共查询到20条相似文献,搜索用时 31 毫秒
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Marco Zanuso Salvatore Levantino Carlo Samori Andrea L. Lacaita 《Analog Integrated Circuits and Signal Processing》2012,73(1):201-208
This paper identifies the unavoidable time skew between counter and TDC inputs, if not properly compensated or corrected, as the major source of spurs in the output spectrum of an All-Digital-Phase-Locked Loops (ADPLLs). The frequency and the level of the main spur induced by the time skew are first analytically estimated. Then, an ADPLL, operating in the 3?C4-GHz band, is designed in 90-nm CMOS technology and the reported simulations confirm the theoretical results. A simple glitch-removal circuit, capable of operating even in the presence of fast and large frequency drifts is proposed. The glitch corrector is demonstrated to cancel out the ?24-dBc spur and its harmonics, without altering the lock transient behavior of the ADPLL. 相似文献
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设计了一个5.156 25 GHz低抖动、低杂散的亚采样锁相环,使用正交压控振荡器产生4路等相位间隔时钟。分析了电荷泵的杂散理论,使用差分缓冲器和互补开关对实现了低杂散。使用Dummy采样器和隔断缓冲器,进一步减小了压控振荡器对杂散的恶化。该亚采样锁相环在40 nm CMOS工艺下实现,在1.1 V的供电电压下,功耗为7.55 mW;在156.25 MHz频偏处,杂散为-81.66 dBc;亚采样锁相环输出时钟的相位噪声在10 kHz~100 MHz区间内积分,得到均方根抖动为0.26 ps。 相似文献
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Long Thanh Bui Tran-Thuyen Chau Jong-Wook Lee 《Analog Integrated Circuits and Signal Processing》2013,76(1):91-102
This paper presents a low phase noise integer-N phase-locked loop (PLL) for V-band signal generation. To enhance the frequency stability, we use a new class of Vackar voltage-controlled oscillator (VCO) in the PLL. The Vackar VCO achieves a low phase noise performance by effectively suppressing the AM-PM conversion. To properly align the locking range with the output of the VCO, a divider with wide locking range is realized by the current-mode logic (CML) D-flip-flops with tunable load. For spur reduction, an enhanced charge-pump structure is used to reject transient current glitches. With good static and dynamic current matching achieved in the charge pump, the reference spur is suppressed down to ?50 dBc. The designed PLL is implemented in a 65 nm RFCMOS process, and the measurement demonstrates a low phase noise signal up to 17 GHz. The in-band phase noise (at 1 MHz offset) and out-band phase noise (at 50 MHz offset) are ?103.6 and ?126.8 dBc/Hz, respectively. The PLL consumes 50.7 mW and occupies a chip area of 0.9 mm2. 相似文献
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由于绝缘监测装置的电流互感器只接在母线馈线回路上,因此不能找出具体的接地支路。基于比较电流幅值的变频信号检测原理在一定程度上实现了自动查找故障支路的功能,但可靠性受故障支路分布电容及接地电阻的影响较大。本文通过改进变频信号检测原理的算法,消除了故障支路分布电容及接地电阻对检测可靠性的影响,并计算出故障支路的接地电阻值,提高了查找的可靠性。 相似文献
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For the design and development of optical semiconductor devices based on quantum-well structures, the investigation of saturation phenomena is necessary for high optical power operation. By applying stationary physical models, nonlinear effects cannot be described adequately; hence, transient models are important for an accurate analysis. By utilizing transient models, saturation phenomena, signal delays, and distortions can be investigated. For the analysis of integrated optoelectronic devices, such as lasers and modulators, transient transport or density matrix equations for carriers and photons and the Poisson equation have to be solved self-consistently. A transient model which is useful for the investigation of a wide range of optoelectronic applications is presented. Quantum optical phenomena are included by applying the interband density matrix formalism in real-space representation, where the Coulomb singularity is treated exactly in the limits of the discretization. As we focus on electroabsorption modulators, a drift-diffusion model adequately approximates the transport properties. Here, quantum effects are considered by a quantum correction, the Bohm potential. The model is applied to investigate transport effects in InP-based waveguide electroabsorption modulators including strained lattices 相似文献
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ElSayed A.M. Elmasry M.I. 《IEEE transactions on circuits and systems. I, Regular papers》2004,51(3):440-449
The concept of phase-domain fractional-N frequency synthesis is presented. Synthesizers using this architecture can achieve fast frequency switching without limiting the minimum channel spacing. In this architecture, a numerical phase comparator is used in conjunction with weighting coefficients, as a linear weighted phase-frequency detector. The synthesizer output spur level is determined by two factors. Namely, the delay of the numerical phase comparator, and the accuracy of the digital-to-analog convertor (DAC) used to convert the phase error to the analog domain. A novel second-order timing-error cancelation scheme is proposed to eliminate the effect of the phase comparator delays. Using this technique together with a 10-bit accuracy DAC, a maximum spur level of less than -65 dBc is simulated for a 900-MHz synthesizer. The settling time of the simulated synthesizer is less than 7 /spl mu/s, and is independent of the channel spacing. The details of the synthesizer architecture, design considerations, and system-level simulations are presented. Implementation issues including the DAC accuracy and timing-error effects are discussed extensively throughout the text. 相似文献
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将用于相控阵天线的随机馈相法,应用于DDS 的设计。这种方法的优点是,采用这种随机馈相,在DDS 中,频率偏差的均值为零,而且其杂散可得到抑制。当采用随机馈相的改进型,即适当随机馈相法时,DDS 杂散的峰值进一步降低。文中,给出了计算结果,并对不同随机馈相方法的计算结果进行了比较。 相似文献
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Spur-reduced digital sinusoid synthesis 总被引:1,自引:0,他引:1
This paper presents and analyzes a technique for reducing the spurious signal content in digital sinusoid synthesis. Spur reduction is accomplished through dithering amplitude and phase values prior to wordlength reduction. The analytical approach developed for analog quantization is used to produce new bounds on spur performance in these dithered systems. Amplitude dithering allows output wordlength reduction without introducing additional spurs. Effects of periodic dither similar to that produced by a pseudo-noise (PN) generator are analyzed. This phase dithering method provides a spur reduction of 6(M+1) dB per phase bit when the dither consists of M uniform variates. While the spur reduction is at the expense of an increase in system noise, the noise can be made white, making the noise power spectral density small. This technique permits the use of a smaller number of phase bits addressing sinusoid look-up tables, resulting in an exponential decrease in system complexity. Amplitude dithering allows the use of less complicated multipliers and narrower data paths in purely digital applications, as well as the use of coarse-resolution, highly-linear digital-to-analog converters (DAC's) to obtain spur performance limited by the DAC linearity rather than its resolution 相似文献
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Jos Mara Tirado Jos Luis Sanchez-Rojas Jos Ignacio Izpura 《Electron Devices, IEEE Transactions on》2007,54(3):410-417
In this paper, the transient analysis of an AlGaN/GaN high-electron mobility transistor (HEMT) device is presented. Drain-current dispersion effects are investigated when gate or drain voltages are pulsed. Gate-lag and drain-lag turn-on measurements are analyzed, revealing clear mechanisms of current collapse and related dispersion effects. Numerical 2-D transient simulations considering surface traps effects in a physical HEMT model have also been carried out. A comparison between experimental and theoretical results is shown. The presence of donor-type traps acting as hole traps, due to their low energy level of 0.25 eV relative to the valence band, with densities >1e20 cm-3 (>5e12 cm-2), uniformly distributed at the HEMT surface, and interacting with the free holes that accumulated at the top surface due to piezoelectric fields, accounts for the experimentally observed effects. Time constants next to 10 ms are deduced. Some additional features in the measured transient currents, with faster time constants, could not be associated with surface states 相似文献
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《Electron Devices, IEEE Transactions on》1978,25(9):1120-1125
A transient analysis of integrated-injection logic I2L structures is presented. This analysis is based on calculating the different depletion and neutral region charges. Doping profile, high-level effects, and geometrical layout are taken into account. To formulate a transient functional model of the structure, regional transient delays are defined as ratios of the corresponding charges to the electron current density Jn of the n-p-n vertical transistor. An analytical expression is given for the dominant storage time; τepi . The ratio of the stored charges in a metal-covered and oxide-covered base region is related to the surface recombination velocity and the ratio of the corresponding current densities. In a partitioned CAD model (as in Berger's injection model), the regional transient delays are expressed in terms of the corresponding current densities rather than Jn . The computed results for a five-state ring oscillator are compared to measurements. 相似文献
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相位量化数字射频存储器的寄生信号性能分析 总被引:9,自引:2,他引:7
本文导出了相位量化数字射频存储器的寄生信号性能。其寄生信号幅度随谐波次数的增加单调减小,峰值寄生信号为2~m-1次谐波(其中m为量化位数),其幅度为(2~m-1)~(-1),而近区(峰值寄生信号之前各次谐波)的寄生信号幅度为零。 相似文献
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Ku波段宽带低噪声雷达频率源的研制 总被引:1,自引:1,他引:0
介绍一种低相噪、低杂散、宽带的雷达频率合成器方案的设计和实现,该方案采用超低相噪模拟锁相环芯片,并采用双环环内下混频结构,通过对环路滤波器的精心设计,大幅度改善相位噪声和杂散性能。给出设计过程及测试结果。实验证明该方案是成功的,达到的主要技术指标为:输出频率12.8~14.8 GHz,相位噪声-90 dBc/Hz@1 kHz,杂散-55 dBc,步进间隔50 MHz。 相似文献
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Enhancing reliability with thermal transient testing 总被引:1,自引:0,他引:1
V. Szkely 《Microelectronics Reliability》2002,42(4-5)
Thermal transient measurement, the method for the characterisation of IC packages is gaining increasing importance. The measurement of these transients requires dedicated equipment. The paper discusses the methodology of thermal transient measurements in details, including the compensation of second order effects as non-linearity, non-constant powering etc. In the following part the evaluation methods and algorithmic solutions are discussed. A typical example is presented. Reliability issues are discussed in the last section of the paper, including the problem of die attach testing. The contribution of the thermal transient measurements to the analysis of thermo-mechanical strain is demonstrated. 相似文献
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A low jitter,low spur multiphase phase-locked loop(PLL) for an impulse radio ultra-wideband(IR-UWB) receiver is presented.The PLL is based on a ring oscillator in order to simultaneously meet the jitter requirement, low power consumption and multiphase clock output.In this design,a noise and matching improved voltage-controlled oscillator(VCO) is devised to enhance the timing accuracy and phase noise performance of multiphase clocks.By good matching achieved in the charge pump and careful choice of the l... 相似文献
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介绍了将I/Q两路8Bit信号转换成射频信号的一种直接数字射频调制实现方式.它通过采用温度计码编码减小数字信号跳变导致的噪声毛刺,而采用8-fold线性内插信号作为一阶保持信号的近似处理.大大抑制了数字信号镜像成分。对电路进行模拟后,双边带调制后信号镜像成分抑制53.52dB以上。噪声毛刺抑制53.01dB以上,单边带调制后信号镜像成分抑制59.15dB以上,噪声毛刺抑制53.92dB以上。 相似文献
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Charge-control analysis of the COMFET turn-off transient 总被引:4,自引:0,他引:4
《Electron Devices, IEEE Transactions on》1986,33(9):1377-1382
A quasi-static charge-control analysis of the unique transient turn-off characteristic of the COMFET is developed. The analysis describes the transient behavior in terms of steady ON-state current components that flow in the constituent MOSFET and BJT in the basic COMFET structure. The effects of the expanding depletion region at the cathode and of minority-carrier injection into the anode are properly accounted for. Consequently, the physics underlying the turnoff time is clarified, and device design criteria for shortening it, without considerably degrading the ON-state current conduction capability, are suggested. 相似文献