위성통신 시스템용 위상 고정 루프 주파수 합성기의 위상 잡음 예측 모델

김영완,박동철 한국전자파학회 2003 한국전자파학회논문지 Vol.14 No.8

본 논문에서는 위성통신에서 사용되는 주파수 합성형 발진기에 대한 위상 잡음원을 분석하고, 주파수 합성기 출력 신호의 위상 잡음 스펙트럼 분포를 보다 더 정확히 예측할 수 있는 위상 잡음 모델을 제안하였다 기준 발진기 및 전압 제어 발진기 출력 주파수를 분주하는 분주기의 위상 잡음을 해석하고, 기준 발진기와 전압 제어 발진기 위상 잡음은 Leeson 모델을 이용하여 1/f$^2$ 이외에 다른 기울기 특성을 갖는 위상 잡음 성분들을 모델링하였다. PLL 발진기에서 각 구성 요소들에 의해 발생되거나 더해지는 잡음은 유용한 신호에 비하여 매우 작으므로 중첩의 원리를 적용하고, 선형 시스템 영역에서 주파수 합성기 회로를 해석하였다. 정립된 위상 예측 모델을 기만으로 주파수 합성기 구성 형태에 따라 각 구성 요소들의 위상 잡음 모델을 적용하여 위성통신용 주파수 합성기의 위상 잡음 스펙트럼 특성을 예측하고, 주파수 합성기를 제작하여 예측 모델과 비교 평가하였다. The phase noise characteristics of the phase-locked loop frequency synthesizer were predicted based on the analysis for phase noise contribution of noise sources. The proposed phase noise model in this paper more accurately predicts the phase noise spectrum of frequency synthesizer. To accurately model the phase noise contribution of noise sources in frequency synthesizer, the phase noise sources were analyzed via modeling of the frequency divider and phase noise components using Leeson model for reference signal source and VCO. The phase noise transfer functions to VCO from noise sources were analyzed by superposition theory and linear operation of phase-locked loop. To evaluate the phase noise prediction model, the frequency synthesizers were fabricated and were evaluated by measured data and prediction data.

Two-Phase Phenomena and Volatility Clusterings in Financial Markets

임규창,Kyungsik Kim,Deock-Ho Ha,Ki-Ho Chang,김수용 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.-

We study the two-phase phenomenon of financial markets for three different markets: stock, foreign exchange, and futures exchange markets. Based on these results, we extract the burst phase series from the original returns time series. In this work, we show that the burst phase does not follow the simple random Poisson process and its inter-burst phase intervals (IBIs) exhibit a weak correlation. On comparison with the duration series of inter-laminar phase intervals (ILIs), the previous result implies that the volatility clustering observed in most financial markets is due mainly to the correlation of the IBIs, not to the duration of a burst phase. We study the two-phase phenomenon of financial markets for three different markets: stock, foreign exchange, and futures exchange markets. Based on these results, we extract the burst phase series from the original returns time series. In this work, we show that the burst phase does not follow the simple random Poisson process and its inter-burst phase intervals (IBIs) exhibit a weak correlation. On comparison with the duration series of inter-laminar phase intervals (ILIs), the previous result implies that the volatility clustering observed in most financial markets is due mainly to the correlation of the IBIs, not to the duration of a burst phase.

2 GHz 8 비트 축차 비교 디지털-위상 변환기

심재훈 한국센서학회 2019 센서학회지 Vol.28 No.4

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 approx- imation, 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 converterexhibits 0.46-LSB integral nonlinearity and 0.31-LSB differential nonlinearity with a power consumption of 3.12 mW from a 1.2-V sup-ply voltage.

Phase Transformation Modeling for Hypo Peritectic Steel in Continuous Cooling

Jun‑hyun Jo,Kyung‑woo Yi 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

Phase change of steel during cooling affects the slab qualities in continuous casting. Especially, crack susceptibility of hypoperitectic steel is high because large volume shrinkage occurs by peritectic phase transformation during solidification andcooling. In continuous cooling, phase change is different from the behaviors under the equilibrium condition, such as undercoolingand extend of peritectic reaction, etc. Therefore, we develop a new phase change model considering thermodynamics,empirical equations, and carbon diffusion in each phase to predict phase change behavior during continuous cooling. Inthis model, phase change of hypo peritectic steel comprises 5 stages until all phases become the γ phase. The velocities ofthe δ/γ interface and phase fractions during cooling are calculated according to cooling rate, undercooling of the γ phase,and carbon contents. The results show that if solidification ends by the δ phase during dTp,the γ phase is formed by massivetransformation. On the contrary, if peritectic reaction starts with liquid, the γ phase is formed and grows by diffusionaltransformation. In latter case, massive transformation of remaining δ phase can occur with high undercooling or very fastcooling rates. This analysis shows that there are several different paths depending on carbon contents of hypo peritectic steels.

Redefinition of a Phase: The Possibility of CP, PredP, and AdjunctP as Genuine Phases

조기석,김성헌,배상희 한국외국어대학교 언어연구소 2014 언어와 언어학 Vol.0 No.64

This study will try to redefine a notion of phases. Two tasks will be carried out to achieve this goal. One is to discuss the current definition of a phase from an empirical perspective and to judge its coverage of application in terms of Chomsky's (2005b) Phase Impenetrability Condition. It will be argued that the standard definition of a phase has limited applicable coverage. The other one is to offer a revised version of the definition of a phase on the basis of proposition, argument structure, and adjunct structure. It will be suggested that complementizer phrases, predicate phrases, and adjunct phrases are genuine phases by which syntactic operations should proceed and locality of movements should be evaluated. Predicate phrases include predicative verb phrases, predicative adjective phrases and predicative noun phrases. The predicative noun phrases have noun heads derived from predicative verbs. The predicate phrases contain predicates that assign theta roles and arguments that receive theta roles. Adjunct phrases include both prepositional phrases and complementizer phrases that do not receive theta roles from the predicate. In the case that an adjunct phrase is a complementizer phrase, the adjunct phrase is a phase for two reasons. It is a phase because it is an adjunct phrase. It is also a phase because it is a complementizer phrase. Therefore the adjunct complementizer phrases constitute double phases. This revised definition of a phase will broaden the applicable coverage of the Phase Impenetrability Condition and solve some of the problems posed by the Phase Impenetrability Condition.

Phase, Spell-Out and Syntactic Derivations

편일범 한국중앙영어영문학회 2008 영어영문학연구 Vol.50 No.4

This paper explores the possibility to define phases in a relative sense rather than in an absolute sense as Chomsky (2000, 2001a,b, 2005) suggested. Unlike the hypothesis that an inherent phase is a proposition, we assume, following Dikken’s (2006) notion of Phase Extension, that the other nodes can acquire phasehood in the course of the syntactic derivation as a result of movement of the head of the inherent small-clause phase to the heads of higher nodes in the structure. Hence, since the predication of a sentence structure is realized in vP, only this unit vP can be an inherent phase and the other maximal nodes can be phases only by means of getting a phasehood by inheritance. We suggest that as a result of v raising to T, TP becomes a phase, unlike Chomsky (2000, 2001a,b, 2005) predicts, and it is an inherited phase. And with T subsequently raising on to C, that also makes CP a derived phase at the next step in the derivation. Thus there are two types of phases : absolute inherent phase vP and inherited/derived phase TP or CP. In Chomsky’s phase system, on the other hand, the edge and the complement of a phase are spelled-out at different times. Such a dispersed double application of Spell-Out within the same phase domain is not ideal syntactic operations. To avoid such double applications of Spell-Out, we suggest that objects for Spell-Out should be qualified full phase domains rather than complements of phase heads as the PIC predicted.

Phase, Spell-Out and Syntactic Derivations

Ilbum Pyun 한국중앙영어영문학회 2008 영어영문학연구 Vol.50 No.4

This paper explores the possibility to define phases in a relative sense rather than in an absolute sense as Chomsky (2000, 2001a,b, 2005) suggested. Unlike the hypothesis that an inherent phase is a proposition, we assume, following Dikken’s (2006) notion of Phase Extension, that the other nodes can acquire phasehood in the course of the syntactic derivation as a result of movement of the head of the inherent small-clause phase to the heads of higher nodes in the structure. Hence, since the predication of a sentence structure is realized in vP, only this unit vP can be an inherent phase and the other maximal nodes can be phases only by means of getting a phasehood by inheritance. We suggest that as a result of v raising to T, TP becomes a phase, unlike Chomsky (2000, 2001a,b, 2005) predicts, and it is an inherited phase. And with T subsequently raising on to C, that also makes CP a derived phase at the next step in the derivation. Thus there are two types of phases : absolute inherent phase vP and inherited/derived phase TP or CP. In Chomsky’s phase system, on the other hand, the edge and the complement of a phase are spelled-out at different times. Such a dispersed double application of Spell-Out within the same phase domain is not ideal syntactic operations. To avoid such double applications of Spell-Out, we suggest that objects for Spell-Out should be qualified full phase domains rather than complements of phase heads as the PIC predicted.

간결한 위상 변위 회로를 갖는 소형 광대역 위상 배열 안테나

한상민,권구형,김영식 한국전자파학회 2003 한국전자파학회논문지 Vol.14 No.10

본 논문에서는 IMT-2000 소형 기지국 시스템 응용을 위한 광대역 특성을 갖는 위상 배열 안테나 시스템의 평판형, 소형 구조를 설계 및 구현하였다. 저비용, 단순 설계의 빔 형성망을 구성하기 위해 두 가지 방법이 제안되었다. 첫번째로 연속적으로 위상을 조정할 수 있는 새로운 소형 광대역 위상 천이기를 병렬 결합선로를 이용하여 설계하였으며, 둘째로는 위상 배열 안테나에서 기준 위상을 갖는 위상 천이기를 대체할 수 있는 등가적인 위상 지연기를 제안하였다. 또한 광대역 시스템 구현을 위해 광대역 위상 천이기와 함께 광대역 특성을 갖는 와이드 슬랏 안테나를 단위 안테나로 설계하였다. 따라서 설계된 위상 배열 안테나 시스템은 낮은 복잡도와 적은 공정 비용에도 불구하고 소형, 광대역, 그리고 넓은 빔 틸팅 각도를 갖도록 설계되었다. 제작된 3${\times}$l 선형 위상 배열 안테나 시스템은 와이드 슬랏 안테나의 접지면으로 충분한 1.6 λ${\times}$ l.6 λ의 소형 구조로 구현되었으며, 실험 결과 IMT-2000 대역 내에서 15 dB 이하의 S$_{11}$을 보였고, E평면 방사 패턴에서 -29$^{\circ}$에서 +30$^{\circ}$의 빔 스캔 각도를 나타내었다.다. In this paper, the planar, compact, and broadband phased array antenna system for IMT-2000 applications has been investigated. Two methods far designing a low-cost and low-complex beam-farming network are proposed. First, a new compact and broadband phase shifter with continuously controlled phase bits is designed by using parallel coupled lines. Second, its equivalent phase delay line is suggested to be capable of replacing the complex phase shifter with a reference phase bit on a phased array antenna. For the purpose of achieving the broadband system, in addition to the broadband phase shifter, a wide-slot antenna with a ground reflector is utilized as an element antenna. Therefore, the phased array antenna system has achieved compact size, broad bandwidth, and wide steering angle, although it has low complexity and low fabrication cost. The 3${\times}$1 phased array antenna system has a compact size of 1.6 λ${\times}$ l.6 λ, which is the sufficient ground plane of the wide-slot antenna. Experimental results present that the S$\_$11/ has less than 15 dB within the band and its radiation patterns on an E-plane have the capability of steering an antenna beam from -29$^{\circ}$to +30$^{\circ}$.

Redefinition of a Phase: The Possibility of CP, PredP, and AdjunctP as Genuine Phases

( Kee Seok Cho ),( Sung Hun Kim ),( Sang Hee Bae ) 한국외국어대학교 언어연구소 2014 언어와 언어학 Vol.0 No.64

This study will try to redefine a notion of phases. Two tasks will be carried out to achieve this goal. One is to discuss the current definition of a phase from an empirical perspective and to judge its coverage of application in terms of Chomsky``s (2005b) Phase Impenetrability Condition. It will be argued that the standard definition of a phase has limited applicable coverage. The other one is to offer a revised version of the definition of a phase on the basis of proposition, argument structure, and adjunct structure. It will be suggested that complementizer phrases, predicate phrases, and adjunct phrases are genuine phases by which syntactic operations should proceed and locality of movements should be evaluated. Predicate phrases include predicative verb phrases, predicative adjective phrases and predicative noun phrases. The predicative noun phrases have noun heads derived from predicative verbs. The predicate phrases contain predicates that assign theta roles and arguments that receive theta roles. Adjunct phrases include both prepositional phrases and complementizer phrases that do not receive theta roles from the predicate. In the case that an adjunct phrase is a complementizer phrase, the adjunct phrase is a phase for two reasons. It is a phase because it is an adjunct phrase. It is also a phase because it is a complementizer phrase. Therefore the adjunct complementizer phrases constitute double phases. This revised definition of a phase will broaden the applicable coverage of the Phase Impenetrability Condition and solve some of the problems posed by the Phase Impenetrability Condition.

25Cr-7Ni-4Mo 수퍼 2상 스테인리스강의 충격인성에 미치는 χ상의 영향

김창룡 ( C Y Kang ),한현성 ( H S Han ),이상희 ( S H Lee ),한태수 ( T S Han ) 한국열처리공학회 2012 熱處理工學會誌 Vol.25 No.2

This study has been carried out to investigate the precipitation behavior of x phase and effect of x-phase precipitation on the impact toughness of 25%Cr-7%Ni-4%Mo super duplex stainless steel. It was proved that the x phase was a inter metallic compound, which represented the higher chromium and molybdenum concentration than the matrix phases, and also showed the higher molybdenum concentration than the σ phase, The x phase was precipitated at the interface between ferrite and austenite or inside the ferrite matrix in the early stage of aging, The number of x phase precipitates increased with increasing aging time, however, after showing the maximum value, the number was decreased due to the gradual transformation of x phase into σ-phase. Aging ferrite phase was decomposed by the y2 phase and σ-phase. Impact toughness rapidly decreased with time in the initial stage of aging at x phase start to precipitate. Thus, the impact toughness was greatly influence for the precipitation of x phase.