• 전자공학회논문지
• /
• 제53권2호
• /
• pp.36-44
• /
• 2016

본 논문에서는 $0.18{\mu}m$ CMOS 공정을 이용하여 WBAN(Wireless Body Area Network)용 IR-UWB(Impulse Radio Ultra Wide Band) RF 송수신기를 제안한다. 설계된 송수신기는 3-5GHz UWB low band를 지원하며 OOK(On-Off Keying) 변조 방식을 사용한다. 수신기는 복잡도와 소모 전력을 줄이기 위해서 비동기식 에너지 검출 방식을 사용하였다. 원하지 않는 잡음을 제거하고 감도를 개선하기 위하여 RF active notch filter가 내장되어 있다. VCO 기반의 수신기는 switch mechanism을 사용하였다. 사용된 switch mechanism은 소모 전력을 줄이고 VCO leakage를 최소화 할 수 있다. 또한, 중심주파수가 변해도 항상 동일한 spectrum mask를 가진다. 측정된 수신기의 감도는 3.5 GHz의 중심주파수에서 1.579 Mbps의 전송 속도를 가질 때 -84.1 dBm을 가진다. 송신기와 수신기는 각각 0.3 nJ/bit, 41 mW의 소모 전력을 사용한다.

• Journal of Multimedia Information System
• /
• 제9권2호
• /
• pp.145-154
• /
• 2022

The authors are making a prototype flexible board of a radio-frequency transmitter for measuring an electromyogram (EMG) of a flying moth and plan to apply for an experimental station license from the Ministry of Internal Affairs and Communications of Japan in the summer of 2022. The goal is to create a continuous low-dose exposure standard that incorporates scientific and physiological functional assessments to replace the current standard based on lethal dose 50. This paper describes the technical evaluation of the hardware. The signal of a bipolar EMG electrode is amplified by an operational amplifier. This potential is added to a voltage-controlled crystal oscillator (27 MHz, bandwidth: 4 kHz), frequency-converted, and transmitted from an antenna about 10 cm long (diameter: 0.03 mm). The power source is a 1.55-V wristwatch battery that has a total weight of about 0.3 g (one dry battery and analog circuit) and an expected operating time of 20 minutes. The output power is -7 dBm and the effective isotropic radiated power is -40 dBm. The signal is received by a dual-whip antenna (2.15 dBi) at a distance of about 100 m from the moth. The link margin of the communication circuit is above 30 dB within 100 m. The concepts of this hardware and the measurement data are presented in this paper. This will be the first biological data transmission from a moth with an official license. In future, this telemetry system will improve the detection of physiological abnormalities of moths.

• 제어로봇시스템학회논문지
• /
• 제21권7호
• /
• pp.609-614
• /
• 2015

Implanted telemetry systems provide the ability to monitor different species of animals while they move within their cages. Species monitored include mice, rats, rabbits, dogs, pigs, primates, sheep, horses, cattle, and others. A miniature transmitter implanted in each animal measures one or more parameters. Parameters measured include arterial pressure, intra-pleural pressure, left ventricular pressure, intra-ocular pressure, bladder pressure, ECG, EMG, EEG, EOG, temperature, activity, and other parameters and transmits the data via radio frequency signals to a nearby receiver. Every conventional dedicated transmitter contains one or more sensors, cpu and battery. Due to the expected life of the battery, the measuring time is limited. To overcome these problems, electromagnetic inductive coupling based wireless power transmission technology using multiple transmit coils were proposed, with each coil having a different active area driven by the coil driver. In this research, a parallel resonance based coil driver and serial resonance based coil driver are proposed. From the experiments we see that the parallel coil driver shows better performance under a low impedance and multiple coils configuration. However, the serial coil driver is more efficient for high impedance transmit coils.

• 한국압력기기공학회 논문집
• /
• 제6권1호
• /
• pp.16-22
• /
• 2010

Cast austenitic stainless steel(CASS) is used in the primary cooling piping system of nuclear power plant for it's relative low cost, corrosion resistance and easy of welding. However, the coarse-grain structure of cast austenitic stainless steel can strongly affect the inspectability of ultrasonic testing. The major problems encountered during inspection are beam skewing, high attenuation and high background noise of CASS component. So far, the best inspection performance involving CASS components have been achieved using low frequency TRL(Transmitter/Receiver side-by-side L wave) angle beam probe. But TRL technique could not detect shallow defect and it contains an uncertainty for sizing capability. Currently, most of researchers are studying to overcome these challenge issue. In this study, low-frequency phased array TRL technique used to detect and sizing the flaws in CF8A cast austenitic stainless steel.As conclusion, we could detect and size not only axial flaw but also circumferential flaw using low frequency phased array technique.

• 한국컴퓨터정보학회논문지
• /
• 제22권8호
• /
• pp.41-46
• /
• 2017

In this paper, we investigate the D2D Transmitter(Tx) and Receiver(Rx) pair assignment problem in the cellular system where D2D users share the uplink resource of the cellular system. Sharing the uplink resource of the cellular system may cause interference to the cellular system, though it is beneficial to improve the D2D user Capacity. Therefore, to protect the cellular users, D2D transmit power should be carefully controlled. In this work, we focus on optimal Tx-Rx assignment in such a way that the total transmit power of users is minimized. First, we consider the optimum Tx-Rx assignment in general and the corresponding complexity. Then, we propose an iterative D2D Tx-Rx assignment algorithm with low complexity that can minimize total transmit power of users. Finally, we present the numerical examples that show the complexity and the convergence to the unique transmit power level.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2005년도 추계종합학술대회
• /
• pp.805-808
• /
• 2005

In this study, the design of advanced LVDS(Low Voltage Differential Signaling) I/O interface circuit with new structural low triggering ESD(Electro-Static Discharge) protection circuit was investigated. Due to the differential transmission technique and low power consumption at same time. maximum transmission data ratio of designed LVDS transmitter was simulated to 5Gbps, Also, the LIGCSCR(Latch-up Immune Gate Coupled SCR)was designed. It consists of PLVTSCR (P-type Low Voltage Trigger SCR), control NMOS and RC network. The triggering voltage was simulated to 3.6V. And the latch-up characteristics were improved. Finally, we performed the layout high speed I/O interlace circuit with the low triggered ESD protection device in one-chip.

• 정보학연구
• /
• 제6권4호
• /
• pp.1-9
• /
• 2003

본 연구는 저압 전력선 망을 통한 전력선 통신(PLC: Power Line Communication)에 관한 내용이다. 전력선 통신이 가지는 주요 잇점은 기존의 인프라구조의 사용이다. 전력선 통신 채널은 전형적으로 전력선의 길이와 주파수가 증가함에 의해 신호 감쇠를 나타내는 주파수 선택적 페이딩(Frequency-Selective Fading)을 가지는 다중경로 반사 전파로 모델링 할 수 있다. OFDM(Orthogonal Frequency Division Multiplexing)은 다수개의 낮은 데이터 율의 반송파들이 높은 전송율을 이루는 형태로 송신기에서 조합되는 변조 기법이다. 모델링한 다중 경로 반사 전력선 채널에 음향 신호를 입력하여 체계의 성능을 모의 실험을 통해 분석, 검증하였다.

• 한국전자파학회논문지
• /
• 제16권7호
• /
• pp.671-680
• /
• 2005

CQPSK(Compatible QPSK) 디지털 변조 기술을 이용하는 초협대역 단말기용 송신기에 가장 핵심적인 부품들 중의 하나인 카테지안 궤환 루프(CFL: Cartesian Feedback Loop) 선형화 칩을 $0.35{\mu}m$ CMOS 기술을 이용하여 설계 및 제작하였다. 직접 변환 방식 및 CFL칩을 이용하여 요구되는 부품 수를 줄임에 의하여 송신기의 저비용 및 소형화가 가능하고, 이를 통하여 송신 전력 효율 및 선형성을 향상시켰다. 또한 CMOS기술을 통하여 저전력 구동이 가능하도록 하였다. 송신 성능 시험 결과 PEP 37 dBm(5 W)의 출력 전력에서 CFL 칩을 구동하여 -25 dBc의 상호 변조 왜곡(@ 3 kHz주파수 오프셋) 개선을 통하여 FCC 47 CFR 90.210 E에 정의된 방사 마스크 규격을 만족함을 확인하였다. 또한 상기 언급된 송신 특성 개선에 가장 영 향을 미치는 성분들인 DC-offset 성분, 궤환 루프에서 발생하는 왜곡 성분을 보상하기 위한 루프 이득 및 위상 값들을 조정할 수 있도록 컴퓨터와의 외부 인터페이스를 구현하여 소프트웨어적으로 이러한 값들을 제어할 수 있도록 프로그램화 하였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2005년도 추계종합학술대회
• /
• pp.731-734
• /
• 2005

In this study, the design of advanced LVDS(Low Voltage Differential Signaling) I/O interface circuit with new structural low triggering ESD (Electro-Static Discharge) protection circuit was investigated. Due to the differential transmission technique and low power consumption at the same time. Maximum transmission data ratio of designed LVDS transmitter was simulated to 5Gbps. And Zener Triggered SCR devices to protect the ESD phenomenon were designed. This structure reduces the trigger voltage by making the zener junction between the lateral PNP and base of lateral NPN in SCR structure. The triggering voltage was simulated to 5.8V. Finally, we performed the layout high speed I/O interface circuit with the low triggered ESD protection device in one-chip.

• 한국전자파학회논문지
• /
• 제15권3호
• /
• pp.251-257
• /
• 2004

연안에서 선박의 안전한 항행과 관제를 위해 선박간 또는 선박과 관제소간의 항행정보를 교환할 수 있도록 하는 AIS(Automatic Identification System)는 운용 방식(Low setting, High setting)에 따라 서로 다른 송신 출력 크기를 가지며, 1 ms(Transmitter Setting Time)안에 각각의 최종 출력 크기 의 20% 이내로 도달하도록 하는 동작 성능을 요구한다. 본 논문에서는 이와 같은 AIS의 송신 출력 특성에 부합할 수 있도록 전력 증폭기 모듈에 적절한 궤환 회로를 제안하고 이를 설계, 제작하였다.