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.     

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.     

Colorimetric noise analysis of an optical fiber video transmissionsystem

The theoretical aspects of colorimetric noise analysis of an optical fiber receiving system for multichannel television signals is investigated. The effect of display tube nonlinearity on the optical front-end receiver noise is discussed, and an expression for display signal-to-noise ratio (DSNR) is derived. A relation between the standard International Radio Consultative Committee (CCIR) SNR and the DSNR is established. This is used to analyze the displayed picture quality quantitatively in terms of various hues of different saturations. The way in which the displayed picture quality can change under different luminances, is shown     

基于射频前端的动态频谱共享无线通信系统工作信道选择分析

由于有主用户信号的存在和部分射频器件具有不可消除的非线性特性,将在射频接收机前端中产生三阶交调等干扰信号。为了减小干扰信号的影响,从射频接收机前端的角度分析了主用户信号对动态频谱共享无线通信系统的干扰特性,得出了频谱共享无线通信系统工作信道的选择约束条件,遵循此约束条件可以降低干扰信号带来的负面影响,保障频谱共享无线通信系统的通信质量。最后,在UHF频段动态频谱共享无线通信系统中,实验验证了工作信道选择约束条件的有效性。     

Ultrafast Operation of Digital Coherent Receivers Using Their Time-Division Demultiplexing Function

The digital coherent receiver, which is a combination of a phase-diversity optical homodyne receiver and digital signal processing (DSP), can demodulate any multilevel coded optical signals without relying upon an optical phase-locked loop. However, the maximum symbol rate processed by such a receiver is limited by the speed of electric analog-to-digital converters and digital signal processors. Although real-time operation at 10 Gsymbol/s using an application-specific integrated circuit has recently been demonstrated, it is still difficult to increase the symbol rate beyond 40 Gsymbol/s. In order to cope with this difficulty, we propose a novel scheme, which employs a local oscillator (LO) pulsed at the subharmonic frequency of the symbol rate, enabling time-division demultiplexing of the signal at the digital coherent receiver. We demonstrate that the new type of digital coherent receiver operating at 10 Gsymbol/s can demodulate the aggregate symbol rate of 160 Gsymbol/s. From these results, we can expect ultrafast coherent optical fiber communication in the future.      

Multilevel coherent optical system based on Stokes parametersmodulation

A multilevel transmission system that allows efficient exploitation of a single-channel bandwidth in coherent optical communication systems is proposed. It is based on Stokes parameter modulation and a decision on the Poincare sphere. The block scheme of the transmitter, which is able to provide a generic output state of polarization (SOP) starting from a linearly polarized optical field, is shown and described. The propagation along the fiber is described in order to derive the expression of the optical field at the receiver input. The spectral characteristics of the transmitted and the received optical signals are analyzed     

一种T型调谐光接收机前端的改进设计

对T型电感谐振式光接收机进行了详细的理论分析。为了改善调谐前端的低频特性,提出了一种改进型的T型调谐电路结构。采用微波低噪声理论对此进行了分析,结合CAD技术对电路进行优化计算,获得最优参数。构建实验电路对理论分析进行了验证。本文的工作对于调谐光接收机的制作具有较好的实用价值。     

Design and measurements of a RF front-end for Bi-band simultaneous reception

In this paper, we explore spectrum field band simultaneous receivers, with a special emphasis on only one aspect of these systems – the radio front-end. We propose, to validate in the lab, a receiver scheme for the simultaneous down-conversion of two signals in different bands. Obviously, the dedicated scheme is intended for practical use in an integrated circuit. In this work, the chosen receiver is implemented with discrete components. A test set is evaluated and compared to simulations; it contains mostly standard lab equipment, processing signals, according to the receiver scheme; this receiver presents merits and it is worth demonstrating in an integrated circuit.In order to give credit to the use of this type of receiver, the EDA model and results have to be validated by measurement. Therefore, based on the receiver architecture dedicated to an 802.11/UMTS simultaneous dual-channel processing, we design and fabricate a prototype. Firstly, we measure the intrinsic metrics of this prototype in terms of noise figure, gain, linearity, phase and gain mismatch between the two branches of the quadrature mounted mixers. In the present work, we demonstrate that, for instance, as NF and IIP3 change with the RF front-end gain with the improvement of the RF front-end performance, the linearity and the noise requirements are well handled. Afterwards, these metrics are injected in the EDA receiver model and simulations are done in order to evaluate the BER evolution.     

A 5-GHz CMOS double-quadrature receiver front-end with single-stage quadrature generator

A 5-GHz CMOS double-quadrature front-end receiver for wireless LAN application is proposed. In the receiver, a one-stage RLC phase shifter is used to generate quadrature RF signals. Implemented in 0.18 /spl mu/m CMOS technology, the receiver chip can achieve 50.6-dB image rejection with power dissipation of 22.4 mW at 1.8-V voltage supply.     

基于GP2010的移动GPS射频前端设计

对GPS射频前端进行了研究与设计,实现了GPS信号射频到数字中频的转化过程。应用GP2010芯片设计出了符合要求的GPS射频前端,包括前端滤波器、低噪声放大器,以及中频滤波器。介绍测试系统的搭建,对实际制作的电路板进行调试,并得出测试结果,为后期基于FPGA实现GPS基带数字信号处理提供GPS数字中频信号,为自主设计GPS接收机奠定了基础。     

基于ADS的无线接收机数模混合系统级仿真

采用自顶向下的方法，设计了工作于L波段的宽带无线接收机。该接收机采用数模混合的weaver结构。构造了接收机模拟前端和数字基带的各个功能模块，并用ADS(Advanced Design System)软件完成了接收链路的系统级混合信号仿真。     

A 90-dBΩ 10-Gb/s Optical Receiver Analog Front-End in a 0.18-μm CMOS Technology

A 10-Gb/s 90-dBOmega optical receiver analog front-end (AFE), including a transimpedance amplifier (TIA), an automatic gain control circuit, and a postamplifier (PA), is fabricated using a 0.18-mum CMOS technology. In contrast with a conventional limiting amplifier architecture, the PA is consisted of a voltage amplifier followed by a slicer. By means of the TIA and the PA codesign, the receiver front-end provides a -3-dB bandwidth of 7.86 GHz and a gain bandwidth product (GBW) of 248.5 THz-Omega. The tiny photocurrent received by the AFE is amplified to a differential voltage swing of 900 mV_pp when driving 50-Omega output loads. The measured input sensitivity of the optical receiver is -13 dBm at a bit-error rate of 10^-12 with a 2³¹-1 pseudorandom test pattern. The optical receiver AFE dissipates a total power of 199 mW from a 1.8-V supply, among which 35 mW is consumed by the output buffer. The chip size is 1300 mumtimes1796 mum     

MMSE receivers for multirate DS-CDMA systems

Minimum-mean squared error (MMSE) receivers are designed and analyzed for multiple data rate direct-sequence code-division multiple-access (DS-CDMA) systems. The inherent cyclostationarity of the DS-CDMA signal is exploited to construct receivers for asynchronous multipath channels. Multiple- and single-bandwidth access are treated for both single and multicarrier scenarios. In general, the optimal receiver is periodically time-varying. When the period of the optimal receiver is large, suboptimal receivers are proposed to achieve a lower complexity implementation; the receivers are designed as a function of the cyclic statistics of the signals. In multiple chipping rate systems, the complexity of receivers for smaller bandwidth users can also be controlled by changing their front-end filter bandwidth. The effect of front-end filter bandwidth on receiver performance and system capacity is quantified for a variable chipping rate system. Analysis and simulation show that significant performance gains are realized by the periodically time-varying MMSE receivers over their time-invariant counterparts     

Adaptive analog equalization and receiver front-end control formultilevel partial-response transmission over metallic cables

This paper deals with multilevel partial-response class-IV (PRIV) transmission over unshielded twisted-pair (UTP) cables. Specifically, transmission at a rate of 155.52 Mb/s over data-grade UTP cables for local-area networking is considered. As a low-complexity method used to compensate for cable-length dependent signal distortion, adaptive analog equalization with two controlled parameters is proposed: one parameter determines a frequency-independent receiver gain, the other parameter controls the transfer characteristic of a variable analog receive-filter section. For the stepwise design of the transmit and receive filters, a combination of analytic techniques and simulated annealing is employed. First, the variable equalizer section, then the remaining fixed analog receive filter section are developed and finally the analog transmit filter is determined. The paper also describes the adjustment of the equalizer section, and the control of the sampling phase in the receiver front-end. The two equalizer parameters are controlled by an algorithm that operates on the sampled signals and adjusts these parameters to optimum settings independently of the sampling phase. The latter is controlled by a decision-directed phase-locked loop algorithm that becomes effective when equalization has been achieved. The dynamic behaviour and mean-square error in steady-state obtained with these control algorithms are investigated     

采用LTCC技术的X波段接收前端MCM设计

多芯片组件(MCM)是目前实现机载雷达接收前端小型化的最有效途径。文中对X波段全频段多功能接收前端的组成、采用LTCC技术的MCM设计实现及实物测试数据进行了叙述和分析,给出了采用LTCC技术的X波段多功能接收前端MCM设计的一种解决方案。该MCM接收前端的测试指标满足雷达通用接收前端要求,为雷达小型化多功能接收前端的设计提供了参考依据。     

A 1.8-V 10-Gb/s fully integrated CMOS optical receiver analog front-end

A fully integrated 10-Gb/s optical receiver analog front-end (AFE) design that includes a transimpedance amplifier (TIA) and a limiting amplifier (LA) is demonstrated to require less chip area and is suitable for both low-cost and low-voltage applications. The AFE is fabricated using a 0.18-/spl mu/m CMOS technology. The tiny photo current received by the receiver AFE is amplified to a differential voltage swing of 400 mV/sub (pp)/. In order to avoid off-chip noise interference, the TIA and LA are dc-coupled on the chip instead of ac-coupled though a large external capacitor. The receiver front-end provides a conversion gain of up to 87 dB/spl Omega/ and -3dB bandwidth of 7.6 GHz. The measured sensitivity of the optical receiver is -12dBm at a bit-error rate of 10/sup -12/ with a 2/sup 31/-1 pseudorandom test pattern. Three-dimensional symmetric transformers are utilized in the AFE design for bandwidth enhancement. Operating under a 1.8-V supply, the power dissipation is 210 mW, and the chip size is 1028 /spl mu/m/spl times/1796 /spl mu/m.     

Wide bandwidth low noise pinFET receiver for high-bit-rate opticalpreamplifier applications

A wide bandwidth low noise pinFET receiver has been fabricated and characterised for optical preamplifier applications. The receiver uses a low capacitance planar pin diode as the photodetector. A bandwidth of 7.08 GHz was measured. The measured input noise current for the receiver front-end is lower than 12 pA/√(f). Using a 1.3 μm DFB laser as the transmitter, at a data rate of 4 Gbit/s, the measured receiver sensitivity is -25.5 dBm with a bit-error-rate of 1×10 ^-9. A set of two of such receivers has also been tested in a 1.3 μm polarisation-insensitive optical preamplifier system experiment. The measured receiver sensitivity, including an optical insertion loss of 1.5 dB, is -29.3 dBm     

Double turbo equalization of continuous phase modulation with frequency domain processing

In this paper, a doubly-iterative linear receiver, equipped with a soft-information aided frequency domain minimum mean-squared error (MMSE) equalizer, is proposed for the combined equalization and decoding of coded continuous phase modulation (CPM) signals over long multipath fading channels. In the proposed receiver architecture, the front-end frequency domain equalizer (FDE) is followed by the soft-input, softoutput (SISO) CPM demodulator and channel decoder modules. The receiver employs double turbo processing by performing back-end demodulation/decoding iterations per each equalization iteration to improve the a priori information for the front-end FDE. As presented by the computational complexity analysis and simulations, this process provides not only a significant reduction in the overall computational complexity, but also a performance improvement over the previously proposed iterative and noniterative MMSE receivers.     

Receiver designs and channel characterization for multi-spothigh-bit-rate wireless infrared communications

This paper addresses one of the most promising candidates for high-speed in-house wireless communications, namely, the multi-spot diffusing configuration (MSDC). Since it uses the optical infrared medium for data transmission, it has the inherent potential for achieving very high capacities. The channel characteristics in MSDC are simulated and the causes for channel distortion are analyzed. Then, conditions for creation of a virtually ideal channel are derived. It is shown that the 3-dB channel bandwidth can be extended up to beyond 2 GHz. This bandwidth comes at the cost of a poor power efficiency. In order to compensate for that, a novel receiver optical front-end design is proposed and its performance is analyzed. Taking advantage of the unique properties of the holographic optical elements, the conventional optical front-end, consisting of a concentrator and a filter, is replaced by a single holographic curved mirror. The utilization of such a holographic optical element improves the signal-to-shot noise ratio by up to 18.5 dB