Ku波段模拟预失真线性化器

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°。     

Realization of an analog predistortion circuit for RF optical fiber links

This paper presents an analog predistortion circuit for RF optical fiber links. The circuit consists of two source-coupled differential transconductance amplifiers which could provide linear and nonlinear transfer charac-teristics by adjusting the bias voltage and the transistor sizes. The circuit was designed and realized in a standard 0.18-μm CMOS technology of SMIC. The chip occupies 0.48 × 0.24 mm~2. The DC supply is 3.3 V. Using this circuit, the third-order intermodulation distortion (IMD) suppression of a directly modulated RF optical fiber link can be improved by 9-16 dBc at relatively low cost.     

A reconfigurable analog baseband circuit for WLAN,WCDMA,and Bluetooth

A reconfigurable analog baseband circuit for WLAN,WCDMA,and Bluetooth in 0.35 μm CMOS is presented.The circuit consists of two variable gain amplifiers (VGA) in cascade and a Gm-C elliptic low-pass filter (LPF).The filter-order and the cut-off frequency of the LPF can be reconfigured to satisfy the requirements of various applications.In order to achieve the optimum power consumption,the bandwidth of the VGAs can also be dynamically reconfigured and some Gm cells can be cut off in the given application.Simulation results show that the analog baseband circuit consumes 16.8 mW for WLAN,8.9 mW for WCDMA and only 6.5 mW for Bluetooth,all with a 3 V power supply.The analog baseband circuit could provide-10 to +40 dB variable gain,third-order low pass filtering with 1 MHz cut-off frequency for Bluetooth,fourth-order low pass filtering with 2.2 MHz cut-off frequency for WCDMA,and fifth-order low pass filtering with 11 MHz cut-off frequency for WLAN,respectively.     

Linearised HBT MMIC power amplifier with partially RF coupled active bias circuit for W-CDMA portable terminals applications

A highly linear MMIC power amplifier for wideband code-division multiple-access (W-CDMA) portable terminals has been devised and implemented with a new integrated on-chip lineariser. The proposed lineariser, consisting of an InGaP/GaAs heterojunction bipolar transistor (HBT) active bias circuit partially coupled to RF input power together with a feedback capacitor, effectively improves gain compression with little insertion power loss and no additional die area. The optimised lineariser improves maximum output power (P1 dB) by 2 dB and adjacent channel leakage power ratio (ACLR) by 4 dB, and the implemented HBT MMIC power amplifier exhibits a P1 dB of 30 dBm, a power gain of 30 dB, a power added efficiency of 42% at the maximum output power under an operation voltage of 3.4 V, and an ACLR of -34 dBc at 27 dBm of output power.     

一种实用模拟温度控制电路设计

介绍了一种实用的模拟温度控制电路设计。该电路主要由运算放大器、单结晶体管及可控硅器件组成,通过比例积分、电压比较及移相触发等电路实现对电源输出功率大小进行控制,从而达到控制加热装置功率的目的。该电路温控精度较高、工作状态稳定可靠、实用性较强,可应用于工业温度控制场所。     

基于光电耦合器的线性隔离方法及电路

利用普通光电耦合器和常用运算放大器设计一种低成本、高线性度的模拟信号隔离电路.提出了利用负反馈改善输出信号线性的新思路.该电路抛弃了传统的在输入端使用隔离电源和运算放大器跟踪补偿的方法,而是使用输出信号对输入电流进行反馈补偿.尤其适合高压模拟信号输入的场合.该电路线性范围宽,可以根据不同的使用条件调节线性范围,线性度可...     

RF CMOS reliability simulations

We present a simulation approach to assess the reliability of an RF CMOS circuit under user conditions, based on existing DC degradation models for gate-oxide breakdown and hot-carrier degradation. The simulator allows for lifetime prediction of circuits that can withstand multiple breakdown events. Simulation results show that three power amplifiers with comparable initial circuit performance show an astronomic difference in reliability. The tool thus proves to be an asset in the analog design process.     

Low-voltage and low-power circuit design for mixed analog/digitalsystems in portable equipment

This paper describes low-voltage and low-power (LV/LP) circuit design for both analog LSI's and digital LSI's which are used in mixed analog/digital systems in portable equipment. We review some LV/LP circuits used in digital LSI's, such as general logic gate, DSP, and DRAM, and others used in analog LSI's, such as operational amplifiers, video-signal processing circuits, A/D and D/A converters, filters, and RF circuits, along with a wide range of items used in recently developed LSI's. Since analog circuits have fundamental difficulties in reducing the operating voltage and the power consumption, in spite of recent progress in LV/LP circuit techniques, these difficulties will be a major issue for decreasing the total power consumption of some mixed analog/digital systems used in portable equipment     

The Circuit Implementation of a Wavelet Function Approximator

This paper describes the analog synthesis of a wavelet function approximator using sigmoidal mother wavelet. Any finite energy multivariate function can be approximated by this analog circuit using the multiresolution approximation property of the wavelet decomposition. The approximator circuit includes bipolar junction transistors, operational amplifiers and linear passive circuit elements.     

提高接收机无虚假响应动态范围的研究

复杂的电磁环境要求侦察接收机同时具有高的灵敏度和高的动态范围,侦察接收机中的虚假响应制约着接收机动态范围的提高。侦察接收机中的射频模拟前端由放大器、滤波器及混频器等多级模块构成,其产生的虚假响应是实现大动态接收机的技术瓶颈之一。工程上要有效提高接收系统的无虚假响应动态范围,需要针对接收机射频模拟前端采取优化系统设计、采用高性能器件、提高线性度等很多措施。     

小波函数的电路合成方法

针对国内对小波的研究主要集中在算法和应用方面,小波的电路实现方法研究还鲜见的现状,提出了一种小波函数的电路实现方法。小波函数使用反曲型母小波模拟,电路由双极型晶体管、可控放大器和线性无源电子元件等组成。根据小波分解的多分辨率近似特性,有限能量多变量函数能使用这个模拟电路近似表示,结合实例,PSpice仿真实验表明,小波函数的电路合成方法是有效、可靠的。     

Velocity tapering in microwave amplifiers

The low-to-moderate RF conversion efficiencies characteristic of kinetic energy conversion devices may be enhanced by appropriately tapering the RF circuit phase velocity. The nonlinear interaction equations have been solved in closed form for an HKB (hard-kernel-bunch) model to obtain an optimum taper form. Several velocity taper forms have been investigated in experimental amplifiers and the power output, gain, efficiency, and phase shift characteristics of these amplifiers are discussed in detail. Conversion efficiencies up to 50 percent and near constant output power for a 20-dB variation in RF drive power have been realized in near optimally tapered circuit amplifiers. Further improvements realized include operation at a single voltage for maximum gain and power output and a nearly linear phase shift characteristic for a ±10 percent voltage modulation.     

Design of an analog front-end for ambulatory biopotential measurement systems

A continuously tunable gain and bandwidth analog front-end for ambulatory biopotential measurement systems is presented.The front-end circuit is capable of amplifying and conditioning different biosignals.To optimize the power consumption and simplify the system architecture,the front-end only adopts two-stage amplifiers.In addition, careful design eliminates the need for chopping circuits.The input-referred noise of the system is only 1.19μVrms (0.48-2000 Hz).The chip is fabricated via a SMIC 0.18μm CMO...     

A Low-Power 100 MHz Analog FIR Filter for PRML Equalization

This paper presents design of a low-power 100 MHz analog FIR filter for PRML equalization used in the read channel of hard disk drives. The chip consists of 16 channels to provide 15-tap FIR filter operation. By using rotating clocks for sample/hold operation with one dummy channel, timing constraints can be relieved, which results in low-power consumption. The chip incorporates the parallel array of sample-and-hold amplifiers for analog delay line. The sample-and-hold amplifier includes the open-loop unity-gain amplifier with gain-control circuit using replica-biasing scheme, which also improves uniformity among amplifiers. It was fabricated in a 0.8-m CMOS technology and consumes power of 200 mW for V power supply voltage.     

A Voltage-Translinear Based CMOS Signal Component Separator Chip for Linear LINC Transmitters

The LINC transmitter is an architecture that provides linear amplification using nonlinear but power efficient amplifiers. One crucial signal processing function of LINC is the signal component separator (SCS) which forms two constant-amplitude phase-modulated signals from the source signal. This paper presents an analog SCS chip implemented in a 0.35 m CMOS process using a novel design based on the so-called voltage-translinear circuit principle. An experimental LINC transmitter was built with the SCS chip, nonlinear amplifiers and a power combiner. Test results showed that all output spurious levels some -55 dBc and -48 dBc could be obtained with a North American Digital Cellular (NADC) signal and an IS-95 signal, respectively. This implies a high degree of linearity.     

基于Silicon Tuner的TV射频信号接收电路

设计了一种体积更小的TV射频信号电路系统以取代传统高频头.该系统基于Silicon Tuner、配合数字解调芯片、模拟解调芯片以及外围电路共同完成TV射频信号的处理,满足中国大陆及香港地区模拟电视广播标准和中国数字电视地面广播传输标准GB20600-2006,可应用于超薄平板电视信号终端接收机中.     

Low Cost On-Line Testing Strategy for RF Circuits

This work proposes the use of a simple 1-bit digitizer as an analog block observer, in order to enable the implementation of on-line test strategies for RF analog circuits in the System-on-Chip environment. The main advantages of using a simple digitizer for RF circuits are related to the increased observability of the RF signal path and minimum RF signal degradation, as neither reconfiguration of the signal path nor variable load for the analog RF circuit are introduced. As an additional advantage, the same digitizer can be used to implement BIST strategies, if required. The feasibility of using a 1-bit digitizer for the test of analog signals has already been presented in the literature for low frequency linear analog systems. This paper discusses the implementation of an on-line test strategy for analog RF circuits in the SoC environment, and presents new results for on-line RF testing. Moreover, we also provide detailed analysis regarding the overhead of the test strategy implementation. Experimental results illustrate the feasibility of the proposed technique.Marcelo Negreiros was born in Porto Alegre, Brazil, in 1969. He received the electrical engineering degree in 1992 and the M.S. degree in 1994, both from Universidade Federal do Rio Grande do Sul (UFRGS), Brazil. Since then he was been working as an associate researcher in the Signal Processing Lab. (LaPSI) of the Electrical Engineering Department at UFRGS. Since 2000 he also works toward a Ph.D. in Computer Science from UFRGS. His main research interests include mixed-signal and analog testing and digital signal processing.Luigi Carro was born in Porto Alegre, Brazil, in 1962. He received the Electrical Engineering and the MSc. degrees from Universidade Federal do Rio Grande do Sul (UFRGS), Brazil, in 1985 and 1989, respectively. From 1989 to 1991 he worked at ST-Microelectronics, Agrate, Italy, in the R&D group. In 1996 he received the Ph.D. degree in the area of Computer Science from Universidade Federal do Rio Grande do Sul (UFRGS), Brazil. He is presently a lecturer at the Electrical Engineering Department of UFRGS, in charge of Digital Systems Design and Digital Signal processing disciplines at the graduate and undergraduate level. He is also a member of the Graduation Program in Computer Science of UFRGS, where he is responsible for courses in Embedded Systems, Digital Signal Processing, and VLSI Design. His primary research interests include mixed-signal design, digital signal processing, mixed-signal and analog testing, and fast system prototyping. He has published more than 90 technical papers in those topics and is the author of the book Digital Systems Design and Prototyping (in portuguese).Altamiro A. Susin was born in Vacaria-RS, Brazil, in 1945. He received the Electrical Engineering and the MSc. degrees from Universidade Federal do Rio Grande do Sul (UFRGS), Brazil, in 1972 and 1977, respectively. Since 1968 he worked in the start up of Computer Centers of two local Universities. In 1981 he got his Dr Eng degree from Institut National Polytechnique de Grenoble-France. He is presently a lecturer at the Electrical Engineering Department of UFRGS, in charge of Digital Systems Design disciplines at the graduate and undergraduate level. He is also a member of the Graduation Program in Computer Science of UFRGS, where he is responsible for courses in VLSI Architecture and is also thesis director. His main research interests are integrated circuit architecture, embedded systems, signal processing with more than 50 technical papers published in those domains. He is/was responsible for several R&D projects either funded with public and/or industry resources.     

无源UHF RFID电子标签模拟前端设计

提出了一种符合ISO/IEC 18000-6B标准的高性能无源UHF RFID电子标签模拟前端,在915MHz ISM频带下工作时其电流小于8μA.该模拟前端除天线外无外接元器件,通过肖特基二极管整流器从射频电磁场接收能量.该RFID模拟前端包括本地振荡器、时钟产生电路、复位电路、匹配网络和反向散射电路、整流器、稳压器以及AM解调器等.该芯片采用支持肖特基二极管和EEPROM的Chartered 0.35μm 2P4M CMOS工艺进行流片,读取距离大于3m,芯片面积为300μm×720μm.     

Linearised InGaP/GaAs HBT MMIC power amplifier with active biascircuit for W-CDMA application

A high linearity InGaP/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (MMIC) power amplifier is demonstrated using a new structure for a bias circuit for wideband-code division multiple access (W-CDMA) application. A one shunt capacitor is added to a novel active bias circuit and acts as a lineariser improving input P_{1 dB} of 16 dB and phase distortion of 5.1° for the hybrid phase shift keying (HPSK) modulated signal at the 28 dBm output power; the lineariser showing no significant increase of signal loss and chip area. The two-stage HBT MMIC amplifier exhibits a power-added efficiency (PAE) of 37%, a linear power gain of 24.5 dB, and an output power of 28 dBm with an adjacent channel power ratio (ACPR) of -45 dBc, under a 3 V operation voltage     

简洁构型与馈电的宽带双极化金属锥阵列天线北大核心CSCD

本文提出了一种宽带双极化金属锥阵列天线。该阵列天线以传统的旋转体天线结构为主体,通过在锥体底部开设四道正交的直通槽,以便在锥状单元内部形成可与地板间构成匹配谐振腔的开放式空腔结构。在阵列中,任意两个相邻的锥状单元之间可形成类似于Vivaldi天线的辐射缝隙结构。馈电采用同轴馈电方式,探针无弯折结构,金属锥体无弯折过孔。每个金属锥状单元独立,可极大简化加工、装配和维护过程。该天线具有两个正交极化,分别由左右和前后相邻单元构成。仿真结果表明,在频率范围为2～8GHz内,阵列大部分有源VSWR小于2,小部分端口有源VSWR小于2.5 (相对带宽为120%)。