scholarly journals Research on Continuous Wave Electromagnetic Effect in Swept Frequency Radar

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xue Du ◽  
Guanghui Wei ◽  
Hongze Zhao ◽  
Xiaodong Pan
Keyword(s):  
Field Strength ◽  
False Alarm ◽  
Electromagnetic Interference ◽  
Continuous Wave ◽  
Single Frequency ◽  
Electromagnetic Effect ◽  
Interference Field ◽  
Electromagnetic Environment ◽  
Front End ◽  
Interference Mechanism

In order to establish the prediction model of radar equipment in multisource complex electromagnetic environment, the blocking effect and false alarm interference effect caused by single-frequency CW (continuous wave) electromagnetic interference on typical radar equipment are studied. Taking a certain sweep radar as the research object, the equivalent injection test of EMI (electromagnetic interference) is carried out. Based on the theory of radar front door coupling, the interference mechanism of EMI to radar receiver RF front end is revealed, and the variation law of blocking target and false alarm target level is analyzed. The results show that, under the single-frequency CW-EMI, the target echo level decreases with the increase of the interference field strength, and the false alarm level increases with the increase of the interference field strength. The blocking jamming sensitive bandwidth is about f 0 ± 200   MHz , and the false alarm jamming sensitive bandwidth is about f 0 ± 80   MHz .

Search on Ignition Interference Prevention of Vehicle Safety System

2014 ◽  
Vol 556-562 ◽  
pp. 6123-6127
Author(s):  
Wei Zhou ◽  
Shi Shun Dai ◽  
Xuan Dong ◽  
Chun Xiao Ren
Keyword(s):  
Software Design ◽  
Electromagnetic Interference ◽  
Safety System ◽  
Vehicle Safety ◽  
Prevention Measures ◽  
Electromagnetic Environment ◽  
Simulation Experiments ◽  
The Stability ◽  
The Moment ◽  
Interference Mechanism

Basic on the problem that the electromagnetic environment in vehicles which formed at the moment of ignition will cause interference to the stability and reliability of vehicle safety system, the paper takes vehicle fire protection system as the research object, and analyzes the interference mechanism and harmfulness through the simulation experiments. Finally uses the related software design and some prevention measures for electromagnetic interference such as shielding, grounding to protect the system, then through experiment to verify that it’s scientific and reasonable.

scholarly journals Digital Suppression of EMI-Induced Errors in a Baseband Acquisition Front-End including Off-the-Shelf, EMI-Sensitive Operational Amplifiers

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2096
Author(s):  
Paolo Crovetti ◽  
Francesco Musolino
Keyword(s):  
Electromagnetic Interference ◽  
Continuous Wave ◽  
Analog Signal ◽  
Operational Amplifiers ◽  
Signal Acquisition ◽  
Experimental Characterization ◽  
Post Processing ◽  
Front End ◽  
First Time

In this paper, the susceptibility to Electromagnetic Interference (EMI) of an analog signal acquisition front-end (AFE) due to EMI distortion in opamp-based pre-conditioning amplifiers is addressed. More specifically, the possibility to correct EMI-induced errors in the digital domain by post-processing the acquired digital waveforms is discussed and experimentally demonstrated for the first time with reference to an AFE based on EMI-sensitive, off-the-shelf operational amplifiers mounted on a specific EMI test PCB. Extensive experimental characterization in the presence of continuous wave and amplitude modulated EMI reveals the superior immunity to EMI of the proposed AFE and the robustness of the approach.

scholarly journals Sensitivity Criterion and Law on a Navigation Receiver under Single Frequency Electromagnetic Radiation

2021 ◽  
Vol 12 (1) ◽  
pp. 204
Author(s):  
Mei Li ◽  
Guanghui Wei
Keyword(s):  
Electromagnetic Radiation ◽  
Electromagnetic Interference ◽  
Continuous Wave ◽  
Density Ratio ◽  
Single Frequency ◽  
Initial Value ◽  
Step Size ◽  
Testing Method ◽  
Noise Density ◽  
Working Frequency

To objectively assess the anti-electromagnetic interference ability of the navigation receiver, the sensitivity criterion of a certain type of navigation receiver is tested under single-frequency continuous wave electromagnetic radiation with an optimized testing method. The experimental results show that it is difficult to guarantee the accuracy of the measurement value of the sensitivity level by using the carrier-to-noise density ratio (C/N0) as the sensitivity criterion, but the initial C/N0 of each satellite can be used as the basis for identifying whether the navigation system has recovered from the interference. The experimental error is dramatically decreased when the sensitivity criterion of “the sensitive phenomenon appears within the first 4 s, and the loss of positioning lasts for 30 s” is employed, the variable interference power step size is adopted and all of the satellites C/N0 are required to recover to the initial value after an interference. The critical interference field intensity error can be controlled within 1 dB by using all these measures. The sensitivity law of the navigation receiver is the same under different working signal intensities. It is significantly sensitive in the working frequency bandwidth. It is also quite sensitive in −11.5 MHz~55.5 MHz of the frequency offset range. The positive sensitive bandwidth is about 5 times that of the negative sensitive bandwidth.

scholarly journals A Survey of Electromagnetic Influence on UAVs from an EHV Power Converter Stations and Possible Countermeasures

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 701
Author(s):  
Yanchu Li ◽  
Qingqing Ding ◽  
Keyue Li ◽  
Stanimir Valtchev ◽  
Shufang Li ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Wide Spectrum ◽  
Electromagnetic Emission ◽  
Power Converter ◽  
Electromagnetic Environment ◽  
Communication Circuits ◽  
Electromagnetic Emissions ◽  
Surrounding Space ◽  
Extra High Voltage ◽  
The Impact

It is inevitable that high-intensity, wide-spectrum electromagnetic emissions are generated by the power electronic equipment of the Extra High Voltage (EHV) power converter station. The surveillance flight of Unmanned Aerial Vehicles (UAVs) is thus, situated in a complex electromagnetic environment. The ubiquitous electromagnetic interference demands higher electromagnetic protection requirements from the UAV construction and operation. This article is related to the UAVs patrol inspections of the power line in the vicinity of the EHV converter station. The article analyzes the electromagnetic interference characteristics of the converter station equipment in the surrounding space and the impact of the electromagnetic emission on the communication circuits of the UAV. The anti-electromagnetic interference countermeasures strive to eliminate or reduce the threats of electromagnetic emissions on the UAV’s hardware and its communication network.

scholarly journals A Local Oscillator Phase Compensation Technique for Ultra-Wideband Stepped-Frequency Continuous Wave Radar Based on a Low-Cost Software-Defined Radio

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 780
Author(s):  
Kazunori Takahashi ◽  
Takashi Miwa
Keyword(s):  
Software Defined Radio ◽  
Initial Phase ◽  
Continuous Wave ◽  
Low Cost ◽  
Local Oscillator ◽  
The Other ◽  
Ultra Wideband ◽  
Single Frequency ◽  
Wave Radar ◽  
Stepped Frequency

The paper discusses a way to configure a stepped-frequency continuous wave (SFCW) radar using a low-cost software-defined radio (SDR). The most of high-end SDRs offer multiple transmitter (TX) and receiver (RX) channels, one of which can be used as the reference channel for compensating the initial phases of TX and RX local oscillator (LO) signals. It is same as how commercial vector network analyzers (VNAs) compensate for the LO initial phase. These SDRs can thus acquire phase-coherent in-phase and quadrature (I/Q) data without additional components and an SFCW radar can be easily configured. On the other hand, low-cost SDRs typically have only one transmitter and receiver. Therefore, the LO initial phase has to be compensated and the phases of the received I/Q signals have to be retrieved, preferably without employing an additional receiver and components to retain the system low-cost and simple. The present paper illustrates that the difference between the phases of TX and RX LO signals varies when the LO frequency is changed because of the timing of the commencement of the mixing. The paper then proposes a technique to compensate for the LO initial phases using the internal RF loopback of the transceiver chip and to reconstruct a pulse, which requires two streaming: one for the device under test (DUT) channel and the other for the internal RF loopback channel. The effect of the LO initial phase and the proposed method for the compensation are demonstrated by experiments at a single frequency and sweeping frequency, respectively. The results show that the proposed method can compensate for the LO initial phases and ultra-wideband (UWB) pulses can be reconstructed correctly from the data sampled by a low-cost SDR.

High-power, continuous-wave, single-frequency, all-periodically-poled, near-infrared source

2012 ◽  
Vol 37 (24) ◽  
pp. 5049 ◽  
Author(s):  
Kavita Devi ◽  
S. Chaitanya Kumar ◽  
M. Ebrahim-Zadeh
Keyword(s):  
High Power ◽  
Near Infrared ◽  
Continuous Wave ◽  
Single Frequency ◽  
Periodically Poled ◽  
Infrared Source

scholarly journals A 1.5–40 GHz frequency modulated continuous wave radar receiver front-end

2021 ◽  
pp. 1-11
Author(s):  
Mantas Sakalas ◽  
Niko Joram ◽  
Frank Ellinger
Keyword(s):  
Continuous Wave ◽  
Noise Figure ◽  
Supply Voltage ◽  
Low Noise ◽  
Ultra Wideband ◽  
Front End ◽  
Wave Radar ◽  
Bicmos Technology ◽  
Circuit Components ◽  
High Band

Abstract This study presents an ultra-wideband receiver front-end, designed for a reconfigurable frequency modulated continuous wave radar in a 130 nm SiGe BiCMOS technology. A variety of innovative circuit components and design techniques were employed to achieve the ultra-wide bandwidth, low noise figure (NF), good linearity, and circuit ruggedness to high input power levels. The designed front-end is capable of achieving 1.5–40 GHz bandwidth, 30 dB conversion gain, a double sideband NF of 6–10.7 dB, input return loss better than 7.5 dB and an input referred 1 dB compression point of −23 dBm. The front-end withstands continuous wave power levels of at least 25 and 20 dBm at low band and high band inputs respectively. At 3 V supply voltage, the DC power consumption amounts to 302 mW when the low band is active and 352 mW for the high band case, whereas the total IC size is $3.08\, {\rm nm{^2}}$ .

scholarly journals Stable, 12 W, continuous-wave single-frequency Nd:YVO_4 green laser polarized and dual-end pumped at 880 nm

2011 ◽  
Vol 19 (7) ◽  
pp. 6777 ◽  
Author(s):  
Jianli Liu ◽  
Zhiyong Wang ◽  
Hong Li ◽  
Qin Liu ◽  
Kuanshou Zhang
Keyword(s):  
Continuous Wave ◽  
Green Laser ◽  
Single Frequency

scholarly journals Observing the neutron component during thunderstorm activity at a mountain CR station

2019 ◽  
Vol 5 (3) ◽  
pp. 54-58
Author(s):  
Анна Луковникова ◽  
Anna Lukovnikova ◽  
Виктор Алешков ◽  
Viktor Aleshkov ◽  
Алексей Лысак ◽  
...  
Keyword(s):  
Field Strength ◽  
Sea Level ◽  
Neutron Monitor ◽  
Electromagnetic Interference ◽  
Count Rate ◽  
Cosmic Ray ◽  
Thunderstorm Activity ◽  
Signal Discrimination ◽  
Lightning Discharges ◽  
Neutron Component

During three summer months in 2015, the Cosmic Ray (CR) station Irkutsk-3000, located at 3000 m above sea level, measured the CR neutron component intensity with the 6NM64 neutron monitor, as well as the atmospheric electric field strength and the level of electromagnetic interference during lightning discharges. It is shown that the level of electromagnetic interference, when registered during lightning discharges, depends considerably on the fixed level of signal discrimination. During observations, we observed no effects of thunderstorm discharges at the neutron monitor count rate at the CR station Irkutsk-3000.

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