共查询到20条相似文献,搜索用时 31 毫秒
1.
《Circuits and Systems II: Express Briefs, IEEE Transactions on》2009,56(3):200-204
2.
《IEEE transactions on circuits and systems. I, Regular papers》2009,56(7):1467-1477
3.
《Circuits and Systems II: Express Briefs, IEEE Transactions on》2009,56(2):107-111
4.
《Microwave and Wireless Components Letters, IEEE》2009,19(2):83-85
5.
《Lightwave Technology, Journal of》2008,26(15):2355-2363
6.
提出了一种基于三波长注入法布里-珀罗型激光二极管(FP-LD)产生超宽带(UWB)信号的方案。在FP-LD不同激射模式中注入一路信号光和两路直流探测光,实现多波长变换并得到两路反码输出和一路正码输出;再通过光纤进行色散走离,使不同波长信号之间产生时延,形成UWB脉冲,最后经过光电转换产生UWB信号。对所提出的UWB信号产生方案的原理进行分析,并对UWB信号的波形以及频谱特性进行了实验研究。在此基础上,进行了1.25Gb/s非归零码(NRZ)信号注入FP-LD产生差分编码UWB信号的实验。实验产生的UWB脉冲信号半峰全宽最小为83.3ps,10dB谱宽约为4.6GHz,其频宽比为107%。 相似文献
7.
Tai-Cheng Lee Keng-Jan Hsiao 《Solid-State Circuits, IEEE Journal of》2006,41(6):1245-1252
A delay-locked loop (DLL)-based frequency synthesizer is designed for the ultrawideband (UWB) Mode-1 system. This frequency synthesizer with 528-MHz input reference frequency achieves less than 9.5-ns settling time by utilizing wide loop bandwidth and fast-settling architecture. Additionally, a discrete-time model of the DLL and an analytical model of phase noise of the delay line are proposed in this work. Experimental results show great consistency with predicted settling time and phase noise. The circuit has been fabricated in a 0.18-/spl mu/m CMOS technology and consumes only 54 mW from a 1.8-V supply. It exhibits a sideband magnitude of -35.4 dBc and -120-dBc/Hz phase noise at the frequency offset of 1 MHz. 相似文献
8.
Bourdel S. Bachelet Y. Gaubert J. Vauche R. Fourquin O. Dehaese N. Barthelemy H. 《Microwave Theory and Techniques》2010,58(1):65-73
9.
This paper presents a novel,fully integrated transmitter for 3-5 GHz pulsed UWB.The BPSK modulation transmitter has been implemented in SMIC CMOS 0.13μm technology with a 1.2-V supply voitage and a die size of 0.8×0.95 mm~2.This transmitter is based on the impulse response filter method,which uses a tunable R paralleled with a LC frequency selection network to realize continuously adjustable pulse parameters,including bandwidth,width and amplitude.Due to the extremely low duty of the pulsed UWB,a proposed output buffer is employed to save power consumption significantly.Finally,measurement results show that the transmitter consumes only 16.3 pJ/pulse to achieve a pulse repetition rate of 100 Mb/s.Generated pulses strictly comply with the FCC spectral mask.The continuously variable pulse width is from 900 to 1.5 ns and the amplitude with the minimum 178 mVpp and the maximum 432 mVpp can be achieved. 相似文献
10.
《IEEE transactions on circuits and systems. I, Regular papers》2009,56(7):1500-1512
11.
超宽带无线信道的频率依赖特性直接影响到超宽带接收机的设计和以脉冲波形为基础的多址技术。本文针对频率依赖特性对超宽带脉冲信号波形产生的影响,分别从相位谱和幅度谱两个方面分析超宽带脉冲信号的相位失真和幅频失真特性,建立了描述脉冲波形失真特性的数学模型。使用该模型对高斯二阶导数脉冲信号的波形失真进行仿真分析,得到了只发生相位响应失真、只发生幅度响应失真、以及同时发生相位—幅度响应失真的脉冲波形。 相似文献
12.
Fei Zeng Jianping Yao 《Photonics Technology Letters, IEEE》2006,18(7):823-825
We propose a novel approach to generating and distributing ultrawideband (UWB) pulse signals over optical fiber. The proposed system consists of a single-wavelength laser source, an electrooptic phase modulator (EOPM), a length of single-mode fiber (SMF), and a photodetector (PD). The combination of the EOPM, the SMF link, and the PD forms an all-optical microwave bandpass filter, which is used to generate a UWB signal with a spectrum meeting the regulation of the Federal Communication Commission. Gaussian doublet pulses are obtained at the receiver front-end, which can provide several gigahertz bandwidths for applications in high-bit-rate UWB wireless communications. Experimental results measured in both temporal and frequency domains are presented. 相似文献
13.
《Antennas and Propagation, IEEE Transactions on》2009,57(5):1345-1352
14.
A 6.3-9-GHz CMOS fast settling PLL for MB-OFDM UWB applications 总被引:1,自引:0,他引:1
Geum-Young Tak Seok-Bong Hyun Tae Young Kang Byoung Gun Choi Seong Su Park 《Solid-State Circuits, IEEE Journal of》2005,40(8):1671-1679
A CMOS phase-locked loop (PLL) which synthesizes frequencies between 6.336 and 8.976 GHz in steps of 528 MHz and settles in approximately 150 ns is presented. The proposed PLL can be employed as a building block for a frequency synthesizer which generates a seven-band hopping carrier for multiband orthogonal frequency division multiplexing (MB-OFDM) ultrawideband (UWB) radio. To achieve fast loop settling, integer-N architecture that operates with 528-MHz reference frequency is implemented and a wideband active-loop filter is integrated. An improved phase-frequency detector (PFD) is proposed for faster loop settling. To reduce reference sidebands, a feedback circuit using replica bias is implemented in the charge pump. I/Q carriers are generated by two cross-coupled LC VCOs. The output current of the charge pump is controlled to compensate for the VCO gain nonlinearity and a programmable frequency divider (12/spl les/N/spl les/17) that reliably operates at 9 GHz is designed. Fabricated in 0.18-/spl mu/m CMOS technology, the PLL consumes 32 mA from a 1.8-V supply and achieves phase noise of -109.6dBc/Hz at 1-MHz offset and spurs of -52 dBc. 相似文献
15.
On the UWB system coexistence with GSM900, UMTS/WCDMA, and GPS 总被引:14,自引:0,他引:14
Hamalainen M. Hovinen V. Tesi R. Iinatti J.H.J. Latva-aho M. 《Selected Areas in Communications, IEEE Journal on》2002,20(9):1712-1721
This paper evaluates the level of interference caused by different ultra-wideband (UWB) signals to other various radio systems, as well as the performance degradation of UWB systems in the presence of narrowband interference and pulsed jamming. The in-band interference caused by a selection of UWB signals is calculated at GSM900, UMTS/wideband code-division multiple-access (WCDMA), and Global Position System (GPS) frequency bands as a function of the UWB pulsewidth. Several short-pulse waveforms, based on the Gaussian pulse, can be used to generate UWB transmission. The two UWB system concepts studied here are time hopping and direct sequence spread spectrum. Baseband binary pulse amplitude modulation is used as the data modulation scheme. Proper selection of pulse waveform and pulsewidth allows one to avoid some rejected frequency bands up to a certain limit. However, the pulse shape is also intertwined with the data rate demands. If short-pulses are used in UWB communication the high-pass filtered waveforms are preferred according to the results. The use of long pulses, however, favors the generic Gaussian waveform instead. An UWB system suffers most from narrowband systems if the narrowband interference and the nominal center frequency of the UWB signal overlap. This is proved by bit-error rate simulations in an additive white Gaussian noise (AWGN) channel with interference at global system for mobile communication (GSM) and UMTS/WCDMA frequencies. 相似文献
16.
《IEEE transactions on circuits and systems. I, Regular papers》2009,56(2):320-326
17.
《Microwave and Wireless Components Letters, IEEE》2009,19(6):386-388
18.
In this paper, analog and digital optical pulse synthesizers using high-resolution arrayed-waveguide gratings (AWG) have been developed. The analog type of optical synthesizer consists of an AWG with an integrated 45deg, curved-surfaced mirror, a 4-f lens system, and an optically addressable spatial light modulator. The effective frequency resolution is 14.5 GHz. A dispersion compensation experiment is successfully carried out and a transform-limited short pulse has been obtained. This digital type of optical synthesizer comprises 30 frequency separated channels with a spacing of 12.5 GHz, where each channel includes an amplitude modulator and a phase modulator. The rectangular-shaped pulse is generated with this pulse synthesizer, together with a 12.5-GHz-spacing, optical frequency comb. The synthesizer can generate an optical pulse with any waveform. Moreover, using periodic characteristics of the pulse synthesizer, a 250-GHz repetition rate pulse train was generated, in combination with an ultrawideband, waveguide type of Fabry-Perot electrooptic modulator. 相似文献
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20.
We study the problem of adaptive channel estimation for a multipath channel on an ultrawideband (UWB) impulse radio (IR) system. The purpose of the work is to demonstrate that the statistical characteristics of the UWB‐IR environment are strongly non‐Gaussian and that as a result, non‐Gaussian signal processing techniques are both efficient and powerful in a UWB‐IR environment. The multipath channel estimation problem has been chosen as an illustrative example because UWB‐IR systems often operate in complex multipath environments. We study both blind and training‐based estimation techniques and demonstrate that even simple non‐Gaussian strategies can achieve significant performance improvement when compared to more common second‐order estimation techniques. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献