Research of Methods for Suppression of Parasitic Components in RF Quadrature Modulator Output Signal Spectrum

2021 ◽  
Vol 26 (1) ◽  
pp. 54-63
Author(s):  
T.Yu. Krupkina ◽  
◽  
V.V. Losev ◽  
L.V. Nedashkovskiy ◽  
Yu.A. Chaplygin ◽  
...  
Keyword(s):  
Output Signal ◽  
Communication Systems ◽  
Point Of View ◽  
Phase Shifting ◽  
Signal Spectrum ◽  
Polyphase Filter ◽  
Digital To Analog Converters ◽  
Quadrature Modulator ◽  
Phase Amplitude ◽  
Parasitic Components

The quadrature modulators and demodulators are widely used to create modern wireless communication systems. It is important to ensure high quality of the transmitted signals in order to have the exchange of information without loss or failure. From the point of view of the spectral decomposition of the signal (Fourier series decomposition), the useful component of the spectrum must be much larger than all other components. The carrier (LO frequency and spurious sideband are the most critical and undesirable quadrature modulator output signal spectral components. In the work, in the course of the research using the methods of suppressing the parasitic components, based on minimizing phase, amplitude and current imbalances in various nodes of the quadrature modulator circuit, have been revealed. In order to realize suppression, the special digital-to-analog converters are used in conjunction with a polyphase filter on varicaps, a phase-shifting block and current sources. The effectiveness of these methods is confirmed by the achievement of suppression of parasitic components in prototypes of 50 dB or more. It has been stated that the phase unbalance minimization is more effective than the amplitude unbalance minimization to sideband suppression. It has been revealed that the use of a phase-shifting block is a more suitable architecture to control the phase unbalance. The obtained results can be useful in the design of high-precision radio frequency units for various purposes.

scholarly journals NOISE STABILITY OF SIGNAL RECEPTION ALGORITHMS WITH MULTIPULSE PULSE-POSITION MODULATION

2018 ◽  
Vol 42 (1) ◽  
pp. 167-174 ◽  
Author(s):  
V. I. Parfenov ◽  
D. Y. Golovanov
Keyword(s):  
Communication Systems ◽  
Pulse Sequence ◽  
Signal To Noise Ratio ◽  
Point Of View ◽  
Estimation Accuracy ◽  
Pulse Position Modulation ◽  
Signal To Noise ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Noise Ratio

An algorithm for estimating time positions and amplitudes of a periodic pulse sequence from a small number of samples was proposed. The number of these samples was determined only by the number of pulses. The performance of this algorithm was considered on the assumption that the spectrum of the original signal is limited with an ideal low-pass filter or the Nyquist filter, and conditions for the conversion from one filter to the other were determined. The efficiency of the proposed algorithm was investigated through analyzing in which way the dispersion of estimates of time positions and amplitudes depends on the signal-to-noise ratio and on the number of pulses in the sequence. It was shown that, from this point of view, the efficiency of the algorithm decreases with increasing number of sequence pulses. Besides, the efficiency of the proposed algorithm decreases with decreasing signal-to-noise ratio.It was found that, unlike the classical maximum likelihood algorithm, the proposed algorithm does not require a search for the maximum of a multivariable function, meanwhile characteristics of the estimates are practically the same for both these methods. Also, it was shown that the estimation accuracy of the proposed algorithm can be increased by an insignificant increase in the number of signal samples.The results obtained may be used in the practical design of laser communication systems, in which the multipulse pulse-position modulation is used for message transmission. 

Field Test of a Leak Detection System: Planning, Execution and Results

2010 ◽  
Author(s):  
Daniel Sampaio da Silva ◽  
Si´lvio A. Melo Filho ◽  
Mauro Niehues de Farias ◽  
Anderson Pacheco
Keyword(s):  
Steady State ◽  
Field Test ◽  
Communication Systems ◽  
Detection System ◽  
Transient State ◽  
Leak Detection ◽  
Point Of View ◽  
Measuring System ◽  
Operational Parameters ◽  
Pump Station

The OLAPA pipeline (Oleoduto Arauca´ria–Paranagua´) is a 12in diameter pipeline and, with its 97,6 km in length, crosses a mountain region called “Serra do Mar” attaining elevations of about 900m in a dense forest region. Besides that, this pipeline crosses cities, farms, rivers, including a short submerse stretch in the Paranagua´’s bay. An incident in this pipeline could result in severe consequences, especially under the environmental point of view. Therefore, this pipeline was chosen to test the performance of a new leak detector system in Transpetro. The test consists in comparing the theoretical results with practical values of alarm times obtained from a controlled removal of product in an adequate point, in the middle of the pipeline, simulating a real leak. The system chosen to be tested was the LeakWarn system, which is a computational system that uses the mass balance principle with line pack change to analyze the pipeline operational parameters in order to alert when there is a risk of product leak. This test had the objective to evaluate the LDS and help Transpetro’s management team to analyze and decide whether or not to replace its current leak management system, since this new one showed the expected results and was compatible with the excellence level already achieved in the company. The field test was performed in July 7th 2009, through a vent valve far from the ends of the pipeline and it was made in three different conditions: 1) A big leak in the steady state of operation; 2) A small leak also in the steady state of operation; and 3) A big leak in the transient state of operation (immediately after the pump station start up). In order to proceed this test, a multidisciplinary team was assigned and several resources were used such as: Two tank trucks, a specially designed leakage line with control valves, measuring system, flexible hoses, communication systems and emergency equipments. The complete operation was monitored from the Control Center in Transpetro’s Headquarter, Rio de Janeiro. This paper describes the way the tests were performed and presents the results in order to contribute with useful information to be used in any field test for any other leak detection system. It shows how planning were done in order to insure that all operations would be performed according to strict procedures and in a safe way. It also describes the milestones and the work of each team involved in the activity, as well as their constraints and difficulties that had to be overcome during the planning and execution phases, that lasted approximately one year.

A 5GHz-band SiGe-MMIC quadrature modulator using a circular polyphase filter for 1Gbps transmission

2005 ◽  
Author(s):  
K. Nakajima ◽  
N. Suematsu ◽  
K. Murakami ◽  
T. Takagi ◽  
H. Nakase ◽  
...  
Keyword(s):  
Polyphase Filter ◽  
Quadrature Modulator

scholarly journals Construction Features of the Transceiver Antenna-Waveguide Device of К/Ka-Band Communication Systems

2020 ◽  
Vol 7 (4) ◽  
pp. 56-62
Author(s):  
S. I. Boychuk ◽  
◽  
V. I. Demchenko ◽  
A. E. Korovkin ◽  
A. V. Shipulin ◽  
...  
Keyword(s):  
Transmission Line ◽  
Communication Systems ◽  
Phase Shifting ◽  
Polarization Conversion ◽  
Ka Band ◽  
Higher Types ◽  
Waveguide Transmission ◽  
Waveguide Device

The paper presents the results of the development of an antenna and waveguide transmission line providing reception and transmission of signals in the extended K/Ka-band with an autotracking mode implemented on the excitation of higher types of waves. The indicators efficiency of the feed, parameters of the waveguide device for extracting error signals, frequency duplexer, phase-shifting sections, and polarization conversion devices were determined.

scholarly journals ANALYSIS OF THE PARAMETRIC SENSITIVITY OF THE METHOD FOR OPTIMIZING THE STRUCTURE OF SPECTRALLY EFFECTIVE RADIO SIGNALS

T-Comm ◽  
2021 ◽  
Vol 15 (3) ◽  
pp. 50-58
Author(s):  
Sergei S. Pechnikov ◽  
◽  
Sergey A. Sherstyukov ◽  
Keyword(s):  
Power Amplifiers ◽  
Spectral Efficiency ◽  
Output Signal ◽  
Phase Modulation ◽  
Communication Systems ◽  
Phase Shifters ◽  
Radio Communications ◽  
Parametric Sensitivity ◽  
Radio Signals ◽  
Vector Modulation

Currently, increasing the speed of information transmission in wireless communication networks is a topical issue. The growing demand for spectral efficiency in radio communication systems gives rise to the introduction of signals with amplitude-phase modulation. Despite all its advantages, signals with vector modulation are characterized by a change in the envelope, which makes it impossible to use highly efficient nonlinear power amplifiers. Energy efficiency is clearly a critical factor in portable radio communications systems, where power supplies are often used in small packages, and the presence of energy losses due to heat dissipation is a significant drawback that requires additional cooling systems. In this connection, when developing modern radio communications, radio engineers are faced with the contradictory task of achieving maximum energy and spectral efficiency. One of the approaches to reduce nonlinear distortion of vector modulation is the use linearization schemes for nonlinear power amplifiers. This work is devoted to increasing the energy and spectral efficiency of signals with amplitude-phase modulation. The article discusses the restrictions imposed on the input signals for the method for optimizing of structure of spectrally effective radio signals with vector modulation, the formation of the output signal, the influence of phase shifters phase imbalance on p/2, the index of balance modulation, and the analysis of parametric sensitivity. The possibility of using quadrature modulators to form components with phase modulation and constant envelope is considered. This method was simulated and the effect of phase imbalance on the shape of the output signal constellation was revealed.

scholarly journals Quantum Determinism of Relative Spacetime Counting

2020 ◽  
Author(s):  
Eugene Machusky ◽  
Ljubov Lisovska ◽  
Olexander Goncharov
Keyword(s):  
Functional Analysis ◽  
Communication Systems ◽  
High Speed ◽  
Quantum Physics ◽  
Maximum Level ◽  
Point Of View ◽  
Engineering Practice ◽  
Simple Explanation ◽  
Computational Accuracy ◽  
Quantum Calculus

The phenomenal mathematical efficiency of quantum field theories in modern high-speed information and communication systems has a very simple explanation from the point of view of common sense and higher mathematical logic: all of them – quantum cosmology, quantum physics, quantum metrics and quantum calculus – are the self-informational mathematical systems based on symbolic and numerical functional analysis and elementary recursive calculations of interrelated space and time parameters of matter motion in various states of the material environment.For the first time in scientific and engineering practice, it was clearly shown that the information entropy of both standard symbolic and non-standard numerical functional analysis has absolute exact limits of computational accuracy – 1/10^16 and 1/10^64, respectively. Moreover, the second limit determines the maximum level of accuracy of practical quantum metrics and calculations and fully coordinates four branches of classical physics – thermodynamics, electrodynamics, gravidynamics, chromodynamics with special and general relativity.

scholarly journals Effective teaching methods of English-speaking students in communication with patients

2021 ◽  
Author(s):  
И.О. Бугаева ◽  
Н.А. Клоктунова ◽  
М.И. Барсукова ◽  
А.Я. Рамазанова ◽  
А.С. Сергеев
Keyword(s):  
Teaching Methods ◽  
Foreign Students ◽  
Communication Systems ◽  
Teaching Practice ◽  
Professional Competence ◽  
Point Of View ◽  
Professional Communication ◽  
Wide Audience ◽  
Communicative Behavior ◽  
English Speaking

Данная работа посвящена анализу методов обучения, способствующих созданию оптимальных условий для подготовки иностранных студентов к будущей профессиональной деятельности, повышению эффективности их коммуникативного поведения, а также успешной интеграции в процесс обучения в медицинском вузе. Анализируется место и роль дисциплины «Профессиональная коммуникация» в самоопределении студентов, развитии их профессиональной компетентности, клинического мышления, а также готовности взаимодействовать в различных системах общения («пациент – врач»; «врач – врач», «врач – пациент – родственники пациента»). Анализируются конкретные педагогические приемы, используемые в рамках практических занятий, и их результативность. В статье приводятся данные проведенного анкетирования, отражающие оценку эффективности применяемых методов обучения с точки зрения студентов. В результате выявлена эффективность разработанных и примененных методов обучения, доказана необходимость формирования корпуса ситуационных задач и обучающих материалов, предлагаемых авторами статьи. Таким образом, представленный опыт осмысления методических приемов требует обсуждения широкой аудиторией научно-педагогического сообщества и его внедрения в практику обучения англоговорящих студентов навыкам профессиональной коммуникации. This work is dedicated to the analysis of factors contributing to the creation of optimal conditions for preparing foreign students for future professional activities, increasing the effectiveness of their communicative behavior, as well as successful integration into the learning process at a medical university. Place and role of the subject “Professional Communication” within the self-determination of students, the development of their professional competence, clinical thinking and willingness to interact in various communication systems (“patient - physician”; “physician - physician”, “physician - patient - relatives of the patient”) are considered. Specific teaching methods used in the framework of lessons and their effectiveness are analyzed. The article presents the data of the survey reflecting the assessment of the effectiveness of the applied teaching methods from the students' point of view. As a result, the effectiveness of the developed and applied teaching methods is revealed, the necessity of forming a corpus of situational tasks and training materials proposed by the authors of the article is proved. Thus, the presented experience of understanding methodological techniques requires discussion by a wide audience of the scientific and pedagogical community and implementation in teaching practice English-speaking students' professional communication skills.

Wideband DOA estimation based on incoherent signal subspace method

2018 ◽  
Vol 37 (3) ◽  
pp. 1271-1289 ◽  
Author(s):  
Zeeshan Ahmad ◽  
Yaoliang Song ◽  
Qiang Du
Keyword(s):  
Computational Complexity ◽  
Communication Systems ◽  
Recent Decade ◽  
Doa Estimation ◽  
Signal Spectrum ◽  
Signal Subspace ◽  
Subspace Method ◽  
Content Type ◽  
Wideband Signals ◽  
Analysis Computer

Purpose Direction-of-arrival (DOA) estimation for wideband sources has attracted a growing interest in the recent decade because wideband sources are incorporated in many real-world applications such as communication systems, radar, sonar and acoustics. One way to estimate the DOAs of wideband signals is to decompose it into narrowband signals using discrete Fourier transform (DFT) and then apply well-established narrowband algorithms to each signal. Afterwards, results are averaged to yield the final DOAs. These techniques require scanning the full band of wideband sources, ultimately degrading the resolution and increasing complexity. This paper aims to propose a new DOA estimation methodology to solve these problems. Design/methodology/approach The new DOA estimation methodology is based on incoherent signal subspace method (ISSM). The proposed approach presents a criterion to select a single sub-band of the selected narrowband signals instead of scanning the whole signal spectrum. Then, the DOAs of wideband signals are estimated using the selected sub-band. Therefore, it is named as single sub-band (SSB)-ISSM. Findings The computational complexity of the proposed method is much lower than that of traditional DFT-based methods. The effectiveness and advantages of the proposed methodology are theoretically investigated, and computational complexity is also addressed. Originality/value To verify the theoretical analysis, computer simulations are implemented, and comparisons with other algorithms are made. The simulation results show that the proposed method achieves better performance and accurately estimates the DOAs of wideband sources.

Sign in / Sign up

Export Citation Format

Share Document