• 스마트미디어저널
• /
• 제4권2호
• /
• pp.55-61
• /
• 2015

A bandwidth-enhanced ultra-wide band (UWB) CMOS balun-LNA is implemented as a part of a software defined radio (SDR) receiver which supports multi-band and multi-standard. The proposed balun-LNA is composed of a single-to-differential converter, a differential-to-single voltage summer with inductive shunt peaking, a negative feedback network, and a differential output buffer with composite common-drain (CD) and common-source (CS) amplifiers. By feeding the single-ended output of the voltage summer to the input of the LNA through a feedback network, a wideband balun-LNA exploiting negative feedback is implemented. By adopting a source follower-based inductive shunt peaking, the proposed balun-LNA achieves a wider gain bandwidth. Two LNA design examples are presented to demonstrate the usefulness of the proposed approach. The LNA I adopts the CS amplifier with a common gate common source (CGCS) balun load as the S-to-D converter for high gain and low noise figure (NF) and the LNA II uses the differential amplifier with the ac-grounded second input terminal as the S-to-D converter for high second-order input-referred intercept point (IIP2). The 3 dB gain bandwidth of the proposed balun-LNA (LNA I) is above 5 GHz and the NF is below 4 dB from 100 MHz to 5 GHz. An average power gain of 18 dB and an IIP3 of -8 ~ -2 dBm are obtained. In simulation, IIP2 of the LNA II is at least 5 dB higher than that of the LNA I with same power consumption.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 추계학술대회논문집
• /
• pp.512-514
• /
• 2008

In this paper, a new electromagnetic circuit is proposed for an optical pickup actuator with high sensitivity. Contrary to those of conventional actuators, the proposed circuit has two focusing coils which are diagonally placed at the front and rear of a moving part. The configuration which makes the effective length of the focusing coil longer and the moving part lighter, is helpful in increasing the sensitivity of the actuator. However, the asymmetry of the moving part by two focusing coils causes flexible node vibrations in quite low frequency range. This paper shows that the design modification of the moving part for the reconfiguration of mass moment of inertia can reduce the mode vibrations.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2004년도 추계학술대회 논문집
• /
• pp.32-36
• /
• 2004

In order to achieve high performance vector control, it is essential to measure accurate ac current. The errors generated from current path are inevitable, and they could be divided into two categories: offset error and scaling error. The current data including these errors cause periodic speed ripples which are one and two times of stator electrical frequency respectively. Since these undesirable ripples bring about bad influences to motor driving system, a compensation algorithm must be needed in the control algorithm of the motor drive. In this paper, a new compensation algorithm is proposed. The signal of the integrator output of the d-axis current regulator is chosen and processed to compensate the current measurement errors. The compensation of the current measurement errors is easily implemented to smooth the signal of the integrator output of the d-axis current regulator by subtracting the DC offset value or rescaling the gain of the hall sensor. Therefore, the proposed algorithm has several features: the robustness of the variation of the mechanical parameters, the application of the steady and transient state, the easy implementation, and less computation time.

• 대한전자공학회논문지SD
• /
• 제38권1호
• /
• pp.30-36
• /
• 2001

본 논문에서는 전자선 묘화 방법을 이용하여 게이트 길이가 0.35 ㎛인 AlGaAs/InGaAs PHEMT를 제작하였다. 다른 게이트 폭과 게이트 핑거 수를 갖도록 제작된 PHEMT의 DC 및 AC 특성은 여러 가지의 바이어스 조건에서 측정하였다. 또한, 제작된 PHEMT와 수동 소자의 라이브러리를 이용하여 35 GHz에서 동작 가능한 MIMIC 전력증폭기를 설계 및 제작하였다. 제작된 MIMIC 전력증폭기는 27.6 GHz에서 7.9㏈의 이득과 -15 ㏈의 입력 반사 계수를 나타내었다.

• Journal of Magnetics
• /
• 제12권1호
• /
• pp.35-39
• /
• 2007

A highly sensitive magnetic sensor using the Giant MagnetoImpedance effect has been developed. The sensor performance is studied and estimated. The sensor circuitry consists of a square wave generator (driving source), a sensing element in a form of composite wire of a 25 $\mu$m copper core electrodeposited with a thin layer of soft magnetic material ($Ni_{80}Fe_{20}$), and two amplifier stages for improving the gain, switching mechanism, scaler circuit, an AC power source driving the permeability of the magnetic coating layer of the sensing element into a dynamic state, and a signal pickup LC circuit formed by a pickup coil and an capacitor. Experimental studies on sensor have been carried out to investigate the key parameters in relation to the sensor sensitivity and resolution. The results showed that for high sensitivity and resolution, the frequency and magnitude of the ac driving current through the sensing element each has an optimum value, the resonance frequency of the signal pickup LC circuit should be equal to or twice as the driving frequency on the sensing element, and the anisotropy of the magnetic coating layer of the sensing wire element should be longitudinal.

• 전자공학회논문지A
• /
• 제31A권9호
• /
• pp.104-113
• /
• 1994

We have fabricated n-p-n HBTs using 3-inchAlgaAs/GaAs hetero structure epi-wafers grown by MBE. DC and AC characteristics of HBT devices were measured and analyzed. For HBT epi-structure, Al composition of emitter was graded in the region between emitter cap and emitter. And base layer was designed with concentration of 1${\times}10^{19}/cm^{3}$ and thickness of 50nm, and Be was used as the p-type dopant. Principal processes for device fabrication consist of photolithography using i-line stepper, wet mesa etching, and lift-off of each ohmic metal. The PECVD SiN film was used as the inslator for the metal interconnection. HBT device with emitter size of 3${\times}10{\mu}m^{2}$ resulted in cut-off frequency of 35GHz, maximum oscillation frequency of 21GHz, and current gain of 60. The distribution of the ideality factor of collector and base current was very uniform, and the average values of off-set voltage and current was very uniform, and the average values of off-set voltage and current gain were 0.32V and 32 within a 3-inch wafer.

• 한국식품영양과학회지
• /
• 제42권2호
• /
• pp.182-187
• /
• 2013

멸치젓으로부터 추출한 칼슘이 체내의 칼슘대사에 미치는 영향을 알아보기 위하여 흰쥐를 대상으로 칼슘급원을 달리하여 섭취시킨 후 체내의 골격대사에 관련된 지표를 비교 평가하였다. 식이구성은 탄산칼슘군(calcium carbonate, CC), 젖산칼슘군(calcium lactate, CL), 해조칼슘군(seaweed calcium, SC), 멸치칼슘(anchovy calcium, AC), 저칼슘(low calcium, LC)군으로 총 5군으로 구성하였으며, 실험결과는 다음과 같다. 실험 종료까지의 체중은 탄산칼슘을 섭취한 CC군과 AC군에서 가장 많이 증가하였으며, LC군에서 체중 증가가 낮았고 식이섭취량도 LC군에서 가장 낮았으며, 정상칼슘군에서는 차이를 보이지 않았다. 칼슘 섭취량은 LC군에서 가장 낮은 수치를 나타내었고 정상칼슘군들 사이에는 유의적인 차이가 없었다. 칼슘 흡수율은 LC군에서 가장 높게 나타나 식이 칼슘수준이 적을수록 흡수율이 높아지는 것을 알 수 있었다. 칼슘 보유량은 저칼슘군에서 가장 낮았으며, CC군, CL군, AC군은 SC군에 비해 유의적으로 높은 수치를 나타내었다. 혈중 ALP 수준은 LC군에서 유의하게 높은 반면 정상칼슘군에서는 낮게 나타났으며, 특히 CC군과 AC군에서 현저히 낮게 나타났다. 칼시토닌 농도는 LC군에서 정상칼슘군보다 유의적으로 낮게 나타났고(p<0.05) 요중 DPD수치는 LC군에서 가장 높은 수치를 보였으며, CC군과 AC군에서 유의적으로 낮은 수치를 보였다. 대퇴골의 체중 100 g당 습윤무게는 실험군간에는 차이를 나타내지 않았으나, 건조무게는 정상칼슘군보다 LC군에서 유의적으로 낮은 결과를 보였다(p<0.05). 대퇴골의 골밀도는 LC군에서 정상칼슘군에 비해 유의하게 낮았고(p<0.05), 동일한 정상수준의 칼슘이 공급된 실험군 사이에서는 CL군에서 AC, CC, SC보다 유의적인 차이는 아니지만 감소경향을 보였다. 실험동물의 칼슘대사에 관련된 호르몬의 변화나 대퇴골의 골밀도 결과로 보아 멸치젓에서 추출한 칼슘은 기존에 사용해오던 탄산칼슘 수준으로 칼슘대사에 긍정적인 가치를 부여할 수 있을 것으로 사료되고, 멸치 부산물을 활용한 칼슘제 개발에 응용할 수 있을 것으로 본다.

• Journal of Power Electronics
• /
• 제15권3호
• /
• pp.786-795
• /
• 2015

In this paper, an active damping control scheme for LLCL filters based on the PR (proportional-resonant) regulator is proposed for grid-connected three-level T-type PWM converter systems. The PR controller gives an infinite gain at the resonance frequency. As a result, the oscillation can be suppressed at that frequency. In order to improve the stability of the system in the case of grid impedance variations, online grid impedance estimation is applied. Simulation and experimental results have verified the effectiveness of the proposed scheme for three-phase T-type AC/DC PWM converters.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2016년도 전력전자학술대회 논문집
• /
• pp.405-406
• /
• 2016

A bidirectional secondary LLC resonant converter with auxiliary switches and an additional inductor is proposed to achieve the high gain characteristics of LLC resonant convertors. Auxiliary switches, an additional inductor and a resonant capacitor are connected in the high voltage secondary side of the proposed converter. The ac analysis and operating characteristics of bidirectional secondary LLC resonant converter are investigated. A 1kW prototype bidirectional secondary LLC resonant converter connected to the $400V_{DC}$ buses is designed and tested to confirm the validity and applicability of the proposed converter.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
• /
• pp.184-188
• /
• 2001

In this paper, a new fully digital control method for single-phase UPS inverter, which is based on the double control loop such as the outer voltage control loop and inner current control loop, is proposed. The inner current control loop is designed and implemented in the form of internal model control and takes the presence of computational time-delay into account. Therefore, this method provides an overshoot-free reference-to-output response. In the proposed scheme, the outer voltage control loop employing P controller with resonance model implemented by a DSP is introduced. The proposed resonance model has an infinite gain at resonant frequency, and it exhibits a function similar to an integrator for AC component. Thus the outer voltage control loop causes no steady state error as regard to both magnitude and phase. The effectiveness of the proposed control system has been demonstrated by the simulation and experimental results respectively.