微波反馈放大器的匹配和增益带宽的探讨

本文介绍了小信号微波反馈放大器的分析与综合。放大器采用通常的增益级框图表示和并联反馈。文中提供了全部网络元件的估算值和闭环宽频带增益、带宽和双端口的匹配值。用图解法对匹配值与增益进行了权衡。最后用实例描述了综合方法。     

980nm高稳定度激光泵浦源控制系统

设计、制作了一款980nm高稳定度激光泵浦源控制系统,以满足掺铒光纤放大器(EDFA)稳定工作的需要。首先,以恒流激励原理设计了控制系统的驱动单元。接着,使用半导体制冷器(TEC)作为泵浦源的温度控制手段,设计了控制系统的温度控制单元。为了验证控制系统的有效性,选用一款激光泵浦模块组成了完整的激光泵浦源系统。最后,对激光泵浦源的激光输出进行了实验,研究了光功率与驱动电流的关系,以及系统的光功率稳定度与光谱稳定性等。对系统进行了相关测试实验,结果显示:应用了本控制系统的激光泵浦源的激光输出中心波长为975.2nm,光功率可达600mW,短期光功率稳定度为±0.008dB,长期光功率稳定度为±0.05dB,比同类激光泵浦源具有更高的稳定度。得到的结果表明:所设计的激光泵浦源控制系统满足设计要求,具有一定的实用价值。     

基于EDFA+FRA的增益平坦补偿

采用光子转换理论和数值分析方法,研究了采用DCF光纤的喇曼放大器和掺铒光纤放大器组成的混合放大器在DWDM系统中的应用。通过对喇曼光纤放大器的光纤长度、泵浦功率的选择,使得混合放大器的总增益达到一定的平坦度;并分析设计了增益均衡器,让混合放大器最后的总增益达到更高的平坦度。     

Single CDTA-based current-mode quadrature oscillator

This letter presents a single CDTA (Current Differencing Transconductance Amplifier)-based current-mode quadrature oscillator (QO). The proposed circuit structure is very simple, which only consists of one CDTA, one resistor and two capacitors, and it is easy for monolithic integration. The oscillation frequency of the QO can be electronically controlled by the bias current of the CDTA. Moreover, the oscillator can provide two quadrature current outputs. PSPICE simulation results are provided to verify all the theoretical analysis.     

An Inductor-less Sub-mW Low Noise Amplifier for Wireless Sensor Network Applications

This paper presents a Sub-mW differential Common-Gate Low Noise Amplifier (CGLNA) for ZigBee standard. The circuit takes the advantage of shunt feedback and Dual Capacitive Cross Coupling (DCCC) to reduce power consumption and the bandwidth extension capacitors to support 2.4 GHz ISM band. An amplifier employing these techniques has been designed and simulated in 0.18 µm TSMC CMOS technology. The Simulation results show a gain of 18.2 dB, an IIP3 of −4.32 dBm and a noise figure of 3.38 dB at 2.4 GHz. The proposed LNA consumes only 967 µW from a 1-V supply.     

A new 0.35 μm CMOS electronic interface for wide range floating capacitive and grounded/floating resistive sensor applications

In this paper we propose a novel interface circuit suitable for the read-out of both wide range floating capacitive and grounded/floating resistive sensors. This solution, employing only two Operational Amplifiers (OAs) as active blocks and some passive components, is based on a square-wave oscillating circuit topology which, instead of a voltage integration typically performed by other solutions in the literature, operates a voltage differentiation. Therefore, the proposed circuit, performing an impedance-to-period (Z–T) conversion, results to be suitable as first analog front-end for both wide variation capacitive (e.g., relative humidity) and resistive (e.g., gas) sensors. Its sensitivity and dynamic range can be easily set through external passive components. Preliminary experimental measurements, which have characterized and validated this solution, have been conducted through a suitable prototype PCB fabricated with discrete commercial components. Then, the proposed interface has been also designed at transistor level, in a standard CMOS technology (AMS 0.35 um), developing a single-chip integrated circuit with low-voltage (1.8 V, single supply) low-power (about 350 μW) characteristics in a very small silicon area (lower than 0.6 mm²) which results to be suitable for sensor array configurations and portable applications. Further experimental results, achieved utilizing commercial sample resistors and capacitors to emulate sensor behavior, have shown a linear trend and a satisfactory accuracy in the evaluation of floating capacitive (in the range 10 pF–1 μF), grounded resistive (in the range 150 kΩ–1.5 MΩ) and floating resistive (in the range 10 MΩ–1 GΩ) variations, also when compared to other solutions presented in the literature. The satisfactory interface behavior has been also confirmed by the measurement of both relative humidity through the commercial sensor Honeywell HCH-1000 (capacitive) and carbon monoxide CO through the commercial air quality sensor FIGARO TGS-2600 (resistive).     

高效率Doherty放大器的设计与仿真

效率和线性度是功率放大器的两个重要指标,影响着整个系统的性能.通过比较各种提高效率的方法中,选择结构简单的基于Doherty技术的功率放大器来实现.首先介绍了Doherty功率放大器的基本工作原理,然后选用飞思卡尔的MRF6S21140H芯片,应用微波仿真软件ADS设计了频段在2110～2170MHz的高效率Doher...     

高输出电压的宽带程控增益放大系统

设计了以电压控制可变增益放大器AD603为程控增益主体,以MSP430F449单片机为控制核心的高电压输出宽带程控增益放大系统.系统电压增益为0～60 dB可调,3 dB带宽2.5 MHz、5 MHz、10 MHz、15 MHz可调,最小输入电压有效值为1 mV,在50 Ω负载下最大不失真输出电压峰峰值为28 V,电压...     

0.25W射频功率放大器

安华高的MGA-30489是一款0.25瓦高动态范围的驱动放大MMIC,它采用SOT-89的标准塑封。拥有极好的输入输出回损和良好的线性度。芯片很容易匹配,并获得最佳的功率和线性。     

X 波段雷达接收机中低噪声放大器的研究

现代雷达系统结构对接收机的性能提出了更高的要求.低噪声放大器能降低系统的噪声和提高接收机灵敏度,是接收系统的重要组成部分.本文设计的低噪声放大器应用于接收机的前端,利用集成芯片 ATF36163完成了电路的设计并且通过研究 RF 电路中的参数灵敏度对该低噪声放大器进行了灵敏度分析.结果表明:经过参数灵敏度分析的低噪声放大器不仅符合接收机对 LNA 的指标要求,还能使性能更加稳定