共查询到20条相似文献,搜索用时 62 毫秒
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电视发射机射频功率放大器的调试·调试与维护·河南鹤壁市广播电视局刘志学电视发射机末级电子管功率放大器是整机发射功率扩展的关键部位。它工作状态的好坏,直接影响到整机的性能和技术指标。由于该级功率放大器,一般均采用矩形谐振腔(米波)、同轴谐振腔(分米波)... 相似文献
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提出一种神经网络结合分离信号对功率放大器预失真建模的方法。将输入/输出信号的线性与非线性部分分开处理,利用神经网络良好的逼近能力,采用LM算法,拟合出功率放大器特性曲线,进而建立预失真模型,使非线性功率放大器的输入/输出曲线整体呈线性化。在保证输出幅度限制和输出功率最大化的前提下,与未作信号分离的神经网络建模方法、多项式建模方法以及Saleh函数模型方法相比较,发现信号分离神经网络建模方法能得到较小的归一化均方误差和误差矢量幅度。仿真结果表明,采用信号分离神经网络对功率放大器及其预失真建模,整体线性化误差较小、精度高、效果更佳。 相似文献
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基于0.13μm SiGe HBT工艺,设计应用于无线局域网(WLAN)802.11b/g频段范围内的高增益射频功率放大器.该功放工作在AB类,由三级放大电路级联构成,并带有温度补偿和线性化的偏置电路.仿真结果显示:功率增益高达30dB,1dB压缩点输出功率为24dBm,电路的S参数S11在1.5~4GHz大的频率范围内均小于-17dB,S21大于30dB,输出匹配S22小于-10dB,S12小于-90dB.最高效率可达42.7%,1dB压缩点效率为37%. 相似文献
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《Solid-State Circuits, IEEE Journal of》1977,12(3):291-298
Class B and class D operation of the same RF power amplifier circuit is not normally possible because of constraints imposed by the tuned output circuit and DC power input circuit. The use of square-wave drive in a current switching class D RF amplifier circuit allows the amplifier to move gradually from current source to current switch operation. This amplifier, called class BD, has a linear transfer characteristic (drive envelope to output envelope) and an efficiency 1.23 times that of a class B RF amplifier with the same peak output. The addition of a resistive AC current path to ground in the DC power input circuit of the class BD RF amplifier allows operation with sinewave driving waveforms. While this lowers the efficiency at the peak output, it can raise it at lower outputs, making possible a factor of 1.57 improvement in efficiency in the amplification of signals with large peak-to-average ratios. The class BD RF amplifier may therefore be used as a broad-band replacement for a Doherty-type amplifier. 相似文献
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A junction-gate power field-effect transistor of recent design has been found to yield greater than 25 watts CW at 30 MHz in two modes of circuit configuration. In this investigation, favorable characteristics are explored for potential device utility as a high-reliability low-distortion RF power amplifier. 相似文献
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Design of high-efficiency RF Class-D power amplifier 总被引:2,自引:0,他引:2
In this paper, the losses in a Class-D RF switching power amplifier and their frequency dependence are described. The losses analyzed are the switching, conduction, and gate drive losses. A 300 W, 13.56 MHz, Class-D circuit is designed in the traditional manner to illustrate the magnitude of the different types of loss. A circuit using the ZVS equations developed in this paper is designed. An experimental circuit is built using standard IRF540 devices in TO220 packages. That circuit does not meet its performance goals because of the package inductance. A new low inductance half-bridge package is introduced to solve this problem. Techniques for circuit layout and power measurements for RF applications are also presented in the experimental section. A low loss gate drive circuit is also presented using a Class-E circuit to provide the drive power. The experimental results confirm the accuracy of the design equations derived in this paper 相似文献
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A CMOS RF power amplifier that can change the output transformer ratio is presented. The CMOS power amplifier is fully integrated in a 0.13 /spl mu/m process and has a power added efficiency (PAE) of 38% at 2.1 GHz and an output power of 30.7 dBm with 3.0 V supply voltage. The PAE at an output power of 16 dBm was increased by 40% by altering the transformer ratio. 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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Youngchang Yoon Hyoungsoo Kim Chang-Ho Lee J. Stevenson Kenney 《Analog Integrated Circuits and Signal Processing》2013,77(3):495-502
An inductive antenna mismatch recovery method is presented. The proposed method uses series LC matching network to maintain a power amplifier (PA) performance under an inductive antenna mismatch condition. This method requires only the voltage amplitude information, which reduces the complexity in implementation. This paper also presents design considerations of integrated recovery system in a complementary metal-oxide semiconductor (CMOS) process. Simulation results show that the proposed CMOS PA maintains its output power as well as efficiency very close to the well-matched 50 Ω condition with inductively mismatched antenna impedance up to +j·70 which is corresponding to the voltage standing wave ratio of 2.5. 相似文献
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Scuderi A. La Paglia L. Carrara F. Palmisano G. 《Solid-State Circuits, IEEE Journal of》2005,40(3):611-621
This paper presents the design and measured performance of a 1.8-GHz power amplifier featuring load mismatch protection and soft-slope power control. Load-mismatch-induced breakdown can be avoided by attenuating the RF power to the final stage during overvoltage conditions. This was accomplished by means of a feedback control system, which detects the peak voltage at the output collector node and clamps its value to a given threshold by varying the circuit gain. The issue of output power control has been addressed as well. To this end, a temperature-compensated bias network is proposed, which allows a moderate power control slope (dB/V) to be achieved by varying the circuit quiescent current according to an exponential law. The nonlinear power amplifier was fabricated using a low-cost silicon bipolar process with a 6.4-V breakdown voltage. It delivers a 33.5-dBm saturated output power with 46% maximum power-added efficiency and 36-dB gain at a nominal 3.5-V supply voltage. The device is able to tolerate a 10:1 load standing-wave ratio up to a 5.1-V supply voltage. Power control slope is lower than 80 dB/V between -15 dBm and the saturated output power level. 相似文献