共查询到20条相似文献,搜索用时 15 毫秒
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E. B. Solovyeva 《Radioelectronics and Communications Systems》2011,54(10):546-553
Polynomial models of predistorter combined by the “black box” principle have been considered. A Volterra model using one-dimensional
dynamic deviation was proposed. An adaptive predistorter was synthesized for linearizing the Wiener-Hammerstein model of power
amplifiers. Estimates of the linearization accuracy and a comparative analysis of predistorter models were also presented. 相似文献
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Thermal memory effects modeling and compensation in RF power amplifiers and predistortion linearizers 总被引:3,自引:0,他引:3
Memory effects, which influence the performance of RF power amplifiers (PAs) and predistortion-based linearizers, become more significant and critical in designing these circuits as the modulation signal bandwidth and operation power increase. This paper reports on an attempt to investigate, model, and quantify the contributions of the electrical nonlinearity effects and the thermal memory effects to a PA's distortion generation, as well as how to compensate for these effects in designing baseband predistortion schemes. The first part of this paper reports on the development of an accurate dynamic expression of the instantaneous junction temperature as a function of the instantaneous dissipated power. This expression has been used in the construction of an electrothermal model for the PA. Parameters for the new proposed behavior model were determined from the PA measurements obtained under different excitation conditions (e.g., small-signal and pulsed RF tests). This study led us to conclude that the effects of the transistor self-heating phenomenon are more important under narrow-band signal (e.g., enhanced data for global evolution of global system for mobile communications) than for signals with wide modulation bandwidth (CDMA2000, Universal Mobile Telecommunications System). In the second part of this paper, the newly developed model has also been used to design a temperature-compensated predistortion function to compensate for these effects. The linearized PA output spectrum and error vector magnitude show a significant performance improvement in the temperature-compensated predistortion function over a memoryless predistortion. The results of these measurements that have been conducted on a 90-W peak lateral double-diffused metal-oxide-semiconductor PA are in agreement with those obtained from simulations using the developed PA and the predistorter models implemented in an ADS environment. 相似文献
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The large signal RF power transmission characteristics of an advanced InGaP HBT in an RF power amplifier are investigated and analyzed experimentally. The realistic RF powers reflected by the transistor, transmitted from the transistor and reflected by the load are investigated at small signal and large signal levels. The RF power multiple frequency components at the input and output ports are investigated at small signal and large signal levels, including their effects on RF power gain compression and nonlinearity. The results show that the RF power reflections are different between the output and input ports. At the input port the reflected power is not always proportional to input power level; at large power levels the reflected power becomes more serious than that at small signal levels, and there is a knee point at large power levels. The results also show the effects of the power multiple frequency components on RF amplification. 相似文献
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Quantifying memory effects in RF power amplifiers 总被引:5,自引:0,他引:5
This paper proposes a system-level behavioral model for RF power amplifiers (PAs), which exhibit memory effects, that is based on the parallel Wiener system. The model extraction is performed using two-tone intermodulation distortion (IMD) measurements with different tone frequency spacings and power levels. It is found that by using such a model, more accurate adjacent-channel power-ratio levels may be predicted for high PAS close to the carrier frequency. This is validated using IS-95B CDMA signals on a low-power (0.5 W) class-AB PA, and on a high-power (45 W) class-B PA. The model also provides a means to quantify memory effects in terms of a figure-of-merit that calculates the relative contribution to the IMD of the memoryless and memory portion of the PA nonlinearity. This figure-of-merit is useful in providing an estimate of the amount of correction that a memoryless predistortion system may have on PAS that exhibit memory effects. 相似文献
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In this paper, the synchronous concurrent dual-band RF signal is used to drive the RF Power Amplifier (PA). The nonlinear characterization of a concurrent dual-band RF PA is discussed while two band signals in the dual-band are modulated by CDMA2000 and WCDMA signals. When the two band signals in the dual-band of the PA are modulated with the same signals, it is found that the nonlinearity of the PA can be expressed by any of the two corresponding baseband data. On the other hand, when the two band signals in the dual-band of the PA are modulated with two different signals, the PA nonlinearity cannot be characterized by any of the two corresponding baseband data. In this case, its nonlinearity has to be denoted by a composite signals consisting of the two baseband signals. Consequently, the requirements for the speed of the A/D converter can be largely reduced. The experimental results with CDMA2000 and WCDMA signals demonstrate the speed of the A/D converter required is only 30 M Sample Per Second (SaPS), but it will be at least 70 M SaPS for the conventional method. 相似文献
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A CMOS radio-frequency power amplifier including on-chip matching networks has been designed in a 0.6-μm n-well triple-metal digital CMOS process, and optimized using a simulated-annealing-based custom computer-aided design tool. A compact inductor model enables the incorporation of parasitics as an integral part of the parasitic-aware design and CAD optimization; low-Q metal3 spiral inductors are used in the input and output matching networks. A 3-V 85-mW balanced fully integrated Class-C power amplifier with a measured drain efficiency of 55% at 900 MHz has been designed, optimized, integrated, and tested 相似文献
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Patrick Reynaert Michiel Steyaert 《Analog Integrated Circuits and Signal Processing》2009,59(1):13-20
Polar modulation of a switching RF amplifier is an excellent candidate to combine both linearity, efficiency and CMOS integration
for RF power amplifiers used in mobile and wireless communication systems. In this paper, the different sources of distortion
associated with polar modulation are discussed and verified by measurement results. A fully integrated linearized CMOS RF
Power Amplifier for GSM–EDGE, realized in a 0.18 μm CMOS technology, is used as a benchmark to validate the presented theory.
It is demonstrated how the combination of a differential delay between the amplitude signal and the phase signal, together
with the AM–PM distortion of the Class E amplifier, generates an asymmetry in the output spectrum. The effect of low-pass
filtering of the envelope signal is investigated and the degradation on the linearity with and without delay adjustment is
given. 相似文献
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A digital VLSI chip is presented that implements the most critical part of a predistortion system for linearisation of RF power amplifiers. Measurements have shown that the chip provides seven times higher modulation bandwidth (208 kHz) at 10% power (100 mW) compared with a standard digital signal processor 相似文献
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本文研究了一种用于改善射频功率放大器非线性失真的预失真技术.首先,对预失真技术的原理进行了简单的论述,随后,给出了谐波发生器的电路结构,并对其特性进行了分析,在此基础上添加了自适应控制电路,并对其进行了深入的算法推导,通过与自适应技术的结合,整个系统的稳定性得到提高.将此预失真线性化电路用于射频放大器中,IMD3的性能... 相似文献
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Naskas N. Papananos Y. 《Circuits and Systems II: Express Briefs, IEEE Transactions on》2004,51(11):619-623
An adaptive baseband predistortion method for RF power amplifier (PA) linearization is proposed and experimentally demonstrated. The predistortion component is implemented by a single-input dual-output multilayer perceptron (MLP). Both amplitude-to-amplitude and amplitude-to-phase distortion products are compensated by backpropagation training of the neural network including the response of the PA. Effects of modulator and demodulator imperfections on system performance are examined. Measurements on a system prototype reveal a significant linearity improvement that reaches 25 dB. 相似文献
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The transmit RF power amplifiers remain one of the most challenging building blocks for wireless transmitters. This article is intended to provide the reader with an understanding of the basic operation of Class A, B, AB, and C RF power amplifiers. With the numerous advantages associated with highly integrated transceiver implementations in mind, some examples of designs of integrated power amplifiers, as opposed to discrete or hybrid implementations, are enumerated. These examples also give the reader an understanding of the current trend in the design and implementation of fully integrated RF power amplifiers in CMOS and other silicon-based technologies 相似文献
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Z. Radivojevic K. Andersson J. A. Bielen P. J. van der Wel J. Rantala 《Microelectronics Reliability》2004,44(6):963-972
LDMOS RF––power amplifier components usually operate under severe conditions challenging long-term reliability. These components are subjected to high power dissipation and consequently high junction temperatures. Failure mechanisms are highly temperature dependent and driven by coupled electro-thermo-mechanical fields as a function of stress time. In this work we have investigated the reliability of such a component. Power cycling was used to assess its reliability by introduction of temperature gradients and transient at elevated junction temperatures. The experimental lifetime acceleration conditions provided transient thermal constraints to the thermo-mechanical strength of the silicon die. Power dissipation has been adjusted to cover a broad temperature range (Tj max: 200–300 °C) in the peak of a single power cycle. Different failure modes have been observed and related to the different temperature ranges. The experimental results have been combined with thermo-mechanical FE-simulations in ANSYS, leading to the validation of simulation models and implementation in a larger simulation network. The power cycling approach as applied in this paper provided a useful addition to the steady state reliability information. In this way, clear information about margins for safe operation under dynamical conditions has been obtained. This information is needed to fully exploit the functional capability of the component and avoid over-specification in the final application. Overall, the LDMOS RF–PA component showed excellent reliability which makes it suitable for application in telecom devices. 相似文献
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Sundstrom L. Faulkner M. Johansson M. 《Vehicular Technology, IEEE Transactions on》1995,44(1):131-139
The reconstruction filters are a major source of error in digital predistortion linearizers for RF power amplifiers. This paper presents a method that enables these filters to be designed for lowest filter complexity and minimum degradation of the linearizer performance. Furthermore, a method to choose an appropriate sampling rate for the predistorter is presented. Different filter approximations and orders are examined for different amplifier configurations by means of simulation. Of the filters tried, low-ripple Chebyshev and Butterworth filters perform best. It is demonstrated that it is possible to account for reasonable filter misalignment with only a small degradation in performance. It is also shown that the effect on the modulation is small with respect to intersymbol interference 相似文献