Balanced Detection of Correlated Incoherent Signals: A Statistical Analysis of Intensity Noise With Experimental Validation

We study the balanced detection of broadband incoherent optical signals-signals characterized by high-intensity noise. We consider signals generated from a single incoherent source with two types of correlation: identical spectra, but delayed in time, and overlapping, nonidentical spectra but zero time delay. Our statistical analysis yields equations for the probability density function (pdf) of the balanced detector output for partially correlated input signals based on easily measured system parameters (power spectral densities in one case, relative time delay in the other). Using analytical tools we derive expressions for output pdfs giving extremely good prediction of measured pdfs for signals with correlation coefficient up to 95%. The analytic expressions can be used to characterize system performance, in particular, bit error rate for communications systems.     

Experimental demonstration of variable weight SAC-OCDMA system for QoS differentiation

In this paper the experimental and simulation results of variable-weight spectral amplitude coding optical code division multiple access (VW-SAC-OCDMA) system is demonstrated. In the proposed system, three users with weights of 6, 4 and 2 each operating at data rate of 1.25 Gb/s represent video, data and voice services, respectively. Results show that for back-to-back system minimum average power of −20 dBm per chip is required to maintain the acceptable performance. Transmission up to 60 km of fiber is demonstrated. Using mathematical approximation the capacity of VW-SAC-OCDMA system is demonstrated.     

一种用于GPS接收机的低噪声放大器

针对GPS接收机低功耗、低噪声、高增益的要求,采用功率限制下噪声匹配技术、阻抗匹配技术和电源复用技术,设计了一款可应用于GPS接收机的单端输入差分输出低噪声放大器,减少了巴伦损耗。采用SMIC 0.13 SymbolmAm CMOS RF工艺和全定制集成电路设计方法,工作频率为1575 GHz,对电路进行版图后仿真。仿真结果表明,该低噪声放大器在1.2 V电源电压下,功耗为4.8 mW,增益为22.65 dB,噪声系数为1.388 dB。     

S波段雷达接收机前端低噪声放大器

采用0.35μm SiGe BiCMOS工艺设计了用于S波段雷达接收机前端电路的低噪声放大器。对于现代无线接收机来说,其动态范围和灵敏度很大程度上都取决于低噪声放大器的噪声性能和线性度。相对于CMOS工艺来说,SiGe BiCMOS工艺具有更高的截止频率、更好的噪声性能和更高的电流增益,非常适合微波集成电路的设计。该低噪声放大器采用三级放大器级联的结构以满足高达30dB的增益要求。在5V的电源电压下,满足绝对稳定条件,在3GHz-3.5GHz频段内,功率增益为34.5dB,噪声系数为1.5dB,输出1dB功率压缩点为11dBm。     

An Enhanced SOA-Based Double-Loop Optical Buffer for Storage of Variable-Length Packet

To extend the buffer depth of a fiber loop optical buffer, we have experimentally demonstrated an enhanced semiconductor optical amplifier (SOA)-based dual-loop optical buffer (DLOB) for storing variable-length optical packets. We have theoretically derived constraints governing the buffer depth of the DLOB, in which the SOA not only provides a nonlinear phase shift in the loop to implement the buffer function but also compensates for the fiber loop attenuation during long-time storage. It is found that the maximum allowable length of a stored packet to avoid the counter-propagation packet collision inside the SOA depends on the SOA bias position as well as the length of the fiber loop. To demonstrate the effectiveness of the proposed enhanced configuration, we have successfully demonstrated the storage of 2.5-Gbps variable-length packets even when the length of the input packet exceeds the corresponding length of the fiber loop. Another unique advantage of the proposed enhanced DLOB configuration is that it can also overcome the problem of power leakage of the stored packet due to a directional gain difference of single SOA and gain saturation. Index     

超宽带低温接收机后级低噪声放大器设计

设计了一种用于超宽频低温接收机后级放大的宽带低噪声放大器,并给出了仿真和测试结果。该低噪声放大器采用三个单片级联,并在级间加入了均衡和衰减网络对增益进行修正,使增益平坦度得到很大改善,同时对噪声等指标影响较小。最终实现的低噪声放大器在1～9GHz 频率范围内,常温噪声系数优于2dB,增益大于35dB,平坦度小于3.5dB,输入输出驻波比小于2.5,输出1dB 压缩点功率大于10dBm。     

双频段接收机中的BiFET低噪声放大器

设计了一种采用BiFET结构的低噪声放大器（LNA）,这种结构通过BiCMOS工艺使低噪声放大电路集合了双极型晶体管的低噪声特性和CMOS晶体管的高线性度。应用优化的BiFET Cascode共源共栅结构能够明显地提高低噪声放大器的性能,并且能应用于两个不同频率。本文设计的低噪声放大器在低偏置电流（1．7mA）和低功耗（5．7mW）的情况下能取得1．69dB的噪声系数、15．96dB的电压增益、一8．5dBm的IIP3和-67dB的反向隔离。设计的BiFET低噪声放大器是采用了AMS0．8μm的BiCMOS混合信号工艺,经过优化可以用于工业、室内的远程无线控制系统包括无线门禁系统。     

Multilevel Converters: An Enabling Technology for High-Power Applications

Multilevel converters are considered today as the state-of-the-art power-conversion systems for high-power and power-quality demanding applications. This paper presents a tutorial on this technology, covering the operating principle and the different power circuit topologies, modulation methods, technical issues and industry applications. Special attention is given to established technology already found in industry with more in-depth and self-contained information, while recent advances and state-of-the-art contributions are addressed with useful references. This paper serves as an introduction to the subject for the not-familiarized reader, as well as an update or reference for academics and practicing engineers working in the field of industrial and power electronics.      

一种用于卫星导航接收机的低噪声放大器设计

设计了一种可用于多模式卫星导航接收机的射频前端低噪声放大器,设计电路可在1.13～1.95 GHz工作,兼容了GPS,北斗及GLONOSS导航系统的工作频段。电路采用0.18 μm CMOS工艺实现。仿真结果表明,频带内S11和S22均在-10 dB以下,功率增益＞10 dB,带内最小噪声系数可达到2.2 dB,输出1 dB压缩点为-5.585 dBm,在1.8 V电源电压下,主体电路消耗12 mA电流。因此,该低频噪声放大器模块可满足当前各种导航系统的工作要求。     

一种抑制相位噪声的多通道变时延下变频全双工收发方法

相位噪声会限制全双工(FD)收发机的自干扰抑制能力,恶化有用信号解调性能,即使全双工收发机采用发射机、接收机共用本振的结构,也无法消除相位噪声的限制作用。为了降低多径自干扰(SI)分量中相位噪声的影响,该文提出一种多通道变时延下变频全双工收发方法,具体包括可以补偿相位噪声的全双工收发机设计和能够抑制残余相位噪声的自干扰抑制算法。多通道变时延下变频全双工收发机采用多条通道接收同一天线的信号,各接收本振信号为经过不同延时调整的发射本振信号,可以在下变频时补偿多径自干扰中的相位噪声。自干扰抑制算法利用不同接收信号估计相位噪声参数,进一步降低残余相位噪声的影响。此外,该文推导了这种全双工收发方法的自干扰抑制能力,并给出了其随发射功率、接收通道数量的变化关系。分析与仿真结果表明,当接收通道数量高于自干扰信道强径数量时,多通道变时延下变频全双工接收方法不受相位噪声影响。     

用于GPS接收机的130 nm PD-SOI低噪声放大器

基于130 nm PD-SOI工艺,设计了一种用于GPS接收机射频前端的单片低噪声放大器(LNA)。利用SOI工艺特有的低噪声特性,降低了衬底耦合到电路的噪声。采用单独的带隙基准源和LDO为低噪声放大器供电,降低了电源纹波和高频噪声对放大器噪声性能的影响。测试结果表明,在3.3 V电源电压、1.575 GHz工作频率下,该LNA的噪声系数仅为1.49 dB,增益为13.7 dB,输入回波损耗S11、输出回波损耗S22均小于-15 dB,输入P1 dB为-13 dBm,IIP3为-0.34 dBm。     

光接收机前端等效输入噪声电流谱密度与噪声系数间的关系

根据光接收机前端等效电路模型,建立了噪声系数与等效输入噪声电流谱密度的关系.提出通过测量光接收机前端电路噪声系数间接获得等效输入噪声电流谱密度的方法.155Mb/s高阻结构光接收机前置放大器的电路仿真与计算验证了推导公式的正确性.最后给出在芯片测试实例.     

光接收机前端等效输入噪声电流谱密度与噪声系数间的关系

根据光接收机前端等效电路模型,建立了噪声系数与等效输入噪声电流谱密度的关系.提出通过测量光接收机前端电路噪声系数间接获得等效输入噪声电流谱密度的方法.155Mb/s高阻结构光接收机前置放大器的电路仿真与计算验证了推导公式的正确性.最后给出在芯片测试实例.     

Canonical Non-Gaussian Noise Models: Their Implications for Measurement and for Prediction of Receiver Performance

The chief aim of this paper is to provide a short technical summary of the principal noise-model results (11-[11], developed by the author to date, and to consider their major implications for 1) measurement, and 2) performance prediction and evaluation. The discussion is illustrated by a concise review of model statistics, methods of estimating the model parameters, including the effects on accuracy of finite data samples. A variety of signal detection problems are similarly used to illustrate the very large potential improvement possible when optimum algorithms are employed, vis-a-vis most of the currently used systems, which are conventionally optimized for Gaussian interference. Conditions for realizing such gains are also given, and the principal key properties of these new, general models are discussed. These models make possible, for the first time, a systematic treatment of real-world EMI environments, both for measurement and assessment, and for receiver performance therein.     

全数字突发信号接收机实现

突发通信具有环境噪声大,突发帧短等特点,常规的解调器不能满足要求,文中提出了一种全数字突发信号实现方案,以并行进行位同步,载波同步等加快捕获速度.通过在Xilinx的FPGA上实现,并经工程测试表明,该接收机具有高速传输、捕获速度快等特点,适合高速突发通信场合使用.     

光纤通信接收机放大器的等效噪声模型

许多光纤通信文献给出了如图1所示的光接收放大器的等效噪声模型。本文证明了这个等效噪声模型与原始噪声模型不等价，并且也不具有可测性。所以，这个等效噪声模型是不正确的，因而不宜采用。作者认为，在光纤通信接收机的设计中，噪声计算只是为了分析接收机的灵敏度，而不是用来确定最佳信号源电阻，因而可以不用等效噪声模型，直接用原始的噪声模型反而更简单和更精确。     

Receiver IQ Imbalance Estimation via Pure Noise for 60 GHz Systems

This paper proposes to estimate receiver (RX) IQ imbalance via pure noise for 60 GHz millimeter-wave systems. We study the impact of RX IQ imbalance on noise, and derive the maximum-likelihood algorithm to acquire the imbalance parameters, which is decoupled from transmitter IQ imbalance, channel response, and carrier offset. Also, the proposed method has low computational complexity and meets the low-power and low-cost requirements of 60 GHz systems. Moreover, the jitter performance of the estimation reaches the corresponding Cramer–Rao lower bound under a wide range of imbalance parameters.     

433 MHz ASK接收机中低噪声锁相环的设计

采用0.18 μm CMOS RF工艺,实现了一款用于433 MHz ASK接收机的低噪声锁相环.系统采用优化的电源组合和合理的版图布局避免模块间的噪声干扰;VCO模块运用LC滤波器、LDO调压器,结合开关电容阵列调谐技术,提高相位噪声性能;针对鉴频鉴相器和电荷泵的非线性问题进行详细讨论和优化,提高了线性度.测试结果表明,电源电压为3.3 V时,偏置电流为7 mA,中心频率为433 MHz,在频偏100 kHz和1 MHz处,相位噪声分别为-96.47 dBc/Hz和-126.96 dBc/Hz.