一种新型前馈自动增益控制光接收机的研究

自动增益控制模拟光接收机广泛应用于光纤有线电视、光纤直播卫星电视、无线通讯及雷达等射频微波信号光传输,是实现大动态范围光载波信号高质量接收必不可少的一项技术.我们采用一种入射光功率电平检测与处理的新方法,对模拟光接收机的增益进行控制,将接收机输出电平控制在要求的范围内,实现了一种新型的无射频反馈电路的自动增益控制光接收机.     

外调制微波光子链路性能研究

针对外调制方式工作的微波光子链路,建立了链路的小信号分析模型,理论仿真了调制器输入光功率及调制器直流偏置点对链路增益、噪声系数和线性动态范围的影响。理论仿真与实验结果表明,适当增大调制器输入光功率以及使调制器工作在最佳线性偏置点,可提高链路增益和线性动态范围,同时降低链路噪声系数。该研究为优化外调制微波光子链路性能提供了有益参考。     

Thermoelectric power sensor for microwave applications bycommercial CMOS fabrication

This work describes an implementation of a thermoelectric microwave power sensor fabricated through commercial CMOS process with additional maskless etching. The sensor combines micromachined coplanar waveguide and contact pads, a microwave termination which dissipates heat proportionally to input microwave power, and many aluminum-polysilicon thermocouples. The device was designed and fabricated in standard CMOS technology, including the appropriate superimposed dielectric openings for post-fabrication micromachining. By removing the bulk silicon located beneath the device through micromachining, thermal and electromagnetic losses are minimized. The sensor measures signal true RMS power in the frequency range up to 20 GHz with input power in the -30 dBm to +10 dBm range. Over this 40 dB dynamic range, output voltage versus input power is linear within less than ±0.16%. Automatic network analyzer data show an acceptable input return loss of less than -30 dB over the entire frequency range     

真对数放大器原理及特性分析

提出了利用真对数放大器扩展数字接收机动态范围的方法.对真对数放大器的双音互调特性及其DBF应用进行仿真验证.结果表明,真对数放大器在保留输入信号幅度、相位信息等特性的情况下,把较大的输入功率范围压缩成较小的功率范围,从而实现了比采用线性放大器的接收机更大的动态范围.但是,其较强的非线性效应影响了它在宽带数字接收机中的广泛应用.     

Microwave amplifier based RF optical receivers

Simple architectures for narrowband optical receivers are discussed. The proposed receivers are based on high-impedance photodiodes, lossless distributed matching circuits and matched impedance microwave amplifiers. The gain and noise properties of an experimental C-band receiver are reported.     

Multifunction MMIC history from a process technology perspective

The different types of multifunction microwave monolithic integrated circuits (MMICs) that have been developed to date are reviewed, and projections for the future direction of the technology are made. Various innovative circuit design techniques have allowed a wide range of functions to be performed using the same processes as single-function MMICs. These circuits are almost exclusively based on GaAs Schottky-barrier-gate ion-implanted MESFETs, MIM capacitors, inductors, and (sometimes) through-substrate vias on GaAs substrates. Chips performing all the microwave functions of radar transmit/receive modules, receivers, and frequency synthesizers have been developed. Process complexity is a dominant factor determining their practicality and cost, and the most successful circuits have been designed with process limitations in mind. In the future, proliferation of multifunction MMICs with even greater functional complexity is expected, but additional process complexities will be added sparingly     

An application of FD-TD method for studying the effects of packageson the performance of microwave and high speed digital circuits

The finite-difference time-domain (FD-TD) method is combined with an appropriate time-frequency discrete conversion technique to analyze packaging and time domain transition effects of microwave and high speed digital circuits. The output response of a given input pulse is obtained by linear convolution of the input signal with time domain system function, which is obtained through FD-TD simulation of the whole packaging system including coaxial to microstrip line transitions. As an example, a shielded microstrip line which is connected with coaxial lines, is analyzed and measured. The comparison between experimental and numerical results shows very a good agreement     

微波功率器件的扇形线测试电路

在微波电路原理和半导体器件物理的基础上,设计和模拟了两种用于微波功率器件的测试电路,并且设计了与之配套的测试夹具.采用矢量网络分析仪对该测试电路和夹具在3～8GHz范围内进行了小信号测试.模拟和测试结果都表明,采用扇形线的测试电路性能较好.最后采用该电路和夹具对C波段AlGaN/GaN HEMT微波功率器件进行了微波功率测试,测试频率为5.4GHz.实验测得最大功率增益为8.75dB,最大输出功率为33.2dBm.     

微波功率器件的扇形线测试电路

在微波电路原理和半导体器件物理的基础上,设计和模拟了两种用于微波功率器件的测试电路,并且设计了与之配套的测试夹具.采用矢量网络分析仪对该测试电路和夹具在3～8GHz范围内进行了小信号测试.模拟和测试结果都表明,采用扇形线的测试电路性能较好.最后采用该电路和夹具对C波段AlGaN/GaN HEMT微波功率器件进行了微波功率测试,测试频率为5.4GHz.实验测得最大功率增益为8.75dB,最大输出功率为33.2dBm.     

一种雷达微波接收机电路的集成化设计与实现

文章叙述了实现雷达接收机立体微波集成电路的基板及焊接工艺,研制了一种针对多通道雷达接收机的接收集成电路.提出了芯片电路设计,多层基板实现,以及芯片封装等实现方法.测试结果表明,电路达到了预期的设计目标.该集成电路的实现,提高了雷达整机的集成化水平.     

The design of tuned front-end GaAs MMIC optical receivers

Recently, much interest has been shown in the design of very low noise tuned front-end optical receivers for use in lightwave systems. This paper looks at the accurate design of such receivers. Simplified design expressions are presented for a number of tuning configurations with theoretical and measured results being presented. The designs were realized as GaAs monolithic microwave/millimeter-wave integrated circuits (MMIC's)     

Wide Dynamic Range CMOS Pseudo-differential Current Conveyors: CMOS Realizations and Applications

This paper presents two new CMOS realization circuits of the pseudo-differential current conveyor (PDCC) in which the second realization is a modified version of the first one. The modified PDCC has a wide dynamic input and output ranges with low distortion. The PDCC CMOS circuits are formed from two stages, input stage and output stage, and operating under a supply voltage of ±1.5 V. The input stage of the PDCC is realized using two wide linear range transconductors, and the output stage consists of a class AB push-pull network, which guarantees high current driving capability and low standby current. The first realization of PDCC exhibits dynamic input range of ±1.4 V with a total standby power dissipation of 4.08 mW, while the second realization of the PDCC exhibits a wide dynamic input range of ±2.1 V with a total standby power dissipation of 3.68 mW. The PDCC is used to realize mixed-mode fully differential VGA and a differential-mode bandpass filter. PSPICE simulations of the proposed PDCC and its based applications are given using 0.25-μm CMOS technology from TMSC MOSIS.     

Macromodeling of nonlinear transistor-level receiver circuits

In this paper, a modeling methodology for macromodeling transistor-level receiver circuits has been presented. A few receiver modeling techniques have been proposed in the past, but these modeling techniques only address the loading effect of the receiver circuits, i.e., the input characteristics of the receivers. In this paper, a modeling methodology that addresses both the loading effect as well as the output characteristics of the receiver has been proposed. This modeling technique is simple, accurate, and has huge computational speed-up over transistor-level receiver circuits. To model the input characteristics of the receiver, spline function with finite time difference (SFWFTD) and recurrent neural network (RNN) modeling methods have been used. The output characteristics of the receiver are modeled using a combination of receiver static characteristics and a delay element that takes into account the timing delay of the receiver. The accuracy of the modeling approach has been tested on some test cases and results show good accuracy and substantial speed-up compare to transistor-level receiver circuits. The proposed modeling technique has been extended to multiple ports to estimate sensitive effects like simultaneous switching noise (SSN) when multiple receivers are switching.     

Intermodulation distortion in high dynamic range microwavefiber-optic links with linearized modulators

Linearization of integrated optic intensity modulators significantly reduces the two-tone intermodulation distortion. The resulting intermodulation distortion produced by these modulators then varies as the input power to the fifth-order link system, the overall intermodulation product is a combination of third-order and higher-order terms. The authors determine the dynamic range of a cascaded microwave network consisting of a preamplifier, a high-dynamic-range fiber-optic link with a highly linear modulator, and a postamplifier. An expression is found that relates the intermodulation power at the output to the relative suppression from the signal level. As an example, a hypothetical 10-GHz low-distortion fiber-optic link that has a dynamic range of 125 dB in a bandwidth of 1 Hz is cascaded with various preamplifiers, and it is shown that the dynamic range of the system is reduced by as much as 20 dB, depending on the third-order intercept of the amplifier     

一种新型的宽线性范围差分电压输入电流传输器及其应用

设计了一种带有共模检测电路的宽线性范围差分电压输入电流传输器(DVCCⅡ).所提出的电路具有动态的长尾电流的差分对,可获得较大的动态线性输入范围.所提出的电路可以得到精确跟随特性和宽线性输入范围,且比较已有电路具有低电压低功耗等特点.采用SMIC 0.18μm工艺,用Spectre对电路进行仿真,电源电压是1.8 V,...     

大动态范围抗干扰导航接收机AGC 电路性能分析与优化设计

导航接收机的特点是信号比较微弱,通常淹没于噪声以下,其入口电平的波动几乎都由干扰引起。针对这一特点,存在干扰情况下,要求接收机的噪声系数不能显著恶化。射频通道的噪声系数是制约接收机噪声系数的因素之一,本文在给定射频通道噪声系数恶化容限的条件下,以射频通道能实现最大动态范围为优化目标,分析了动态范围及各级电路增益的求解方法;进一步,针对特殊的纯电阻网络AGC 电路,得到了更为简洁的求解方法;最后,本文给出了该类AGC 电路动态范围的设计实例并进行了测试,设计预期与测试结果得到较好的吻合。本文虽然针对导航接收机设计,但可推广应用于指导各类接收机的设计。     

New miniature 15-20-GHz continuous-phase/amplitude control MMICs using 0.18-/spl mu/m CMOS technology

The design and performance of two new miniature 360/spl deg/ continuous-phase-control monolithic microwave integrated circuits (MMICs) using the vector sum method are presented. Both are implemented using commercial 0.18-/spl mu/m CMOS process. The first phase shifter demonstrates all continuous phase and an insertion loss of 8 dB with a 37-dB dynamic range from 15 to 20 GHz. The chip size is 0.95 mm /spl times/ 0.76 mm. The second phase shifter can achieve all continuous phase and an insertion loss of 16.2 dB with a 38.8-dB dynamic range at the same frequency range. The chip size is 0.71 mm /spl times/ 0.82 mm. To the best of the authors' knowledge, these circuits are the first demonstration of microwave CMOS phase shifters using the vector sum method with the smallest chip size for all MMIC phase shifters with 360/spl deg/ phase-control range above 5 GHz reported to date.     

单通道角跟踪系统接收机AGC控制环路设计

单通道角跟踪系统中角误差信息通常以调幅的形式调制在接收信号包络上,接收机AGC电路必须能够补偿由于传输距离变化引起信号电平起伏,而不引入角误差信息失真。文中采用拉普拉斯变换方式对采用两阶环路滤波器的AGC电路进行分析,得到了电路输出信号以及其失真与输入信号和环路参数的关系。进一步研究表明根据信号传输电平变化最大变化率,合理的设计单脉冲调制速率和环路滤波器的参数,AGC电路能够准确补偿信号传输引起的信号电平变化而几乎不会引入角误差信息失真。     

Stable broadband microwave amplifier design using the simplifiedreal frequency technique

B.S. Yarman's (RCA Rev., vol.43, p.529-41, Sept. 1982) simplified real frequency technique is modified and used to design a stability-guaranteed broadband microwave amplifier consisting of a potentially unstable transistor. The source and load terminations can be complex impedances. The stability is maintained by the conductances resulted from transforming the source and load terminations through the input and output matching circuits. The input and output matching circuits are derived concurrently, instead of sequentially. Repeating the design of an example from a previous paper shows that the transducer gain obtained by using this method is higher, with fewer matching circuit elements, than that obtained by using supercompact optimizers. Moreover, with the same number of matching circuit elements, the transducer gain is slightly higher than that obtained by using the dynamic CAD technique     

一种双通道接收机的设计

工程中,对数放大接收机的动态范围很大,但只能保持频率和相位信息,损失幅度信息.而线性接收机在AGC未建立时的动态范围很小,却可以完整保留幅度信息.文中介绍了一种双通道接收机的设计方法,该设计具有一个线性通道和一个对数通道.利用对数通道的输出,扩大了线性通道的瞬态响应范围.