共查询到20条相似文献,搜索用时 0 毫秒
1.
《Solid-State Circuits, IEEE Journal of》1993,28(1):90-92
A bandwidth-enhancing technique is presented for wideband amplifiers. In this technique a capacitive feedback scheme is used in analogy to resistive feedback amplifiers. As capacitive feedback does not lower gain, the technique does not trade off gain for bandwidth. Computer simulations and practical circuits show a considerable improvement over the conventional widebanding techniques 相似文献
2.
Optimal design of flat-gain wide-band fiber Raman amplifiers 总被引:21,自引:0,他引:21
We present a novel method for designing multiwavelength pumped fiber Raman amplifiers with optimal gain-flatness and gain-bandwidth performance. We show that by solving the inverse amplifier design problem, relative gain flatness well below 1% can be achieved over bandwidths of up to 12 THz without any gain equalization devices. This constitutes a substantial improvement in gain flatness compared to the existing wide-band optical fiber amplifiers 相似文献
3.
Analysis and design of HBT Cherry-Hooper amplifiers with emitter-follower feedback for optical communications 总被引:3,自引:0,他引:3
Holdenried C.D. Haslett J.W. Lynch M.W. 《Solid-State Circuits, IEEE Journal of》2004,39(11):1959-1967
In this article, the large-signal, small-signal, and noise performance of the Cherry-Hooper amplifier with emitter-follower feedback are analyzed from a design perspective. A method for choosing the component values to obtain a low group delay distortion or Bessel transfer function is given. The design theory is illustrated with an implementation of the circuit in a 47-GHz SiGe process. The amplifier has 19.7-dB gain, 13.7-GHz bandwidth, and /spl plusmn/10-ps group delay distortion. The amplifier core consumes 34 mW from a -3.3-V supply. 相似文献
4.
DC boosting effect of active bias circuits and its optimization for class-AB InGaP-GaAs HBT power amplifiers 总被引:1,自引:0,他引:1
In this paper, dc sourcing capability (DSC), which is a very important consideration in design of active bias circuits for power amplifiers based on bipolar technologies, will be explained. The nonlinear effect of bias circuits on the dc sourcing characteristics has been analyzed with simplified circuits for power amplifiers using the Volterra series. The analysis shows that the second-order distortion generated by a bias buffer transistor can boost bias level of the RF transistor to compensate finite DSC available in the absence of this effect. The bias-level boosting due to RF injection can be optimized by tuning the value of a series resistor between the emitter of the buffer transistor and the base of the RF transistor. Amplifiers with different series resistors have been implemented and tested with an IS95-B code-division multiple-access signal at the cellular band (824-849 MHz). The experimental results verify that a circuit-level optimization for the second-order distortion of the bias circuits is very important for optimizing the linearity and efficiency of the HBT amplifiers. 相似文献
5.
《Electron Devices, IEEE Transactions on》1968,15(7):491-501
The problem of wide bandwidth and flat in-band gain response for microwave transistor amplifiers has been reduced to the optimization of a number of important variables from computer prepared design charts. Through the general flexibility of the computer-generated data, a large variety of amplifier responses are possible - using distributed circuit matching networks. As experimental verification of the overall design procedure, single-stage and two-stage octave wide transistor amplifiers were fabricated on 1 inch by 1 inch and 1 inch by ½ inch 20 mil thick alumina, respectively. The experimental data gained from these units showed excellent correlation with the computer predicted response. 相似文献
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7.
van der Heijden M.P. de Vreede L.C.N. Burghartz J.N. 《Solid-State Circuits, IEEE Journal of》2004,39(10):1727-1736
This work describes the theory and design of a nonenergetic dual-loop feedback low-noise amplifier (LNA) that provides maximum unilateral gain and simultaneous noise and impedance matching conditions. The dual-loop feedback is implemented in the form of transformer current-feedback and inductive series feedback (emitter degeneration). The current-feedback transformer is also used to neutralize the base-collector capacitance (C/sub bc/), by combining it with a properly dimensioned shunt admittance at the collector output. The result is a single-transistor unilateral-gain amplifier with high isolation and good stability, eliminating the need for a cascode stage and thus enableing the use of a lower dc-supply voltage. For the complete LNA, simple design equations are derived for the unilateralization, noise, and impedance matching requirements. Finally, second-harmonic tuning at the source improves the linearity without compromising the simultaneous noise and impedance match. To verify the presented theory, a 900-MHz hybrid Si BJT LNA has been implemented, which achieves 1.3-dB noise figure, 15-dB gain, -55dB isolation, and +10dBm IIP3 using a conventional double poly transistor, consuming I/sub C/=2.5 mA at V/sub CE/=1.5 V. 相似文献
8.
Yang C.C. Nelson B.L. Allen B.R. Jones W.L. Horton J.B. 《Microwave Theory and Techniques》1993,41(6):992-997
Two wideband (8-18-GHz) single-stage MMIC (monolithic microwave integrated circuit) low-noise amplifiers (LNAs) using 0.2-μm T-gate InGaAs pseudomorphic HEMT (high-electron-mobility transistor) technology, designed and fabricated for room temperature operation, were evaluated and compared at cryogenic temperatures below 20 K. One is a balanced design using 3-dB Lange couplers, and the other is a feedback design using a series RLC parallel feedback network. The gain flatness over the 8-18-GHz frequency band was maintained for both amplifiers at room and cyrogenic temperatures, indicating that the topology for wideband designs is insensitive to temperature of operation. As the physical temperature decreased from 297 K to below 20 K, the balanced LNA exhibited an average gain increase of 2 dB and as much as an eightfold reduction of noise temperature to 20 K, while the feedback LNA exhibited an average gain increase of less than 1 dB and an average foufold reduction of noise temperature to 50 K. The negative feedback network of the feedback LNA resulted in less gain increase and less noise temperature reduction at cryogenic temperatures 相似文献
9.
Maundy B.J. Sarkar A.R. Gift S.J. 《Circuits and Systems II: Express Briefs, IEEE Transactions on》2006,53(1):34-38
A new topology for designing low-voltage current feedback amplifiers (CFAs) is presented. By employing a second-generation positive current conveyor followed by an operational amplifier in an unconventional manner, the design circumvents the problem of trying to achieve large transimpedance in a low-voltage environment. It is shown that this CFA configuration also results in near gain independent closed-loop bandwidth defined by a single feedback resistor. The proposed amplifier was verified experimentally by a chip designed using Taiwan Semiconductor Manufacturing Company's 0.18-/spl mu/m digital CMOS process of a single-ended power supply of 1.8 V. 相似文献
10.
Yong-Sang Cho Woo-Young Choi 《Quantum Electronics, IEEE Journal of》2001,37(4):574-579
Polarization sensitivity of semiconductor optical amplifiers (SOAs) with delta-strained quantum-well (QW) structures is investigated. The valence band structures and TE, TM optical gain spectra are calculated for the various delta-strained QW structures. It is shown that the number and location of the delta layers affect the polarization dependence of the delta-strained quantum well SOA signal gains. The optimal delta-strained QW structure for the SOA application is identified and its theoretical verification is provided 相似文献
11.
I. M. Pandiev 《International Journal of Electronics》2013,100(10):663-677
The present paper discusses specific types of LC amplifier and LC oscillator using a current-feedback amplifier (CFA). The main advantage of the CFAs versus voltage-feedback amplifiers (VFAs) is their gain-bandwidth independence. Some of the monolithic CFAs provide an additional pin between the first stage (current-controlled current source) and the second stage (voltage follower), where the resistance is very high. This allows a parallel resonance LC tank to be connected to the additional op amp correction pin. The main advantage of this new configurations is the insignificant influence of the load over the parameters of the circuit (voltage gain, Q-factor, etc.). Some recommendations for designing this kind of analogue circuit are given, based on simulation results, symbol analysis of the transfer function and physical experiments as well as elements’ values calculation using centre frequency, voltage gain, bandwidth and Q-factor of the LC amplifiers as input parameters. 相似文献
12.
Zhengyu Sun Hongwen Yang Lijun Zhang Yuepeng Yan 《Analog Integrated Circuits and Signal Processing》2013,74(1):203-213
A technique for bandwidth extension and noise optimization of wideband low-noise amplifier with dual feedback loops is presented. A LC-ladder matching network has been added in front of conventional amplifier with dual feedback loops. Detailed circuit analysis and general design procedures for the modified amplifier have been provided. The technique is applied to an amplifier covering the frequency range from DC to 6 GHz in a 0.5 μm InGaAs E-mode pHEMT process. Post-layout simulation shows S 11 below ?10 dB, S 22 below ?10 dB, flat S 21 of 16 ± 0.2 dB, and flat NF of 1.85 ± 0.35 dB across the entire band, which confirms the improvement in bandwidth and noise performance. 相似文献
13.
Analysis and design of wide-band SiGe HBT active mixers 总被引:1,自引:0,他引:1
The frequency response of SiGe HBT active mixers based on the Gilbert cell topology is analyzed theoretically. The time-varying operation of the active mixer is taken into account by applying conversion matrix analysis. The main bandwidth-limiting mechanisms experienced in SiGe HBT active mixers performing frequency conversion of wide-band signals is discussed. The analysis is verified by computer simulations using a realistic high-frequency large-signal SiGe HBT model. An active mixer design based on the Gilbert cell topology modified for wide-band operation using emitter degenerated transconductance stage and shunt feedback load stage is discussed. Experimental results are given for an active mixer implemented in a 0.8-/spl mu/m 35-GHz f/sub T/ SiGe HBT BiCMOS process. 相似文献
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15.
Oscar Belotti Edoardo Bonizzoni Franco Maloberti 《Analog Integrated Circuits and Signal Processing》2012,73(1):255-264
A technique for the exact design of the noise transfer function of Continuous-Time (CT) Sigma-Delta modulators with arbitrary and multiple DAC responses and real op-amps is here presented. The approach, that presupposes linear behavior of active blocks, produces a CT modulator with the same noise shaping as its Discrete-Time counterpart. The method operates entirely in the time domain and accounts for non-idealities of real implementations such as finite gain and bandwidth of integrators. The procedure can be effectively implemented with circuit simulators to allow the exact design with transistor level blocks. A design example on a third-order scheme confirms the effectiveness of the method. 相似文献
16.
Loeda S. Reekie H.M. Mulgrew B. 《IEEE transactions on circuits and systems. I, Regular papers》2006,53(4):802-810
Continuous-time (CT) sigma-delta (/spl Sigma//spl Delta/) modulators are growing increasingly popular in wide-band analog-digital conversion. High orders of quantization noise shaping, and multibit quantizers, are used to compensate for the low oversampling ratios in wide-band applications. These, however, add circuit complexities and excess loop delay that are detrimental to the /spl Sigma//spl Delta/ control loop. This paper presents an exact mathematical analysis technique, based on the CT-discrete time equivalence, that can take these effects into account. A design-by-optimization approach based on that analysis is used to compensate for these effects, avoid intractability issues and to gain flexibility in the design. It is also shown that it is advantageous not to fix the position of the quantization noise-shaping zeros in the signal band. 相似文献
17.
《Solid-State Circuits, IEEE Journal of》1973,8(6):471-475
A method is presented for the optimization of the overall delay and overall rise time in iterative multistage wide-band amplifier circuits. The method is applied to an amplifier consisting of emitter-degenerated stages with distributed ohmic base resistances and lumped collector-base capacitances. Explicit expressions are given for the delay and the rise time, and optimization criteria are presented in graphs suitable for use in circuit design. 相似文献
18.
探讨了宽频段电台机内干扰频点的来源、产生机理及途径。应用频率设计流程,分析了宽频段电台机内干扰与时钟、本振等主要设计要素的关系,提出了一种新的频率流程设计思路及消除机内干扰频点的方法。工程应用表明,宽频带电台的机内干扰频点控制在总工作点数的0.2%以内。 相似文献
19.
A new performance-boosting frequency compensation technique is presented, named Transconductance with Capacitances Feedback Compensation (TCFC). A transconductance stage and two capacitors introduce negative feedback to a three-stage amplifier, which significantly improves the performance such as gain-bandwidth product, slew rate, stability and sensitivity. An optimized TCFC amplifier has been implemented, and fabricated in a 0.35-/spl mu/m CMOS process. The TCFC amplifier driving a 150-pF load capacitor achieved 2.9-MHz gain-bandwidth product dissipating only 45-/spl mu/W power with a 1.5 V supply, which shows a significant improvement in MHz/spl middot/pF/mA performance. 相似文献
20.
A new fully differential CMOS operational amplifier (op amp) without extra common-mode feedback (CMFB) circuit is proposed and analyzed. In this op amp, simple inversely connected current-mirror pairs are used as active loads. From the theoretical analysis, it is shown that the common-mode signal can be efficiently suppressed by the reduced effective common-mode resistance of the active load. The proposed op amp with 2 pF capacitance loadings has an open-loop unity-gain bandwidth of 63 MHz, a phase margin 47°, and a dc gain of 67 dB in 3.5µm p-well CMOS technology. The common-mode gain at a single output node can be as low as —38 dB without extra CMFB circuit. Experimental results have successfully confirmed the capability of the efficient common-mode rejection.This work was supported by the United Microelectronics Corporation (UMC), Republic of China, under Grant C80054. 相似文献