FPGA. 

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