S波段低噪声放大器的ADS仿真与设计

介绍低噪声放大器设计的理论基础,并重点介绍了低噪声放大器的主要性能指标:噪声系数、功率增益、驻波比、稳定性等。以ATF38143晶体管为例介绍了ADS仿真软件设计低噪声放大器的方法和主要步骤。采用三级级联结构设计出满足指标的S波段低噪声放大器链路。该放大器链路的指标为噪声系数小于1.2,功率增益大于50dB,增益平坦度小于0.5dB,VSWR小于1.8的低噪声放大器,带宽为6MHz,并具有一定的带外抑制能力。     

小信号低噪声有源器件

当晶体管放大器变得可在指定频率范围内用时,它们正在迅速取代低噪声的行波管放大器和返波管放大器来作为与电子防御有关的应用方面的前置放大器。这就意味着在讨论今日低噪声微波放大器的技术时,在很大程度上势必要讨论砷化镓场效应晶体管(GaAs FET)。但是也不能忽视其它低噪声放大器技术,例如,在大容量的地面站和其它需要低噪声的     

五公分宽带常温参量放大器

一、引言参量放大器具有低噪声特性。但由于它窄带特性往往使其应用受到一定的限制。宽带参量放大器同窄带参量放大器相比,不论在相位特性方面还是在工作稳定性方面都有很大的改善。特别是工作在常温的宽带参量放大器,由于它不用庞大复杂的致冷系统,应用起来就更为方便。因此,在对相位有一定要求的微波接收机中使用宽带常温参量放大器是有一定的使用     

低噪声行波管放大器向固态器件挑战

目前有关低噪声微波放大器的文献,大多数是讨论固态器件的,而对低噪声行波管放大器的最近的革新发表的实际数据很少。这就会使人认为,全固态化办法是解决微波低噪声放大的最好途径。这种想法有一定道理,但是不能说低噪声行波管已经陈旧过时了。本文介绍低噪声行波管的现状,其主要优缺点,工作特性方面最近取得的一些进展以及行波管独特性能的典型应用。     

微波低噪声放大器

关于微波低噪声放大器,本文以使晶体管放大器的低噪声化的设计方法为中心,介绍各种低功率放大器及功率放大器的现状。微波低噪声放大器的现状图1就目前的各种微波放大器表示了它们的噪声系数及频率特性。双极晶体管放大器、隧道二极管放大器和参量放大器等是过去人们已热知的低电平工作的低噪声放大器,近几年来晶体管的性能惊人地提高,已出现了在4千兆赫下噪声系数3分贝左     

低噪声的弹丸信号放大电路设计

针对传统放大电路设计出了一种用于红外光电立靶测试系统的前置放大器的电路,在设计中选用低噪声运算放大器和仪表放大器组成电路,同时论述了关于低噪声放大电路设计中的屏蔽和接地措施.     

全球LNB市场大观(上)

卫星高频头(LNB,也称电视低噪声下变频器或卫星电视室外单元,台湾称低杂讯降频器)是卫星电视接收系统中不可获缺的器材,它由微波低噪声放大器、微波混频器、第一本振和第一中频前置放大器组成。LNB中的低噪声放大器一般是将波导同轴转换器与低噪声放大器合成一个部件,包含3～4级放大,前两级为低噪声放大器,采用高电子迁移率晶体管HEMT器件,后两级为高增益放大器,采用砷化镓场效应晶体管GaAsFET。     

声频放大器低噪声化的设计

本文首先从低噪声放大器设计的基本原理和方法入手，对晶体管放大器的噪声模型（Ｅｎ－Ｉｎ模型）做了分析，并以实现放大器低噪声化为出发点，阐述了具体设计的几个过程，最后对级联放大器的低噪声设计进行探讨。本文并非从工程设计的角度全面论述低噪声设计的各个方面，而是仅就低噪声设计中需要考虑的一些问题做一概述，从而为一些有志于音响工作的人们研究低噪声系统的设计问题提供方便。     

S波段低噪声放大器研究

本文主要在对低噪声放大器研究现状进行整体论述的基础上,结合S波段低噪声放大器原理对低噪声放大器的设计优化进行分析讨论。     

无线传输系统中低噪声放大器的设计

文章介绍了一种增益为30 dB的低噪声无线传输系统低噪声放大器设计方法。根据设计指标,应用安捷伦ADS仿真软件对低噪声放大器的参数进行仿真分析,然后进行放大器输入输出阻抗匹配,在优化放大器的增益和噪声系数后,完成电路设计,同时文章还给出PCB板的设计结果。测试表明,该法设计的低噪声放大器完全达到设计指标。     

Jitter considerations in the design of a 10-Gb/s automatic gain control amplifier

The effects of noise on random jitter in multistage broad-band amplifiers are analyzed. Limiting amplifiers are compared to automatic gain control (AGC) amplifiers with different gain profiles. Results are presented for a 10-Gb/s AGC amplifier implemented in an SiGe process with f_T of 45 GHz. Active peaking techniques were used to achieve a maximum gain of 48 dB with 7.8 GHz of bandwidth. The amplifier demonstrates low jitter and less than 0.5 dB of peak-to-peak output amplitude variation over a 50-dB input amplitude range. It consumes 30 mW of power from a 3.3-V supply. The amplifier core occupies 0.1 mm² and requires no external components     

大幅度CCD输出信号降噪的相关双取样电路

电荷耦合器件(CCD)的输出信号构成复杂,包含有典型的KTC、1/f等类型的噪声,需要进行专门处理后才能获得与入射光信号相对应的高信噪比信号。文章针对具有较大幅度的CCD输出信号,采用宽电压工作的独立运放满足幅度较大的信号处理要求;通过在同一个运算放大器上实现噪声保持及信号采样的形式,消除了不同通道增益差异对信号的影响,获得了较高线性度的信号处理效果;同时结合CCD驱动器的设计,获取相关双取样技术所需的采样及保持脉冲信号,增强了采样与CCD输出信号间的关联程度,从而进一步提高了相关双取样技术消除CCD噪声的效果。采用这种信号处理电路后,将原来噪声处理的水平从约22 mV提高到了约1 mV,并且在一种精密的位移测量系统中得到应用,最后就具体电路设计的难点及注意事项进行了阐述。     

0-40 GHz GaAs MESFET distributed baseband amplifier ICs forhigh-speed optical transmission

We describe distributed amplifiers built using advanced circuit design techniques to improve gain and noise performance at low frequencies. Using these techniques we have developed an amplifier IC with a 0-36 GHz bandwidth and a noise figure of 4 dB at low frequencies. This frequency range starting from 0 Hz makes it possible to use the IC as a baseband amplifier for SDH optical transmission systems and this noise figure is about 1 dB better than conventional distributed amplifiers. We also present another amplifier IC built using our loss compensation technique to improve high-frequency performance of the amplifier. This IC has a 0-44-GHz bandwidth, which is the widest among all reported GaAs MESFET baseband amplifiers     

Molecular amplification and generation of microwaves

This paper is a general introduction to the field of amplification and generation of microwaves using molecular rather than electronic processes. The basic physical properties of molecular systems as related to amplification are reviewed. The properties of molecular amplifiers, such as gain, bandwidth, saturation power, and noise figure are discussed and several specific types of amplifiers are described. These include the molecular-beam maser, the “hot-grid cell”, amplifiers excited by radio-frequency pulses and by “adiabatic fast passage”, and amplifiers based on multilevel molecular internal energy systems, including “optically pumped” amplifiers. Molecular amplifiers may add very little noise to the signal to be amplified: noise figures under 1 dB can be obtained. With suitable feedback, such amplifiers become oscillators of extremely high spectral purity. High gains can be achieved using regeneration, but bandwidths are relatively small. These range from the order of tens of kilocycles for amplifiers using a gaseous molecular system, to megacycles, using solids. Molecular amplifiers saturate at low input powers, of the order of microwatts. Variations of the devices discussed may provide a means of generating millimeter and submillimeter waves     

A low-noise multiresolution high-dynamic ultra-broad-band time-domain EMI measurement system

A time-domain electromagnetic interference (EMI) measurement system allows to reduce measurement time by several orders of magnitude in comparison with conventional systems. This will considerably reduce the costs of compliance tests. In this paper, a novel multiresolution time-domain EMI measurement system is presented. The multiresolution time-domain EMI measurement system exhibits several channels with limiters, amplifiers, and analog-to-digital converters. The amplitude range of the signal is subdivided into several intervals. In each interval the analog-to-digital conversion is performed with an amplitude discretization proportional to the width of the amplitude interval. The signal-to-noise ratio of the multiresolution time-domain EMI measurement system compared with a conventional time-domain measurement system for transient signals is enhanced by at least 50 dB. It is shown that the multiresolution time-domain EMI measurement system has a higher overload factor than conventional systems working frequency domain. The noise floor is 5 dB lower than the noise floor of a conventional EMI receiver. The multiresolution time-domain EMI measurement system shows a higher 1-dB compression point than conventional EMI receivers. Measurements were performed in the frequency range from 30 MHz to 1 GHz and compared with results obtained by an EMI receiver.     

高一致性低噪声多路水声信号预处理设计方法

随着水下探测技术的发展,对于多路微弱水声信号预处理的指标要求越来越高。由于运算放大器和RC网络组成的高阶数带通滤波器,需要大量的外接电阻和电容,在较多通道数量的应用条件下,通道间的信号幅度和相位一致性很难控制。提出了一种新的高一致性低噪声多通道信号预处理方法。经过实验分析,在等效输入噪声、幅频特性、相频特性等方面效果很好,能够达到要求的技术指标。该方法能够在高一致性低噪声的多通路水声信号预处理中得到广泛的应用。     

Investigation of Different Input-Matching Mechanisms Used in Wide-Band LNA Design

This paper analyzes different input-matching mechanisms used in designing the wide-band amplifiers in general, and the low noise amplifiers (LNA) in particular, and their corresponding noise impact. Among them, the most promising one is the reactive-feedback circuit configuration, which is a combination of high-frequency inductive feedback and low frequency capacitive feedback. In this paper the simulated result that both matched input impedance and low noise temperature T _n can be achieved simultaneously over a wide bandwidth in the single-ended low noise amplifier is proved mathematically and is well interpreted. This understanding of reactive feedback is crucial for the future development of ultra-wide-band low-noise amplifiers.     

不同抽运方式下掺Yb3+光纤放大器的增益和噪声特性

为了探讨不同抽运方式下掺Yb3+光纤放大器的增益和噪声特性,对910nm掺Yb3+光纤放大器进行数值模拟。结果表明,抽运方式对增益影响较小,但对噪声特性影响较大,光纤达最佳长度时,正向和双向抽运方式的掺Yb3+光纤放大器要优于反向抽运方式。这一结果对掺Yb3+光纤放大器的试验设计具有重要的作用。     

12GHz单片组合低噪声GaAs MESFET放大器

本文叙述了12GHz单片组合的低噪声GaAs MESFET放大器的设计和制造.每级单片放大器包含一个有源元件FET、一个隔直电容和两个射频旁路电容.在11.7～12.2GHz范围内,单级放大器增益6.0dB,噪声系数3～3.5dB,三级放大器增益16～18dB,噪声系数≤4.0dB.     

Noise in Single-Frequlency Oscillators and Amplifiers

A generalization of previous oscillator noise analyses has been developed to permit reliable noise characterization of active nonlinear devices. Effects due to sideband correlation in the equivalent noise source are included. A rotating wave approximation (RWA) developed by Lax is used in obtaining the amplitude and phase noise spectra. Conditions are given for phase stabilization of free-running oscillators and for minimum phase noise in phase-Iocked oscillators and amplifiers. Stability criteria, discussion of spurious sidetones, and effects of a noisy synchronizing signal are given. The noise measure is used to obtain alternative expressions for the noise spectra and the carrier-to-noise ratios of locked oscillators and amplifiers. It is shown that the noise power gain of AM fluctuations is usually much lower than the corresponding gain for FM noise. The theory should be useful in optimizing the noise performance of nonlinear RF generators, such as IMPATT, BARITT, and Gunn diode oscillators.