Monitoring microbiological changes in drinking water systems using a fast and reproducible flow cytometric method

Flow cytometry (FCM) is a rapid, cultivation-independent tool to assess and evaluate bacteriological quality and biological stability of water. Here we demonstrate that a stringent, reproducible staining protocol combined with fixed FCM operational and gating settings is essential for reliable quantification of bacteria and detection of changes in aquatic bacterial communities. Triplicate measurements of diverse water samples with this protocol typically showed relative standard deviation values and 95% confidence interval values below 2.5% on all the main FCM parameters. We propose a straightforward and instrument-independent method for the characterization of water samples based on the combination of bacterial cell concentration and fluorescence distribution. Analysis of the fluorescence distribution (or so-called fluorescence fingerprint) was accomplished firstly through a direct comparison of the raw FCM data and subsequently simplified by quantifying the percentage of large and brightly fluorescent high nucleic acid (HNA) content bacteria in each sample. Our approach enables fast differentiation of dissimilar bacterial communities (less than 15 min from sampling to final result), and allows accurate detection of even small changes in aquatic environments (detection above 3% change). Demonstrative studies on (a) indigenous bacterial growth in water, (b) contamination of drinking water with wastewater, (c) household drinking water stagnation and (d) mixing of two drinking water types, univocally showed that this FCM approach enables detection and quantification of relevant bacterial water quality changes with high sensitivity. This approach has the potential to be used as a new tool for application in the drinking water field, e.g. for rapid screening of the microbial water quality and stability during water treatment and distribution in networks and premise plumbing.     

24Gb/s GaAs PHEMT激光二极管/调制器驱动器

采用0.2μm GaAs PHEMT工艺设计并实现了超高速光纤通信系统用激光二极管/调制器集成驱动器电路.整个电路由带源极跟随器的两级差分放大电路、电容耦合电流放大器和输出电路组成.电路芯片面积为1.0mm×0.9mm.测试结果表明,采用单一 5V电源供电时直流功耗为1.5W,输出最高电压幅度为2.4V,电路最高工作速率高于24Gb/s,可以应用于光纤通信SDH(synchronous digital hierarchy)传输系统.     

2~26GHzGaAs单片功率放大器

报道了一个具有低噪声性能的2~26GHz GaAs超宽带单片功率放大器的研究结果,介绍了模型提取、电路设计和单片制作的全过程.放大器采用分布式设计,在超宽带频率范围内增益为6.5±0.5dB,输入输出驻波比小于2.0.在2~20GHz内测得输出功率大于300mW,噪声系数为3.5~5.5dB.单片放大器包括所有匹配、隔直及偏置电路,芯片面积为3.2mm×1.275mm×0.1mm.     

一款基于0.13微米CMOS工艺，0.1-18GHz采用双反馈和噪声消除技术的低噪声放大器设计

介绍一款1.2伏0.1-18GHz超带宽级联型低噪声放大器。该LNA采用反馈网络来简化超宽带匹配并且不导致振荡。引入反相器结构作为第二级从而实现噪声消除。同时采用了感性尖峰技术来拓展带宽,所采用电感占用较小面积。带内噪声指数小于4dB,输入输出反射系数均优于-10dB。最大,最小正向增益分别为15.34dB,14.54d,带内平稳增益得以实现。9GHz得到的IIP3和1dB增益压缩点分别为-4dBm及-24dbm。总功耗为30mW。     

20~26 GHz硅基氮化镓可变增益低噪声放大器

基于100 nm硅基氮化镓(GaN)工艺,本文设计并实现了一款工作频段为20～26 GHz且增益平坦的可变增益低噪声放大器(VGLNA).该放大器采用三级共源级级联来实现高增益,并通过调节第二、第三级的栅极偏置实现增益控制.测试结果表明,该放大器在工作频段内实现了超过20 dB的增益可变范围和±1.5 dB的增益平坦度,在增益可变范围内功耗为126 mW至413 mW.在最大增益状态下,该放大器在整个频段内可实现大于20 dB的小信号增益且噪声系数(NF)为2.95 dB至3.5 dB,平均输出1dB压缩点(OP1dB)约为14.5 dBm.该芯片的面积为2 mm~2.     

新型短波窄带接收机射频前端的设计与实现

提出了一种基于射频直接数字化的短波窄带接收机射频前端的设计实现方案,并且着重讨论了作为此方案关键技术的射频AGC及电调谐滤波器的具体设计方案和实现过程。最后给出了电路仿真和测试的结果。     

A front‐end receiver with a dual cross‐coupling technique for MICS applications

This paper presents a front‐end receiver with a dual cross‐couple technique for Medical Implant Communication Services M applications, using a standard complementary metal‐oxide semiconductor process. A lower‐power design is achieved using a resistive feedback, g_m‐boosting technique along with a current reuse topology in the receiver's transconductance stage. In addition, a dual cross‐coupling configuration applied at the input stage increases overall gain performance and reduces power consumption. The measured power dissipation of the low‐noise amplifier is only 0.51 mW. The conversion gain of the receiver is 19.74 dB, while the radio frequency and local oscillator frequencies are respectively 403.5 and 393.5 MHz, and the LO power is 0 dBm. The chip exhibits excellent isolation below −70 dB from LO to intermediate frequency and LO to radio frequency. Copyright © 2016 John Wiley & Sons, Ltd.     

0.03～4.5GHz超宽带低噪声放大器设计与实现

采用负反馈和均衡器结构,选用Avago公司生产的增强型高电子迁移率晶体管ATF55143,利用ADS软件设计、仿真和优化,最终实现了一款覆盖0.03~4.5 GHz频段的低噪声放大器,该模块中的低噪声放大器使用分立元件搭建,匹配电路调试灵活,满足了模块对输入输出驻波的高要求。其增益大于25 d B,平坦度小于等于±0.9 d B,噪声系数小于1.2 d B,输入输出驻波比小于1.75。该放大器模块体积小巧,成本较低,调试灵活,可望在通讯领域得到广泛应用。     

Design and analysis of 0.9 and 2.3-GHz concurrent dual-band CMOS LNA for mobile communication

A complementary metal-oxide-semiconductor (CMOS) dual-band low-noise amplifier (LNA) for 2G/3G/4G mobile communications is presented. It operates at 0.9 and 2.3 GHz of frequencies. The dual-band operation is achieved by adding a modified notch-filtering path in the wideband LNA. The modified notch-filtering path does not require additional power to cancel the signals of the stop band frequency. The impact of the filtering path in the proposed LNA is analyzed. Improved results are observed in dual bands of frequency. Sustainability of the LNA under process corner variation and temperature variation are examined, and it is found to be suitable for the application. The proposed LNA is designed at 90-nm technology in Cadence Virtuoso with 0.5 and 0.6-V supply. The post-layout simulation shows 22 dB of gain (S₂₁), 2 dB of Noise Figure (NF), and −5.5 dBm of IIP3 at the high band. In the low band, 24 dB of S₂₁, 2.7 dB of NF, and −6.65 dBm of IIP3 are reached. The circuit consumes 5.2 mW of power and 0.0918 mm² of area. The efficiency of the LNA is estimated by the figure of merit, and comparable results are secured in the proposed work.     

应用于智能水表的低功耗低噪声放大器设计

提出了基于多管并联结构的低功耗低噪声放大器(LNA),讨论了这种结构下噪声与功耗的相互关系,提出了低功耗LNA基于优化区概念的设计准则.提出的电路具有结构简单对称的特点.在0.35 μm CMOS工艺下进行PSPICE仿真测试.结果表明,新的低噪声放大器在(2.5) V电压下功耗仅为110 μW,等效输入噪声为16.5 nV/Hz~(1/2).与已发表的低噪声放大器比较,具有明显的低功耗特点.