선형화기를 이용한 위성통신용 X-밴드 TWT 증폭기 선형특성 개선

최원 ( Won Choi ),양홍선 ( Hong Sun Yang ),구경헌 ( Kyung Heon Koo ) 한국항행학회 2011 韓國航行學會論文誌 Vol.15 No.5

본 논문에서는 7.9 GHz∼8.4 GHz 에서 동작하는 위성통신용 X-밴드 TWT의 AM-AM과 AM-PM 변환특성을 분석하고 선형화기를 이용하여 선형성과 IMD 특성을 개선하였다. 선형화기를 포함하는 TWT는 개선된 AM-AM과 AM-PM 변환특성을 나타내며, 1 dB 압축점은 12.3 dB, 2.0°/dB 위상왜곡점은 10 dB 개선되었다. 또한 동작출력에서 3차 상호변조 특성인 IMD3는 16.2 dB 개선되어 37.0 dBc로 측정되었다. 또한, 고출력 증폭기의 IMD 측정 방안을 제시하고, TWT의 AM-PM 왜곡 특성을 보상하여 출력전력과 선형 특성을 개선할 수 있음을 나타내었다. This paper has analyzed the AM-AM and AM-PM characteristics of 7.9 GHz∼8.4 GHz X-band TWT used for satellite communication and improved its linearity and IMD performance by using linearizer. The TWT amplifier with the linearizer shows better AM-AM and AM-PM conversion, and has increased 1 dB compression point by 12.3 dB and 2.0 °/dB phase distortion point by 10 dB. The 3rd order intermodulation distortion, IMD3 is measured to be 37.0 dBc that is 16.2 dB improvement at the operating output. This paper also proposed the measurement method of IMD for high power amplifier, and that TWT amplifier can have better linearity and output power by compensating for the AM-PM characteristics.

통신용 전력증폭기의 AM/AM과 AM/PM을 독립적으로 제어하는 전치왜곡보상기 설계에 대한 연구

원용규(Yong-Kyu Won) 산업기술교육훈련학회 2010 산업기술연구논문지 (JITR) Vol.15 No.4

Amplifier linearity plays a major role in the quality of mordern communication systems. The power amplifier should be operated near saturation region to achieve high efficiency. But at this region amplitude and phase distortions of the amplifier remarkably increase with the input power increase and cause a significant adjacent channel interference. In this paper, an independently controllable AM/AM and AM/PM predistortion linearizers consisted of two bias feed resistance linearizers is proposed. This linearizer allows independent adjustment of the AM/AM and AM/PM curves by using two adjustable voltages to compensate the power amplifier non-linearities. The predistortion linearizer can improve the ACPR by 5.3dB with cdma2000 multi carrier signals. And by applying this linearizer to two-tone(880MHz) power amplifier, third order IMD products are improved up to 8[dB].

HPA의 비선형 위상 왜곡을 고려한 타입기반 군 지연 등화기

김용국(Yongguk Kim),조병각(Byung Gak Jo),백광훈(Gwang Hoon Baek),유흥균(Heung-Gyoon Ryu) 한국통신학회 2012 韓國通信學會論文誌 Vol.37 No.10C

본 논문에서는 비선형 전력증폭기(PA:power amplifier)의 AM/PM 비선형 왜곡특성을 포함하는 군 지연을 보상하는 새로운 등화기를 제안한다. 군 지연 특성은 각 주파수 성분에 따라 서로 다르게 나타나는 상수가 아닌 비선형 시간지연이다. 전력증폭기에서 발생되는 AM/PM 특성으로 인한 위상 왜곡 현상은 군 지연을 증가시키는 주요한 요인이다. 이러한 군 지연 왜곡으로 신호 성상도에서 신호는 퍼지면서 회전하게 된다. 위와 같은 문제점을 고려하여 각 주파수 성분에 따라 다르게 나타나는 비선형 시간지연을 정적인 군지연으로 구분하고, PA의 AM/PM 특성인 입력신호 크기에 따라서 위상 천이가 다르게 발생하는 것을 동적인 군 지연으로 구분한다. 정적인 군 지연은 주파수 영역에서 Type-Based 방법으로 위상 왜곡을 추정 및 보상하고 동적인 군 지연은 시간영역에서 위상회전을 보상한다. 제안된 군 지연 보상기법으로 전력증폭기의 AM/PM 특성을 포함한 군 지연 특성을 충분히 보상할 수 있음을 확인하였다. In this paper, we propose a novel equalizer to compensate for the group delay including AM/PM nonlinear distortion characteristics by the nonlinear power amplifier (PA). The group delay characteristic is a nonlinear non-constant time delay that appears differently depending on each frequency component. The phase distortion by AM/PM characteristics arising from the power amplifier is a major factor to increase group delay. By the group delay distortion, the signal in the constellation expands and is rotated. Considering the problem mentioned above, the nonlinear time delay that appears differently depending on each frequency component is classified as a static group delay and AM/PM characteristic of PA, the different phase transitions depending on the size of input signal as a dynamic group delay. Static group delay estimates and compensate for phase distortions in the frequency domain with type-based method and dynamic group delay compensates for phase rotation in the time domain. We confirmed that the group delay compensation techniques were enough to compensate the group delay characteristics including AM/PM characteristics of the power amplifier.

서울 상공의 에어로졸 화학적 성분 특성에 관한 연구 (I) - NR-PM-1.0의 화학적 구성

김현재,최진수,안준영,김정호,이태형,조석연,박진수 한국도시환경학회 2022 한국도시환경학회지 Vol.22 No.2

In this study, we carried out the aircraft measurement over Seoul air-shed with a HR-ToF-AMS integrated on an aircraft in the spring of 2020. During the aircraft measurement period, the westerly wind was dominant in the Korean Peninsula and the high-concentration fine dust phenomenon occurred in the Seoul metropolitan area from March 21 to 23, 2020. The average concentration of NR-PM-1.0 for 6 research flights (RF01 to RF06) was 10.0 ± 2.7 μg/m3 to 52.9 ± 14.4 μg/ m3. The chemical composition of NR-PM-1.0 was 36-57% organic, 12-34% sulfate, 11-25% nitrate, and 10-14% ammonium, and organic component was dominant. The NR-PM-1.0 concentration (52.9 ± 14.4 μg/m3) of the Seoul flight corresponding to RF05 was the highest, and organic components and sulfate were identified as major components. The flight zone was designed into three zones according to the flight route. The highest NR-PM-1.0 concentration was shown in the Seoul downtown area (a), and the organic component was confirmed as the dominant component of NR-PM-1.0 at a level of about 50%. It was found that the aerosol flowed into the Seoul air-shed with a strong westerly wind and moved to the east and affected rural areas in the downwind direction. 2020년 봄철 항공기에 HR-ToF-AMS를 탑재하여 서울 상공에서 항공관측을 수행하였다 . 고농도 미세먼지 사례시 NR- PM-1.0의 화학적 성분의 특성을 파악하였다 . 고농도 미세먼지 현상은 2020년 3월 21부터 23일에 걸쳐 수도권에 광역적 으로 발생하였다 . 항공관측 기간동안 우리나라를 포함한 한반도는 서풍이 지배적으로 나타났다 . 항공관측 기간 우리나라 를 포함한 서울지역은 서풍이 유입되는 조건에서 고농도 미세먼지 현상이 발생하였으며 , 서울과 경기 지역의 PM-2.5는 24 ± 12 g/m3, 30 ± 16 g/m3으로 년평균 기준치보다 높은 수준으로 나타났다 . 연구비행 6회에 대한 NR-PM-1.0 평균 농 도는 10.0 ± 2.7 g/m3 - 52.9 ± 14.4 g/m3이었고 , 유기성분 36-57%, 황산염 12-34%, 질산염 11-25%, 암모늄 10-14% 비 율로 유기성분이 가장 높은 구성비를 보였다 . 유기성분에 대한 OM/OC 비는 1.85-2.02, H/C는 1.42-1.51, O/C는 0.54- 0.67 범위로 산화비율이 높은 특징을 나타냈다 . RF05에 해당하는 서울 비행의 NR-PM-1.0 농도 (52.9 ± 14.4 g/m3)가 가 장 높았는데 , 유기성분과 황산염이 주요성분으로 확인되었다 . 비행경로에 따라 3권역으로 구분하였다 . 서울을 포함한 수 도권역 (a), 충남 대형 배출원을 포함한 태안권역 (b), 강원도 전원 (숲) 지역을 포함한 (c) 영역으로 구분한다 . 도심지인 (a) 영역에서 가장 높은 NR-PM-1.0 농도를 보였으며 , 유기성분이 약 50% 수준으로 NR-PM-1.0의 주요성분으로 확인되었다 . 에어로졸은 강한 서풍을 타고 유입되었고 , 동쪽으로 이동하며 풍하 방향의 전원 지역에 영향을 미치는 것으로 나타났다 .

Breeding and Genetics : Estimation of Daily Milk Yields from AM/PM Milking Records

( Deuk Hwan Lee ),( Hong Rip Min ) 한국동물자원과학회(구 한국축산학회) 2013 한국축산학회지 Vol.55 No.6

Daily milk yields on test days were estimated using morning or afternoon partial milk yields collected by official agencies and the accuracy of the estimates was determined. Test-day data for milk yields consisted of 3,156,734 records of AM/PM partial milking measurements of 255,437 milking Holstein cows from 3,708 farms collected from December 2008 to April 2013. A linear regression model(LRM) was applied to estimate daily milk yields using alternate AM/PM milk yield records within lactation stages, milking intervals, and parities on every daily milk yield. The alternate statistical approach was a non-linear hierarchical model(NHM) in which Brody`s growth function was implemented by reflecting an animal`s physiological milk production cycle. When compared with LRM, daily milk yields predicted by the NHM were assumed to be functionally related to day in milk(or lactation) stage, milking intervals, and partial milk yields. Since the results were in terms of accuracies based on comparisons of different statistical models, accuracies of estimates of daily milk yields by NHM were close to those determined by the LRM. The average of these accuracies was 0.94 for AM partial milk yields and 0.93 for PM partial milk yields for first calving cows. However, the accuracies of AM/PM milk yield estimations from cows under a calving stage higher than the first parity were 0.96 and 0.95, respectively. Correlations between the estimated daily milk yields and the actual daily milk yields ranged from 0.96~ 0.98. These accuracies were lower for unbalanced AM/PM milking intervals and the first calving cows. Overall, prediction of daily milk yields by NHM would be more appropriate than by LRM due to its flexibility under different milk yield-related circumstances, which provides an idea of the functional relationship between milking intervals and days in milk with daily milk yields from statistical viewpoints.

Analysis of Data Spectral Regrowth from Nonlinear Amplification

Amoroso, Frank,Monzingo, Robert A. The Korean Institute of Communications and Informa 1999 Journal of communications and networks Vol.1 No.2

The regrowth of OQPSK power spectral sidelobes from AM/AM and AM/PM amplifier nonlinearity is analyzed. The time-domain expression for amplifier output shows how spectral re-growth will depend on the cubic coefficient of the Taylor's series of the amplifier nonlinearity as well as input amplitude ripple. Closed form spectrum calculations show that the spectral sidelobes produced by AM/PM take the same form as those produced by AM/AM. The rate of growth of AM/PM sidelobes is, however, not as great as for AM/AM.

안산 도심지 계절별 PM1 화학적 성분 특성

박종성,김종법,신수현,김필호,김창혁,황규철,이재영,조석연,김정호 한국환경분석학회 2023 환경분석과 독성보건 Vol.26 No.3

In this study, chemical properties of particulate matter (PM1) present in the urban area of Ansan in 2021 were analyzed using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Intensive observation was conducted during the measurement periods of spring (22 days), summer (29 days), autumn (60 days), and winter (29 days). High concentrations of PM1 were observed when a wind speed was low (< 0.81 m/s) and a direction of air flow was the east. PM1 concentration was the highest in spring (March), followed by summer (June and August), winter (December), and autumn (September and October). The main components of PM1 were organic, followed by nitrate, ammonium, and sulfate. The ratio of organic oxygen to organic carbon (O/C) was high in summer (0.64) and low in winter (0.51); conversely, the ratio of organic hydrogen to organic carbon (H/C) was higher in winter (1.66) than in summer (1.58). As for the oxidation rates of inorganic components, the nitrogen oxidation rate and sulfur oxidation rate were the highest in spring (NOR, 0.12; SOR, 0.64), which directly affected the rise in PM1 mass concentration in spring. Highly soluble nitrate was the largest component among the inorganic components of PM1, and the PM1 was found to be rich in ammonium in all seasons. PM1mass concentration and chemical composition increased with an increase of relative humidity (RH): the concentration of PM1 in wet conditions (RH > 60%) was found to be more than twice of that in dry conditions (RH < 40%). The largest component of PM1 in Ansan consisted of organic compounds; however, a high proportion of inorganic components, including nitrate, was also recorded.

비선형 증폭기의 위상 오차 보정을 위한 적응형 보상 시스템

한상민(Han, Sang-Min),임종식(Lim Jong-Sik),손태호(Son, Tae-Ho),윤원상(Yoon, Won-Sang),표성민(Pyo, Seong-Min),김영식(Kim, Young-Shik) 한국산학기술학회 2009 한국산학기술학회논문지 Vol.10 No.9

본 논문에서는 비선형 증폭기의 위상 오차의 보정 방법을 채용한 시스템을 제안하였다. 간단한 위상 벡터의 적응형 응답 방식을 이용하여, 다양한 입력 전력 변화에 대해 매우 큰 폭의 AM/PM 왜곡 감소 효과를 얻을 수 있었 다. 제안된 방법은 다양한 위상 오차 변화 환경에 대해 본 보정 시스템을 채용하지 않았을 경우와 비교하여, AM/PM 왜곡을 최대 80 %까지 감소시킬 수 있는 것으로 평가되었다. 또한 추가적으로 입력 신호에 대한 포락선 보상 기법을 추가하여 출력 신호의 인접채널 전력 비율의 향상시킨 결과를 보였다. A novel adaptive phase calibration method is proposed for nonlinear amplifiers. Based on the adaptive process of simple phase vector calculations, the AM/PM distortion can be significantly reduced for various input power. The performance of the proposed method is evaluated for up to 80 % improvements in AM/PM distortions, compared with the distortion of a conventional amplifier. Moreover, by means of an additional envelope-compensation technique, the improvement of the adjacent channel power ratio (ACPR) is presented.

AMS를 이용한 초미세입자의 서울지역 2014년 봄철 고농도 사례 특성 연구

박종성 ( Jong Sung Park ),송인호 ( In Ho Song ),박승명 ( Seung Myung Park ),신혜정 ( Hye Jung Shin ),홍유덕 ( You Deog Hong ) 한국환경분석학회 2015 환경분석과 독성보건 Vol.18 No.1

This study is aimed to qualitatively estimate the source of high PM episodes in Seoul metropolitan area. The inorganic and organic composition of non-refractory PM1.0 was measured by high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) during high PM episodes (Feb. ``14~Mar. ``14). The ionized mass spectrum data of organic matter was then analyzed by PMF (Positive Matrix Factorization) in order to identify the account of local emission and long range transport in high PM episodes and to provide scientific data for improvement of national air quality forecasting. As a result, six components of the organics were resolved including organic aerosols emitted from various primary combustion sources such as hydrocarbon-like organic aerosol (HOA), and cooking-related organic aerosol (COA) as well as three types of oxidized organic aerosols (OOAs), and nitrogen-rich organic aerosol (NOA). Real-time component analysis of fine particle (PM1.0) using AMS can identify the characteristics and cause of various air pollution cases and effectively measure the trend of air quality, making it a crucial component in national air quality forecasting. Through component analysis of high PM episodes, the effect of local emission and long range transport has been identified. Further, We believe this would provide important information required for validation and improvement of chemical model in national air quality forecasting.

전력 증폭기의 왜곡해석 및 개선에 관한 연구

하성재(Sung-Jae Ha),홍의석(Ui-Seok Hong) 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.10A

본 논문에서는 전력증폭기의 선형성을 개선하기위해서 전력증폭기에서 발생되는 왜곡을 해석하여 전력 증폭기의 선형성 개선 개념을 제시하고 검증하였다. 연구에서는 전력증폭기를 구동 증폭기와 종단 증폭기로 구분하여 종단 증폭기에서 발생되는 비선형 왜곡 성분을 구동증폭기의 왜곡성분으로 상쇄시키는 개념이 제시된다. 본 논문에서 전력증폭기의 AM to AM은 Power Series로 해석하였으며, AM to PM 왜곡은 Bessel 함수를 이용하여 해석하였다. 본 개념을 검증하기위하여 셀룰라 대역의 30W 전력 증폭기를 구현하여 검증하였다. 설계 및 제작된 전력 증폭기는z대역에서 30W@20FA 출력할 경우 스퓨리어스 특성이 51dBc @ 1FA,20FA ±1.98 ㎒의 특성을 나타내었다. 이러한 결과는 10㏈의 스퓨리어스 특성 개선을 보였다. In this paper, a power amplifier intermodulation distortion has been analyzed to improve linearity and the analysis results are used to minimize the distortion for linear power amplifier design. The proposed design technique is which the intermodulation distortions of the final amplifier are removed by driver intermodulation distortions. This proposed technique is based on AM to AM distortion analysis using power series, and AM to PM distortion analysis results using Bessel function. To verify this technique implement a cellular HPA(High Power Amplifier) 30W. From the results of the implementation and measurement for the linear power amplifier, the spurious characteristic is shown as 50 dBc at 1.98 ㎒ with 30 W with 20FA. These results show that distortion characteristics are improved as much as 10 ㏈ in spurious characteristic compared with conventional design method.