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.     

低噪声、宽带调谐光接收机的分析与设计

通过对最优噪声匹配网络的分析，提出了光接收机的设计方法。它基于噪声系数概念和宽带匹配理论，同时引入了等效输入热噪声电流的概念。由于在分析过程中直接利用有源器件的噪声参数(最小噪声系数、噪声阻抗和最佳源阻抗)，这种设计方法是很精确的。通过分析，确定了调谐网络噪声匹配的—般条件，其目标是使光接收机获得最小等效输入噪声电流。     

低噪声、宽带调谐光接收机的分析与设计

通过对最优噪声匹配网络的分析,提出了光接收机的设计方法。它基于噪声系数概念和宽带匹配理论,同时引入了等效输入热噪声电流的概念。由于在分析过程中直接利用有源器件的噪声参数(最小噪声系数、噪声阻抗和最佳源阻抗),这种设计方法是很精确的。通过分析,确定了调谐网络噪声匹配的一般条件,其目标是使光接收机获得最小等效输入噪声电流。     

结型场效应晶体管低频噪声测试方法研究

在深入研究JFET低频噪声特性及产生机理的基础上,提出了一种通过测试宽频带功率谱密度得到其规定频率处等效输入噪声电压功率谱密度和噪声系数的测试方法,并给出了低频噪声测试的偏置电路、测试设备和测试方法。结合3DJ4和3DJ6型JFET器件的测试结果表明,采用本文提出的方法可适用于JFET的低频噪声的测试。     

长波长PIN／HBT集成光接收机前端噪声分析

文章研究磷化铟(InP)基异质结双极晶体管(HBT)和PIN光电二极管(PIN-PD)单片集成技术,利用器件的小信号等效电路详细计算了长波长PIN/HBT光电子集成电路(OEIC)光接收机前端等效输入噪声电流均方根(RMS)功率谱密度.分析表明:对于高速光电器件,当频率在100 MHz～2 GHz范围内时,基极电流引起的散粒噪声和基极电阻引起的热噪声起主要作用;频率大于5 GHz时,集电极电流引起的散粒噪声和基极电阻引起的热噪声起主要作用.在上述结论的基础上,文章最后讨论了在集成前端设计的过程中减小噪声影响的基本方法.     

接收机射频前端噪声特性分析

噪声是影响接收机灵敏度的重要因素之一。接收机引入的噪声越小,接收机灵敏度就越高。分析了接收机噪声,给出了射频前端噪声系数与接收机灵敏度的关系,论述了几种改善射频前端噪声系数的方法。     

基于MC2045的1550nm的SFF光接收机噪声特性分析及设计

分析了光接收机噪声特性,讨论了Peraonick定义的加权常数I1I2I3和∑1与输入输出脉冲的形状、输入光功率产生的与信号有关的等效输入噪声功率之间的关系,选择适当的灵敏度与动态范围,具体阐述了光收发合一模块SFF中接收部分构成,设计出基于MC2045的1 550nm的SFF.     

10Gb/s光接收机跨阻前置放大器芯片设计研究

采用0.18 μm BiCMOS工艺设计并实现了一种高增益、低噪声、宽带宽以及大输入动态范围的光接收机跨阻前置放大器.在寄生电容为250 fF的情况下,采用全集成的四级放大电路,合理实现了上述各项参数指标间的折中.测试结果表明:放大器单端跨阻增益为73 dB,-3 dB带宽为7.6 GHz,灵敏度低至-20.44 dBm,功耗为74 mW,最大差分输出电压为200 mV,最大输入饱和光电流峰-峰值为1 mA,等效输入噪声为17.1 pA/√Hz,芯片面积为800 μ.m×950μm.     

城市无线电噪声的测量及分布规律研究

本文以等效天线噪声系数作为测量参数，测量了南京地区的城市无线电噪声，得到各类地区的噪声—频率预测方程和噪声与汽车流量的关系方程，并分析了我国城市无线电噪声的特性。     

多通道射频接收机测量噪声系数的新方法

噪声系数是多通道射频接收机的一个重要参数。传统的噪声系数测量方法对大噪声系数测量存在不足,且测量时通道间会有噪声干扰。提出一种多通道切换优化测量噪声系数的方法:通过设计1个八选一的射频开关实现信道切换,并引入前置低噪声放大器的控制电路提供冷热噪声源,优化Y因子测量噪声系数的方法,实现对各通道的精确测量。由于接收机前端的相似性,该方法可推广应用到其他的射频接收机。     

Noise in distributed MESFET preamplifiers

The theory of noise in a distributed MESFET preamplifier is developed. From this, it is shown that the equivalent input noise current density of a distributed preamplifier of an optical receiver can be improved by using large gate line matching impedance and appropriate scaling of the MESFET width. A front-end tuning circuit was designed using filter theory to further improve the noise performance of the preamplifier. A monolithic GaAs MESFET distributed preamplifier was fabricated with on chip front-end tuning components. Using a 35 μm InGaAs p-i-n photodiode, the preamplifier was shown to have an equivalent input noise current density of 8 pA/√Hz and an 8 GHz bandwidth. To date, this is the best known result for a 0.8 μm GaAs MESFET process     

Noise performance of optical receivers: comparison of directional coupler and resistive feedback based front ends

Noise properties of a directional-coupler-based optical receiver (DCOR) and the resistive-feedback optical receiver (RFOR) topologies are compared. For the DCOR the authors have both simulated and subsequently measured an input equivalent noise current of 3 pA/ square root (Hz) for a bandwidth of up to 2.5 GHz. By using the same noise modelling approach the simulation results for the RFOR topology gave a noise current of 10 pA/ square root (Hz) over the same bandwidth thus verifying the superiority of the DCOR over the resistive feedback optical receiver.<>     

Fiber-optic multigigabit GaAs MIC front-end circuit with inductorpeaking

The design and performance of a multigigabit optical front-end circuit are discussed. Inductor peaking is applied to the GaAs MIC preamplifiers and a 3-dB down bandwidth of 6.5 GHz, 15.5-pA/√Hz averaged input equivalent noise current density from 10 MHz to 6.5 GHz, and transimpedance gain of 57 dB are achieved. A 3-dB down bandwidth of 6.1 GHz is achieved in an optical front-end circuit with a InGaAs p-i-n photodiode. This performance indicates that the optical front-end circuit with inductor peaking is promising for multigigabit optical receivers     

Using High Frequency Operational Amplifiers for Low Noise Design

In this paper we present a comprehensive noise and stability analysis of both the current feedback and the voltage feedback op-amp when connected as transimpedance amplifiers with capacitive current sources. It is generally assumed that the current feedback op-amp is noisier than the voltage feedback op-amp; we show how external component values play an important role in determining the total equivalent input noise current spectral density and show that the voltage feedback op-amp may, in certain cases, be noisier than the current feedback op-amp. Both amplifier types are compared in terms of stability, noise and bandwidth; we find that the current feedback op-amp is particularly suited for operation as a transimpedance amplifier. Theoretical analysis is confirmed by simulations of equivalent circuits of the current feedback op-amp and the voltage feedback op-amp, and simulations of the macro models of two high performance commercially available op-amps, namely the Elantec EL2260 current feedback op-amp and the Elantec EL2244 voltage feedback op-amp.     

High-performance monolithically integratedIn0.53Ga0.47As/InP p-i-n /JFET optical receiverfront-end with adaptive feedback control

An optical transimpedance receiver front-end that is adaptable to a wide range of bit-rates up to 3 Gb/s has been realized by monolithically integrating high efficiency p-i-n photodiodes with low noise InGaAs junction field effect transistors. The transimpedance-bandwidth product of the receiver is 2.8 THz Ω. The average equivalent input noise current for full circuit bandwidth is 4.0 pA/√Hz. The preamplifier for nonreturn to zero data transmission without equalization of the frequency response at 1.55 μm offers a sensitivity of -41.5 dBm and -29.5 dBm at 140 Mb/s and 2.4 Gb/s, respectively. The dynamic range is 17 dB at 2.4 Gb/s and exceeds 30 dB at 500 Mb/s     

Design and anaylsis of a 2.5-Gbps optical receiver analog front-end in a 0.35-/spl mu/m digital CMOS technology

This paper presents the design of an optical receiver analog front-end circuit capable of operating at 2.5 Gbit/s. Fabricated in a low-cost 0.35-/spl mu/m digital CMOS process, this integrated circuit integrates both transimpedance amplifier and post limiting amplifier on a single chip. In order to facilitate high-speed operations in a low-cost CMOS technology, the receiver front-end has been designed utilizing several enhanced bandwidth techniques, including inductive peaking and current injection. Moreover, a power optimization methodology for a multistage wide band amplifier has been proposed. The measured input-referred noise of the optical receiver is about 0.8 /spl mu/A/sub rms/. The input sensitivity of the receiver front-end is 16 /spl mu/A for 2.5-Gbps operation with bit-error rate less than 10/sup -12/, and the output swing is about 250 mV (single-ended). The front-end circuit drains a total current of 33 mA from a 3-V supply. Chip size is 1650 /spl mu/m/spl times/1500 /spl mu/m.     

Analysis of the transistor-related noise in integrated p-i-n-HBToptical receiver front-ends

The equivalent-input-noise-current spectral density for a monolithically integrated optical receiver front-end using InP/InGaAs heterojunction bipolar transistors and a p-i-n photodiode is computed from a small-signal model. Particular attention is paid to the contributions to the noise from the HBT in the first stage of the amplifier. It is shown that with transistors designed for 1-10-Gb/s receivers the base current shot noise dominates in the frequency range from 10 MHz to 1 GHz, and both the base resistance thermal noise and the collector current shot noise are important at higher frequencies. Device features which determine the extent of these noise sources are identified, and ways to improve the noise performance are discussed