scholarly journals A High-Resolution Leaky Coaxial Cable Sensor Using a Wideband Chaotic Signal

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4154
Author(s):  
Hang Xu ◽  
Jun Qiao ◽  
Jianguo Zhang ◽  
Hong Han ◽  
Jingxia Li ◽  
...  
Keyword(s):  
High Resolution ◽  
Dynamic Range ◽  
Chaotic Signal ◽  
Coaxial Cable ◽  
Probe Signal ◽  
Echo Signal ◽  
Robust Performance ◽  
Range Resolution ◽  
System A ◽  
Before And After

A high-resolution leaky coaxial cable (LCX) sensor for perimeter intrusion detection is proposed and experimentally demonstrated. In our proposed sensor system, a wideband Boolean-chaos signal is used as the probe signal, and a pair of leaky coaxial cables (LCXs) is applied for transmitting the probe signal and receiving the echo signal, respectively. By correlating the chaotic echo signal with its delayed duplicate and comparing the correlation traces before and after intrusion, the intruder can be accurately located. Experimental results demonstrate the proposed sensor can simultaneously detect multiple intruders. The range resolution reaches 30 cm, whilst the dynamic range can achieve 50 dB. In addition, this sensor possesses the excellent anti-interference performance to the noise and uncorrelated chaotic signal, which makes it show robust performance in the detection environment with noise or multiple chaotic LCX sensors cooperation.

Chaos-Based Through-Wall Life-Detection Radar

2019 ◽  
Vol 29 (07) ◽  
pp. 1930020 ◽  
Author(s):  
Hang Xu ◽  
Liqiang Li ◽  
Ying Li ◽  
Jianguo Zhang ◽  
Hong Han ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Modulation Frequency ◽  
Correlation Method ◽  
Chaotic Signal ◽  
Detection Algorithm ◽  
Respiratory Frequency ◽  
Thick Wall ◽  
Probe Signal ◽  
Range Resolution ◽  
Life Detection

We propose a chaos-based through-wall life-detection radar utilizing a wideband Boolean-chaos signal as the radar probe signal. The range between the radar and the human target can be obtained by correlating the chaotic signal reflected from the human target with its delayed duplicate. Actually, this range is modulated periodically by human chest wall displacements along the time axis of recording signal and the modulation frequency is equal to the respiratory frequency. Therefore, we design a life-detection algorithm based on correlation method to extract the human’s respiratory frequency and range information from echo signals. Experimental results demonstrate that our radar can simultaneously detect the respiratory frequency and range of the human target behind a 20-cm-thick wall within the range of at least 5[Formula: see text]m. The dynamic range and range resolution can reach 35[Formula: see text]dB and 15[Formula: see text]cm, respectively. Furthermore, the excellent anti-interference performance of the proposed radar has also been demonstrated, which makes it especially suitable for search and rescue missions in complex electromagnetic environments.

scholarly journals Locating Underground Pipe Using Wideband Chaotic Ground Penetrating Radar

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2913 ◽  
Author(s):  
Jingxia Li ◽  
Tian Guo ◽  
Henry Leung ◽  
Hang Xu ◽  
Li Liu ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Chaotic Signal ◽  
Projection Algorithm ◽  
Back Projection ◽  
Probe Signal ◽  
Echo Signal ◽  
Buried Pipes ◽  
Range Resolution ◽  
Detectable Range ◽  
Ground Penetrating

An experimental wideband chaotic ground penetrating radar is proposed to locate underground pipes. A chaotic signal with a bandwidth of 1.56 GHz is utilized as the probe signal. The localization of the pipes is achieved by correlating the chaotic echo signal with its delayed duplicate and back-projection algorithm. Experimental results demonstrate that plastic pipe, metallic pipe, and multiple pipes can be located with a range resolution of 10 cm. Limited by the height of the sand, the detectable range is estimated to be 0.7 m for both the plastic pipes and the metallic pipes when the transmitting power is −12 dBm. The proposed system has the potential to detect buried pipes, and it is suitable for geological and civil engineering applications.

Ultra-Wideband Chaos Life-Detection Radar with Sinusoidal Wave Modulation

2017 ◽  
Vol 27 (13) ◽  
pp. 1730046 ◽  
Author(s):  
Hang Xu ◽  
Ying Li ◽  
Jianguo Zhang ◽  
Hong Han ◽  
Bing Zhang ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Vital Signs ◽  
Radar System ◽  
Ultra Wideband ◽  
Thick Wall ◽  
Sinusoidal Wave ◽  
Echo Signal ◽  
Range Resolution ◽  
Life Detection ◽  
Lock In

We propose and experimentally demonstrate an ultra-wideband (UWB) chaos life-detection radar. The proposed radar transmits a wideband chaotic-pulse-position modulation (CPPM) signal modulated by a single-tone sinusoidal wave. A narrow-band split ring sensor is used to collect the reflected sinusoidal wave, and a lock-in amplifier is utilized to identify frequencies of respiration and heartbeat by detecting the phase change of the sinusoidal echo signal. Meanwhile, human location is realized by correlating the CPPM echo signal with its delayed duplicate and combining the synthetic aperture technology. Experimental results demonstrate that the human target can be located accurately and his vital signs can be detected in a large dynamic range through a 20-cm-thick wall using our radar system. The down-range resolution is 15[Formula: see text]cm, benefiting from the 1-GHz bandwidth of the CPPM signal. The dynamic range for human location is 50[Formula: see text]dB, and the dynamic ranges for heartbeat and respiration detection respectively are 20[Formula: see text]dB and 60[Formula: see text]dB in our radar system. In addition, the bandwidth of the CPPM signal can be adjusted from 620[Formula: see text]MHz to 1.56[Formula: see text]GHz to adapt to different requirements.

High Resolution Noise Radar without Fast ADC

2012 ◽  
Vol 58 (2) ◽  
pp. 135-140 ◽  
Author(s):  
Konstantin Lukin ◽  
Pavlo Vyplavin ◽  
Oleg Zemlyaniy ◽  
Volodymyr Palamarchuk ◽  
Sergii Lukin
Keyword(s):  
Signal Processing ◽  
High Resolution ◽  
Dynamic Range ◽  
Sampling Rate ◽  
High Dynamic Range ◽  
Frequency Noise ◽  
Processing Scheme ◽  
Range Resolution ◽  
Noise Radar ◽  
High Dynamic

High Resolution Noise Radar without Fast ADCConventional digital signal processing scheme in noise radars has certain limitations related to combination of high resolution and high dynamic range. The bandwidth of radar signal defines range resolution of any radar: the wider the spectrum the better the resolution. In noise radar with conventional processing the sounding and reference signals are to be digitized at intermediate frequency band and to be processed digitally. The power spectrum bandwidth of noise signal which can be digitized with ADC depends on its sampling rate. In currently available ADCs the faster is sampling rate the smaller is its depth (number of bits). Depth of the ADC determines relation between the smallest and highest observable signals and thus limits its dynamic range. Actually this is the main bottleneck of high resolution Noise Radars: conventional processing does not enable getting high range resolution and high dynamic range at the same time. In the paper we discuss ways to go around this drawback by changing signal processing ideology in noise radar. We present results of our consideration and design of two types of high resolution Noise Radar which uses slow ADCs: noise radar with digital generation of sounding signal and analog evaluation of cross-correlation and stepped frequency noise radar. We describe main ideas of these radar schemes and results of experimental tests of the approaches.

Remote Imaging Radar with Ultra-Wideband Chaotic Signals Over Fiber Links

2015 ◽  
Vol 25 (11) ◽  
pp. 1530029 ◽  
Author(s):  
Hang Xu ◽  
Bingjie Wang ◽  
Hong Han ◽  
Li Liu ◽  
Jingxia Li ◽  
...  
Keyword(s):  
Chaotic Signal ◽  
Base Station ◽  
Ultra Wideband ◽  
Probe Signal ◽  
Range Resolution ◽  
Remote Imaging ◽  
Chaotic Signals ◽  
Fiber Link ◽  
Fiber Links ◽  
Central Station

We experimentally demonstrate radar remote imaging using a radio technique based on ultra-wideband chaotic signals over fiber links. The radar system includes three parts, i.e. a central station, some optical fiber links and a base station. At the central station, an ultra-wideband chaotic signal is generated from an improved Colpitts oscillator and then is up-converted as a probe signal. The probe signal is then converted to be in optical domain by the external modulation technique on laser diode for transmitting over a fiber link to a remote base station. At the base station, the probe signal is converted to be in electrical domain and then launched by a microwave antenna. After being received by another antenna, the echo signal from a target is converted to be in optical domain and then transmitted over a fiber link back to the central station. By optical-to-electrical conversion and down conversion, the echo chaotic signal is recovered. Utilizing the correlation method and back projection algorithm, an image of the target in the two-dimensional space can be realized at the central station. Our experiments successfully performed remote imaging for both planar and spherical reflectors with a distance over 10 km. The down-range resolution of 6-cm and 8-cm cross-range resolution were obtained, respectively. We will show that the power spectrum of the probe signal is adjustable in the spectral mask according to the Federal Communications Commission standards, therefore can avoid interference to the existing narrowband radio signals.

High-resolution electron microscopy of Cu2O surfaces

1986 ◽  
Vol 44 ◽  
pp. 396-397
Author(s):  
V. Castano ◽  
W. Krakow
Keyword(s):  
High Resolution ◽  
Natural Extension ◽  
High Resolution Electron Microscopy ◽  
Point Of View ◽  
Initial Oxidation ◽  
System A ◽  
Resolution Electron ◽  
Surface Reconstructions ◽  
Atomic Surface ◽  
Au Thin Films

In non-UHV microscope environments atomic surface structure has been observed for flat-on for various orientations of Au thin films and edge-on for columns of atoms in small particles. The problem of oxidation of surfaces has only recently been reported from the point of view of high resolution microscopy revealing surface reconstructions for the Ag2O system. A natural extension of these initial oxidation studies is to explore other materials areas which are technologically more significant such as that of Cu2O, which will now be described.

Slow-scan CCD cameras and low-dose High-Resolution Electron Microscopy: Direct and quantitative

1994 ◽  
Vol 52 ◽  
pp. 412-413
Author(s):  
M. Pan
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Structural Damage ◽  
Low Dose ◽  
Dynamic Range ◽  
High Resolution Electron Microscopy ◽  
Operating Conditions ◽  
Digital Data ◽  
Ccd Cameras ◽  
Resolution Electron

It has been known for many years that materials such as zeolites, polymers, and biological specimens have crystalline structures that are vulnerable to electron beam irradiation. This radiation damage severely restrains the use of high resolution electron microscopy (HREM). As a result, structural characterization of these materials using HREM techniques becomes difficult and challenging. The emergence of slow-scan CCD cameras in recent years has made it possible to record high resolution (∽2Å) structural images with low beam intensity before any apparent structural damage occurs. Among the many ideal properties of slow-scan CCD cameras, the low readout noise and digital recording allow for low-dose HREM to be carried out in an efficient and quantitative way. For example, the image quality (or resolution) can be readily evaluated on-line at the microscope and this information can then be used to optimize the operating conditions, thus ensuring that high quality images are recorded. Since slow-scan CCD cameras output (undistorted) digital data within the large dynamic range (103-104), they are ideal for quantitative electron diffraction and microscopy.

scholarly journals High-resolution VLA low radio frequency observations of the Perseus cluster: radio lobes, mini-halo, and bent-jet radio galaxies

2020 ◽  
Vol 499 (4) ◽  
pp. 5791-5805
Author(s):  
M Gendron-Marsolais ◽  
J Hlavacek-Larrondo ◽  
R J van Weeren ◽  
L Rudnick ◽  
T E Clarke ◽  
...  
Keyword(s):  
High Resolution ◽  
Dynamic Range ◽  
Galaxy Cluster ◽  
High Dynamic Range ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Nearby Galaxy ◽  
Cluster Galaxy ◽  
Ngc 1275 ◽  
Perseus Cluster

ABSTRACT We present the first high-resolution 230–470 MHz map of the Perseus cluster obtained with the Karl G. Jansky Very Large Array. The high dynamic range and resolution achieved have allowed the identification of previously unknown structures in this nearby galaxy cluster. New hints of sub-structures appear in the inner radio lobes of the brightest cluster galaxy NGC 1275. The spurs of radio emission extending into the outer X-ray cavities, inflated by past nuclear outbursts, are seen for the first time at these frequencies, consistent with spectral aging. Beyond NGC 1275, we also analyse complex radio sources harboured in the cluster. Two new distinct, narrowly collimated jets are visible in IC 310, consistent with a highly projected narrow-angle tail radio galaxy infalling into the cluster. We show how this is in agreement with its blazar-like behaviour, implying that blazars and bent-jet radio galaxies are not mutually exclusive. We report the presence of filamentary structures across the entire tail of NGC 1265, including two new pairs of long filaments in the faintest bent extension of the tail. Such filaments have been seen in other cluster radio sources such as relics and radio lobes, indicating that there may be a fundamental connection between all these radio structures. We resolve the very narrow and straight tail of CR 15 without indication of double jets, so that the interpretation of such head–tail sources is yet unclear. Finally, we note that only the brightest western parts of the mini-halo remain, near NGC 1272 and its bent double jets.

scholarly journals PTU-151 High Resolution Manometry Profile of Hiatal Hernia in Patients before and after Fundoplication: Abstract PTU-151 Table

Gut ◽  
2013 ◽  
Vol 62 (Suppl 1) ◽  
pp. A109.2-A110 ◽  
Author(s):  
K Bilnik ◽  
E Klimacka-Nawrot ◽  
J Kurek ◽  
B Blonska-Fajfrowska ◽  
A Stadnicki
Keyword(s):  
High Resolution ◽  
Hiatal Hernia ◽  
High Resolution Manometry ◽  
Before And After
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