• 한국통신학회논문지
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• 제19권5호
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• pp.872-882
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• 1994

본 논문에서는 통신위성중계기의 송, 수신 신호의 크기에 따른 안테나부의 시스템 특성으로 고려하여 대역통과여파기 형태의 이득특성을 갖는 저잡음증폭기를 설계, 제작하였다. 한 예로써, 위성통신용 수신주파수인 14.0~14.5GHz.에서 2단 저잡음증폭기와 4단 증폭기를 설계, 제작하였다. 제작된 2단 저잡음증폭기는 대역내에서 20.3dB +- 0.1dB의 이득, 1.44dB+-0.04dB의 잡음지수, 송신주파수 대역(12.25~12.75GHz)에서 14dB의 Rejection을 보여주었다 이 저잡음증폭기는 이득, 잡음지수, 군지연 특성면에서도 모두 설계치와 잘 일치하였다. 또한 제작된 4단 증폭기는 42dB 이상의 이득에 +-0.25dB 이내의 평탄도를 보여 주었고, 송신주파수 대역에서의 Rejection은 28dB로 측정되었다. 본 논문에서 제작된 협대역 저잡음 증폭기는 위와 같은 송신대역 Rejection 특성으로 인하여 중계기의 수신부 입력여파기와 주파수변환부내의 여파기의 설계 사양을 완화시키고 설계 및 제작비용을 낮출 수 있다.

• 한국정밀공학회지
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• 제16권1호통권94호
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• pp.61-67
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• 1999

A laser Doppler vibrometer based on the laser heterodyne interferometry is employed to measure the vibration velocity of vibrating objects. In this paper, we propose a real time analog signal processor of a laser Doppler vibrometer to reduce the degradation of Doppler signals mainly caused by environmental noises. In the proposed real time signal processor of an laser Doppler vibrometer, a pre-processor and a logical motion direction detector are designed to reduce the detection errors of the object motion direction. Also, a noise detection and rejection circuit is designed to reject the unfiltered noises.

• 전기전자학회논문지
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• 제21권3호
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• pp.264-267
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• 2017

본 논문에서는 잡음 제거 회로를 이용하여 공급 전원 제거 비를 향상시킨 LDO(Low drop-out) 레귤레이터를 제안하였다. LDO 레귤레이터 내부의 오차증폭기와 패스 트랜지스터 사이에 잡음 제거 회로를 두어 전압 라인에서 들어오는 노이즈에 패스 트랜지스터가 받는 영향을 줄일 수 있게 설계하였으며, 기존의 LDO 레귤레이터와 동일한 레귤레이션 특성을 갖도록 했다. 제안한 회로는 0.18um 공정을 사용하였고 Cadence의 Virtuoso, Spectre 시뮬레이터를 사용하였다.

• 대한의용생체공학회:의공학회지
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• 제23권5호
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• pp.333-340
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• 2002

생체신호 수집시 전력선 잡음은 일반적인 잡음원이다. 증가평가필터(Incremental Estimation Filter. IEF)는 생체신호, 특히, 심전도 (Electrocadiogram, ECG) 신호에 있어서 전력선 잡음을 제거하기 위해 사용되어 왔다. 증가평가필터의 잡음제거 성능에 영향을 미치는 상수 값의 증가인자는 입력신호에 따라서 경험적으로 혹은 실험적으로 결정되고 있다. 본 논문에서는 증가인자의 시변(time-varying) 제어를 위해 신경망을 이용한 증가평가필터 설계를 제시하고 있다. 제안된 증가평가필터는 인위적인 신호뿐만 아니라 MIT/BIH 데이터베이스의 실제 심전도 신호에 적용함으로써 평가하였으며, 잡음제거 성능의 상대적인 비교를 위해 적응잡음제거기와 기존의 증가평가필터등과 비교하였다. 실험결과 신경망에 근거한 증가평가필터는 수렴속도와 특정 주파수에서의 잡음제거에서 기존의 적응필터보다 우수함을 보여주었다.

• IEIE Transactions on Smart Processing and Computing
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• 제4권3호
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• pp.152-157
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• 2015

Various power supply noise sources in a system integrated circuit degrade the performance of a low dropout (LDO) regulator. In this paper, a capacitor-less low dropout regulator for enhanced power supply rejection is proposed to provide good power supply rejection (PSR) performance. The proposed scheme is implemented by an additional capacitor at a gate node of a pass transistor. Simulation results show that the PSR performance of the proposed LDO regulator depends on the capacitance value at the gate node of the pass transistor, that it can be maximized, and that it outperforms a conventional LDO regulator.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권3호
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• pp.313-319
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• 2012

The power supply rejection (PSR) of low drop-out (LDO) voltage regulator is improved by employing an error amplifier (EA) which is configured so the power supply noise be cancelled at the output. The LDO regulator is implemented in a 0.13-${\mu}m$ standard CMOS technology. The external supply voltage level is 1.2-V and the output is 1.0-V while the load current can range from 0-mA to 50-mA. The power supply rejection is 46-dB, 49-dB, and 38-dB at DC, 2-MHz, and 10-MHz, respectively. The quiescent current consumption is 65-${\mu}A$.

• Journal of Power Electronics
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• 제14권5호
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• pp.1057-1068
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• 2014

Phase-locked loops (PLL) based on the synchronous reference frame (SRF-PLL) have recently become the most widely-used for grid synchronization in three phase grid-connected inverters. However, it is difficult to study their performance since they are nonlinear systems. To estimate the performances of a SRF-PLL, a canonical small-signal linearized model has been developed in this paper. Based on the proposed model, several significant specifications of a SRF-PLL, such as the capture time, capture rang, bandwidth, the product of capture time and bandwidth, and steady-state error have been investigated. Finally, a noise model of a SRF-PLL has been put forward to analyze the noise rejection ability by computing the SNR (signal-to-noise ratio) of a SRF-PLL. Several simulation and experimental results have been provided to verify and validate the obtained conclusions. Although the proposed model and analysis method are based on a SRF-PLL, they are also suitable for analyzing other types of PLLs.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1212-1217
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• 2006

This study is concerned with static and sinusoidal disturbance rejection for a single periodic input disturbance with known period. In the area of active elimination of a disturbance force, the control input should have two different kinds of gains: one is to deliver a stable control and the other is a force component to cancel the external disturbance force. In this paper we employ a simple state feedback control law to make the balance beam stable and employ a linear observer to estimate the states which represent the external disturbance force components. Simulation results verify our proposed control method to reject a static and sinusoidal disturbance force.

• 제어로봇시스템학회논문지
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• 제9권6호
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• pp.425-434
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• 2003

The disturbance observer(DOB) has been widely used in high speed and high precision motion control applications and the characteristics of DOB have been investigated in depth. Though most of DOB's have been implemented as the discrete-time form in digital devices, we are still short of the researches on discrete-time DOB (DDOB) in spite of rich references on continuous-time DOB. In this paper, we discuss about the disturbance rejection property and measurement noise effect of discrete-time DOB. Especially, we will focus on revealing the role of sampling time in designing the discrete-time DOB and show the validity of analysis through simulations and experiments for optical disk drive systems.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.247-251
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• 2003

The velocity of train which is measured from pulse generator attached to TM is used for displaying or control signal of inverter and so on. Measured signals increase and decrease step-by-step by pulse counting or monotonously by F/V conversion. But noises and signal distortions by measuring error like alias make it difficult to provide correct velocity infomation and estimate the acceleration. In this paper, we investigated the performance of Smoothing method for suppressing the noises in velocity signals. And the difference between Smoothed signal and origin velocity signals is inspected and the comparison with low pass filtering show applicable of Smoothing method for noise rejection and the estimation of signal. Finally, acceleration curves estimated from Smoothing method are compared with real accelerator signal attached to train.