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A Low Phase Noise Integer-N Frequency Synthesizer for 2.4GHz ZigBee Application
윤성욱,김창열,전양지,남일구 한국과학기술원 반도체설계교육센터 2019 IDEC Journal of Integrated Circuits and Systems Vol.5 No.2
A low phase noise and low power consumption integer-N frequency synthesizer for ZigBee application (IEEE 802.15.4) in the frequency range of 2.39-2.51GHz with channel spacing of 5MHz is designed through Samsung CMOS 65nm process. The phase noise and low power consumption are important factors for phase locked loop (PLL) design considering RF transceiver performance. The phase noise characteristics of proposed frequency synthesizer can be improved by dividing the large tuning range into a sub-band range with a small gain of VCO. Phase noise can be reduced by choosing the appropriate code value assigned to the desired channel using AFC (auto frequency calibration). Also, AFC’s power consumption could be decreased in coarse tuning mode. It consumes 14 mW during the coarse tuning mode and 11 mW during the fine tuning mode at 1.2V supply, respectively. It occupies an area of 1.73 mm × 1.73 mm including PADs. The simulated phase noise characteristic of the frequency synthesizer is -125dBc/Hz at 1 MHz offset from the carrier.
GSM 간섭 신호에 강인한 광대역 UHF 대역 CMOS 수신기 프런트 엔드
윤성욱(Sung Wook Yoon),전양지(Yangji Jeon),김창열(Changyeol Kim),이옥구(Ockgoo Lee),남일구(Ilku Nam) 대한전자공학회 2018 전자공학회논문지 Vol.55 No.12
본 논문에서는 단말기에서 GSM 수신기와 DVB-H와 같은 디지털 TV 튜너 수신기가 공존할 때 GSM 상호운용성을 지원할 수 있는 UHF 대역 (470-868 MHz) 수신기 프런트엔드 회로를 제안한다. 제안한 수신기 프런트엔드 회로는 저잡음 증폭기, 싱글 입력 차동 출력 증폭기, 전류미러 기반의 I/Q 하향 혼합기로 구성되어 있다. 광대역 신호를 수신하기 위해 저항성 피드백 형태의 구조를 사용하였고, GSM IOP를 지원할 수 있도록 노치 필터를 포함하여 저잡음 증폭기를 구성하였다. 전류미러 회로를 사용하여 고선형 하향 혼합기 특성을 얻어 수신기 프런트 엔드의 전체 선형성 특성을 개선하였다. 제안한 수신기 프런트엔드는 130 nm RF CMOS 공정을 사용하여 설계하였고, 전원 전압 1.2 V에서 14 mW의 전력를 소모한다. 제안한 수신기 프런트엔드는 노치필터가 동작할 경우 470-748 MHz에서 동작하고 이득이 28 dB, 잡음 지수 3 dB, IIP3 -11 dBm의 성능을 보이고, 노치필터가 동작하지 않을 경우 470-868 MHz에서 동작하고 이득이 30 dB, 잡음 지수 3 dB, IIP3 -11 dBm의 성능을 가진다. This paper presents a UHF band (470-868 MHz) receiver front-end circuit that can support GSM interoperability when a digital TV tuner receiver coexists with a GSM receiver on a cellular phone. The proposed receiver front-end circuit consists of a low-noise amplifier, a single-input differential-output amplifier, and a current-mirror based I/Q down-conversion mixer. The low-noise amplifier employs a resistive feedback topology to receive broadband input signals and notch filter in the signal path in order to support GSM interoperability. Using current-mirror circuits, the overall linearity characteristics of the receiver front end were improved by obtaining the high linearity of the down-conversion mixer. The proposed receiver front end was designed using a 130 nm RF CMOS process and consumes power of 14 mW at supply voltage of 1.2 V. The proposed receiver front end shows a gain of 28 dB, an IIP3 of -11 dBm, and a NF of 3 dB at 470-748 MHz when the notch filter is operating, and a gain of 30 dB, an IIP3 of -11 dB, and a NF of 3 dB at 470-868 MHz when the notch filter is not operational.
남녀 대학생의 신체만족도, 자아존중감과 우울에 대한 비교연구
김나영,김민정,김진경,박민주,박민지,이다솜,이민경,이지영,전양지,정하은 이화여자대학교 간호과학대학 2010 이화간호학회지 Vol.- No.44
The purpose of this study was to know relationship among body image and self esteem, depression obtained from male and female. Also we wanted to know what is differences between male and female groups. We intended to provide basis materials for developing programs to increase body image, self esteem and to decrease depression at the same time. Object of our study were male and female who are in collage. There were 90 people in each group. We used frequency analysis to know general characteristics, and we use frequency analysis and descriptive statistic analysis to know question distribution. We studied relationship among body image and self esteem and depression with using Spearman Correlation and analysised the differences between male and female groups with using T-test. This is the result of our research. 1. ale show higher BCS and BET scores than women. Between male and female, self-esteem have no big differences. And female is more depressive than male. 2. he two elements that body image and depression are in inverse proportion to each other in both male and female university students. 3. The two elements that self-esteem and depression are in inverse proportion to each other in both male and female university students. 4. The two elements that body image and self-esteem are in inverse proportion to each other in both male and female university students. And male have high correlation between BCS and BET, BCS and self-esteem, self-esteem and depression tha female. On the other hand, female have high correlation between BET and self-esteem, BET and depression In short, both male and female have correlation between body image, self-esteem and depression. Especially, between self-esteem snd depression have high correlation. In body image, especially female have high correlation between BET and depression. Finally we found the fact that female is more sensitively react than male about appearance.