一种宽禁带器件的高效E类功率放大器设计

E类功率放大器是一种新型高效率放大器,属于开关模式功率放大器,其理论效率可以达到100%。可用于雷达、通信和电子对抗等领域的末级功率放大器,是系统高效率、高功率和小型化功率放大器的重要途径。通过分析其工作原理,设计了一款L波段高效E类功率放大器,输出功率大于10 W,实际漏极效率达到74.8%。     

3A5线路放大器的制作

CD的最大输出电压可以达到2V,对于输入1V就可以输出最大输出功率的功率放大器来说,完全不需要对CD输出的信号进行放大。但是由于使用者的喜好不同,有的喜欢接人线路放大器,有的喜欢接入衰减器。喜欢接人线路放大器的人     

基于编码—解码模型的D类功率放大器行为建模

D类功率放大器具有优异的传输效率,属于开关类功放,其输出信号存在较大的非线性失真。对D类功率放大器进行行为建模时要同时考虑其非线性和记忆特性。文中将小波变换引入到编码—解码神经网络模型中,提出了小波编码—解码神经网络模型。使用基于门限循环单元的编码—解码模型和小波编码—解码模型进行D类功率放大器的行为建模。实验结果表明,文中提出的D类功率放大器行为模型相比于传统的Voterra-Laguerre模型而言,在信号的时域和频域都具有更高的精度。     

用于无线电发射机的射频功率放大器

发明背景本文发明的射频功率放大器是其元件均以特定的相对位置构成立体方位的射频功率放大器。射频功率放大器过去一般是用电子管做为放大器的有源元件,虽然这种电子管放大器的设计和安装较为容易,且能工作于高频和提供大功率输出信号,但这种电子管功率放大器一般是体积庞大,重量重而且效力差。对于需要重量轻和体积小的装置,例如便携式无线电发射机则常常采用晶体管射频功率放大器。到目前为止,这种晶体管功率放大器对减小电路体积和小型化极为有利,且各元件互相靠近造成的元件间干扰问题也得到了改善。对元件进行     

WPT中高效E类功率放大器的研究

作为无线电能传输(WPT)系统的核心部件之一,E类功率放大器的理论效率可达100%,具有很好的研究前景。本文对E类功率放大器进行理论分析与设计建模,运用电磁仿真软件ADS进行仿真,通过源牵引和负载牵引进行最佳阻抗匹配以优化效率,基于仿真结果进行了硬件电路设计制作。结果表明,设计制作的E类功放在27~29MHz输出的最大功率附加效率(PAE)为91.3%,同时获得17.5 d B的功率增益,验证了设计的正确性与可行性。     

功率放大器的输出级电路设计与应用

对于低频功率放大器,集成甲类与乙类工作状态的互补特点可以获得失真小、效率高的输出。探讨提高功放的路径,给出了一种在非线性失真允许的范围内获得最大输出功率的方法,最后应用在一个小信号功放的电路设计上,通过模拟仿真与实际应用,说明了这种电路的有效性,为实际电路设计与分析提供了一种参考。     

新型BTL伴音功放TDA7056A

<正> 在彩电中,音频功率放大器的任务是将伴音音频信号进行放大,输出足够的功率去推动扬声器,得到洪亮优美的电视伴音,以满足人们对视听设备中听觉的要求。彩电中伴音功放的发展大致经历了变压器耦合功率放大器、OTL功率放大器和OCL功率放大器三个阶段。飞利浦公司最近新推出了一种新型BTL(Bridge Tied Load)音频功率放大器TDA7056A。这种新型的BTL电视伴音功率放大器供电电源范围宽     

功率放大器非线性对Chirp信号的影响 及预补偿方法研究

本文研究功率放大器非线性失真对Chirp信号幅频和相频特性的影响及预补偿方法.在雷达系统中,为了获得足够的作用距离,需要增加发射机的发射功率.对输出功率的要求越高,功率放大器(HPA)的工作点就越接近饱和区.这就使得功率放大器的输出信号产生了非线性失真.功率放大器的非线性失真直接影响了发射线性调频(Chirp)信号的质量,对后续的信号处理带来一定程度的影响.以脉冲压缩为例,分析了非线性失真对主瓣宽度和第一旁瓣抑制的恶化.提出了两种建立在直接数字合成(DDS)技术基础上的预补偿方法.通过理论分析和计算机仿真,证明了两种预补偿方法都可以有效地减小非线性失真.最后对影响两种预补偿方法性能的因素和收敛性进行了分析,对两种预补偿方法的结果进行了比较.     

TD—SCDMA宽带非对称Doherty功放设计

文章介绍了Doheny功放的基本原理,设计并实现了1880MHz-2025MHz（TD—F＋A频段）频段的Doherty功率放大器。实测结果表明,以TD单载波为测试信号源,在最大输出功率回退9．0dB的情况下,其漏极效率达到35％以上。未加DPD时的ACPR小于-29．7dBm,完全满足要求。     

输出波形可控的高精度数控电源设计

针对精密仪器和精密机电系统中对任意波形电源的应用需求,设计一种输出波形可控的高精度数控电源。系统采用模块化设计,主要包括信号发生器、电压幅值调节、功率放大器、A/D转换和触摸式液晶屏显示等模块。信号发生器采用直接数字频率合成技术和积分电路,得到电压幅值固定的正弦波、方波、三角波和锯齿波等模拟信号,并通过电压幅值调节模块实现模拟信号电压幅值可调,最后经功率放大器后输出以驱动负载。实验测试结果表明:该电源可以输出频率范围为1~50 k Hz,最大峰值电压为40 V的任意波形。     

高效率谐波调谐功率放大器的发展综述

作为发射机中耗能最高的器件,功率放大器(功放)产生的热量也最多,提升其效率对整个系统至关重要,因此关于提高功放效率的研究从未间断.回顾了谐波调谐功放的数学推导过程,讨论了其提升功放性能的数学原理,从增益、效率和输出功率等方面对比了各种谐波功放的性能,在此基础上总结了各类型谐波控制功放的特点及其发展现状.随后将其与近年来...     

Digital Predistortion for Spectrum Compliance in the Internet of Things

Many different wireless personal communication technologies including Bluetooth, ZigBee, Wi-Fi, even LTE-M, can connect Internet of Things (IoT) products, such as personal electronics or industrial machine sensors. However, the nonlinearity and linear distortion produced by RF power amplifiers (PAs) will degrade the quality of transmitted signals. In this article, based on an inverse autoregressive moving-average (IM-ARMA) model, we applied a method of digital predistortion (DPD) to linearize the RF PAs for several typical protocols in the IoT.     

On leaky mode approximations for modal expansion in multilayer openwaveguides

We propose an analytic method to calculate the leaky mode functions to enable modal expansion without encountering the normalization and orthogonality problems of the unphysical mode shape. The wave functions of leaky modes are derived from the explicit formulas of normalized radiation modes. Using leaky modes to approximate a continuum of radiation modes greatly simplifies the analysis of excitation, transitions, propagation, and radiation of light waves in multilayer waveguide structures. Upon comparison with the beam propagation method and modal propagation method, we show that the leaky mode approximation while requiring a much simpler computation is as accurate. This method can also provide better physical insight to device operations     

缓冲质子源LiNbO3波导折射率计算及实验

为实现铌酸锂退火质子交换(APE)波导折射率分布的准确计算,选择含苯甲酸锂的苯甲酸缓冲液作为质子交换质子源,高温退火制作了波导样本.针对该工艺过程建立退火质子交换波导模型,包括非线性扩散模块和光学数值仿真模块,分别计算APE波导折射率及其模式有效折射率.以测得的样本波导模式有效折射率和计算的有效折射率差的均方根构建评价函数(FOM),结合遗传算法提取该工艺条件下质子扩散参数,实现了不同交换深度和退火时间波导折射率分布及其光学特性的一体化计算.实验表明:FOM小于0.001,计算折射率分布同IWKB方法测得结果吻合较好,最大偏差约0.002.     

音频功放环路频率响应的测试

音频功放的稳定性是由环路频率响应的增益与相位曲线决定的。在设计时可以通过仿真软件分析,在实际测试时由于测试误差和动态范围的限制很难得到准确的结果。本文以AB类音频功放为例,介绍了一种采用网络分析仪的增益和相位端口,测试环路频率响应的方法。     

线性啁啾布拉格光纤光栅的色散补偿特性研究

本文将全面分析Ｃｈｉｒｐｅｄ Ｂｒａｇｇ光纤光栅的色散特性，并对色散特性作一定性分析，利用耦合模方程导出ＣｈｉｒｐｅｄＢｒａｇｇ光栅的反射率方程，从而推导出Ｃｈｉｒｐｅｄ Ｂｒａｇｇ光纤光栅的色散计算公式，然后，引入微波领域的“品质因素”概念，从而量化了色散补偿器的补偿能力。     

Impact of Feedback Delay on Closed-Loop Stability in Semiconductor Optical Amplifier Control Circuits

Semiconductor optical amplifiers (SOAs) are attractive for integrated photonic signal processing, but because their response is so fast, delays in a controller feedback path can jeopardize performance and stability. Using state-space methods, we quantify the constraints imposed on feedback controllers by closed-loop delay. We first derive a complete nonlinear state-space control model of a SOA with an equivalent circuit containing parasitics and dynamic impedance; the analytical state-space model agrees well with a validated photonic-only control model. Using a linearized version of the model we demonstrate that time delay in the feedback path can destabilize the SOA through phase accumulation. We then apply linear system theory to calculate the best-case stable delay margin for a given controller norm, and find a potentially severe inverse relationship between delay margin and controller norm. Finally, guided by the delay-controller relationship we design a hybrid feedforward-feedback controller to illustrate that good transient and steady-state regulation is obtained by carefully balancing the feedforward and feedback components. Our state-space modeling and design methods are general and are easily adapted to the design and analysis of more complex photonic circuits.     

Krylov subspace iterative techniques: on the detection of brain activity with electrical impedance tomography

In this paper, we review some numerical techniques based on the linear Krylov subspace iteration that can be used for the efficient calculation of the forward and the inverse electrical impedance tomography problems. Exploring their computational advantages in solving large-scale systems of equations, we specifically address their implementation in reconstructing localized impedance changes occurring within the human brain. If the conductivity of the head tissues is assumed to be real, the pre-conditioned conjugate gradients (PCGs) algorithm can be used to calculate efficiently the approximate forward solution to a given error tolerance. The performance and the regularizing properties of the PCG iteration for solving ill-conditioned systems of equations (PCGNs) is then explored, and a suitable preconditioning matrix is suggested in order to enhance its convergence rate. For image reconstruction, the nonlinear inverse problem is considered. Based on the Gauss-Newton method for solving nonlinear problems we have developed two algorithms that implement the PCGN iteration to calculate the linear step solution. Using an anatomically detailed model of the human head and a specific scalp electrode arrangement, images of a simulated impedance change inside brain's white matter have been reconstructed.     

Efficiency and mode discrimination of a linear array of square CO2 waveguide lasers phase-coupled by an intracavity spatialfilter

In this paper, we present a theoretical analysis of a linear array of square waveguide CO₂ lasers phase-coupled with an intracavity spatial filter. Using a Rigrod-like method, we calculate the efficiency of the device and analyze its capability to discriminate between the fundamental mode and the transverse modes of both the array and the individual square waveguide