• Title/Summary/Keyword: Gain saturation

Search Result 178, Processing Time 0.021 seconds

0.18 μm CMOS Power Amplifier for Subgigahertz Short-Range Wireless Communications (Sub-GHz 근거리 무선통신을 위한 0.18 μm CMOS 전력증폭기)

  • Lim, Jeong-Taek;Choi, Han-Woong;Lee, Eun-Gyu;Choi, Sun-Kyu;Song, Jae-Hyeok;Kim, Sang-Hyo;Lee, Dongju;Kim, Wansik;Kim, Sosu;Seo, Mihui;Jung, Bang-Chul;Kim, Choul-Young
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.29 no.11
    • /
    • pp.834-841
    • /
    • 2018
  • A power amplifier for subgigahertz short-range wireless communication using $0.18-{\mu}m$ CMOS technology is presented. It is designed as a differential structure to form easily a virtual ground node, to increase output power, and to design a cascode structure to prevent breakdown. The transistor gate width was determined to maximize the output power and power-added efficiency(PAE), and the balun was optimized through electromagnetic simulation to minimize the loss caused by the matching network. This power amplifier had a gain of more than 49.5 dB, a saturation power of 26.7 dBm, a peak PAE of 20.7 % in the frequency range of 860 to 960 MHz, and a chip size of $2.14mm^2$.

A CMOS Image Sensor with Analog Gamma Correction using a Nonlinear Single Slope ADC (비선형 단일 기울기 ADC를 사용하여 아날로그 감마 보정을 적용한 CMOS 이미지 센서)

  • Ham Seog-Heon;Han Gunhee
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.43 no.1 s.343
    • /
    • pp.65-70
    • /
    • 2006
  • An image sensor has limited dynamic range while the human eye has logarithmic response over wide range of light intensity. Although the sensor gain can be set high to identify details in darker area on the image, this results in saturation in brighter area. The gamma correction is essential to fit the human eye response. However, the digital gamma correction degrades image quality especially for darker area on the image due to the limited ADC resolution and the dynamic range. This Paper proposes a CMOS image sensor (CIS) with a nonlinear analog-to-digital converter (AU) which performs analog gamma correction. The CIS with the proposed nonlinear analog-to-digital conversion scheme was fabricated with a $0.35{\mu}m$ CMOS process. The analog gamma correction using the proposed nonlinear ADC CIS provides the 2.2dB peak-signal-to-noise-ratio(PSM) improved image qualify than conventional digital gamma correction. The PSNR of the image obtain from the digital gamma correction is 25.6dB while it is 27.8dB for analog gamma correction. The PSNR improvement over digital gamma correction is about $28.8\%$.

Enhancement of Classification Accuracy and Environmental Information Extraction Ability for KOMPSAT-1 EOC using Image Fusion (영상합성을 통한 KOMPSAT-1 EOC의 분류정확도 및 환경정보 추출능력 향상)

  • Ha, Sung Ryong;Park, Dae Hee;Park, Sang Young
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.5 no.2
    • /
    • pp.16-24
    • /
    • 2002
  • Classification of the land cover characteristics is a major application of remote sensing. The goal of this study is to propose an optimal classification process for electro-optical camera(EOC) of Korea Multi-Purpose Satellite(KOMPSAT). The study was carried out on Landsat TM, high spectral resolution image and KOMPSAT EOC, high spatial resolution image of Miho river basin, Korea. The study was conducted in two stages: one was image fusion of TM and EOC to gain high spectral and spatial resolution image, the other was land cover classification on fused image. Four fusion techniques were applied and compared for its topographic interpretation such as IHS, HPF, CN and wavelet transform. The fused images were classified by radial basis function neural network(RBF-NN) and artificial neural network(ANN) classification model. The proposed RBF-NN was validated for the study area and the optimal model structure and parameter were respectively identified for different input band combinations. The results of the study propose an optimal classification process of KOMPSAT EOC to improve the thematic mapping and extraction of environmental information.

  • PDF

Consideration on Application of Modified Monitored Anesthetic Care in Plastic Surgery (성형외과 영역의 수술 시 마취하 감시관리의 응용에 대한 고찰)

  • Cho, Geon;Suh, In-Suck;Choi, Young-Ryong;Chung, Mi-Hwa;Tak, Kyoung-Seok;Park, Young-Kyu;Kim, Jae-Hyun;Ko, Eung-Yeol;Sung, Ha-Min
    • Archives of Plastic Surgery
    • /
    • v.38 no.1
    • /
    • pp.7-14
    • /
    • 2011
  • Purpose: Many patients have fear for surgery owing to the injection of lidocaine and the possible pain in the course of the operation. To resolve such a problem the cases to do plastic surgery with monitored anesthetic care are increasing, in which something like sedatives is injected into vein without endotracheal intubation and under voluntary respiration, but the usage is now under the controversy. Methods: There were 25 patients who had surgery with local anesthesia, and another 25 patients who had surgery with monitored anesthetic care which belongs to ASA class 1 and 2 from January to April, 2009. Their anesthesia records were collected and surveys were given before and after the surgery and the surgery staff recorded OAA/S during the surgery. The postoperative surveys included the awakening during the surgery, pain, anxiety, and the degree of patient's satisfaction through visual analogue scale to identify the difference between the two methods. Results: The OAA/S results according to time lapse show that it is possible to lead a fast effective sedation and recovery with monitored anesthetic care, and monitored anesthetic care enhances both surgeon's convenience level and patient's satisfaction level, and reduces awakening, pain, and anxiety, compared to local anesthesia. Conclusion: The current paper shows about the plastic surgery, particularly the outpatient surgery, when monitored anesthetic care method is applied, it could gain a fast sedation and recovery or an effective sedation of patients. The method also has some affirmative effects in regard with surgeon's convenience and the patients' satisfaction degree and the reduction of their awakening, pain, and anxiety. With careful and adequate watch on the measures about vital signs like electrocardiogram, the degree of oxygen saturation, and blood pressure, it could clinically be very useful.

GPS L1, L2C Signal Acquisition Performance of GPS Software Receiver with respect to Pseudolite Pulsing Scheme (의사위성의 펄싱 방법에 대한 GPS L2C 신호획득 성 소능프분트석웨어 수신기의 L1, L2C 신호획득 성능분석)

  • Kwon, Keum-Cheol;Yand, Cheol-Kwan;Shim, Duk-Sun;Chung, Tae-Sang;Kee, Chand-Don
    • Journal of Advanced Navigation Technology
    • /
    • v.16 no.1
    • /
    • pp.16-26
    • /
    • 2012
  • Pseudolites are ground-based transmitters that can be configured to emit GPS-like signals for enhancing the GPS by providing increased accuracy, integrity, and availability. However, a pseudolite (PL) can interfere with GPS satellite signals while it is transmitting or cause saturation to automatic gain control circuit. To solve these problems pulsing scheme is used, which transmits PL signal during a short period of time. In this paper the effect of the number of PL and pulsing scheme on the software GPS L1 and L2C signal acquisition performance is studied for the three pulsing schemes such as static pulsing, sweep pulsing, and pseudo random pulsing. For GPS L1 signal, static pulsing shows the best signal acquisition and tracking performance with one PL, and random pulsing shows the best performance with more than or equal to two PLs. For GPS L2C signal, all three pulsing schemes show the similar signal acquisition and tracking performance, but static pulsing shows a little better performance. For GPS L1 and L2C signals, software GPS receivers can do positioning with up to three PLs.

Design of a Holter Monitoring System with Flash Memory Card (플레쉬 메모리 카드를 이용한 홀터 심전계의 설계)

  • 송근국;이경중
    • Journal of Biomedical Engineering Research
    • /
    • v.19 no.3
    • /
    • pp.251-260
    • /
    • 1998
  • The Holter monitoring system is a widely used noninvasive diagnostic tool for ambulatory patient who may be at risk from latent life-threatening cardiac abnormalities. In this paper, we design a high performance intelligent holter monitoring system which is characterized by the small-sized and the low-power consumption. The system hardware consists of one-chip microcontroller(68HC11E9), ECG preprocessing circuit, and flash memory card. ECG preprocessing circuit is made of ECG preamplifier with gain of 250, 500 and 1000, the bandpass filter with bandwidth of 0.05-100Hz, the auto-balancing circuit and the saturation-calibrating circuit to eliminate baseline wandering, ECG signal sampled at 240 samples/sec is converted to the digital signal. We use a linear recursive filter and preprocessing algorithm to detect the ECG parameters which are QRS complex, and Q-R-T points, ST-level, HR, QT interval. The long-term acquired ECG signals and diagnostic parameters are compressed by the MFan(Modified Fan) and the delta modulation method. To easily interface with the PC based analyzer program which is operated in DOS and Windows, the compressed data, that are compatible to FFS(flash file system) format, are stored at the flash memory card with SBF(symmetric block format).

  • PDF

Fabrication and Characterization of Lead Oxide (PbO) Film for High Efficiency X-ray Detector (고효율 X선 검출기 적용을 위한 PbO 필름 제작 및 특성 연구)

  • Cho, Sung-Ho;Kang, Sang-Sik;Choi, Chi-Won;Kwun, Chul;Nam, Sang-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2007.06a
    • /
    • pp.329-329
    • /
    • 2007
  • Photoconductive poly crystalline lead oxide coated on amorphous thin film transistor (TFT) arrays is the best candidate for direct digital x-ray detector for medical imaging. Thicker films with lessening density often show lower x-ray induced charge generation and collection becomes less efficient. In this work, we present a new methodology used for the high density deposition of PbO. We investigate the structural properties of the films using X-ray diffraction and electron microscopy experiments. The film coatings of approximately $200\;{\mu}m$ thickness were deposited on $2"{\times}2"$ conductive-coated glass substrates for measurements of dark current and x-ray sensitivity. The lead oxide (PbO) films of $200\;{\mu}m$ thickness were deposited on glass substrates using a wet coating process in room temperature. The influence of post-deposition annealing on the characteristics of the lead oxide films was investigated in detail. X-ray diffraction and scanning electron microscopy, and atomic force microscopy have been employed to obtain information on the morphology and crystallization of the films. Also we measured dark current, x-ray sensitivity and linearity for investigation of the electrical characteristics of films. It was found that the annealing conditions strongly affect the electrical properties of the films. The x-ray induced output charges of films annealed in oxygen gas increases dramatically with increasing annealing temperatures up to $500^{\circ}C$ but then drops for higher temperature anneals. Consequently, the more we increase the annealing temperatures, the better density and film quality of the lead oxide. Analysis of this data suggests that incorporation and decomposition reactions of oxygen can be controlled to change the detection properties of the lead oxide film significantly. Post-deposition thermal annealing is also used for densely film. The PbO films that are grown by new methodology exhibit good morphology of high density structure and provide less than $10\;pA/mm^2$ dark currents as they show saturation in gain (at approximate fields of $4\;V/{\mu}m$). The ability to operate at low voltage gives adequate dark currents for most applications and allows voltage electronics designs.

  • PDF

Effects of Simulated Acid Rain on Growth and Physiological Characteristics of Ginkgo biloba L. Seedlings and on Chemical Properties of the Tested Soil -III. Effects on Chemical Properties of the Tested Soil- (인공산성우(人工酸性雨)가 은행(銀杏)나무 Ginkgo biloba L. 유묘(幼苗)의 생장(生長), 생리적(生理的) 특성(特性) 및 토양(土壤)의 화학적(化學的) 성질(性質)에 미치는 영향(影響) -III. 토양(土壤)의 화학적(化學的) 성질(性質)에 미치는 영향(影響)-)

  • Kim, Gab Tae;Lee, Don Koo
    • Journal of Korean Society of Forest Science
    • /
    • v.77 no.1
    • /
    • pp.43-52
    • /
    • 1988
  • One-year-old seedlings of Ginkgo biloba were treated with various simulated acid rains(pH 2.0, pH 3.0, pH 9.0 and pH 5.0) to examine the effects of simulated acid rain on the chemical properties of the tested soil. The seedlings were grown in a pot($4500cm^3$)containing one of three different soils(nursery soil, mixed soil and sandy soil). Simulated acid rain was made by diluting sulfuric and nitric acid solution($H^1SO^4$ : $HNO^3$ =3 : 1, V/V) with tap water and tap water(pH 6.4), and treated by 5mm each time for three minutes during the growing seasons(April to October 1985). Acid rain treatments were done three times per week to potted seedlings by spraying the solutions. The chemical properties of potting media were compared among three soil types as well as among the various pH levels. The results obtained in this study were as follows : 1. Exchangeable calcium and magnesium contents and base saturation of the soil decreased with decreasing pH levels of acid rain, and their decreasing rates were as follows : sandy soil was the highest, followed by mixed and nursery soils, However, exchangeable aluminum content rather increased as the pH levels decreased. 2. Available phosphate in the soil decreased as the pH levels of acid rain decreased. Its content increased in nursery soil, compared with those before acid gain treatment, Gut decreased in mined and sandy soils. 3. Soil sulfate and nitrate contents increased remarkably as the pH levels decreased, and the only significant difference in the sulfate was found among the pH levels. Soil sulfate content was the highest in nursery soil, followed by mixed and sandy soils.

  • PDF