• Title/Summary/Keyword: modulators

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Multiplex Digital SSB Modulators and TDM/FDM Translator (다중 디지털 단측파대 변조기와 TDM/FDM 변환 장치에 관한 연구)

  • 박종연;박의열
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.20 no.1
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    • pp.27-36
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    • 1983
  • The 12-Channe1 TDM/FDM translator is proposed which uses a periodically varying digital filter and the multiplexing weaver modulators. The general 12-Channel TDM/FDM translator using the Weaver modulators requires 24 interpolating FIR(finite impulse response) filters and 24 sinusoidal modulators, however the TDM/FDM translator proposed in this paper consists of one interpolating periodically varying digital filter and 12 sinusoidal modulators. The results obtained in this paper show that the system is simplified and the computation time is reduced. These facts are verified by the computer simulation.

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Effect of the Hesperetin and Naringenin on $pp60^{v-src}$-induced $NF-{\kappa}B$ Activation ($pp60^{v-src}$에 의한 $NF-{\kappa}B$ 활성화에 대한 헤스페레틴과 나린제닌의 저해 효과)

  • Kwon, O-Song;Kim, Bo-Yeon;Kim, Kyoung-A;Kim, Min-Soo;Oh, Hyun-Cheol;Kim, Beom-Seok;Kim, Young-Ho;Ahn, Jong-Seog
    • Korean Journal of Pharmacognosy
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    • v.35 no.3 s.138
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    • pp.244-249
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    • 2004
  • The effects of hesperetin and naringenin on $NF-{\kappa}B$ activation were investigated in normal rat kidney cells transformed by temperature sensitive Rous Sarcoma Virus (tsNRK). The flavonoids, naringenin and hesperetin, significantly reduced v-Src-induced $NF-{\kappa}B$ activation as well as phosphorylation of Akt and GSK-3 in tsNRK cells, whereas these compounds did not effect on platelet-derived growth factor (PDGF)-induced $NF-{\kappa}B$ activation in $NIH3T3{\gamma}l$ cells. In addition, the DNA binding activity of SP-I was also reduced but that of AP-1 was not affected by the compounds. Our study suggests that Src-induced $NF-{\kappa}B$ activation could occur via Akt-GSK-3 pathway without $IkB{\alpha}$ degradation and that naringenin and hesperetin could be used in the treatment of cancer through the inhibition of $NF-{\kappa}B$ activation.

A Multiple Quantum Well Electro-absorption Modulator for Broadband Picocell Applications (광대역 피코셀 응용을 위한 다중양자우물 광전흡수 변조기)

  • Song, Ju Bin
    • Journal of Advanced Navigation Technology
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    • v.8 no.2
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    • pp.91-97
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    • 2004
  • This paper presents the development of InGaAsP multiple quantum well asymmetric Fabry-Perot modulators(AFPM), which have a vertical structure and high performance and describes measurements of devices operating at 10GHz for next generation broadband wireless communication applications such as picocell systems. Advantages of the AFPM include low drive voltage, which is less than -2V, and -3dB coupling loss, good flatness of the frequency response and simple fiber alignment. A simple link demonstration has been introduced, resulting in 92dB/Hz spurious free dynamic range and 40dB inter-modulation distortion. This modulator could be use for broadband radio over fiber systems such as picocell and multiple RF links.

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A Clock Regenerator using Two 2nd Order Sigma-Delta Modulators for Wide Range of Dividing Ratio

  • Oh, Seung-Wuk;Kim, Sang-Ho;Im, Sang-Soon;Ahn, Yong-Sung;Kang, Jin-Ku
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.12 no.1
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    • pp.10-17
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    • 2012
  • This paper presents a clock regenerator using two $2^{nd}$ order ${\sum}-{\Delta}$ (sigma-delta) modulators for wide range of dividing ratio as defined in HDMI standard. The proposed circuit adopts a fractional-N frequency synthesis architecture for PLL-based clock regeneration. By converting the integer and decimal part of the N and CTS values in HDMI format and processing separately at two different ${\sum}-{\Delta}$ modulators, the proposed circuit covers a very wide range of the dividing ratio as HDMI standard. The circuit is fabricated using 0.18 ${\mu}m$ CMOS and shows 13 mW power consumption with an on-chip loop filter implementation.

Systematic Design of High-Resolution High-Frequency Cascade Continuous-Time Sigma-Delta Modulators

  • Tortosa, Ramon;Castro-Lopez, Rafael;De La Rosa, J.M.;Roca, Elisenda;Rodriguez-Vazquez, Angel;Fernandez, F.V.
    • ETRI Journal
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    • v.30 no.4
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    • pp.535-545
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    • 2008
  • This paper introduces a systematic top-down and bottom-up design methodology to assist the designer in the implementation of continuous-time (CT) cascade sigma-delta (${\Sigma}{\Delta}$) modulators. The salient features of this methodology are (a) flexible behavioral modeling for optimum accuracy-efficiency trade-offs at different stages of the top-down synthesis process, (b) direct synthesis in the continuous-time domain for minimum circuit complexity and sensitivity, (c) mixed knowledge-based and optimization-based architectural exploration and specification transmission for enhanced circuit performance, and (d) use of Pareto-optimal fronts of building blocks to reduce re-design iterations. The applicability of this methodology will be illustrated via the design of a 12-bit 20 MHz CT ${\Sigma}{\Delta}$ modulator in a 1.2 V 130 nm CMOS technology.

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Binary-phase Complex Spatial Light Modulators Driven by Mirror Symmetry

  • Choi, Minho;Choi, Jaewu
    • Current Optics and Photonics
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    • v.5 no.3
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    • pp.261-269
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    • 2021
  • Binary-phase complex spatial light modulators (BP-C-SLMs) are proposed and simulated. This study shows that bottom-top mirror-symmetrical uniaxial systems between two orthogonal polarizers allow one to construct BP-C-SLMs. BP-C-SLMs double the information-handling capacity per pixel, compared to the conventional amplitude-only spatial light modulators (A-SLMs), as well as being simply implemented with a single spatial light modulator (SLM), rather than a combination of an A-SLM and a binary-phase SLMs. Under limited conditions, BP-C-SLMs can control only the amplitude in single-phase space, and act as A-SLMs.

Interferometric Color Display Using Micromechanically Coupled Digital Mirror Arrays (기계적으로 연동된 디지털 미소거울을 이용한 광간섭형 컬러 디스플레이 구현)

  • Han, Won;Cho, Young-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.5
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    • pp.487-493
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    • 2012
  • We present interferometric modulators that reproduce RGB colors through the selective actuation of mechanically coupled mirror arrays having identical air gaps. The conventional transmittive interferometric modulators need additional backlights, which leads to high power consumption. The previous reflective interferometric modulators using ambient lights need three different air gaps for reproducing the three RGB colors, thus giving rise to process complexity. For process simplicity, we propose the use of reflective interferometric modulators that are capable of producing green, blue, red, and black colors with the aid of mechanically coupled mirrors with identical air gaps. In an experimental study, the present interferometric modulators reproduce green, blue, and red colors at the switching modes (000), (010), and (101). The spectrum peaks for the colors are measured at the wavelengths $511{\pm}5nm$, $478{\pm}3nm$, and $644{\pm}9nm$, respectively, with the bandwidths being $60{\pm}1nm$, $45{\pm}2nm$, and $105{\pm}4nm$, respectively; further, the maximum intensities of the colors are $77{\pm}5%$, $73{\pm}2%$, and $81{\pm}5%$, respectively. The black spectrum is measured below the intensity of $27{\pm}0%$. Thus, we experimentally demonstrate the color reproduction capability of interferometric modulators fabricated by using a simple process.

Detection of Recombinant Marker DNA in Genetically Modified Glyphosate- Tolerant Soybean and Use in Environmental Risk Assessment

  • Kim, Young-Tae;Park, Byoung-Keun;Hwang, Eui-Il;Yim, Nam-Hui;Lee, Sang-Han;Kim, Sung-Uk
    • Journal of Microbiology and Biotechnology
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    • v.14 no.2
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    • pp.390-394
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    • 2004
  • The genetically modified glyphosate-tolerant soybean contains the following introduced DNA sequences: the EPSPS (5-enol-pyruvylshikimate-3-phosphate synthase) gene from Agrobacterium sp. strain CP4, the 35S promoter from the cauliflower mosaic virus, and the NOS terminator from Agrobacterium tumefaciens. In the present study, detection of these introduced DNAs was performed by amplification using the polymerase chain reaction (PCR). A multiplex PCR method was also applied to prevent false positive results. When primers for 35S promoter, nos3', CTP(chloroplast transit peptide), and CP4 EPSPS (EPSPS from Agrobacterium sp. CP4) were used, positive results were obtained in PCR reactions using DNA from genetically modified glyphosate-tolerant soybeans. There were no false positive results when using DNA from non-genetically modified soybeans. The CP4 EPSPS gene was detected when less than 125 pg glyphosate-tolerant soybean DNA was amplified. Lectin Lel and psb A were amplified from both non-genetically modified and genetically modified glyphosate-tolerant soybean DNA. Multiplex PCR was performed using different primer sets for actin Sacl, 35S promoter and CP4 EPSPS. The actin gene was detectable in both non-genetically modified and glyphosate-tolerant soybeans as a constant endogenous gene. Target DNAs for the 35S promoter, and CP4 EPSPS were detected in samples containing 0.01-0.1% glyphosate-tolerant soybean, although there were variations depending on primers by multiplex PCR. Soybean seeds from five plants of non-genetically modified soybean were co-cultivated for six months with those of genetically modified soybean, and they were analyzed by PCR. As a result, they were not positive for 35S promoter, nos3' or CP4 EPSPS. Therefore, these results suggest there was no natural crossing of genes between glyphosate-tolerant and non-genetically modified soybean during co-cultivation, which indicates that gene transfer between these plants is unlikely to occur in nature.

Optical Harmonic Modulation-Demodulation Techniques for High-Speed Light wave Transmission

  • Choi, Young-Kyu
    • Journal of information and communication convergence engineering
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    • v.6 no.2
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    • pp.192-197
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    • 2008
  • High-speed harmonic optical modulation-demodulation schemes are presented and a possibility of the schemes for applying to high-speed light wave transmission system is tested at microwave frequency range. An example of this concept is as follows : Light wave is modulated succeedingly through cascaded optical modulators by a sub-carrier to produce a modulated light wave at harmonic frequency which is higher than the feasible frequency of the individual modulators. For demodulation of the base-band signal, the high frequency optical sub-carrier is down-converted by the same kind of optical modulator with the same concept of harmonic modulation.

Review of Liquid Crystal Spatial Light Modulators at Thales Research & Technology;technology and applications

  • Lee, Mane-Si Laure;Loiseaux, Brigitte;Dolfi, Daniel;Tonda, Sylvie;Huignard, Jean-Pierre
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.943-946
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    • 2002
  • Liquid Crystal Spatial Light Modulators (LC-SLMs) provide many interesting applications in laser optics and opto-electronic systems, in addition to displays. Among them, three topics developed at Thales Research & Technology are reviewed: wavefront correction for laser beam control, microwave processing in radar systems and holography for TN-LCDs viewing angle compensation.

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