共查询到20条相似文献,搜索用时 19 毫秒
1.
《IEEE transactions on image processing》2009,18(9):2012-2021
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Hangai M. Hieda M. Yunoue N. Sasaki Y. Miyazaki M. 《Microwave Theory and Techniques》2010,58(1):41-47
3.
Zimmermann L. Voigt K. Winzer G. Petermann K. Weinert C.M. 《Photonics Technology Letters, IEEE》2009,21(3):143-145
We demonstrate 4times4 multimode interference couplers in a silicon-on-insulator rib waveguide technology that enable compact integrated fully passive optical 90deg-hybrid devices with operation across the C-band. 相似文献
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《Solid-State Circuits, IEEE Journal of》2009,44(5):1582-1592
6.
《IEEE transactions on image processing》2008,17(11):1985-1999
The non-Bayesian detection of an anomaly from a single or a few noisy tomographic projections is considered as a statistical hypotheses testing problem. It is supposed that a radiography is composed of an imaged nonanomalous background medium, considered as a deterministic nuisance parameter, with a possibly hidden anomaly. Because the full voxel-by-voxel reconstruction is impossible, an original tomographic method based on the parametric models of the nonanomalous background medium and radiographic process is proposed to fill up the gap in the missing data. Exploiting this ldquoparametric tomography,rdquo a new detection scheme with a limited loss of optimality is proposed as an alternative to the nonlinear generalized likelihood ratio test, which is untractable in the context of nondestructive testing for the objects with uncertainties in their physical/geometrical properties. The theoretical results are illustrated by the processing of real radiographies for the nuclear fuel rod inspection. 相似文献
7.
《Microwave Theory and Techniques》2009,57(3):708-715
8.
《Vehicular Technology, IEEE Transactions on》2009,58(7):3145-3153
9.
Frappe A. Flament A. Stefanelli B. Kaiser A. Cathelin A. 《Solid-State Circuits, IEEE Journal of》2009,44(10):2722-2732
An all-digital RF signal generator using DeltaSigma modulation and targeted at transmitters for mobile communication terminals has been implemented in 90 nm CMOS. Techniques such as redundant logic and non-exact quantization allow operation at up to 4 GHz sample rate, providing a 50 MHz bandwidth at a 1 GHz center frequency. The peak output power into a 100 Omega diff. load is 3.1 dBm with 53.6 dB SNDR. By adjusting the sample rate, carriers from 50 MHz to 1 GHz can be synthesized. RF signals up to 3 GHz can be synthesized when using the first image band. As an example, UMTS standard can be addressed by using a 2.6 GHz clock frequency. The measured ACPR is then 44 dB for a 5 MHz WCDMA channel at 1.95 GHz with output power of -16 dBm and 3.4% EVM. At 4 GHz clock frequency the total power consumption is 120 mW (49 mW for DeltaSigma modulator core) on a 1 V supply voltage, total die area is 3.2 mm2 (0.15 mm2 for the active area). 相似文献
10.
Zhaobing Tian Yang R.Q. Mishima T.D. Santos M.B. Johnson M.B. 《Photonics Technology Letters, IEEE》2009,21(21):1588-1590
Broad-area plasmon-waveguide interband cascade lasers with emission wavelengths near 7.5 mu m were demonstrated at temperatures up to 121 K in continuous-wave mode. Their threshold current densities and voltages varied from 72 A/cm2 and 2.1 V at 84 K to 400 A/cm2 and 2.7 V at 121 K, showing very efficient use of bias voltage (e.g., voltage efficiency of about 90% at 84 K) at this long wavelength. These plasmon-waveguide lasers also operated in pulsed mode at temperatures up to 165 K with emission wavelengths near 7.6 mum and threshold current density of 1100 A/cm2. 相似文献
11.
《Photonics Technology Letters, IEEE》2009,21(5):334-336
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13.
《Microwave Theory and Techniques》2008,56(9):2046-2053
14.
《Quantum Electronics, IEEE Journal of》2010,46(2):272-276
15.
A $Q$ – $f$ Droop Curve for Facilitating Islanding Detection of Inverter-Based Distributed Generation
This paper presents a new method for islanding detection of distributed generation (DG) inverter that relies on analyzing the reactive power versus frequency (Q-f) characteristic of the DG and the islanded load. The proposed method is based on equipping the DG interface with a Q-f droop curve that forces the DG to lose its stable operation once an islanding condition occurs. A simple passive islanding detection scheme that relies on frequency relays can then be used to detect the moment of islanding. The performance of the proposed method is evaluated under the IEEE 1547 and UL 1741 antiislanding test configuration. The studies reported in this paper are based on time-domain simulations in the power systems computer-aided design (PSCAD)/EMTDC environment. The results show that the proposed technique has negligible nondetection zone and is capable of accurately detecting islanding within the standard permissible detection times. In addition, the technique proves to be robust under multiple-DG operation. 相似文献
16.
This paper addresses two important problems of interest for deep-space optical communications, quantum inter-chip/intra-chip optical communications and quantum-key distribution: 1) the problem of coded M-ary phase-shift keying optical coherent-state quantum communication in the absence of background radiation, and 2) the problem of coded binary coherent state communication in the presence of background radiation. In both cases large girth low-density parity-check (LDPC) codes are used as channel codes. With girth-10 LDPC-code of rate 0.8 and BPSK, the bit-error ratio of 10- 8 can be achieved for average number of signal photons of 0.73, resulting in net-effective coding gain of 7.63 dB. 相似文献
17.
《Microwave and Wireless Components Letters, IEEE》2009,19(5):308-310
18.
《Quantum Electronics, IEEE Journal of》2009,45(7):830-832
19.
Prefasi E. Hernandez L. Paton S. Wiesbauer A. Gaggl R. Pun E. 《Solid-State Circuits, IEEE Journal of》2009,44(10):2745-2754
The ADC shown in this paper uses an innovative sigma-delta (SigmaDelta) architecture that replaces the flash quantizer and mismatch corrected DAC of a multibit continuous time (CT) modulator by a time domain encoder similar to a PWM modulator to reduce the effective ADC area. The modulator achieves the resolution of a multibit design using single bit circuitry by concentrating most of the quantization error energy around a single frequency, which is afterwards removed, seizing the zeros of a sinc decimation filter. The non flat error spectrum is accomplished by use of two filter loops, one of which is made to operate in a self-oscillating mode. An experimental CT-SigmaDelta ADC prototype has been fabricated in 0.13 mum CMOS which implements a third order modulator with two operating modes. Measurements show an effective number of bits (ENOB) of 10 bits and 12 bits in a signal bandwidth of 17 MHz and 6.4 MHz, respectively, and a power-efficient figure of merit (FoM = Pwr/2 middot BW middot 2ENOB) of 0.48 pJ/conversion at 1.5 V supply. The active area of the ADC is 0.105 mm2. 相似文献