共查询到19条相似文献,搜索用时 250 毫秒
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Ku波段模拟预失真线性化器 总被引:1,自引:0,他引:1
提出了一种基于模拟预失真方法的线性化器设计。利用预失真技术设计行波管配用线性化器的数学模型,得出了预失真电路的功率转移特性曲线和相位特性曲线。预失真电路采用上下支路对消结构,通过二极管产生失真信号,并利用2个可调衰减器和可调移相器来调节其幅度和相位,以此补偿功率放大器的AM-AM,AM-PM失真特性,改善输出信号的线性度。此外通过改变二极管的偏压,线性化器能够提供不同种幅度和相位特性的组合方式,用于不同特性的功放。基于该模拟预失真方法设计了行波管线性化器,在给定的动态范围内幅度扩张5 dB,相位扩张40°。 相似文献
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一种用于微波功放的新型预失真结构 总被引:1,自引:1,他引:0
预失真技术是一种能有效的改善宽带信号线性度的方法。在普通的反向并联二极管预失真技术基础上做出了一定改进,提出了一种新的预失真线性化器电路结构。这种预失器结构简单,可以直接与功放级联,不需要延时线,相移器和衰减器等额外器件。通过调节二极管的偏置电压,电阻值和可调增益放大器,同时控制载波信号和IMD的相位和幅度变化。采用这种预失真器能够有效地补偿微波功放的非线性失真,ADS双音测试表明,IMD3和IMD5分别改善了41 dB和2.4 dB。 相似文献
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文章提出了一种Ka波段的射频预失真线性化器.它由一个GaAs肖特基二极管和一个电容并联构成,通过一个偏置电阻加入直流馈电,具有增益扩展和相位延迟的特性,并且其增益和相位特性具有可调性,尤其其相位特性可调性更强.将其应用于工作频率为30GHz饱和输出功率为10W的功放,输出三阶交调失真(IMD3)可以改善15dBc以上,此时功放输入的双音激励信号频率间隔为5MHz.该线性化器可调性强、结构简单、成本低廉、易于实现,有着非常大的工程应用价值. 相似文献
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模拟预失真器具有带宽宽、结构简单、功耗低和延时少等优点,满足第五代移动通信系统(5G)及超
5G 的功放线性化对大带宽、低功耗和低延时的要求。然而随着移动通信系统的发展,信号的带宽和调制度越来越
高,功率放大器的记忆效应影响也越来越强,而传统的模拟预失真器无法补偿功放的记忆效应。为了解决模拟预失
真电路的记忆效应补偿问题,文中提出了一种基于延迟线补偿记忆效应的肖特基二极管模拟预失真器(SDD-APD)。
该模拟预失真器采用不等长微带线作为延迟线,用来补偿功放的记忆效应。采用100 MHz 带宽5G 新无线电(NR)
信号对工作在3. 5 GHz 的AB 类功放进行测试,结果表明该模拟预失真器可以补偿功放的记忆效应,并能将功放的
非线性改善10 dB 以上。 相似文献
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为解决传统反射式预失真电路可调性不高、对功率放大器的邻信道泄漏比(ACLR)改善量小的问题,文
中提出了一种基于肖特基二极管的反射式可调模拟预失真电路。该电路由90°电桥、肖特基二极管以及偏置电路组
成。每条支路采用两个并联肖特基二极管产生非线性信号,以抵消功放的非线性失真。每一个肖特基二极管都有独立
的偏置电路,从而可以增加电路调节的自由度。通过改变每个肖特基二极管的偏压,可实现更大动态范围的幅度和相
位的补偿。基于此原理加工的S 波段模拟预失真电路对中心频率为3. 5 GHz 的Doherty 功率放大器进行线性化测试,
实验结果证明:加上提出的模拟预失真电路后,在输出功率为-28 dBm 时被测功放的ACLR 改善了14. 6 dBc 以上。 相似文献
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为了改善功率放大器的三阶交调失真,提出了一种基于90°分支线电桥的C波段预失真线性化器,使用肖特基二极管产生非线性信号。通过改变线性化器的偏置电压及电容,可调整线性化器的增益扩张和相位延迟特性,与功放级联后对功放的三阶交调失真有改善作用。将该线性化器应用到工作频率为7 GHz,饱和功率为20 dBm的放大器上,在输出功率回退5 dBm处对放大器的三阶交调有10 dBc的改善。 相似文献
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Hyun-Min Park Dong-Hyun Baek Kye-Ik Jeon Songcheol Hong 《Microwave Theory and Techniques》2000,48(6):898-904
A predistortion linearization method using an envelope-feedback technique is proposed and implemented in this paper. This linearizer compensates the gain and phase nonlinearity of power amplifier (PA) simultaneously by controlling both variable attenuator and phase shifter with the feedback of only the difference signal between input and output envelopes. A new carrier cancellation scheme composed of a minimization circuit, log detector, and vector modulator is also presented. This circuit achieves adaptive control of the linearizer by enabling direct measurement of out-of-band power. It is well suited to a multichannel system where the allocated channels are time variant. The principle of the proposed linearizer is described and simple AM-AM distortion analysis is presented analytically and graphically based on the conceptual schematic diagram. A two-tone test for a class-A PA at 1.855 GHz with frequency spacing of 1 MHz showed intermodulation-distortion reduction of maximum 16 dB and stable operation over 5-dB output power variation up to 4-dB backoff from the saturation power level. The proposed linearizer is also applicable to class-AB PA's without further special adjustments. The adaptation circuit is fully implemented with analog integrated circuits, which can further extend its applicability with the integration technology 相似文献
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A miniaturized RF predistortion linearizer for a GaAs field-effect transistor power amplifier applicable to 256 quadrature-amplitude modulation (QAM) digital microwave systems is presented. This linearizer, which is based upon the cuber linearizer technique, utilizes circulators and a pair of diodes in the distortion generator to obtain high signal component isolation, and in the variable phase shifter to compensate for temperature variations. This allows miniaturization and easy adjustment of the circuit. Results show that a distortion reduction of more than 10 dB is obtained over a 300 MHz bandwidth. It was verified that distortion reduction can be achieved over a temperature range from 0 to 50°C. The fundamental characteristics of the linearizer and its effect on the 256-QAM signal are shown. The results show an improvement of more than 6 dB in the output back-off of the amplifier 相似文献
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This paper presents a novel technique for power amplifier linearization in digital microwave radio systems. The proposed technique is based on the use of a predistortion circuit, whose AM/AM and AM/PM responses are separately implemented as polynomial approximations of the respective responses of the ideal linearizer. The proposed scheme is shown to attain superior performance in comparison with other well-known predistortion structures, such as those based on the cancellation of third or fifth order distortion, with no substantial aggravation in implementation complexity 相似文献
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Sundstrom L. Faulkner M. Johansson M. 《Vehicular Technology, IEEE Transactions on》1996,45(4):707-719
Significant improvements in terms of reduced power consumption and increased bandwidth are obtained if a digital predistortion linearizer is implemented with an application specific digital signal processor. This paper investigates the quantization effects in different parts of a table based complex gain predistortion linearizer. The analysis can be used to optimize the predistortion linearizer with respect to word length based on the knowledge of the RF amplifier gain characteristic, the probability density function for the modulation scheme and the maximum allowable adjacent channel interference level. A predistorter chip is described that has been designed using the analysis. The chip has been fabricated and tested. Compared with a standard digital signal processing (DSP) solution it provides seven times higher bandwidth but consumes only 10% of the power 相似文献
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《Circuits and Systems II: Express Briefs, IEEE Transactions on》2006,53(8):612-616
Digital predistortion at baseband is an efficient and low-cost method for the linearization of a power amplifier (PA) in a wireless system employing a nonconstant-envelop modulation scheme, so as to reduce the adjacent channel interference. The polynomial and the look-up table (LUT) predistortion schemes are two commonly used approaches. However, in each of the two approaches, to reach a satisfactory adjacent channel power ratio (ACPR) in the PA output signal, people usually end up with a complex system having the involved algorithms converge rather slowly. In this brief, we propose a low-complexity joint-polynomial-and-LUT predistortion PA linearizer, where the two mutually dependent predistortion schemes can skillfully help each other. Simulation results show that the proposed joint linearizer can reduce the algorithm convergence time while achieving an excellent ACPR. 相似文献