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1
Content available Effect of Power Amplifier Distortion on the Speech Transmission Index for Public Address Systems
Dziechciński Paweł
Archives of Acoustics
|
2022
|
Vol. 47, No. 2
191--199
EN
The effect of the power amplifier on speech intelligibility in public address systems is often marginalised – i.e. it is assumed that it does not introduce significant signal distortion. This approach is justified when the linear range of the amplifier is used. The large crest factor of the speech signal and economic considerations mean that the amplifier also works in the non-linear range. In this paper, the effect of power amplifier distortion on the speech transmission index for public address systems (STIPA) is presented. In the first step, this influence was evaluated by measurements for Class AB and D amplifiers. Then, a computer model of the public address system based on the direct STIPA method, taking into account the non-linear properties of the amplifier, was proposed. Using the computer model, the optimum amplifier driving values were determined taking into account the reverberation time and interfering noise.speech transmission index; power amplifier; public address system.
2
A S-band Inverted 3-way Doherty amplifier with GaN HEMT transistors
Góralczyk Marcin
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2021
|
nr 4
97--101
EN
This article presents partial result of the PhD thesis on the topic of the Doherty power amplifiers. The design of high-efficiency 3way Doherty amplifier with the use of Wolfspeed CG2H40010 transistors is presented. A newly invented 3-way power splitter architecture is also shown. The proposed splitter and the properties of GaN HEMT technology enable the design of the Inverted 3-way Doherty amplifier in closed, compact form without additional, long phase lines. The amplifier operates in the frequency range from 3.4 to 3.8 GHz and achieves up to 46W of saturated output power with a drain efficiency of 75% at full drive and 53% at 10dB output power back-off.
PL
Przedstawiono częściowe wyniki pracy doktorskiej na temat mikrofalowych wzmacniaczy mocy typu Doherty. Zaprezentowano projekt wysokosprawnego trójdrożnego wzmacniacza typu Doherty z tranzystorami Wolfspeed CG2H40010. Ponadto przedstawiono unikalną konstrukcję trójdrożnego dzielnika mocy, która umożliwiła zaprojektowanie trójdrożnego wzmacniacza typu Doherty w konfiguracji odwróconej. Przedstawiony wzmacniacz charakteryzuje się zwartą konstrukcją, która nie wymaga dodatkowych linii fazowych, co umożliwia poszerzenie pasma pracy. Układ pracuje w paśmie telekomunikacyjnym 3,4 – 3,8 GHz i osiąga w nasyceniu 46 W mocy przy sprawności drenowej 75%. Dla sygnałów o mocy wyjściowej niższej o 10 dB względem nasycenia wzmacniacz uzyskuje sprawność 53%.
3
Content available Digital Predistortion of Wideband Signals with Reduced Complexity Based on Feedback Wiener System
Bouazza Tayeb H. C., Bachir Smail, Duvanaud Claude
Journal of Telecommunications and Information Technology
|
2021
|
nr 2
1--10
EN
Digital predistortion (DPD) using baseband signals is commonly used for power amplifier linearization. This paper is devoted to this subject and aims to reduce DPD complexity. In this study, we propose a structure that allows to decrease the number of DPD parameters by using multiple blocks, with each one of them dedicated to characterizing the non-linear behavior and/or memory effects. Such a structure is based on the feedback Wiener system, involving a FIR filter used as a feedback path to reproduce the PA inverse dynamics. A memory polynomial block (MP) is inserted as the final element to minimize the modeling errors. A relevant model identification method, based on an iterative algorithm, has been developed as well. The proposed architecture is used for the linearization of a commercial class-AB LDMOS RF PA by NXP Semiconductors, in wideband communication systems. Comparison of performance with the conventional generalized memory polynomial model (GMP) shows that the proposed model offers similar results, with its advantage consisting in the reduced number of parameters.
4
Content available remote Analysis, simulation and hardware implementation of singles witch power amplifier for Active Magnetic Bearing (AMB) system
Debnath Sukanta, Biswas Pabitra Kumar, Laldingliana Jonathan
Journal of Power Technologies
|
2020
|
Vol. 100, nr 4
308--314
EN
Active Magnetic Bearing is the advancement of habitual technology and is used to increase the rotational speed. AMB isusing power electronics drives, which is the key features of this technology. In this paper, a simple and cheap converter with reduced switch is simulated and implemented in hardware for the validation of simulation result is presented. The principle of the active magnetic bearing and power amplifier is introducedand the generation of pulse is also described. Then, result of simulation and hardware output is compared. Based on the output of hardware setup simulation result is validated. With the help of this amplifier cheapest and better control for active magnetic bearing can be achieved.
5
Content available On Correct Understanding and Classification of Saleh’s and Related Models of AM/AM and AM/PM Conversions
Borys A.
International Journal of Electronics and Telecommunications
|
2018
|
Vol. 64, No. 1
39--44
EN
In this paper, some of the existing classifications of the Saleh’s and related models of the AM/AM and AM/PM conversions occurring in communication power amplifiers (PA) are reviewed. It is shown that these classifications are inconsistent and must be refined. Obviously, carrying out such a refinement properly needs a good knowledge and correct understanding of the mechanisms leading to the AM/AM and AM/PM conversions. This was achieved in this paper by performing a thorough analysis of the PA behavior using an analytical tool, the Volterra series. The main points of this analysis are presented here in great detail. Among others, it is shown that the influence of the PA memory on the AM/PM conversion is two-fold: direct and indirect. The former can be however fully neglected. On the other hand, the indirect influence caused by “the interaction of the carrier with the PA memory” cannot be neglected when the PA has not enough wideband frequency characteristics. The latter effect mentioned causes changes in the carrier phase that are received as the phase changes of the baseband modulating signal.
6
Content available Saleh's Model of AM/AM and AM/PM Conversions is not a Model without Memory : Another Proof
Borys A.
International Journal of Electronics and Telecommunications
|
2017
|
Vol. 63, No. 1
73--77
EN
The so-called Saleh's representation for description of the AM/AM and AM/PM conversions, occurring in communication power amplifiers, consists of two expressions that describe them as functions of a real-valued baseband signal modulating the carrier amplitude. It is a common view that this description forms a model without memory. We show here that the above belief is not correct; just the opposite is true. To prove this, we take into account an equivalent description of the Saleh's model called the quadrature model of bandpass nonlinearities and express it in a form of a nonlinear operator. Afterwards, we check whether this operator possesses a zero memory. To this end, we use an appropriate theorem of the nonlinear systems theory. Finally, as a result of this investigation, we observe that the memory of the above operator is nonzero.
7
Content available remote Unique micro system stimulator with high data rate and efficient power recovery circuit
Alghrairi M. K., Sulaiman N. B., Sidek R., Mutashar S.
Przegląd Elektrotechniczny
|
2016
|
R. 92, nr 11
213--220
EN
This paper present an efficient micro-system stimulator to transfer data and power in biomedical implanted device by using Amplitude shift keying (ASK) modulation technique. The proposed system operates with low frequency 6.78MHz accordance to the industrial-scientific-medical (ISM) bands to avoid the biological tissue damage. The system design include new ASK modulator, class-E power amplifier, half wave rectifier, voltage regulator (LDO) and new ASK demodulator structure without passive elements to transfer 500Kb/s of data with modulation index 12.5%. The efficient inductive coupling link with 74.47% of efficiency is driven by class-E power amplifier with high efficiency up to 94.5%. Adequate and stable 1.8V DC are generated by the modified rectifier and voltage regulator to power the implanted electronics which occupies small area and does not have a thermal protection circuit or passive elements. The proposed ASK demodulator structure is developed to collect a synchronised demodulated signal that has minimum error without using delay-locked loops (DLL) circuits and clock recovery circuit. This system designed by using OrCAD Pspice 16.6 software, which employed 0.35 μm CMOS technology as a basis.
PL
W artykule opisano mikrosystem używany w stymulatorach biomedycznych przeznaczony dpo transferu danych i zasilania. System wykorzystuje kodowanie ASK z częstiotliwością 6.78 MHz. System składa się z modulatora ASK, wzmacniacza mocy klasy E, prostownika, regulatora napięcia LDO I dempodulatora ASK.
8
Content available Quadrature Mapping, Saleh’s Representation, and Memory Models
Borys A.
International Journal of Electronics and Telecommunications
|
2016
|
Vol. 62, No. 4
389--394
EN
In the literature, Saleh’s description of the AM/AM and AM/PM conversions occurring in communication power amplifiers (PAs) is classified as a representation without memory. We show here that this view must be revised. The need for such revision follows from the fact that the Saleh’s representation is based on the quadrature mapping which, as we show here, can be expanded in a Volterra series different from an usual Taylor series. That is the resulting Volterra series possesses the nonlinear impulse responses in form of sums of ordinary functions and multidimensional Dirac impulses multiplied by coefficients being real numbers. This property can be also expressed, equivalently, by saying that the nonlinear transfer functions associated with the aforementioned Volterra series are complex-valued functions. In conclusion, the above means that the Saleh’s representation incorporates memory effects.
9
Content available On Modelling AM/AM and AM/PM Conversions via Volterra Series
Borys A., Sieńko W.
International Journal of Electronics and Telecommunications
|
2016
|
Vol. 62, No. 3
267--272
EN
In this paper, we present the expressions, not published up to now, that describe the AM/AM and AM/PM conversions of communication power amplifiers (PAs) via the Volterra series based nonlinear transfer functions. Furthermore, we present a necessary and sufficient condition of occurrence of the nonzero values of AM/PM conversion in PAs. Moreover, it has been shown that Saleh’s approach and related ones, which foresee nonzero level of AM/PM conversion, are not models without memory. It has been also shown that using a polynomial description of a PA does not lead to a nonzero AM/PM conversion. Moreover, a necessary condition of occurrence of an AM/AM conversion in this kind of modelling is existence of at least one nonzero polynomial coefficient associated with its odd terms of degree greater than one.
10
Content available remote Wzmacniacz mocy z tranzystorem GaN PolHEMT na pasmo L
Kuchta D., Wojtasiak W.
Przegląd Elektrotechniczny
|
2015
|
R. 91, nr 9
109-112
PL
Jednym z zadań projektu PolHEMT jest aplikacja wytwarzanych struktur GaN HEMT w realnych układach mikrofalowych stosowanych w radiolokacyjnych modułach N/O. W referacie przedstawiono projekt i wyniki badań wzmacniacza z tranzystorem GaN PolHEMT na pasmo 1,3÷1,7 GHz o mocy wyjściowej 1 W.
EN
One of the Pol-HEMT project aims is to implement the GaN HEMT structures in microwave circuits commonly used in T/R modules for radiolocation systems. In this paper project and experimental results of 1W L-band power amplifier with GaN PolHEMT structure are presented.
11
Content available remote Udoskonalona metoda obliczania mocy traconej w tranzystorach wzmacniacza klasy AB
Modzelewski J.
Przegląd Elektrotechniczny
|
2015
|
R. 91, nr 9
138-142
PL
Przedstawiono udoskonaloną metodę obliczania mocy traconej w elementach aktywnych przeciwsobnego wzmacniacza liniowego klasy AB w funkcji jego wysterowania. Dla charakterystyki przejściowej elementu aktywnego zastosowano aproksymację kwadratową w obszarze zakrzywienia oraz aproksymację liniową w obszarze dużych prądów. Metoda obejmuje także zasady doboru prądu spoczynkowego elementów aktywnych przeciwsobnego wzmacniacza klasy AB zapewniające maksymalną liniowość. Otrzymane wyniki zweryfikowano podczas symulacji komputerowych i pomiarów wzmacniacza z tranzystorami IRF510 (20 W, 1 – 3 MHz) i wzmacniacza z podwójnym tranzystorem w. cz. SD703 (100 W, 3 – 30 MHz).
EN
An improved method of calculating the power dissipated in transistors in the Class-AB push-pull linear amplifier versus the amplifier drive level is presented. A mixed piece-wise square-linear approximation of the transistor transfer characteristic is applied (the square approximation in the “knee” region, and linear in the high-current region). The method describes also how to find the quiescent current of power transistors in the Class- AB push-pull amplifier to maximize its linearity. This method has been verified by PSPICE simulations and measurements of the amplifier with IRF510 transistors (20W, 1 - 3MHz) and the amplifier with the h.f. push-pull SD703 transistor (100W, 3 - 30MHz).
12
Content available remote Power Amplifier Frequency Controller Using feedback control techniques for Bio-implanted Devices
Hussein H. A., Hannan M. A., Mutashar S., Samad S. A., Mikdad A.
Przegląd Elektrotechniczny
|
2015
|
R. 91, nr 12
34-37
EN
Switch mode power amplifier is used in biomedical devices widely. The power amplifier supplies the required operating power to the implanted devices. Zero voltage switching (ZVS) operation of class-E power amplifier leads to convert DC voltage to AC with high efficiency and workings frequency. Frequency has a great function in powering most of the biomedical implanted devices. Frequency shift caused by inductors and capacitors used in the circuit can cause load variation or changing in mutual displacement or they may lead to instability and data loss of the implanted devices. So switching-mode frequency control is the key problem in the biomedical device powering system. This paper focused on the design of a frequency controlled power amplifier to improve the controller’s efficiency in terms of speed and better results. The objective of this work is to control the operating frequency. Feedback control method is used by using proportional integral derivative controller (PID), proportional integral (PI) and voltage controlled oscillator (VCO) to reduce the phase shift and settling time. The Bode plot and Nyquist stability criterion analyses show that the developed power amplifier frequency controller is stable and perform well to improve the controller efficiency.
PL
W artykule opisano wzmacniacz mocy używany w technice bio-implantów. Wzmacniacz klasy E z operacją ZVS przekształca stałe napięcie na napięcia AC. Kontrola częstotliwości tego napięcia ma ważne znaczenie ponieważ częstotliwość może się zmieniać przy obecności elementów L, C w układzie. W pracy opisano metode kontroli częstotliwości tego napięcia.
13
Content available remote Konstrukcje generatorów mocy opracowanych do zastosowań laboratoryjnych
Maśnicki R., Jurek K.
Przegląd Elektrotechniczny
|
2015
|
R. 91, nr 8
30--33
PL
Generatory mocy małej częstotliwości są wykorzystywane przez studentów w trakcie zajęć laboratoryjnych. W artykule przedstawiono konfiguracje układowe generatorów mocy, opracowanych na potrzeby laboratorium miernictwa i podstaw elektrotechniki. Omówiono budowę i wybrane wyniki badań dwóch opracowanych przyrządów.
EN
The low-frequency power generators are used by students during laboratory classes. The article presents the configurations of power generators developed for the laboratories of metrology and fundamentals of electrical engineering. The structures of generators and some selected results of tests of the two elaborated instruments were shown.
14
Content available Derivation of Closed-Form Design Equations for Idealized Operation of Inverse Class-E Power Amplifiers at Any Duty Ratio
Wang Y., Foo S. K., He Q.
International Journal of Electronics and Telecommunications
|
2015
|
Vol. 61, No. 3
281–287
EN
Complementary to the conventional class-E topology, inverse class-E operation has several advantages over the class-E counterpart, such as lower peak switch voltage and smaller circuit inductance, which are attractive to high power RF design and MMIC implementation. This paper derives the closed-form design equations that can be used to synthesize the idealized operation of inverse class-E power amplifiers at any switch duty ratio. Calculation of the key design parameters, such as the maximum switch voltage and circuit components values, is elaborated and compared with the case of conventional class-E operation. Further, the theoretical analysis is confirmed and verified by numerical simulations performed on a 500mW, 2.4 GHz idealized inverse class-E power amplifier.
15
Demonstrator wzmacniacza mocy w technologii wysokonapięciowej
Lewandowski A., Matyszkiel R., Kaniewski P.
Elektronika : konstrukcje, technologie, zastosowania
|
2015
|
Vol. 56, nr 2
69-71
PL
W chwili obecnej rozwój technologii wytwarzania materiałów półprzewodnikowych i ferrytowych powoduje powstanie nowych możliwości. Zastosowanie nowoczesnych rozwiązań technologicznych przyczynia się do rozwiązania szeregu problemów występujących w konstrukcji dotychczas eksploatowanych urządzeń radiokomunikacyjnych wytwarzających dużą moc, takich jak efektywne odprowadzanie ciepła, większa sprawność, mniejsze gabaryty i masa. W chwili obecnej trendem światowym jest zwiększanie sprawności urządzeń, a tym samym zwiększenie ich użyteczności. W artykule przedstawiona zostanie koncepcja zastosowania ultra szerokopasmowych tranzystorów nowej technologii o większych sprawnościach od dotychczas powszechnie stosowanych. Parametry te zostały potwierdzone eksperymentalnie podczas badań demonstratora wzmacniacza mocy opracowanego na potrzeby systemu rozpoznawczo – zakłócającego. W opracowanym demonstratorze wzmacniacza zastosowane zostały tranzystory posiadające sprawność 35-45%, a uzyskana sprawność całkowita wzmacniacza osiągnęła od 25% do prawie 39%. Uniwersalność opracowanego demonstratora wzmacniacza powoduje, że może on być z powodzeniem zastosowany nie tylko w systemach walki elektronicznych ale również we wszystkich systemach gdzie potrzebne jest wytworzenie dużej mocy w tym również w systemach łączności (KF, UKF, VHF, łączność troposferyczna).
EN
At present, the development of semiconductor manufacturing technology and ferrite materials causes new possibilities. The use of modern technology helps to solve a number of problems which occur in the currently operating radio equipment generating high power, such as effective heat dissipation, higher efficiency, smaller size and weight. This article shows the concept of the use of new technology ultra-broadband transistors with higher efficiencies than the currently widely used. These parameters were confirmed experimentally during the tests of a demonstrator of the power amplifier, which was developed for EW system In the developed demonstrator of amplifier were used transistors with 35-45% efficiency. The resulting total efficiency of the amplifier has reached from 25% to almost 39%. The versatility of this amplifier means that it can be successfully applied in electronic warfare systems and also in all systems where it is necessary to produce high power including the communication systems (HF, VHF, UHF, tropospheric communications).
16
Content available remote The power amplifier dedicated for set-up to the measure parameters of magnetic devices
Górski K., Górecki K., Szafek A
Zeszyty Naukowe Akademii Morskiej w Gdyni
|
2014
|
nr 84
37--47
EN
The paper presents the worked out and constructed by the authors power amplifier designed to be used in systems for measuring of parameters of magnetic devices. This amplifier makes possible amplification of the input signal in a wide range of frequency and amplitude of the output voltage. The construction of the system and the results of measurements of characteristics of the constructed amplifier as well as of the system for measuring the characteristics of the pulse transformers are described.
17
Content available A - 5 dBm 400MHz OOK Transmitter for Wireless Medical Application
Yousefi M., Koozehkanani Z. D., Jangi H., Nasirzadeh N., Sobhi J.
International Journal of Electronics and Telecommunications
|
2014
|
Vol. 60, No. 2
193-198
EN
A 400 MHz high efficiency transmitter for wireless medical application is presented in this paper. Transmitter architecture with high-energy efficiencies is proposed to achieve high data rate with low power consumption. In the on-off keying transmitters, the oscillator and power amplifier are turned off when the transmitter sends 0 data. The proposed class-e power amplifier has high efficiency for low level output power. The proposed on-off keying transmitter consumes 1.52 mw at-5 dBm output by 40 Mbps data rate and energy consumption 38 pJ/bit. The proposed transmitter has been designed in 0.18μm CMOS technology.
18
Symulacyjna metoda wyznaczania wpływu temperatury i rozrzutu technologicznego na eksploatację układu elektronicznego
Berczyński R.
Wiadomości Elektrotechniczne
|
2013
|
R. 81, nr 10
16--20
PL
Przedstawiono symulacyjną metodę wyznaczania wpływu temperatury i rozrzutu technologicznego na eksploatację wybranego układu elektronicznego.
EN
The paper presents simulation method of determination an influence of temperature and technology dispersion on operation of selected electronic circuit.
19
Content available Wspomaganie informatyczne w procesie nauczania elektroniki analogowej na przykładzie wzmacniacza mocy
Szulc W., Rosiński A.
TTS Technika Transportu Szynowego
|
2013
|
R. 20, nr 10
463--470, CD
PL
W artykule przedstawiono zagadnienia związane z procesem nauczania podstaw elektroniki analogowej i cyfrowej na przykładzie układu elektronicznego jakim jest scalony wzmacniacz mocy. Ukazano zalety i wady wspomagania informatycznego przy analizie tego układu w rzeczywistości wirtualnej oraz w pomiarach rzeczywistych.
EN
In the paper problems related to learning process of analog and digital electronic principles are presented on the example electronic device being integrated power amplifier. Advantages and disadvantages of TINA - computer aided tool are presented at the device analysis by virtual mean referred to real classical measurements.
20
Wzmacniacz mocy dla pasma VHF
Arvaniti A., Popkowski J.
Elektronika : konstrukcje, technologie, zastosowania
|
2013
|
Vol. 54, nr 11
53-55
PL
W artykule przedstawiono projekt tranzystorowego wzmacniacza dużej mocy opartego na strukturze push - pull, działającego w paśmie VHF. Przedstawiono praktyczną realizację wzmacniacza z wykorzystaniem elementu firmy Freescale Semiconductors oraz wyniki pomiarów układu modelowego. W celu zapewnienia czystości widmowej sygnału wyjściowego zastosowano filtry o dużej odporności na moc wejściową. Przedstawiony wzmacniacz ma zastosowanie w radiolokacji jako element anteny aktywnej.
EN
VHF band, push - pull power amplifier is presented. Practical realization, using Freescale Semiconductors LDMOS power transistor and preliminary parameters are presented. To provide needed spectral purity, high power filters are used. Presented amplifier can be used in radiolocation, as a part of active antenna.
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