scholarly journals Optimal Order of Time-Domain Adaptive Filter for Anti-Jamming Navigation Receiver

2021 ◽  
Vol 14 (1) ◽  
pp. 48
Author(s):  
Jie Song ◽  
Zukun Lu ◽  
Zhibin Xiao ◽  
Baiyu Li ◽  
Guangfu Sun
Keyword(s):  
Time Domain ◽  
High Performance ◽  
Design Method ◽  
Interference Suppression ◽  
Optimal Filter ◽  
Optimal Order ◽  
Signal Ratio ◽  
Filter Length ◽  
Filter Order ◽  
The Time Domain

Adaptive filtering algorithms can be used on the time-domain processing of navigation receivers to suppress interference and maintain the navigation and positioning function. The filter length can affect the interference suppression performance and hardware utilization simultaneously. In practical engineering, the filter length is usually set to a large number to guarantee anti-jamming performance, which means a high-performance receiver requires a high-complexity anti-jamming filter. The study aims at solving the problem by presenting a design method for the optimal filter order in the time-domain anti-jamming receiver, with no need for detailed interference information. According to interference bandwidth and jam-to-signal ratio (JSR), the approach designed a band-stop filter by Kaiser window for calculating the optimal filter order to meet interference suppression requirements. The experimental results show that the time-domain filtering processing has achieved good interference suppression performance for engineering requirements with optimal filter order in satellite navigation receivers.

scholarly journals Orthogonal Time Sequency Multiplexing Modulation

2021 ◽  
Author(s):  
Tharaj Thaj ◽  
Emanuele Viterbo
Keyword(s):  
Time Domain ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Performance ◽  
High Mobility ◽  
Low Complexity ◽  
Modulation Scheme ◽  
Frequency Space ◽  
Time Frequency ◽  
Single Carrier ◽  
The Time Domain

This paper proposes <i>orthogonal time sequency multiplexing</i> (OTSM), a novel single carrier modulation scheme based on the well known Walsh-Hadamard transform (WHT) combined with row-column interleaving, and zero padding (ZP) between blocks in the time-domain. The information symbols in OTSM are multiplexed in the delay and sequency domain using a cascade of time-division and Walsh-Hadamard (sequency) multiplexing. By using the WHT for transmission and reception, the modulation and demodulation steps do not require any complex multiplications. We then propose two low-complexity detectors: (i) a simpler non-iterative detector based on a single tap minimum mean square time-frequency domain equalizer and (ii) an iterative time-domain detector. We demonstrate, via numerical simulations, that the proposed modulation scheme offers high performance gains over orthogonal frequency division multiplexing (OFDM) and exhibits the same performance of orthogonal time frequency space (OTFS) modulation, but with lower complexity. In proposing OTSM, along with simple detection schemes, we offer the lowest complexity solution to achieving reliable communication in high mobility wireless channels, as compared to the available schemes published so far in the literature.

Analysis of Convolution Quadrature Applied to the Time-Domain Electric Field Integral Equation

2012 ◽  
Vol 11 (2) ◽  
pp. 383-399 ◽  
Author(s):  
Q. Chen ◽  
P. Monk ◽  
X. Wang ◽  
D. Weile
Keyword(s):  
Integral Equation ◽  
Electric Field ◽  
Time Domain ◽  
Electromagnetic Scattering ◽  
Optimal Order ◽  
Electric Field Integral Equation ◽  
Optimal Order Of Convergence ◽  
Convolution Quadrature ◽  
The Time Domain ◽  
Field Integral

AbstractWe show how to apply convolution quadrature (CQ) to approximate the time domain electric field integral equation (EFIE) for electromagnetic scattering. By a suitable choice of CQ, we prove that the method is unconditionally stable and has the optimal order of convergence. Surprisingly, the resulting semi discrete EFIE is dispersive and dissipative, and we analyze this phenomena. Finally, we present numerical results supporting and extending our convergence analysis.

scholarly journals Development of a High-Speed Digitizer to Time Resolve Nanosecond Fluorescence Pulses

2012 ◽  
Vol 10 (2) ◽  
Author(s):  
E. Moreno-García ◽  
R. Galicia-Mejía ◽  
D. Jiménez-Olarte ◽  
J. M. de la Rosa Vázquez ◽  
S. Stolik-Isakina
Keyword(s):  
Time Domain ◽  
Digital Signal Processor ◽  
High Speed ◽  
High Performance ◽  
Input Pulse ◽  
Control Program ◽  
Sampling Technique ◽  
Digital Signal ◽  
Time Resolved ◽  
The Time Domain

The development of a high-speed digitizer system to measure time-domain voltage pulses in nanoseconds range is presented in this work. The digitizer design includes a high performance digital signal processor, a high-bandwidth analog-to-digital converter of flash-type, a set of delay lines, and a computer to achieve the time-domain measurements. A program running on the processor applies a time-equivalent sampling technique to acquire the input pulse. The processor communicates with the computer via a serial port RS-232 to receive commands and to transmit data. A control program written in LabVIEW 7.1 starts an acquisition routine in the processor. The program reads data from processor point by point in each occurrence of the signal, and plots each point to recover the time-resolved input pulse after n occurrences. The developed prototype is applied to measure fluorescence pulses from a homemade spectrometer. For this application, the LabVIEW program was improved to control the spectrometer, and to register and plot time-resolved fluorescence pulses produced by a substance. The developed digitizer has 750 MHz of analog input bandwidth, and it is able to resolve 2 ns rise-time pulses with 150 ps of resolution and a temporal error of 2.6 percent.

scholarly journals Modeling, Verification and Signal Integrity Analysis of High-Speed Signaling Channel with Tabbed Routing in High Performance Computing Server Board

Electronics ◽  
2021 ◽  
Vol 10 (13) ◽  
pp. 1590
Author(s):  
Kyunghwan Song ◽  
Jongwook Kim ◽  
Hyunwoong Kim ◽  
Seonghi Lee ◽  
Jangyong Ahn ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
High Speed ◽  
High Performance ◽  
Design Parameters ◽  
Crosstalk Noise ◽  
Segmentation Approach ◽  
The Time Domain ◽  
Integrity Analysis ◽  
3D Em

It is necessary to reduce the crosstalk noise in high-speed signaling channels. In the channel routing area, the tabbed routing pattern is used to mitigate far-end crosstalk (FEXT), and the electrical length is controlled with a time domain reflectometer (TDR) and time domain transmission (TDT). However, unlike traditional channels having uniform width and space, the width and space of tabbed routing changes by segment, and the capacitance and inductance values of tabbed routing also change. In this paper, we propose a tabbed routing equivalent circuit modeling method using the segmentation approach. The proposed model was verified using 3D EM simulation and measurement results in the frequency domain. Based on the calculated inductance and capacitance parameters, we analyzed the insertion loss, FEXT, and self-impedance in the frequency domain, and TDT and FEXT in the time domain, by comparing the values of these metrics with and without tabbed routing. Using the proposed tabbed routing model, we analyzed tabbed routing with variations of design parameters based on self- and mutual-capacitance and inductance.

scholarly journals Characteristic of Neural Signal Feature for Spike Sorting and Detection

2021 ◽  
Vol 2078 (1) ◽  
pp. 012042
Author(s):  
Tongwei Wang
Keyword(s):  
Time Domain ◽  
Dimensional Reduction ◽  
High Performance ◽  
Spike Sorting ◽  
Future Directions ◽  
Feature Extracting ◽  
Advantages And Disadvantages ◽  
Neural Spike ◽  
On Chip ◽  
The Time Domain

Abstract Neural spike plays an important role in understanding brain activities, and in neural spike sorting, the features of signal are of great importance. This paper aims to have a review on features used to discriminate different originated spikes. The features are divided into three categories: features in the time domain, features in the transformation domain, and features of dimensional reduction. For each kind of feature, the basic principle, advantages, and disadvantages are described and discussed. Results showed that features in the time domain are suitable for on-chip or real-time spike sorting, while features in the transformation domain can be used in offline spike sorting aiming at high performance. For features of dimensional reduction, it makes a large number of features available in spike sorting. In conclusion, researchers need to determine features by balancing the minimization of calculation complexity and maximizing sorting performance according to different occasions and demands. Expectations are also made for future directions of spike feature studies. The article may guide both the physiologists who want to determine features in neural spike sorting and researchers who want to work on feature extracting algorithms further to achieve better performance in experimental challenges.

Time and Frequency Domain Performance Comparison for Wheeze Detection Using K-Nearest Neighbor

2014 ◽  
Vol 591 ◽  
pp. 163-166
Author(s):  
Syamimi Mardiah Shaharum ◽  
Kenneth Sundaraj
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
High Performance ◽  
Nearest Neighbor ◽  
Dominant Frequency ◽  
Performance Comparison ◽  
K Nearest Neighbor ◽  
Time Domain Data ◽  
The Time Domain ◽  
Domain Performance

In this Paper, the Comparison between the Performance of Wheezes Data Processing in the Frequency Domain and in the Time Domain is Evaluated Using K-Nearest Neighbor (KNN). the Purpose of this Paper is to Clarify the Confusion Regarding the Methods Used Nowadays, as many of the Previous Researchers have Stated that Wheezes Data are Better Processed in the Frequency Domain due to its Dominant Frequency Peaks but Not a Single Researcher has Made a Direct Comparison to Prove the Reliability of the Method Used. from the Evaluation Made, the Result Shows that the Performance of Wheeze Data Processed in the Frequency Domain is Better as Compared to the Data Processed in the Time Domain. A High Performance Accuracy with 97% is Obtained Comparing to an Accuracy Percentage of 83.13% were only Achieved by Using the Time Domain Data. Thus, this Paper has Successfully Made a Comparison between the Domains Proving the Reliability of the Frequency Domain for Wheeze Detection.

scholarly journals Minimizing the Computational Effort to Optimize Solar Concentrators with the Open-Source Tools SunPATH and Tonatiuh++

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4412
Author(s):  
Manuel J. Blanco ◽  
Victor Grigoriev ◽  
Kypros Milidonis ◽  
George Tsouloupas ◽  
Miguel Larrañeta ◽  
...  
Keyword(s):  
Open Source ◽  
Time Domain ◽  
High Performance ◽  
Software Tool ◽  
Spatial Domain ◽  
Computational Effort ◽  
Test Case ◽  
Optical Efficiency ◽  
The Time Domain

Integrals that are of interest in the analysis, design, and optimization of concentrating solar thermal systems (CST), such as the annual optical efficiency of the light collection and concentration (LCC) subsystem, can be accurately computed or estimated in two distinct ways: on the time domain and on the spatial domain. This article explores these two ways, using a case study that is highly representative of the commercial CST systems being deployed worldwide. In the time domain, the computation of these integrals are explored using 1-min, 10-min, and 1-h solar DNI input data and using The Cyprus Institute (CyI)’s High-Performance Computing (HPC) system and an open-source ray tracer, Tonatiuh++, being actively developed at CyI. In the spatial domain, the computation of these integrals is explored using SunPATH, another open-source software tool being actively developed at CyI, in tandem with Tonatiuh++. The comparison between the time and spatial domain approach clearly indicate that the spatial domain approach using SunPATH is dramatically more computationally efficient than the time domain approach. According to the results obtained, at least for the case study analyzed in this article, to compute the annual energy delivered by the LCC subsystem with a relative error less than 0.1%, it is enough to provide SunPATH with 1-h DNI data as input, request from SunPATH the sun position and weights of just 30 points in the celestial sphere, and run Tonatiuh++ to simulate these 30 points using 15 million rays per run. As the test case is highly representative, it is expected that this approach will yield similar results for most CST systems of interest.

scholarly journals Orthogonal Time Sequency Multiplexing Modulation

2021 ◽  
Author(s):  
Tharaj Thaj ◽  
Emanuele Viterbo
Keyword(s):  
Time Domain ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Performance ◽  
High Mobility ◽  
Low Complexity ◽  
Modulation Scheme ◽  
Frequency Space ◽  
Time Frequency ◽  
Single Carrier ◽  
The Time Domain

This paper proposes <i>orthogonal time sequency multiplexing</i> (OTSM), a novel single carrier modulation scheme based on the well known Walsh-Hadamard transform (WHT) combined with row-column interleaving, and zero padding (ZP) between blocks in the time-domain. The information symbols in OTSM are multiplexed in the delay and sequency domain using a cascade of time-division and Walsh-Hadamard (sequency) multiplexing. By using the WHT for transmission and reception, the modulation and demodulation steps do not require any complex multiplications. We then propose two low-complexity detectors: (i) a simpler non-iterative detector based on a single tap minimum mean square time-frequency domain equalizer and (ii) an iterative time-domain detector. We demonstrate, via numerical simulations, that the proposed modulation scheme offers high performance gains over orthogonal frequency division multiplexing (OFDM) and exhibits the same performance of orthogonal time frequency space (OTFS) modulation, but with lower complexity. In proposing OTSM, along with simple detection schemes, we offer the lowest complexity solution to achieving reliable communication in high mobility wireless channels, as compared to the available schemes published so far in the literature.

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