共查询到19条相似文献,搜索用时 500 毫秒
1.
2.
空间通信系统高保真转发对大功率行波管放大器的线性化度提出了更高的要求。针对高频段和大功率应用,基于预失真和前馈线性化技术,设计了一种K频段50 W自适应前馈线性化行波管放大器,介绍了其基本原理和参数,研究了前馈双检波电路结构及并行变步长的组合自适应控制算法。在K频段400 MHz带宽内,实现了输入功率20 dB大动态调整情况下失真信号自适应对消抑制,在相对于单载波饱和输出功率回退3 dB点,三阶交调小于-35 dBc,验证了前馈线性化技术在线性度改善方面的巨大优势。 相似文献
3.
4.
前馈线性化功率放大器设计 总被引:2,自引:0,他引:2
采用自适应结合查表控制的前馈技术,设计了用于CDMA2000的超线性功率放大器.在连续波输出功率达到45dBm时,双音IMD3低于-62dBc,用CDMA2000信号测试,其ACPR分别低于-54dB@750kHz和-71dB@1.98MHz. 相似文献
5.
6.
7.
针对第三代移动通信中的功率放大器线性化技术,提出了改善线性化带宽的解决方案。该方案通过减少前馈环路中的时延波动来提高互调失真分量的宽带对消特性,同时采用相关复解调来检测残留导频。研制了射频功率放大器,前馈对消环路和信号检测电路,用数字信号处理芯片实现了相关的自适应算法。仿真和实验结果表明,该技术能够在宽频带内对LDMOS高功率放大器的三阶互调(IMD3)改善25dB,对四载波的W-CDMA信号的邻近信道功率泄漏比(ACLR)改善17dB。 相似文献
8.
提出了一种改善射频功率放大器非线性的新的预失真法。该方法没有前馈法复杂,也克服了反馈法增益下降的缺点。首先分析功率放大器的传输特性进行,并从幂级数的展开式中得到方便分析的结论;然后通过对方案中参数的分析,找到能够改善功率放大器非线性的办法;最后给出了计算机模拟实验结果。实验结果表明,用该方法改善功率放大器的非线性比较有效,可以使IMD3的功率电平至少下降34dBm。 相似文献
9.
通信技术的发展对于功率放大器的要求越来越高,主要集中在高线性、高效率的功放.预失真是目前改善功放线性比较好的方法.新的自适应混合预失真系统充分利用模拟预失真,快速简单的和数字预失真算法的精确,输入信号先后经过模拟、数字两级预失真系统,并结合信号包络检测技术进行带外信号调节.通过对仿真结果的比较,IMD性能比单独使用数字预失真系统有了8 dB的改善,同时收敛时间也有所减少. 相似文献
10.
11.
A highly linear and efficient differential CMOS power amplifier with harmonic control 总被引:3,自引:0,他引:3
Jongchan Kang Jehyung Yoon Kyoungjoon Min Daekyu Yu Joongjin Nam Youngoo Yang Bumman Kim 《Solid-State Circuits, IEEE Journal of》2006,41(6):1314-1322
A 2.45 GHz fully differential CMOS power amplifier (PA) with high efficiency and linearity is presented. For this work, a 0.18-/spl mu/m standard CMOS process with Cu-metal is employed and all components of the two-stage circuit except an output transformer and a few bond wires are integrated into one chip. To improve the linearity, an optimum gate bias is applied for the cancellation of the nonlinear harmonic generated by g/sub m3/ and a new harmonic termination technique at the common source node is adopted along with normal harmonic termination at the drain. The harmonic termination at the source effectively suppresses the second harmonic generated from the input and output. The amplifier delivers a 20.5dBm of P/sub 1dB/ with 17.5 dB of power gain and 37% of power-added efficiency (PAE). Linearity measurements from a two-tone test show that the power amplifier with the second harmonic termination improves the IMD3 and IMD5 over the amplifier without the harmonic termination by maximally 6 dB and 7 dB, respectively. Furthermore, the linearity improvements appear over a wide range of the power levels and the linearity is maintained under -45 dBc of IMD3 and -57dBc of IMD5 when the output power is backed off by more than 5dB from P/sub 1dB/. From the OFDM signal test, the second harmonic termination improves the error vector magnitude (EVM) by over 40% for an output power level satisfying the 4.6% EVM specification. 相似文献
12.
13.
传统的单路并联式模拟预失真电路,其可调性不高,对功率放大器的三阶交调改善量也非常有限。为了解决上述问题,提出了一种能用开路短截线进行适当相位补偿的S 波段模拟预失真电路。该模拟预失真电路使用肖特基二极管产生三阶交调信号,通过改变开路短截线的长度,来调整基波信号与三阶交调信号的相位差,使它的特性跟功率放大器的特性相反,从而抵消功放的三阶交调信号。实验结果表明,在3.5 GHz 的AB 类功放的1 dB压缩点处,加模拟预失真电路后,三阶交调量改善了约34 dB。 相似文献
14.
介绍了一种应用于W-LAN系统的5.8 GHz InGaP/GaAs HBT MMIC功率放大器。该功率放大器采用了自适应线性化偏置电路来改善线性度和效率,同时偏置电路中的温度补偿电路可以抑制直流工作点随温度的变化,采用RC稳定网络使放大器在较宽频带内具有绝对稳定性。在单独供电3.6 V电压情况下,功率放大器的增益为26 dB,1 dB压缩点处输出功率为26.4 dBm,功率附加效率(PAE)为25%。三阶交调系数(IMD3)在输出功率为26.4 dBm时为-19 dBc,输出功率为20 dBm时低于-38 dBc,在1 dB压缩点处偏移频率为20 MHz时邻道功率比(ACPR)值为-31 dBc。 相似文献
15.
Ji Han Joo Jin Joo Choi 《Electron Devices, IEEE Transactions on》2005,52(5):728-733
An X-band, low-noise, linearized microwave power amplifier module consisting of a low-noise solid-state amplifier (SSA), predistortion linearizing circuit, and low-gain helix traveling wave tube (TWT) is designed and tested in order to demonstrate both reduced noise figure and suppressed intermodulation distortion ratio. Two-tone intermodulation distortion (IMD) ratios are predicted from simulations obtained from modeling of the TWT, linearizing circuit, and SSA by the use of Agilent's Advanced Design System simulation code. Simulated IMD ratios are in good agreement with measured results. Measurements show a noise figure of 2.2 dB at 9.5 GHz and the third-order IMD ratio of -53 dBc at 10 dB input back off from the input P1dB point. It is found that both noise figure and IMD ratio are significantly improved compared with conventional helix-TWTs and microwave power modules. 相似文献
16.
Do-Gyun Kim Nam Pyo Hong Young-Wan Choi 《Microwave and Wireless Components Letters, IEEE》2009,19(10):671-673
A novel linearization method for CMOS drive amplifier using intermodulation distortion (IMD) canceller is presented. The IMD cancellation method is composed of a cascode main amplifier and a common-source IMD canceller. The additional common-source amplifier generates IMD3 signals with 180deg phase difference against the IMD3 of the cascode main amplifier. The linear drive amplifier is designed and fabricated by CMOS 0.18 mum process. The output IP3 of +13 dBm is achieved with the power gain of +11.6 dB, the output P1 dB of + 5.5 dBm, and the power-added efficiency of 21%. 相似文献
17.
采用A类与B类并联的结构,设计了一种2.4GHz高线性功率放大器.输入信号较小时,A类放大器起主要作用;随着输入信号的增大,B类放大器起的作用越来越明显,来补偿A类的压缩,由此显著提高了放大器的线性度.电路主体为共栅管采用自偏置方法的共源共栅结构,提升了功放大信号工作时的可靠性.电路采用中芯国际0.13 μmCMOS工... 相似文献
18.
Jinho Yoon Chulhun Seo 《Microwave and Wireless Components Letters, IEEE》2001,11(11):450-452
In this paper, the photonic bandgap, the predistortion, and the secondary harmonic tuning are simultaneously employed in a feedforward amplifier to maximize the power added efficiency (PAE) and the operating bandwidth for in IMT-2000 band. In this case, the secondary harmonic tuning and the predistortion linearizer can cancel the second and the third harmonics, respectively. The PBG prevented any more harmonics appearing over 6 GHz. The feedforward amplifier was improved by 4%, and 15 dBc in the PAE and the IMD (intermodulation distortion), respectively. The operation bandwidth achieved was twice as wide as the conventional feedforward amplifier 相似文献
19.
We propose and describe the fabrication of a linear power amplifier (LPA) using a new analog feedforward method for the IMT‐2000 frequency band (2,110–2,170 MHz). The proposed analog feedforward circuit, which operates without a pilot tone or a microprocessor, is a small and simple structure. When the output power of the fabricated LPA is about 44 dBm for a two‐tone input signal in the IMT‐2000 frequency band, the magnitude of the intermodulation signals is below ?60 dBc and the power efficiency is about 7%. In comparison to the fabricated main amplifier, the magnitude of the third intermodulation signal decreases over 24 dB in the IMT‐2000 frequency band. 相似文献