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41.
A 13-bit, 50-MS/s pipeline ADC with IF-sampling capability is presented. A high sampling linearity is obtained through the use of bootstrapped switches. A digital self-calibration algorithm with modified capacitor measurement scheme is employed to improve the accuracy of the first two pipeline stages. The prototype, implemented with a 0.35-m BiCMOS (SiGe) technology, shows a 76.5-dB SFDR at a 194.2-MHz signal frequency and dissipates 715 mW power from a 2.9-V supply.  相似文献   
42.
A new class AB output stage for CMOS op-amps is proposed with simple and accurate quiescent current control using floating gate transistors. The proposed stage can be operated with a supply voltage close to a transistor's threshold voltage. Experimental results are provided showing a 15 MHz gain-bandwidth product when it is used as the second stage of an op-amp with 1.5 V supply voltage in a standard 0.8 m CMOS technology.  相似文献   
43.
This new combined optical–wireless indoor communication system provides an economic and flexible approach for local area networks mainly in large buildings or in a group of several buildings. The radiation from the radio base stations of mobile networks cannot penetrate into large buildings completely. That problem is more serious at higher frequencies. The present approach offers a good solution to this problem. In this approach the wireless communication serves small picocells which are interconnected by an optical backbone. The performance of the system is enhanced by assigning a specific radio frequency for each picocell which enables the transmission of the wireless channels without altering their modulation formats. This method allows for a simple, and low-cost indoor communication system.  相似文献   
44.
In this paper, an improved empirical behavioral model for radio‐frequency power amplifiers (RF‐PAs) is presented. The model was implemented in a commercial nonlinear microwave simulator. It belongs to the category of bandpass PA models, which exhibits memory effects due to the low frequency dependence of bias and temperature. Additionally, it facilitates accurate and efficient system level simulations of RF‐PA large‐signal behaviors such as self‐bias, AM‐AM, AM‐PM, gain expansion effects, and intermodulation distortion (IMD) sweet‐spots. The model was validated using measurement data obtained from a commercial CDMA PA at 1.88 GHz. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.  相似文献   
45.
The promise of a broadband fibre communications network has attracted the interest of CATV and Telco concerns. Various networks and topologies have been discussed. Cost is a drawback in some of the proposed networks, particularly those networks which require switching. This paper discusses a low cost broadcast tree and branch network which uses optical amplifiers to extend the network penetration. Recent work in the development of optical amplifiers suggests that the Erbium fibre amplifier may be compatible with VSB-AM. The characteristics of such an amplifier will be discussed. This scenario allows an orderly transition from the present-day AM backbone system to the tree and branch fibre architecture. Once the broadband fibre plant is in place new services can be implemented that exploit the broadband nature of fibre.  相似文献   
46.
掺Pr^3+硫(卤)系玻璃1.3μm光纤放大器   总被引:1,自引:0,他引:1  
张军杰  胡和方 《功能材料》1999,30(5):459-462,466
介绍了稀土掺杂光纤放大器的发展,总结了用于1.3μm光纤放大器的几种重要的硫系统质玻璃,阐述了接Pr^3+硫(卤)系玻璃1.3μm光纤放大器的光学性质并分析了-OH等杂质对其性能的影响。  相似文献   
47.
《Optical Fiber Technology》2014,20(6):621-630
In this paper we present a review of holmium-doped silica fibre based sources. We discuss recent demonstrations of an efficient cladding-pumped fibre geometry and the impact it has made on the power scaling of these sources. We discuss the wavelength region that is addressable by holmium-doped silica based devices and highlight the advantage over thulium-doped fibres in terms of atmospheric transmission. Finally we review the development and current status of the pulsed and CW operation of holmium fibre sources and discuss the future development potential of sources in the ns-fs pulse-width range.  相似文献   
48.
This paper describes three circuits that implement pseudo‐logarithmic functions, which are simple and easy to implement. The circuits can be realized using operational amplifiers or current feedback amplifiers. Tuning can be achieved using switched resistors, or active resistors, or tunable transconductors, but are best suited for use with digitally switched resistors. Frequency response and stability considerations for two of the circuits are thoroughly discussed and PSPICE results confirming the theoretical results are presented alongside measured results. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
49.
A simple dynamic biasing scheme to extend the input/output range of cascode amplifiers is introduced. It requires minimum extra hardware and no additional power consumption. A dynamic biased telescopic op-amp is discussed as an application example. Experimental results of a fabricated test chip in 0.5 μm CMOS technology are presented that verify the proposed technique.  相似文献   
50.
介绍了远泵放大器大功率泵浦光传输技术的实验研究,该技术应用在大跨距无中继光纤传输系统中,采用G.652光纤,构成了速率为2.5Gb/s、跨距为507km的大跨距无中继光纤传输系统。  相似文献   
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