scholarly journals Design and verification of microwave low frequency band-pass and high frequency band-stop composite structure

2015 ◽  
Vol 64 (18) ◽  
pp. 188401
Author(s):  
Huang Da-Qing ◽  
Kang Fei-Yu ◽  
Zhou Zhuo-Hui ◽  
Liu Xiang ◽  
Cheng Hong-Fei
Keyword(s):  
Frequency Band ◽  
Composite Structure ◽  
High Frequency ◽  
Low Frequency ◽  
High Frequency Band ◽  
Band Pass

scholarly journals Ferrite-Loaded Spidron Fractal Loop VHF Antenna for UAV Applications

2020 ◽  
Vol 10 (15) ◽  
pp. 5392 ◽  
Author(s):  
Won Bin Park ◽  
Young-Mi Park ◽  
Keum Cheol Hwang
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Magnetic Loss ◽  
Low Frequency ◽  
Loop Antenna ◽  
High Frequency Band ◽  
Ferrite Material ◽  
Aerial Vehicle ◽  
Flat Ground ◽  
Good Agreement

In this letter, an electrically small Spidron fractal loop antenna operating in the VHF band is proposed. The ferrite material, which consists of a nickel-zinc combination, is loaded into inside of the loop antenna to increase the gain of the antenna in the low frequency band. To minimize the magnetic loss of the ferrite in the high frequency band, the amount and configuration of the ferrite are optimized using a genetic algorithm. Through this optimization step, the amount of the ferrite is decreased to 37.5% and the gain of the antenna in the high frequency band is improved. The size of the proposed antenna is 0.0242 × 0.0242 × 0.0051 λL3 at the lowest operating frequency. The proposed antenna was fabricated to verify the performance, and the simulated and measured results are in good agreement. The measured peak gains varied from −31.6 to −1.9 dBi within the measured frequency band. To examine the performance of the proposed antenna mounted on an unmanned aerial vehicle model (UAV), the antenna on a UAV was also simulated and the results were discussed. The simulated realized peak gains of the antenna on the UAV and on flat ground are similar.

Fusion Algorithm of Infrared and Visible Images Based on Multiresolution Decomposition

2012 ◽  
Vol 239-240 ◽  
pp. 229-232
Author(s):  
Chen Ding
Keyword(s):  
Statistical Model ◽  
Image Fusion ◽  
Frequency Band ◽  
High Frequency ◽  
Wavelet Coefficient ◽  
Low Frequency ◽  
High Frequency Band ◽  
Fusion Algorithm ◽  
Regional Energy ◽  
Multiresolution Decomposition

Information redundancy and complementarity are existing between the images obtained by multi-sensor, image fusion can improve the certainty and reliability of the information. Traditional method of image fusion based on multiresolution decomposition is susceptible to high frequency noise, fusion is often ineffective. A image fusion algorithm has been studied based on the wavelet multiresolution decomposition which is regional energy maximum for low-frequency decomposition image, and the bivariate statistical model for high-frequency part. The results show that: in the conditions of Daubechies 3 wavelet basis function, decomposition level 5 multiresolution decomposition, the bivariate statistical model for the high-frequency band is robust to noise based on the joint probability of wavelet coefficient pair - a wavelet coefficient and its parent; in the same time, the regional energy maximum for low-frequency band can be effective on the high-frequency band based on the bivariate statistical model. The fusion image has the biggish contrast, the preferable details, the higher gray level resolution.

Herzfrequenzvariabilität als Indikator des Aufmerksamkeitsfokus bei Golfern unterschiedlichen Leistungsniveaus

2012 ◽  
Vol 19 (1) ◽  
pp. 26-36
Author(s):  
Thomas Finkenzeller ◽  
Michael Doppelmayr ◽  
Günter Amesberger
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Low Frequency ◽  
High Frequency Band

Aufmerksamkeitsprozesse, die sowohl für das Erlernen als auch für das optimale Ausführen von Bewegungen von zentraler Bedeutung sind, können an Sportarten wie Golf psychophysiologisch mittels Kenngrößen wie Herzfrequenzvariabilität (HRV) erfasst werden. Ziel dieser Studie ist es zu prüfen, ob sich Kennwerte der HRV von Golf-Experten (n = 12), fortgeschrittenen Golfern (n = 12) und Novizen (n = 11) während der Putt-Ausführung unterscheiden und ob es mit Fortdauer der Putt-Aufgabe zu HRV-Veränderungen kommt. Während aufeinander folgender Putt-Serien absolvierten die Probanden jeweils zehn Putts. Die Experten und Fortgeschrittenen unterscheiden sich signifikant von den Novizen im low frequency-Band (0.04 – 0.15 Hz) und im Verhältnis von low frequency zu high frequency-Band (0.15 – 0.40 Hz). Die HRV-Kennwerte verändern sich nicht mit Fortdauer der Putt-Serien. Die Unterschiede im LF-Band, die bereits bei Golfern mit mäßigem Niveau auftreten, werden als Ausdruck eines externalen Aufmerksamkeitsfokus interpretiert.

scholarly journals Hurricane impacts on a coral reef soundscape

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0244599
Author(s):  
Kayelyn R. Simmons ◽  
David B. Eggleston ◽  
DelWayne R. Bohnenstiehl
Keyword(s):  
Coral Reef ◽  
Frequency Band ◽  
High Frequency ◽  
Sound Production ◽  
Low Frequency ◽  
Benthic Habitat ◽  
Diel Variation ◽  
High Frequency Band ◽  
Frequency Sound ◽  
Snapping Shrimp

Soundscape ecology is an emerging field in both terrestrial and aquatic ecosystems, and provides a powerful approach for assessing habitat quality and the ecological response of sound-producing species to natural and anthropogenic perturbations. Little is known of how underwater soundscapes respond during and after severe episodic disturbances, such as hurricanes. This study addresses the impacts of Hurricane Irma on the coral reef soundscape at two spur-and-groove fore-reef sites within the Florida Keys USA, using passive acoustic data collected before and during the storm at Western Dry Rocks (WDR) and before, during and after the storm at Eastern Sambo (ESB). As the storm passed, the cumulative acoustic exposure near the seabed at these sites was comparable to a small vessel operating continuously overhead for 1–2 weeks. Before the storm, sound pressure levels (SPLs) showed a distinct pattern of low frequency diel variation and increased high frequency sound during crepuscular periods. The low frequency band was partitioned in two groups representative of soniferous reef fish, whereas the high frequency band represented snapping shrimp sound production. Daily daytime patterns in low-frequency sound production largely persisted in the weeks following the hurricane. Crepuscular sound production by snapping shrimp was maintained post-hurricane with only a small shift (~1.5dB) in the level of daytime vs nighttime sound production for this high frequency band. This study suggests that on short time scales, temporal patterns in the coral reef soundscape were relatively resilient to acoustic energy exposure during the storm, as well as changes in the benthic habitat and environmental conditions resulting from hurricane damage.

Comparative Feature Analysis of Ground Surface Vibration Induced by High-Speed Train Running on Viaduct and Embankment

2014 ◽  
Vol 638-640 ◽  
pp. 1229-1232
Author(s):  
Kun Ming Mao ◽  
Ting Ting Wang ◽  
Qian Wen Ru ◽  
Yan Li
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
High Speed ◽  
Fourier Spectrum ◽  
Three Dimensional ◽  
Low Frequency ◽  
Ground Surface ◽  
Vertical Acceleration ◽  
High Frequency Band ◽  
Surface Vibration

Based on the Abaqus parallel computing cluster system platform, the three-dimensional finite element model of train-track-viaduct/embankment-foundation-soil coupling is established. The three-dimensional space-time variation and Fourier spectrums characters of ground surface vibration vertical accelerations by high-speed train running on viaduct and embankment are simulated. The result shows that ground surface vibration is mainly excited by periodic axle force of the train in the site near the viaduct pier. In the site far from the viaduct pier, ground surface vibration is mainly from the transmission of the site near the viaduct pier. With the increased distance between the viaduct pier, the peak value of ground surface vibration vertical acceleration decreases, and decreases significantly when the distance is within 10m. There are two main frequency bands of Fourier spectrum of ground surface vibration vertical acceleration: low-frequency band 0-12Hz and high-frequency band 35-47Hz of viaduct route, and low-frequency band 0-21Hz and high-frequency band 25-45Hz of embankment route. In general, with the increased distance between viaduct/embankment, Fourier spectrum amplitude of every frequency band decrease, and attenuation speed of high-frequency band is much faster than-frequency band’s.

Application of Wavelet Transform in the De-Noising of Angular Displacement Signals of Crank Rocker Mechanism

2014 ◽  
Vol 687-691 ◽  
pp. 1062-1065
Author(s):  
Xiao Cun Jiang ◽  
Xiao Liu ◽  
Kui Xia Han ◽  
Ji Fang Liu ◽  
Xiao Cui
Keyword(s):  
Wavelet Transform ◽  
Frequency Band ◽  
High Frequency ◽  
Angular Displacement ◽  
Low Frequency ◽  
Wavelet Domain ◽  
Test Results ◽  
High Frequency Band ◽  
Transform Method

In order to get rid of noise from the angular displacement of the crank rocker mechanism, the wavelet transform method is introduced. After the noise corresponds to the high frequency band of wavelet domain of the signal and the signal corresponds to the low frequency band of wavelet domain of the signal, the signal is decomposed into four layers, and the high frequency brand is set zero. The test results show that this method was most ideal for the de-noising effect on displacement signals, which is able to not only retain valid signals but to effectively remove the noise.

Strategies for Optimizing the Single-Channel Cochlear Implant: Preliminary Data

1987 ◽  
Vol 96 (1_suppl) ◽  
pp. 134-136
Author(s):  
E. Cudahy ◽  
D. Beck ◽  
J. Danhauer ◽  
M. Danley ◽  
P. Mobley ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Frequency Band ◽  
High Frequency ◽  
Single Channel ◽  
Low Frequency ◽  
High Frequency Band ◽  
Male And Female ◽  
Percent Correct ◽  
Cutoff Frequencies ◽  
Considerable Portion

Perception of consonants for the House 3M single-channel cochlear implant using a two-channel signal processing model was investigated. The input signal was split into a low frequency band and a high frequency band with the cutoff frequencies of the bands adjusted in nine conditions. The conditions ranged from overlapping bands that yielded a flat spectrum to bands that removed a considerable portion of the midrange frequencies. The stimuli for this study were 60-item vowel-consonant-vowel lists with male and female talkers that were presented through direct electrical connection to the implant wearer. The stimuli were recorded on tape in quiet and noise backgrounds to measure interactions among speaker gender, background, and filtering scheme. The four patients in this study were experienced implant wearers. The results were analyzed both in terms of percent correct consonant and in terms of percent correct consonant category. Three of the filter conditions show better performance than the patient's own processor. Interestingly, the best conditions have large portions of the midfrequency regions attenuated.

Design of a Five-Band Internal Antenna for Handsets

Frequenz ◽  
2012 ◽  
Vol 66 (7-8) ◽  
Author(s):  
Anfu Zhu ◽  
Jianxing Li ◽  
Anxue Zhang ◽  
Yansheng Jiang
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Ground Plane ◽  
Low Frequency ◽  
Radiation Patterns ◽  
High Frequency Band ◽  
Rectangular Slot ◽  
Proper Size ◽  
Internal Antenna

AbstractA novel compact five-band internal handset antenna covering LTE (746–806 MHz), GSM850 (824–894 MHz), GSM900 (890–960 MHz), DCS (1710–1880 MHz) and PCS (1850–1990 MHz) bands is presented. To enhance the bandwidths of the proposed antenna both at the low frequency band and high frequency band, a rectangular slot with a proper size is removed in the ground plane at an appropriate location. Both the simulated results and measured results show that reasonable radiation patterns and antenna gains for each frequency band are achieved.

scholarly journals Design of a Multiband Antenna for LTE/GSM/UMTS Band Operation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Youngtaek Hong ◽  
Jinpil Tak ◽  
Jisoo Baek ◽  
Bongsik Myeong ◽  
Jaehoon Choi
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Return Loss ◽  
Low Frequency ◽  
Loop Antenna ◽  
High Frequency Band ◽  
Wide Bandwidth ◽  
Branch Line ◽  
Multiband Antenna ◽  
Additional Branch

This paper proposes a multiband antenna for LTE/GSM/UMTS band operation. The proposed antenna consists of a meandered planar inverted-F antenna with an additional branch line for wide bandwidth and a folded-loop antenna. The antenna provides a wide bandwidth to cover the hepta-band LTE/GSM/UMTS operation. The measured 6 dB return loss bandwidth is 169 MHz (793–962 MHz) at the low-frequency band and 1030 MHz (1700–2730 MHz) at the high-frequency band. The overall dimension of the proposed antenna is 55 mm × 110 mm × 5 mm.

scholarly journals The Correlated Multi-color Optical Variations of BL Lac Object S5 0716+714

2010 ◽  
Vol 27 (3) ◽  
pp. 296-301 ◽  
Author(s):  
Bingkai Zhang ◽  
Benzhong Dai ◽  
Li Zhang ◽  
Jiali Liu ◽  
Zhen Cao
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Cross Correlation ◽  
Function Analysis ◽  
Low Frequency ◽  
Light Curves ◽  
Time Lags ◽  
Strongly Correlated ◽  
High Frequency Band ◽  
Bl Lac

AbstractS5 0716+714 is a well-studied BL Lac object in the sky. Verifying the existence of correlations among the flux variations in different bands serves as an important tool to investigate the emission processes. To examine the possible existence of a lag between variations in different optical bands on this source, we employ a discrete correlation function analysis on the light curves. In order to obtain statistically meaningful values for the cross-correlation time lags and their related uncertainties, we perform Monte Carlo simulations called ‘flux redistribution/random subset selection’. Our analysis confirms that the variations in different optical light curves are strongly correlated. The time lags show a hint of the variations in high frequency band leading those in low frequency band of the order of a few minutes.

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