Simulation of pulse compression performance under influence of background noise in modern surveillance radar

2007 ◽  
Author(s):  
El-Sayed A. Youssef ◽  
Amr Mokhtar ◽  
Mohamed Madkour ◽  
Mohamed Abdel-Latif
Keyword(s):  
Background Noise ◽  
Pulse Compression ◽  
Compression Performance

scholarly journals X-Parameter Measurement of Pulse-Compression Nonlinear Transmission Lines

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Ming Li ◽  
Rony E. Amaya ◽  
Robert G. Harrison ◽  
N. Garry Tarr
Keyword(s):  
Transmission Lines ◽  
Pulse Compression ◽  
Parameter Method ◽  
Large Signal ◽  
Nonlinear Transmission Lines ◽  
Nonlinear Transmission ◽  
Compression Performance ◽  
Rf Components ◽  
Double Edge ◽  
Nonlinear Vector

X-parameters provide a powerful and eminently practical solution for interoperable measurement, modeling, and simulation of nonlinear microwave and RF components. UsingX-parameters to do large-signal measurements has been brought into the spotlight. This paper introduces a newX-parameter application: measuring large-signal behaviour of pulse-compression nonlinear transmission lines (NLTLs). A specially configured Nonlinear Vector Network Analyzer (NVNA) was used to measure theX-parameters in the frequency-domain, and then the measured data was transformed into a nonlinear time-domain waveform. The results show both rise-time and fall-time reduction (double-edge compression) as expected and indicate that this newly developedX-parameter method implemented with an NVNA could correctly predict NLTLs' pulse-compression performance.

Evaluation of contrast enhancement ultrasound images of Sonazoid microbubbles in tissue-mimicking phantom obtained by optimal Golay pulse compression

2022 ◽  
Author(s):  
Shinnosuke Hirata ◽  
Yuki Hagihara ◽  
Kenji YOSHIDA ◽  
Tadashi YAMAGUCHI ◽  
Matthieu E. G. Toulemonde ◽  
...  
Keyword(s):  
Blood Flow ◽  
Contrast Enhancement ◽  
Background Noise ◽  
Pulse Compression ◽  
Binary Code ◽  
Ultrasound Images ◽  
Golay Codes

Abstract In contrast enhancement ultrasound (CEUS), the vasculature image can be formed from nonlinear echoes arising from microbubbles in a blood flow. The use of binary-coded pulse compression is promising for improving the contrast of CEUS images by suppressing background noise. However, the amplitudes of nonlinear echoes can be reduced, and sidelobes by nonlinear echoes can occur depending on the binary code. Optimal Golay codes with slight nonlinear-echo reduction and nonlinear sidelobe have been proposed. In this study, CEUS images obtained by optimal Golay pulse compression are evaluated through experiments using Sonazoid microbubbles flowing in a tissue-mimicking phantom.

Evaluation of Weather Radar with Pulse Compression: Performance of a Fuzzy Logic Tornado Detection Algorithm

2011 ◽  
Vol 28 (3) ◽  
pp. 390-400 ◽  
Author(s):  
Timothy A. Alberts ◽  
Phillip B. Chilson ◽  
B. L. Cheong ◽  
R. D. Palmer
Keyword(s):  
Fuzzy Logic ◽  
Pulse Compression ◽  
Phased Array ◽  
Average Power ◽  
Weather Radar ◽  
Detection Algorithm ◽  
Detection Accuracy ◽  
Compression Performance ◽  
Radar Systems ◽  
Power Capability

Abstract Trends in current weather research involve active phased-array radar systems that have several advantages over conventional radars with klystron or magnetron transmitters. However, phased-array radars generally do not have the same peak transmit power capability as conventional systems so they must transmit longer pulses to maintain an equivalent average power on target. Increasing transmits pulse duration increases range gate size but the use of pulse compression offers a means of recovering the otherwise lost resolution. To evaluate pulse compression for use in future weather radar systems, modifications to a weather radar simulator have been made to incorporate phase-coding into its functionality. Data derived from Barker-coded pulses with matched and mismatched filters were compared with data obtained from uncoded pulses to evaluate the pulse compression performance. Additionally, pulse compression was simulated using data collected from an experimental radar to validate the simulated results. The data derived from both experimental and simulated methods were then applied to a fuzzy logic tornado detection algorithm to examine the effects of the pulse compression process. It was found that the fuzzy logic process was sufficiently robust to maintain high levels of detection accuracy with low false alarm rates even though biases were observed in the pulse-compressed data.

Applying a Mode Selector to Improve the Pulse-Compression Performance of Asymmetric-Coupled-Waveguide-Based Dispersion Compensators

2003 ◽  
Vol 10 (1) ◽  
pp. 38-42 ◽  
Author(s):  
Yong Lee ◽  
Kazuhiko Hosomi ◽  
Hiroyuki Uchiyama ◽  
Toshio Katsuyama ◽  
Shinya Kominami ◽  
...  
Keyword(s):  
Pulse Compression ◽  
Compression Performance

Microdensitometer—computer correlation analysis of ultrastructural periodicity

1978 ◽  
Vol 36 (2) ◽  
pp. 32-33
Author(s):  
D.R. Ensor ◽  
C.G. Jensen ◽  
J.A. Fillery ◽  
R.J.K. Baker
Keyword(s):  
Correlation Analysis ◽  
Background Noise ◽  
Computer Control ◽  
Optical Diffraction ◽  
Screw Thread ◽  
Straight Line ◽  
Computer Storage ◽  
Correlation Process ◽  
Electron Microscope Image ◽  
Fixed Beam

Because periodicity is a major indicator of structural organisation numerous methods have been devised to demonstrate periodicity masked by background “noise” in the electron microscope image (e.g. photographic image reinforcement, Markham et al, 1964; optical diffraction techniques, Horne, 1977; McIntosh,1974). Computer correlation analysis of a densitometer tracing provides another means of minimising "noise". The correlation process uncovers periodic information by cancelling random elements. The technique is easily executed, the results are readily interpreted and the computer removes tedium, lends accuracy and assists in impartiality.A scanning densitometer was adapted to allow computer control of the scan and to give direct computer storage of the data. A photographic transparency of the image to be scanned is mounted on a stage coupled directly to an accurate screw thread driven by a stepping motor. The stage is moved so that the fixed beam of the densitometer (which is directed normal to the transparency) traces a straight line along the structure of interest in the image.

Use of a Mild-Gain Hearing Aid by Middle-Age Normal-Hearing Adults Who Do and Do Not Self-Report Trouble Hearing in Background Noise

2020 ◽  
Vol 29 (3) ◽  
pp. 419-428
Author(s):  
Jasleen Singh ◽  
Karen A. Doherty
Keyword(s):  
Hearing Aids ◽  
Background Noise ◽  
Middle Age ◽  
Hearing Aid ◽  
Normal Hearing ◽  
Self Report ◽  
Hearing Aid Use ◽  
Hearing Handicap ◽  
Before And After ◽  
Hearing Problems

Purpose The aim of the study was to assess how the use of a mild-gain hearing aid can affect hearing handicap, motivation, and attitudes toward hearing aids for middle-age, normal-hearing adults who do and do not self-report trouble hearing in background noise. Method A total of 20 participants (45–60 years of age) with clinically normal-hearing thresholds (< 25 dB HL) were enrolled in this study. Ten self-reported difficulty hearing in background noise, and 10 did not self-report difficulty hearing in background noise. All participants were fit with mild-gain hearing aids, bilaterally, and were asked to wear them for 2 weeks. Hearing handicap, attitudes toward hearing aids and hearing loss, and motivation to address hearing problems were evaluated before and after participants wore the hearing aids. Participants were also asked if they would consider purchasing a hearing aid before and after 2 weeks of hearing aid use. Results After wearing the hearing aids for 2 weeks, hearing handicap scores decreased for the participants who self-reported difficulty hearing in background noise. No changes in hearing handicap scores were observed for the participants who did not self-report trouble hearing in background noise. The participants who self-reported difficulty hearing in background noise also reported greater personal distress from their hearing problems, were more motivated to address their hearing problems, and had higher levels of hearing handicap compared to the participants who did not self-report trouble hearing in background noise. Only 20% (2/10) of the participants who self-reported trouble hearing in background noise reported that they would consider purchasing a hearing aid after 2 weeks of hearing aid use. Conclusions The use of mild-gain hearing aids has the potential to reduce hearing handicap for normal-hearing, middle-age adults who self-report difficulty hearing in background noise. However, this may not be the most appropriate treatment option for their current hearing problems given that only 20% of these participants would consider purchasing a hearing aid after wearing hearing aids for 2 weeks.

Selecting the Optimal FM System for Children With Cochlear Implants

2008 ◽  
Vol 18 (1) ◽  
pp. 19-24
Author(s):  
Erin C. Schafer
Keyword(s):  
Speech Recognition ◽  
Cochlear Implants ◽  
Empirical Research ◽  
Background Noise ◽  
Signal To Noise Ratio ◽  
Evidence Based ◽  
Signal To Noise ◽  
Speech Processor ◽  
System Input ◽  
Optimal Type

Children who use cochlear implants experience significant difficulty hearing speech in the presence of background noise, such as in the classroom. To address these difficulties, audiologists often recommend frequency-modulated (FM) systems for children with cochlear implants. The purpose of this article is to examine current empirical research in the area of FM systems and cochlear implants. Discussion topics will include selecting the optimal type of FM receiver, benefits of binaural FM-system input, importance of DAI receiver-gain settings, and effects of speech-processor programming on speech recognition. FM systems significantly improve the signal-to-noise ratio at the child's ear through the use of three types of FM receivers: mounted speakers, desktop speakers, or direct-audio input (DAI). This discussion will aid audiologists in making evidence-based recommendations for children using cochlear implants and FM systems.

Hearing Aid Design and Evaluation for a Patient with a Severe Discrimination Loss for Speech

1967 ◽  
Vol 10 (2) ◽  
pp. 367-372 ◽  
Author(s):  
James D. Miller ◽  
Arthur F. Niemoeller
Keyword(s):  
Hearing Aids ◽  
Background Noise ◽  
Hearing Aid ◽  
Accurate Estimate ◽  
Single Patient

Results of intelligibility tests on a single patient with a severe discrimination loss for speech are reported. The patient was tested with four different hearing aids and with no aid, and the effects of opportunity for lipreading, background noise, and reverberation were evaluated. The tests appear to allow an accurate estimate of the amount of help to be expected in various situations and show that an aid with good fidelity is clearly superior to the others tested. The destructive effects of background noise and reverberation are demonstrated separately and in combination.

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