scholarly journals Adaptive wideband equalization for frequency dispersion correction in HF band considering variations in interference characteristics and ionosphere parameters

2019 ◽  
Vol 30 ◽  
pp. 15021
Author(s):  
Dmitry Ivanov ◽  
Vladimir Ivanov ◽  
Vladimir Ovchinnikov ◽  
Aleksey Elsukov ◽  
Maria Ryabova
Keyword(s):  
Software Defined Radio ◽  
Continuous Wave ◽  
Software Radio ◽  
Frequency Dispersion ◽  
Propagation Path ◽  
Test Facility ◽  
Propagation Mode ◽  
Dispersion Correction ◽  
Radio Technology ◽  
Continuous Wave Signal

Paper presents the outcomes of the studies into the adaptive wideband equalization for frequency dispersion correction in HF band considering variations in interference characteristics and ionosphere parameters. The subject matter of the research were megahertz-bandwidth channels with single-hop F layer propagation mode. There are presented data on variations in the channel amplitude frequency response that are caused by the interference of magneto-ionic components (intramodal multipath). Test facility for carrying out full-scale experiments was developed with the use of Universal Software Radio Peripheral platform supported by the groundbreaking software-defined radio technology. Verification of the developed methods and algorithms was performed in the experiments on oblique sounding over the Cyprus-to-Yoshkar-Ola propagation path by the linearly frequency modulated continuous wave signal.

scholarly journals 5G F-OFDM Waveform Based Software-Defined Radio Technology

2021 ◽  
Vol 20 ◽  
pp. 68-80
Author(s):  
Dia Mohamad Ali ◽  
Zhraa Zuheir Yahya
Keyword(s):  
Software Defined Radio ◽  
Orthogonal Frequency Division Multiplexing ◽  
Hardware Implementation ◽  
Software Radio ◽  
Spectrum Efficiency ◽  
Practical Implementation ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Fifth Generation ◽  
Radio Technology

Filtered-orthogonal frequency division multiplexing (F-OFDM) is a quasi-orthogonal waveform candidate for the applications of the fifth generation (5G) communication system. In this study, an F-OFDM waveform with unequal sub-band sizes is proposed to improve the spectrum efficiency (SE) of the 5G system. The proposed waveform is modeled with the Blackman window-sinc filter and is developed based on the software-defined radio (SDR) technology for practical implementation. The result shows that the F-OFDM performance of the simulation and hardware implementation is approximately the same. The SE using the proposed F-OFDM waveform is 6% and 5.8% higher than the SE using the conventional OFDM waveform under the simulation in the LabVIEW NXG simulator and under the practical use in the universal software radio peripheral (USRP) platform, respectively.

A Digital Carrier Monitoring System Based on Software Defined Radio

2014 ◽  
Vol 635-637 ◽  
pp. 1067-1071
Author(s):  
Yu Jie Yang ◽  
Gang Weng Han ◽  
Zhe Yang ◽  
Hua Shao
Keyword(s):  
Monitoring System ◽  
Virtual Instrument ◽  
Remote Monitoring ◽  
Software Defined Radio ◽  
Satellite Communication ◽  
Software Radio ◽  
Computer Hardware ◽  
Spectrum Monitoring ◽  
Radio Technology ◽  
New Type

With the development of DSP technology and improvement of computer hardware performance, software radio technology has been widely applied in the area of satellite communication. Digital carrier monitoring system is a new type of satellite communication spectrum monitoring system. It is based on software radio technology and is networked design, having realized functions of spectrum remote monitoring and networked virtual instrument. This article analyzed functions and working principals of this system, and summarized its application in earth station.

A Digital Carrier Monitoring System Based on Software Defined Radio

2014 ◽  
Vol 610 ◽  
pp. 225-228
Author(s):  
Yu Jie Yang ◽  
Gang Weng Han ◽  
Zhe Yang ◽  
Hua Shao
Keyword(s):  
Monitoring System ◽  
Virtual Instrument ◽  
Remote Monitoring ◽  
Software Defined Radio ◽  
Satellite Communication ◽  
Software Radio ◽  
Computer Hardware ◽  
Spectrum Monitoring ◽  
Radio Technology ◽  
New Type

With the development of DSP technology and improvement of computer hardware performance, software radio technology has been widely applied in the area of satellite communication. Digital carrier monitoring system is a new type of satellite communication spectrum monitoring system. It is based on software radio technology and is networked design, having realized functions of spectrum remote monitoring and networked virtual instrument. This article analyzed functions and working principals of this system, and summarized its application in earth station.

scholarly journals Analysis of the Snow Water Equivalent at the AEMet-Formigal Field Laboratory (Spanish Pyrenees) During the 2019/2020 Winter Season Using a Stepped-Frequency Continuous Wave Radar (SFCW)

2021 ◽  
Vol 13 (4) ◽  
pp. 616
Author(s):  
Rafael Alonso ◽  
José María García del Pozo ◽  
Samuel T. Buisán ◽  
José Adolfo Álvarez
Keyword(s):  
Software Defined Radio ◽  
Continuous Wave ◽  
Snow Water Equivalent ◽  
Cosmic Ray ◽  
Relative Dielectric Permittivity ◽  
Near Surface ◽  
Wave Radar ◽  
Spanish Pyrenees ◽  
Snow Water ◽  
Stepped Frequency

Snow makes a great contribution to the hydrological cycle in cold regions. The parameter to characterize available the water from the snow cover is the well-known snow water equivalent (SWE). This paper presents a near-surface-based radar for determining the SWE from the measured complex spectral reflectance of the snowpack. The method is based in a stepped-frequency continuous wave radar (SFCW), implemented in a coherent software defined radio (SDR), in the range from 150 MHz to 6 GHz. An electromagnetic model to solve the electromagnetic reflectance of a snowpack, including the frequency and wetness dependence of the complex relative dielectric permittivity of snow layers, is shown. Using the previous model, an approximated method to calculate the SWE is proposed. The results are presented and compared with those provided by a cosmic-ray neutron SWE gauge over the 2019–2020 winter in the experimental AEMet Formigal-Sarrios test site. This experimental field is located in the Spanish Pyrenees at an elevation of 1800 m a.s.l. The results suggest the viability of the approximate method. Finally, the feasibility of an auxiliary snow height measurement sensor based on a 120 GHz frequency modulated continuous wave (FMCW) radar sensor, is shown.

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.

Spark Ignition of SPP Injector Under Sub-Atmospheric Conditions

2021 ◽  
Author(s):  
Qianpeng Zhao ◽  
Yong Mu ◽  
Jinhu Yang ◽  
Yulan Wang ◽  
Gang Xu
Keyword(s):  
High Speed ◽  
Spark Ignition ◽  
Test Facility ◽  
Propagation Mode ◽  
Inlet Temperature ◽  
Reacting Flow ◽  
Atmospheric Conditions ◽  
Flame Kernel ◽  
Flame Development ◽  
Initial Flame

Abstract The sub-atmospheric ignition performance of an SPP (Stratified Partially Premixed) injector and combustor is investigated experimentally on the high-altitude test facility. In order to explore the influence of sub-atmospheric pressure on reignition performance and flame propagation mode, experiments are conducted under different pressures ranging from 19 kPa to 101 kPa. The inlet temperature and pressure drop of the injector (ΔPsw/P3t) are kept constant at 303 K and 3% respectively. The transparent quartz window mounted on the sidewall of the model combustor provides optical access of flame signals. Ignition fuel-air ratio (FAR) under different inlet pressures are experimentally acquired. The spark ignition processes, including the formation of flame kernel, the flame development and stabilization are recorded by a high-speed camera at a rate of 5kHz. Experimental results indicate that the minimum ignition FAR grows rapidly as the inlet air pressure decreases. An algorithm is developed to track the trajectory of flame kernels within 25ms following the spark during its breakup and motion processes. Results show that the calculated trajectory provides a clear description of the flame evolution process. Under different inlet air pressures, the propagation trajectories of flame kernels share similarities in initial phase. It is pivotal for a successful ignition that the initial flame kernel keeps enough intensity and moves into CTRZ (Center-Toroidal Recirculation Zone) along radial direction. Finally, the time-averaged non-reacting flow field under inlet pressure of 54kPa and fuel mass flow of 8kg/h is simulated. The effects of flow structure and fuel spatial distribution on kernel propagation and flame evolution are analyzed.

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