• 제목/요약/키워드: 2-Phase

검색결과 23,959건 처리시간 0.045초

SPD를 이용한 2.4 GHz PLL의 위상잡음 분석 (Phase Noise Analysis of 2.4 GHz PLL using SPD)

  • 채명호;김지흥;박범준;이규송
    • 한국군사과학기술학회지
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    • 제19권3호
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    • pp.379-386
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    • 2016
  • In this paper, phase noise analysis result for 2.4 GHz PLL(phase locked loop) using SPD(sample phase detector) is proposed. It can be used for high performance frequency synthesizer's LO(local oscillator) to extend output frequency range or for LO of offset PLL to reduce a division rate or for clock signal of DDS(direct digital synthesizer). Before manufacturing, theoretical estimation of PLL's phase noise performance should be performed. In order to calculate phase noise of PLL using SPD, Leeson model is used for modeling phase noise of VCO(voltage controlled oscillator) and OCXO(ovened crystal oscillator). After theoretically analyzing phase noise of PLL, optimized loop filter bandwidth was determined. And then, phase noise of designed loop filter was calculated to find suitable OP-Amp. Also, the calculated result of phase noise was compared with the measured one. The measured phase noise of PLL was -130 dBc/Hz @ 10 kHz.

2 GHz 8 비트 축차 비교 디지털-위상 변환기 (A 2-GHz 8-bit Successive Approximation Digital-to-Phase Converter)

  • 심재훈
    • 센서학회지
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    • 제28권4호
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    • pp.240-245
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    • 2019
  • Phase interpolation is widely adopted in frequency synthesizers and clock-and-data recovery systems to produce an intermediate phase from two existing phases. The intermediate phase is typically generated by combining two input phases with different weights. Unfortunately, this results in non-uniform phase steps. Alternatively, the intermediate phase can be generated by successive approximation, where the interpolated phase at each approximation stage is obtained using the same weight for the two intermediate phases. As a proof of concept, this study presents a 2-GHz 8-bit successive approximation digital-to-phase converter that is designed using 65-nm CMOS technology. The converter receives an 8-phase clock signal as input, and the most significant bit (MSB) section selects four phases to create two sinusoidal waveforms using a harmonic rejection filter. The remaining least significant bit (LSB) section applies the successive approximation to generate the required intermediate phase. Monte-Carlo simulations show that the proposed converter exhibits 0.46-LSB integral nonlinearity and 0.31-LSB differential nonlinearity with a power consumption of 3.12 mW from a 1.2-V supply voltage.

보령제약 중앙연구소 - 연구소 탐방

  • 백우현
    • 미생물과산업
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    • 제20권1호
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    • pp.50-52
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    • 1994
  • Coccidioides immitis의 mycelial phase와 tissue phase에 있어서 미세구조를 다음과 같은 결론을 얻었다. 1. mycelial phase의 세포구조에서는 정상적인 균이 보유하고 있는 내용물질을 관찰할 수 있었으며 이는 다른 eucaryotic cell의 구조와 같았다. 2. tissue phase에서는 mycelial phase의 세포의 크기보다 비교적 크기가 컸으며 mycelial phase에서 보다 많은 종의 vacuole이 관찰되었다. 3. Tissue phase에서는 fibril form의 내연층을 볼 수 있었다.

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Bi-Sr-Ca-O계에서 초전도상의 형성에 관한 상평형 (Phase Equilibria for the Formation of Superconducting Phases in the Bi-Sr-Ca-O System)

  • 김철진
    • 한국재료학회지
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    • 제3권4호
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    • pp.410-421
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    • 1993
  • Bi-Sr-Ca-O 초전도성계에서 $Bi_2O_3-(Sr_2CaCu_2O_x$)의 pseude binary계를 선택하여 $Sr_2CaCu_2O_x$$Bi_2O_3$를 5%단위로 40 cation mole% Bi까지 첨가하면서 $850^{\circ}C$ 초전도상 및 공존하는 상들의 평형 및 반응 경로들을 XRD, SEM, EDS, DTA를 이용하여 분석하였다. Bi의 함량이 35 mole% Bi보다 클 때에는 $Bi_2Sr_2CaCu_2O_8$상과 공존하는 액상이 형성되며 2212상의 액상으로 존재하며 액상의 냉각시 제일 먼저 $Bi_2Sr_2CaCu_2O_8$상 주의에 석출된 것이 관찰되었다.

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複合組織鋼의 第2相 硬度變化가 腐蝕疲勞 크랙傳播에 미치는 影響 (The Influence on the Corrosion Fatigue Crack Propagation in Changing of the Second Phase Hardness of Dual Phase Steel)

  • 오세욱;김웅집
    • Journal of Welding and Joining
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    • 제11권2호
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    • pp.42-52
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    • 1993
  • The corrosion fatigue fracture behaviour of dual phase steel was investigated in 3% NaCl solution at 302MPa and 137MPa. Fatigue test was conducted by cantilever type of self-made rotary bending fatigue testing machine. The fatigue strength increased with increasing the hardness of 2nd phase. Corrosion pit originated at the boundary of the 2nd phase. The size and number of corrosion pits were influenced by the 2nd phase hardness, and pits remained constant in size just after they were transited into cracks. The life of crack initiation was effected by stress level. The shape of relation of .DELTA. K and da/dN has smaller scattering in it in 3% NaCl solution than that in air. The higher the 2nd phase hardness is, the greater the corrosion fatigue life becomes. Corrosion fatigue fracture behaviour was primarily effected by mechanical factor in case of high stress(302MPa), but by electro-chemical reaction in a lower stress(137MPa). As stress level got lower and hardness of the 2nd phase got higher, the roughness of fracture surface increased.

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Ti3SiC2 MAX Phase 합성을 위한 Arc Melting 공정 제어 (Process Parameter Control of Arc Melting Process for Ti3SiC2 MAX Phase Synthesis)

  • 노창완;김병근;배상현;최순목
    • 한국전기전자재료학회논문지
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    • 제33권6호
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    • pp.515-520
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    • 2020
  • The Ti3SiC2 MAX phase was synthesized by arc-melting process under three different processing times. We confirmed that the reaction between the TiCX phase and Ti-Si liquid phase is important for the synthesis of the Ti3SiC2 MAX phase. Results suggest that the Ti3SiC2 MAX phase decomposed when the arc-melting time was greater than 80s. Herein, we aim to determine the detailed parameters for the reported arc-melting process, which can provide useful insights on the synthesis of the Ti3SiC2 MAX phase by arc-melting process. Furthermore, we compared the electrical characteristics and densities of the three samples.

Effect of Cholesterol on the Phase Change of Lipid Membranes by Antimicrobial Peptides

  • Choi, Hyungkeun;Kim, Chul
    • Bulletin of the Korean Chemical Society
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    • 제35권5호
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    • pp.1317-1322
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    • 2014
  • Membrane disruption by an antimicrobial peptide (AMP) was investigated by measuring the $^2H$ solid-state nuclear magnetic resonance spectra of 1-palmitoyl-$d_{31}$-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC_$d_{31}$) in mixtures of POPC_$d_{31}$/cholesterol and either magainin 2 or aurein 3.3 deposited on thin cover-glass plates. The line shapes of the experimental $^2H$ solid-state nuclear magnetic resonance (SSNMR) spectra were best simulated by assuming the coexistence of a mosaic spread of bilayers containing pore structures and a fasttumbling isotropic phase or a hexagonal phase. Within a few days of incubation in a hydration chamber, an isotropic phase and a pore structure were induced by magainin 2, while in case of aurein 3.3 only an isotopic phase was induced in the presence of a bilayer phase. After an incubation period of over 100 days, alignment of the bilayers increased and the amount of the pore structure decreased in case of magainin 2. In contrast with magainin 2, aurein 3.3 induced a hexagonal phase at the peptide-to-lipid ratio of 1/20 and, interestingly, cholesterol was not found in the hexagonal phase induced by aurein 3.3. The experimental results indicate that magainin 2 is more effective in disrupting lipid bilayers containing cholesterol than aurein 3.3.

마이크로파 회로용 Phase Shifter의 설계에 관한 연구 (A study on Design for Phase Shifter for Microwave Circuits)

  • 민경식;강태경;최봉조;김동철;임학규
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2000년도 춘계종합학술대회
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    • pp.152-155
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    • 2000
  • 본 논문은 2 GHz대와 12 GHz대에서 동작하는 Phase Shifter를 제안한다. 이것을 위해 비유전율이 2.6인 마이크로 스트립 선로가 사용되었다. 2 GHz대에서 전송선로 위에 비유전율 9인 유전체를 덮어서 주파수 특성이 좋고 선형적인 phase 변화를 가지는 것을 보았다. 12 GHz대에서도 S21의 위상 변화가 유전체 소자의 위치를 변화시킴으로써 약 30。의 우수한 값을 얻을 수 있었다.

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Fault Current Limiting Characteristics of Separated and Integrated Three-Phase Flux-Lock Type SFCLs

  • Lim, Sung-Hun
    • Journal of Electrical Engineering and Technology
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    • 제2권3호
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    • pp.289-293
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    • 2007
  • The fault current limiting characteristics of the separated and the integrated three-phase flux-lock type superconducting fault current limiters (SFCLs) were analyzed. The three-phase flux-lock type SFCL consisted of three flux-lock reactors and three $high-T_c$ superconducting (HTSC) elements. In the integrated three-phase flux-lock type SFCL, three flux-lock reactors are connected on the same iron core. On the other hand, three flux-lock reactors of the separated three-phase flux-lock type SFCL are connected on three separated iron cores. The integrated three-phase flux-lock type SFCL showed the different fault current limiting characteristics from the separated three-phase flux-lock type SFCL that the fault phase could affect the sound phase, which resulted in quench of the HTSC element in the sound phase. Through the computer simulation applying numerical analysis for its three-phase equivalent circuit, the fault current limiting characteristics of the separated and the integrated three-phase flux-lock type SFCLs according to the ground fault types were compared.

Effects of Competition between Phase Separation and Ester Interchange Reactions on the Phase Behavior in a Phase-Separated Immiscible Polyester Blend: Monte Carlo Simulation

  • Youk, Ji-Ho;Jo, Won-Ho
    • Fibers and Polymers
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    • 제2권2호
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    • pp.81-85
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    • 2001
  • The effects of rate of phase separation to ester interchange reactions and the repulsive pair interaction energy on the phase behavior in a phase-separated immiscible polyester blend are investigated using a Monte Carlo simulation method. The time evolution of structure factor and the degree of randomness are monitored as a function of homogenization time. When the phase separation is dominant over ester interchange reactions, the domain size slowly increases with homogenization time. However, when the pair interaction becomes less repulsive, the domain size does not significantly change with homogenization time. On the other hand, when ester interchange reactions are dominant over the phase separation, the homogenization proceeds without a change in the domain size. The higher the extent of phase separation, the lower the increasing rate of the DR. However, when the phase separation is sufficiently dominant, the effect of the extent of phase separation on the increasing rate of the degree of randomness become less significant.

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