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RF power amplifier
About: RF power amplifier is a research topic. Over the lifetime, 21191 publications have been published within this topic receiving 294253 citations.
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TL;DR: This paper relates the general Volterra representation to the classical Wiener, Hammerstein, Wiener-Hammerstein, and parallel Wiener structures, and describes some state-of-the-art predistortion models based on memory polynomials, and proposes a new generalizedMemory polynomial that achieves the best performance to date.
Abstract: Conventional radio-frequency (RF) power amplifiers operating with wideband signals, such as wideband code-division multiple access (WCDMA) in the Universal Mobile Telecommunications System (UMTS) must be backed off considerably from their peak power level in order to control out-of-band spurious emissions, also known as "spectral regrowth." Adapting these amplifiers to wideband operation therefore entails larger size and higher cost than would otherwise be required for the same power output. An alternative solution, which is gaining widespread popularity, is to employ digital baseband predistortion ahead of the amplifier to compensate for the nonlinearity effects, hence allowing it to run closer to its maximum output power while maintaining low spectral regrowth. Recent improvements to the technique have included memory effects in the predistortion model, which are essential as the bandwidth increases. In this paper, we relate the general Volterra representation to the classical Wiener, Hammerstein, Wiener-Hammerstein, and parallel Wiener structures, and go on to describe some state-of-the-art predistortion models based on memory polynomials. We then propose a new generalized memory polynomial that achieves the best performance to date, as demonstrated herein with experimental results obtained from a testbed using an actual 30-W, 2-GHz power amplifier
1,305 citations
Patent•
04 May 1992
TL;DR: In this paper, an electrical circuit system, which provides electrical energy to a surgical apparatus having ultrasonic fragmentation, aspiration, and electrosurgical coagulation capabilities, is presented, which includes an impedance sensing network and automatic feedback power output control to reduce RF power output as load impedance increases.
Abstract: An electrical circuit system (1) which provides electrical energy to a surgical apparatus having ultrasonic fragmentation, aspiration and electrosurgical coagulation capabilities, which system also includes an impedance sensing network (10) and automatic feedback power output control to reduce RF power output as load impedance increases, thereby reducing RF leakage current.
1,146 citations
TL;DR: In this paper, the Fourier series analysis of the collector voltage waveform is used to determine component values for optimum operation at an efficiency of 100 percent, and other combinations of component values and duty cycles are also determined.
Abstract: The class E tuned power amplifier consists of a load network and a single transistor that is operated as a switch at the carrier frequency of the output signal. The most simple type of load network consists of a capacitor shunting the transistor and a series-tuned output circuit, which may have a residual reactance. Circuit operation is determined by the transistor when it is on, and by the transient response of the load network when the transistor is off. The basic equations governing amplifier operation are derived using Fourier series techniques and a high- Q assumption. These equations are then used to determine component values for optimum operation at an efficiency of 100 percent. Other combinations of component values and duty cycles which result in 100-percent efficiency are also determined. The harmonic structure of the collector voltage waveform is analyzed and related amplifier configurations are discussed. While this analysis is directed toward the design of high-efficiency power amplifiers, it also provides insight into the operation of modern solid-state VHF-UHF tuned power amplifiers.
962 citations
01 Sep 1936
TL;DR: In this paper, a new form of linear power amplifier for modulated radio-frequency waves was introduced, which achieved a plate circuit efficiencies of sixty to sixty-five per cent independent of modulation.
Abstract: This paper introduces a new form of linear power amplifier for modulated radio-frequency waves. Plate circuit efficiencies of sixty to sixty-five per cent independent of modulation are obtained by means of the combined action of varying load distribution among the tubes and varying circuit impedance over the modulation cycle. The theory of operation is developed and detailed observations on the behavior of tubes in the new circuit are given in the paper. The use of stabilized feedback in connection with this circuit is discussed and significant measurements on a laboratory model of a fifty-kilowatt transmitter are shown.
931 citations
10 Dec 2002
TL;DR: In this paper, the performance and other attributes of cellphone RF power amplifiers using Si and GaAs based technologies are reviewed and compared, and a wide variety of semiconductor devices are used in wireless power amplifier.
Abstract: A wide variety of semiconductor devices are used in wireless power amplifiers. The RF performance and other attributes of cellphone RF power amplifiers using Si and GaAs based technologies are reviewed and compared.
890 citations