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1.
Cutoff rate and outage probability performance comparisons between DVB-T and DMB-T systems under mobile multipath channels 总被引:1,自引:0,他引:1
Zi-Wei Zheng Zhi-Xing Yang Chang-Yong Pan Yi-Sheng Zhu 《Broadcasting, IEEE Transactions on》2003,49(4):390-397
As an effective technique for combating multipath fading and for high-bit-rate transmission over wireless channels, orthogonal frequency-division multiplexing (OFDM) is extensively used in modern terrestrial digital television broadcasting systems to support high performance bandwidth-efficient multimedia services. Cutoff rate and outage probability are two important criteria to evaluate the performance of a practical communication system in radio engineering. In this paper, the cutoff rate and outage probability performance are compared between two important terrestrial digital television broadcasting systems, the cyclic prefix OFDM based DVB-T system and the time domain synchronous OFDM based DMB-T system, under different mobile multipath channel conditions. The DVB-T system and the DMB-T system are summarily introduced. The cutoff rate and outage probability expressions are developed, and simulation results are given for both the DVB-T system and the DMB-T system. 相似文献
2.
MOHD Z. ABDULLAH LIM C. GUAN ABDUL M. D. MOHAMED MOHD A. M. NOOR 《Journal of Food Processing and Preservation》2002,26(3):213-235
In checking harvesting discipline and quality control for oil palm fruits, color has presumably been an important guide to whether the oil content has reached a maximum where the fruit bunch is ready for cutting. However, establishing a single and harmonious standard base on color is a very contentious issue in the oil palm industry because of the subjective nature of the human vision of color. This was further complicated due to the lack of information on fruit color upon which to base a definite ripeness criterion. We demonstrated in this paper that this problem can be solved using machine vision technology. Methods used were to treat color in HSI (Hue, Saturation and Intensity) color space and applied multivariate discriminant analysis. These have proven to be highly effective for color evaluation and image processing. The vision system was trained to classify oil palms into four quality grades according to PORIM (Palm Oil Research Institute of Malaysia) inspection standards. These are the unripe, the underripe, the optimally ripe and the overripe classes. Depending upon the quality feature evaluated, misclassification by the vision system varied from 5 to 12% but averaged at about 8%. Machine vision disagreement ranged from 2 to 19%. 相似文献
3.
Design of a 3780-point IFFT processor for TDS-OFDM 总被引:2,自引:0,他引:2
Zhi-Xing Yang Yu-Peng Hu Chang-Yong Pan Lin Yang 《Broadcasting, IEEE Transactions on》2002,48(1):57-61
This correspondence presents a design of 3780-point IFFT processor for TDS-OFDM terrestrial DTV transmitter using FPGA. It demonstrates the algorithm design and error analysis of the processor, which can achieve a throughput of 7.56M complex IFFT operations per second. This design meets the signal-to-quantization noise ratio requirement of the TDS-OFDM system. It consists of two FPGA and one dual-port RAM. The data stream pipeline algorithm is implemented 相似文献
4.
背景与裸支架相比,药物洗脱支架可以显著降低冠心病合并糖尿病患者PCI术后再狭窄率和靶病变重建率.但目前尚未见关于直接比较雷帕霉素洗脱支架(CypherTM)和紫杉醇洗脱支架(TaxusTM)在治疗冠心病合并糖尿病患者中安全性和有效性的研究.目的观察和比较两种药物洗脱支架在冠心病合并糖尿病患者中应用的安全性和有效性.方法自2002年6月~2004年2月新加坡国立大学医院心脏中心所有置入Cypher或Taxus支架冠心病合并糖尿病患者,观察:术后6个月的主要不良心脏事件(包括死亡、心肌梗死、靶病变重建).结果 相似文献
5.
Joo-Youl?HuhEmail author Sang-Uk?Han Chang-Yong?Park 《Metals and Materials International》2004,10(2):123-131
The effect on the growth kinetics of the intermetallic compounds (IMCs) in solder/Cu joints, caused by adding Bi to eutectic
Sn-3.5Ag solder alloy, was examined at the aging temperatures of 150°C and 180°C. The Cu6Sn5 layer growth was significantly enhanced, but the Cu3Sn layer growth was slightly retarded by the addition of Bi, resulting in significant growth enhancement of the total (Cu6Sn5+Cu3Sn) IMC layer with increasing Bi addition. The IMC layer growth in the Bi-containing solder joints was accompanied by the
accumulation of Bi ahead of the Cu6Sn5 layer that resulted in the formation of a liquid layer at the Cu6Sn5/solder interface. A kinetic model was developed for the planar growth of the Cu6Sn5 and Cu3Sn layers in the solder joints, accounting for the existence of interfacial reaction barriers. Predictions from the kinetic
model showed that the experimental results could be well explained by the hypothesis that the formation of a Bi-rich liquid
layer at the Cu6Sn5/solder interface reduces the interfacial reaction barrier at the interface. 相似文献
6.
Pole-assignment controller design suffers from the disadvantage that the prescribed pole locations may not be a suitable choice when the dynamics of the process are changing. A general design method that restricts the closed-loop poles to be within a certain desired region specified by engineering judgement, instead of fixing the poles in a prescribed location, is presented. The method can be used for regulating a process with time delay, non-minimum zero-phase behaviour, and open-loop unstable characteristics. 相似文献
7.
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9.
Myeong-Hoon LEE Yeon-Won KIM Kyung-M in LIM Seung-Hyo LEE Kyung-Man MOON 《中国有色金属学会会刊》2013,23(3):876-880
锌合金镀层由于具有较强的耐腐蚀性能而得到广泛的关注,特别是Zn-Mg合金镀层,其耐腐蚀性能能得到显著提高。采用气相沉积方法制备不同镁含量的Zn-Mg合金镀层,研究Zn-Mg合金镀层中镁含量对其耐腐蚀性能的影响。在3%NaCl溶液中进行浸泡试验、动电位测试和电偶腐蚀试验,研究不同Mg含量镀层的耐腐蚀性能。结果表明,Zn-Mg合金镀层的耐腐蚀性能与Mg含量显著相关,镀层的腐蚀电位随着Mg含量的增加而降低,但是腐蚀电流密度却升高,直至15%Mg含量;在Zn-Mg合金镀层中存在钝化区。 相似文献
10.
Rapeta V. V. V. J. RAO T. C. CHONG L. S. TAN W. S. LAU N. LIM 《International Journal of Electronics》2013,100(9):1039-1050
Low temperature (LT)-grown GaAs and Al0.3Ga0.7As metal-insulator-n+-GaAs (MIN) diodes have been fabricated and their electrical properties analyzed. Studies were carried out to evaluate the interfacial quality of the LT layer and the underlying n+-GaAs layer using transient current spectroscopy (TCS) and capacitance-frequency (C-f) characterization. TCS studies on LT-GaAs revealed a high concentration of a continuum of states anda dominant electron trap with an activation energy of 0.52eV. In LT-Al0.3Ga0.7As, a shallow trap at 0.36eV and two deep level traps at 0.85eV and 1.12eV were observed. Frequency dispersion was observed to be less for LT-GaAs samples with an AlAs barrier layer than without an AlAs barrier layer. However, LT-Al0.3Ga0.7As MIN diodes displayed a smaller frequency dispersion than LT-GaAs MIN diodes. Upon further investigation into MISFET devices, it was found that LT-Al0.3Ga0.7As MISFET devices had better transconductance frequency dispersion characteristics than LT-GaAs MISFET devices did. 相似文献