scholarly journals A Method against Interrupted-Sampling Repeater Jamming Based on Energy Function Detection and Band-Pass Filtering

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Hui Yuan ◽  
Chun-yang Wang ◽  
Xin Li ◽  
Lei An
Keyword(s):  
Frequency Modulation ◽  
Energy Function ◽  
Large Time ◽  
Echo Signal ◽  
Time Frequency ◽  
Low Sidelobe ◽  
Energy Domain ◽  
Band Pass ◽  
Simulation Results ◽  
Filtering Function

Interrupted-sampling repeater jamming (ISRJ) is a new kind of coherent jamming to the large time-bandwidth linear frequency modulation (LFM) signal. Many jamming modes, such as lifelike multiple false targets and dense false targets, can be made through setting up different parameters. According to the “storage-repeater-storage-repeater” characteristics of the ISRJ and the differences in the time-frequency-energy domain between the ISRJ signal and the target echo signal, one new method based on the energy function detection and band-pass filtering is proposed to suppress the ISRJ. The methods mainly consist of two parts: extracting the signal segments without ISRJ and constructing band-pass filtering function with low sidelobe. The simulation results show that the method is effective in the ISRJ with different parameters.

A Direction of Arrival Estimation Method for Wideband LFM Signals Based on RWT and ESPRIT Algorithm

2014 ◽  
Vol 1044-1045 ◽  
pp. 976-981
Author(s):  
Jian Zhong Xu ◽  
Fu Qiang Yu ◽  
Ping Guang Duan ◽  
Shu Hua Li
Keyword(s):  
Frequency Modulation ◽  
Estimation Method ◽  
Direction Of Arrival ◽  
Wigner Transform ◽  
Signal Parameter ◽  
Time Frequency ◽  
Cross Terms ◽  
Stationary Signals ◽  
Simulation Results ◽  
Esprit Algorithm

In this paper, we proposed a new algorithm to estimate the direction of arrival (DOA) for wideband linear frequency modulation (LFM) signals, using Radon-Wigner transform (RWT) and estimation of signal parameter via rotational invariance techniques (ESPRIT). To eliminate the cross-terms, we first utilize the RWT with its excellent time-frequency concentration performance. Then, through peak searching, the number of targets, the initial interference and the frequency modulation slope are estimated. On the this base, the array signals are reconstructed. Finally, we adopt the ESPRIT algorithm to estimate the DOA of the array signals. The simulation results show that the proposed algorithm can estimate the DOA of non-stationary signals with high precision.

scholarly journals Designing a waveform using LFM, NLFM for MIMO radar

2017 ◽  
Vol 7 (1.5) ◽  
pp. 84
Author(s):  
G S Krishnam Naidu Yedla ◽  
D. Siva Sankar Prasad ◽  
P. Raghavendra Rao ◽  
M Siva Kumar ◽  
M VenuGopala Rao
Keyword(s):  
Frequency Modulation ◽  
Frequency Component ◽  
Side Lobe ◽  
Mimo Radar ◽  
Linear Frequency Modulation ◽  
Wave Form ◽  
Boundary Segment ◽  
Middle Segment ◽  
Time Frequency ◽  
Linear Frequency

We propose a waveform that includes Linear frequency modulation and non linear frequency modulation wave applicable for MIMO radar. The wave form consists of three segments where the boundary segment consists of LFM content and the middle segment consists of NLFM. The time frequency component in the middle segment is controlled. The range and Doppler side lobe suppression is improved. The genetic algorithm is implemented to suppress the side lobes in the auto correlation and cross correlation functions. The performance is analysed by using ambiguity function.

The Large Time-Frequency Analysis Toolbox 2.0

2014 ◽  
pp. 419-442 ◽  
Author(s):  
Zdeněk Průša ◽  
Peter L. Søndergaard ◽  
Nicki Holighaus ◽  
Christoph Wiesmeyr ◽  
Peter Balazs
Keyword(s):  
Frequency Analysis ◽  
Large Time ◽  
Time Frequency Analysis ◽  
Time Frequency

Analisa Elemen Multiarms Resonator Open Loop Pada Band-Pass Filter Mikrostrip Yang Bekerja Di Frekuensi EHF

2021 ◽  
Vol 8 (2) ◽  
pp. 93-104
Author(s):  
M. Reza Hidayat ◽  
Difa Dwi Juliantara Sukmawan
Keyword(s):  
Bandpass Filter ◽  
Open Loop ◽  
Band Pass Filter ◽  
Pass Filter ◽  
A Value ◽  
Resonator Design ◽  
Band Pass ◽  
Patch Width ◽  
Simulation Results ◽  
Patch Length

The use of bandpass filters is commonly used but the use of specifications varies depending on needs, in this case the microstrip bandpass filter is expected to observe the multiarms characteristics of the open loop resonator on the performance of the bandpass filter for EHF frequencies. The design of this microstrip bandpass filter uses a multiarms open loop resonator design where at the beginning of the simulation stage uses only 1 arm with patch width, arm spacing, feeder line width and patch length based on trial and error. The final simulation results are obtained with a connector distance of 2 mm and a distance of 1 mm between arms with a value of S11 = -13.8 dB and S21 = -2.8 dB at a frequency of 30.8 GHz based on the simulation results. The filter has been successfully fabricated but cannot be measured because the frequency is too high and the measuring instrument cannot measure the frequency

scholarly journals Arrival-Time Detection in Wind-Speed Measurement: Wavelet Transform and Bayesian Information Criteria

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 269 ◽  
Author(s):  
Wei Zhang ◽  
Zhipeng Li ◽  
Xuyang Gao ◽  
Yanjun Li ◽  
Yibing Shi
Keyword(s):  
Wavelet Transform ◽  
Wind Speed ◽  
Arrival Time ◽  
Time Window ◽  
Signal To Noise Ratio ◽  
Information Criteria ◽  
Echo Signal ◽  
Time Frequency ◽  
Ultrasonic Echo ◽  
Ultrasonic Anemometer

The time-difference method is a common one for measuring wind speed ultrasonically, and its core is the precise arrival-time determination of the ultrasonic echo signal. However, because of background noise and different types of ultrasonic sensors, it is difficult to measure the arrival time of the echo signal accurately in practice. In this paper, a method based on the wavelet transform (WT) and Bayesian information criteria (BIC) is proposed for determining the arrival time of the echo signal. First, the time-frequency distribution of the echo signal is obtained by using the determined WT and rough arrival time. After setting up a time window around the rough arrival time point, the BIC function is calculated in the time window, and the arrival time is determined by using the BIC function. The proposed method is tested in a wind tunnel with an ultrasonic anemometer. The experimental results show that, even in the low-signal-to-noise-ratio area, the deviation between mostly measured values and preset standard values is mostly within 5 μs, and the standard deviation of measured wind speed is within 0.2 m/s.

Power Quality Disturbance Research of Grid-Connected Wind Generation Based on Fractional Fourier Transform with Wavelet Entropy

2011 ◽  
Vol 130-134 ◽  
pp. 1600-1604
Author(s):  
Hua Li Chen ◽  
Yun Lian Sun
Keyword(s):  
Fourier Transform ◽  
Power System ◽  
Power Quality ◽  
Fractional Fourier Transform ◽  
Wind Generation ◽  
Wavelet Entropy ◽  
Time Frequency ◽  
System A ◽  
Power Quality Disturbance ◽  
Simulation Results

In the process of connected wind generation with the power grid, the classification and recognition of power quality disturbance signals which are researched by the scholars at home and abroad are always the hot issues in Power System. A new method using Fractional Fourier Transform (FRFT) with Wavelet Entropy is presented for recognizing the signals of PQ disturbance based on the characteristics of power quality (PQ) signals. FRFT have better time-frequency aggregation and can choose better domain instead of and make PQ disturbance recognize more accurately with wavelet entropy. Simulation results demonstrate its effectiveness.

Rapid Measurement of Power Transformer Winding DC Resistance

2013 ◽  
Vol 333-335 ◽  
pp. 22-26
Author(s):  
Xiao Fei Luo ◽  
Xian Xia ◽  
Kai Jun Wu
Keyword(s):  
Time Constant ◽  
Large Time ◽  
Power Transformer ◽  
Resistance Mutation ◽  
Transition Process ◽  
Measurement Circuit ◽  
Rapid Measurement ◽  
Transformer Winding ◽  
Simulation Results ◽  
Dc Resistance

Aim at the electric power transformer with inductance is large, resistance is small, the inherent characteristics of the large time constant, a fast measurement scheme of power transformer winding DC resistance is proposed. The scheme adopts the increase the measurement circuit loop resistance mutation method, in which the circuit transition process from a time constant is forced to another time constant, to realize the rapid measurement of winding DC resistance in power transformer. Simulation results show the effectiveness of the scheme.

A SAW Filter of Elliptic Structure IDT

2014 ◽  
Vol 665 ◽  
pp. 623-628
Author(s):  
Dai Qiang Wang ◽  
Liang Rong Li ◽  
Yu Qing Chen ◽  
Zu Ming Yao ◽  
Hong Gong ◽  
...  
Keyword(s):  
Thin Films ◽  
Center Frequency ◽  
Band Pass Filter ◽  
Function Model ◽  
Modeling Tools ◽  
Pass Filter ◽  
Band Pass ◽  
Simulation Results ◽  
Weighting Methods ◽  
Piezoelectric Substrate

The design uses silicon-AlN thin films as the piezoelectric substrate, Use apo- dization weighting methods to optimize the design of IDT. The improved δ function model was Modeling Tools of Apodization weighted ellipse IDT structure, According to the result of simulation, we designed a layout of SAW band-pass filter and fabricated a sample of it which center frequency is 300MHz and insertion loss is 7dB, The research shows the consistency of simulation results with the experimental results.

Extracting of Micro Doppler Parameter of Helicopter Rotor Based on Time-Frequency Analysis

2011 ◽  
Vol 130-134 ◽  
pp. 2696-2700 ◽  
Author(s):  
Lei Zhang ◽  
Guo Qing Huang
Keyword(s):  
Frequency Domain ◽  
Frequency Analysis ◽  
Time Domain ◽  
Good Method ◽  
Helicopter Rotor ◽  
Echo Signal ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
Radar Echo ◽  
Doppler Parameter

The micro Doppler effect of the radar echo signal of helicopter rotor is studied, and the formula of helicopter rotor echo is obtained. Then the received echo signal of helicopter rotor simulated is analyzed in time domain, frequency domain and time-frequency domain respectively, the analysis results show that it is a good method to extract micro Doppler of helicopter rotor echo by time-frequency analysis. According to analysis results, obtained a method to determine parity of blades and velocity of helicopter rotor, these methods can be used to identify helicopter.

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