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1.
This work presents a new low distortion and swing suppression second order sigma-delta modulator with extended dynamic range scheme. The proposed modulator is based on the dual-quantizer architecture and can effectively extend the dynamic range by only adding two simple digital filters in the digital circuit. The techniques of low distortion and swing suppression integrator designs are also employed in the new architecture. Accordingly, this new architecture can improve the circuitry nonlinearity, and the in-band noise can be significantly suppressed to achieve a high resolution in mid or wide bandwidth applications. A second order SDM for Bluetooth application with bandwidth of 500 KHz and sampling frequency of 40 MHz was designed and implemented. The peak SNDR of the experimental SDM is 78 dB.  相似文献
2.
1IntroductionLonghaulopticalfibercommunication,multi-channeltransmisionandopticalfiberCATVsystemrequire1.31μmand1.55μmDFBlase...  相似文献
3.
This work presents a means to enhance the immunity of non-ideal opamp gain effect of the fourth order multi-stage noise shaped (MASH) sigma-delta modulator (SDM) for wide bandwidth applications. The first stage of the SDM is a low-distortion single-loop second order SDM, while the second stage is a low-distortion interpolative second order SDM with Chebyshev type II filter technique. Theoretically, the conventional MASH SDM is impacted by the nonlinear finite gain of the operational amplifier. This impact may have two main phenomena. First, it leaks the incompletely corrected quantization error to the output. Secondly, the nonlinearity causes the harmonic distortion of the input signal. The proposed architecture can reduce the distortion and the sensitivity of the nonlinear finite opamp gain to improve the performance by using low-distortion technique in the MASH SDM. Furthermore, the lower power budget and simplified digital cancellation logic can be achieved. The experimental results indicate that the dynamic range (DR) can reach 87dB with power dissipation of 65 mW. A test SDM chip for Asymmetric Digital Subscriber Line (ADSL) application is designed and implemented by TSMC 0.25 um 1P5M process. Jen-Shiun Chiang was born in Taichung Taiwan, ROC in 1960. He received the B.S. degree in electronics engineering from Tamkang University, Taipei, Taiwan in 1983. In 1988, he received the M.S. degree in electrical engineering from University of Idaho, Moscow Idaho, USA. In 1992, he received the Ph.D. degree in the electrical engineering from Texas A & M University, College Station Texas, USA. He joined the faculty member of the Department of Electrical Engineering at Tamkang University in 1992. Currently, he is a Professor and Department Chair of the Department of Electrical Engineering at Tamkang University. Dr. Chaings research interest includes computer arithmetic, computer architecture, digital signal processing for VLSI architecture, architecture for image data compressing, analog to digital data conversion, and low power circuit design. Hsin-Liang Chen was born in Taipei, Taiwan, in 1974. He received the B.S. degree and M.S. degree in the electrical engineering from Tamkang University, Taipei, Taiwan, in 1997 and 2003, respectively. He is currently working toward the Ph.D. degree at Tamkang University. His research interest focuses on mixed-signal CMOS circuit, sigma delta ADC, and low power circuit.  相似文献
4.
A fourth-order low-distortion low-pass sigma-delta (∑△) modulator is presented for micro-machined inertial sensors. The proposed single-loop single-bit feedback modulator is optimized with a feed-forward path to decrease the nonlinearities and power consumption. The IC is implemented in a standard 0.6 μm CMOS technology and operates at a sampling frequency of 3.846 MHz. The chip area is 2.12 mm^2 with 23 pads. The experimental results indicate a signal-to-noise ratio (SNR) of 100 dB and dynamic range (DR) of 103 dB at an oversampling rate (OSR) of 128 with the input signal amplitude of-3.88 dBFS at 9.8 kHz; the power consumption is 15 raW at a 5 V supply.  相似文献
5.
刘松  张水莲  辛刚  刘涛 《信号处理》2012,28(3):425-431
短波信道中窄带干扰分布密集,导致宽带短波探测系统接收信噪比恶化.针对传统子空间跟踪干扰抑制后信号失真较大而严重影响探测系统性能的问题,论文基于自适应子空间跟踪提出了一种新颖的双子空间频谱标识算法,在抑制干扰的同时有效减小了信号失真.该算法利用基带探测信号频谱对称特性,通过干扰子空间标识得到非对称干扰频带内的有用信号,且使用信号子空间标识将干扰频带与信号频带有效分离实现干扰抑制.仿真分析与实测数据处理结果表明,双子空间频谱标识算法较大程度地保持了接收信号的原始状态,处理后数据较传统算法可以获得更高的相关后信噪比,对于短波电离层信道探测具有重要意义.  相似文献
6.
本文提出了一种应用于音频信号处理的具有恒定的跨导Rail-to-Rail放大器,并且恒定跨导是通过一种恒定电流技术来实现。此技术是基于差分输入对工作在弱反型区。对于工作在弱反型区的MOSFET具有低失调和低功耗的优势。采用标准的0.35微米的CMOS工艺对电路进行流片,此芯片占有面积75×183 μm2。测试结果表明:在3.3V电源电压下,电路最大功耗为85.37mW;在2kHz时总谐波失真为1.2%。  相似文献
7.
李宏义  王源  贾嵩  张兴 《半导体学报》2011,32(9):095009-8
传统的前馈结构由于在量化器前存在复杂的加法器因而会造成性能受限。本文给出了一个改进的四阶一位过采样调制器, 它采用了简单的加法器和延时输入前馈通路,从而降低了调制器的时序需求同时实现低失真。调制器由0.35微米工艺流片,完成了92.8dB的信号噪声失真比和101dB的动态范围,信号带宽100kHz,在3.3V电源电压下,消耗8.6mW。本调制器的性能满足GSM系统的需求。  相似文献
8.
9.
An improved low distortion sigma-delta ADC(analog-to-digital converter) for wireless local area network standards is presented.A feed-forward MASH 2-2 multi-bit cascaded sigma-delta ADC is adopted;however,this work shows a much better performance than the ADCs which have been presented to date by adding a feedback factor in the second stage to improve the performance of the in-band SNDR(signal to noise and distortion ratio),using 4-bit ADCs in both stages to minimize the quantization noise.Data weighted ...  相似文献
10.
提出了一种能够传输高速信号的多路选择器,并为其设计了一种低失真、宽带模拟开关.所提出开关的栅源过驱动电压由nMOS和pMOS的开启电压之和决定,并能够确保输入变化时,开关的栅源电压与阈值电压之差(VGST)保持恒定,从而基本消除了体效应的影响.采用TSMC 0.18μm CMOS工艺,HSPICE仿真结果表明,输入信号在0.3~1.7V之间变化时,开关的VGST基本保持恒定,其-3dB带宽大于10GHz,当输入频率为1GHz时,其无杂散动态范围为67.11dB;开关的开启时间为2.98ns,关断时间为1.35ns,确保了多路选择器的break-before-make特性.该结构可应用于高速信号传输系统中.  相似文献
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