• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.359-362
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• 2005

Road traffic noise level and railway noise level are important factors on apartment inhabitant's comforts. The measurement methods which noted by Ministry of Construction & Transportation(MOCT) and Ministry of Environment(ME) are used for measurement of exterior noise at apartment houses. But these methods are out of date because the height of apartment houses have increased dramatically and owing to the sampling methods of the measurement time interval, rating values are induced differently due to sampling methods. In this study, the sound level of each floor of apartment houses is measured and compared. And rating value due to sampling methods are compared. As a result, the KS outline of 'Field Measurement of Exterior Noise at Apartment Housess' is suggested.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.385-390
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• 2006

This paper examines the sampling and jitter specifications and considerations for Global Navigation Satellite Systems (GNSS) software receivers. Software radio (SWR) technologies are being used in the implementation of communication receivers in general and GNSS receivers in particular. With the advent of new GPS signals, and a range of new Galileo and GLONASS signals soon becoming available, GNSS is an application where SWR and software-defined radio (SDR) are likely to have an impact. The sampling process is critical for SWR receivers, where it occurs as close to the antenna as possible. One way to achieve this is by BandPass Sampling (BPS), which is an undersampling technique that exploits aliasing to perform downconversion. BPS enables removal of the IF stage in the radio receiver. The sampling frequency is a very important factor since it influences both receiver performance and implementation efficiency. However, the design of BPS can result in degradation of Signal-to-Noise Ratio (SNR) due to the out-of-band noise being aliased. Important to the specification of both the ADC and its clocking Phase- Locked Loop (PLL) is jitter. Contributing to the system jitter are the aperture jitter of the sample-and-hold switch at the input of ADC and the sampling-clock jitter. Aperture jitter effects have usually been modeled as additive noise, based on a sinusoidal input signal, and limits the achievable Signal-to-Noise Ratio (SNR). Jitter in the sampled signal has several sources: phase noise in the Voltage-Controlled Oscillator (VCO) within the sampling PLL, jitter introduced by variations in the period of the frequency divider used in the sampling PLL and cross-talk from the lock line running parallel to signal lines. Jitter in the sampling process directly acts to degrade the noise floor and selectivity of receiver. Choosing an appropriate VCO for a SWR system is not as simple as finding one with right oscillator frequency. Similarly, it is important to specify the right jitter performance for the ADC. In this paper, the allowable sampling frequencies are calculated and analyzed for the multiple frequency BPS software radio GNSS receivers. The SNR degradation due to jitter in a BPSK system is calculated and required jitter standard deviation allowable for each GNSS band of interest is evaluated. Furthermore, in this paper we have investigated the sources of jitter and a basic jitter budget is calculated that could assist in the design of multiple frequency SWR GNSS receivers. We examine different ADCs and PLLs available in the market and compare known performance with the calculated budget. The results obtained are therefore directly applicable to SWR GNSS receiver design.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2002년도 제7차 학술대회 초록집
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• pp.96-96
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• 2002

목적： MRI 시스템의 비약적인 발전으로 인하여, 시스템에서 발생되는 noise가 상당히 줄었다. 따라서 시스템에서 발생되는 random noise뿐만 아니라 sampling 과정에서 발생되는 quantization noise도 중요하게 고려하여야 할 요소가 되었다. 특히, MRI 신호의 경우 dynamic range가 크기 때문에 bit 수가 큰 ADC를 이용하여 데이터를 얻어야 한다. 그러나, bit 수가 크고 높은 sampling rate를 갖는 ADC의 경우 가격이 높을 뿐만 아니라, 기존의 장비를 교체해야하는 어려움이 있다. 본 연구는 oversampling과 quantization noise와의 관계를 컴퓨터 시뮬레이션을 통하여 알아보고, MRI영상에서 oversampling을 통하여 quantization noise를 줄임으로써 영상의 질을 개선하고자 한다.

• Communications for Statistical Applications and Methods
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• 제23권5호
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• pp.411-421
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• 2016

Large frequency limiting distributions of two errors in realized covariance are investigated under noisy and non-synchronous high frequency sampling situations. The first distribution characterizes increased variance of the realized covariance due to noise for large frequency and the second distribution characterizes decreased variance of the realized covariance due to discretization for large frequency. The distribution of the combined error enables us to determine the sampling frequency which depends on a nuisance parameter. A consistent estimator of the nuisance parameter is proposed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1993년도 추계학술대회논문집; 반도아카데미, 26 Nov. 1993
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• pp.125-130
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• 1993

본 연구에서는 소음의 주기성분에 해당하는 전기적 참조신호인 주기적 펄스 신호(pulse train)를 사용하는 실시간 제어용 어셈블리 프로그램을 작성하고, Synchronous Sampling Method를 사용하여 능동소음제어를 실시, 이것에 대 한 장단점 및 한계를 고찰하는데 있다.

• 대한전자공학회논문지SD
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• 제44권4호
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• pp.10-17
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• 2007

FTIR 분광계는 간섭계를 사용하여 표적 물질에 대한 간섭무늬를 획득하고, 이를 푸리에 변환함으로써 기체상태 물질의 적외선 영역 스펙트럼을 획득하기 위한 유용한 기법이다. 본 논문에서는 불규칙적 위치에서 간섭무늬 샘플링에 관하여 고속 스캔 간섭계의 신호처리에서의 샘플링 노이즈 영향에 대한 연구와 이에 대하여 실험적으로 검증 하였다.

• 한국정보전자통신기술학회논문지
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• 제13권2호
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• pp.113-122
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• 2020

Noise affects the accuracy of three-dimensional shape recovery. Its occurrence is unpredictable and depends on several mechanical, environmental, and other factors. When two-dimensional image sequences are obtained for shape from focus (SFF), mechanical vibration occurs in the translational stage, causing an error in the three-dimensional shape recovery. To address this issue, mechanical vibration is modeled using Newton's second law and the principle of the rack and pinion gear. Then, an optimal sampling step size considering the mechanical vibration is suggested through theoretical demonstration. Experiments conducted with real objects verify the effectiveness of the proposed sampling step size. In this paper, in a realistic environment with noise, the potential of obtaining more accurate three-dimensional reconstruction results of the objects is explored by acquiring the optimal sampling step size, which improves the sampling step size relative to those reported in a previous study performed under similar conditions.

• 응용통계연구
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• 제25권1호
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• pp.15-27
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• 2012

본 논문에서는 KOSPI 시가총액기준 상위 4종목(삼성전자, 현대차, 현대모비스, POSCO)의 고빈도 거래 데이터를 바탕으로 일중 수익률의 실현변동성과 시장미시구조잡음에 대해 연구한다. Volatility signature plot을 통해 실현변동성(Realized Variance; RV)과 편의수정 실현변동성($RV_{AC_1}$)의 편의를 확인하고 시장미시구조 잡음의 특징을 실증적으로 파악한다. 또한, 잡음 대 신호비(Noise-to-Signal Ratio; NSR)를 사용하여, 평균제곱오차(Mean Square Error; MSE) 기준의 실현변동성(RV)과 편의수정 실현변동성($RV_{AC_1}$)의 최적 추출 빈도수를 추정해본다.

• 전자공학회논문지B
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• 제32B권6호
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• pp.876-877
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• 1995

The techniques for the estimation of motion vector from the image sequence assume implicitly that the intensity of image is constant through the time. But this assumption can be distored by such causes as the added noises and the sub-pel motion following the sampling, and the errors can be generated on the motion estimation by the change of intensity. In this paper, we analyzed theoretically the effect of the change of intensity by the noise on the motion estimation with the white Gaussian noise. We know a fact that the signal may be fluctuated to reduce the effect of the noise and so the sampling rate have to make down. Also we confirmed the theoretically analysis through the experiments which investigated the relation between the noises and the sampling rates.

• 한국전기전자재료학회논문지
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• 제23권2호
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• pp.89-92
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• 2010

A bolometer sensor used in an infrared thermal imaging system has many advantages on the process because it does not need a separate cooling system and its manufacturing is easy. However the sensitivity of the bolometer is low and the fixed pattern noise(FPN) is large, because the bolometer sensor is made by micro electro mechanical systems (MEMS). These problems can be fixed-by using the high performance readout integrated circuit(ROIC) with noise reduction techniques. In this paper, we propose differential delta sampling circuit to remove the mismatch noise of ROIC itself, the FPN of the bolometer. And for reduction of FPN noise, the reference signal compensation circuit which compensate the reference signal by using on-resistance of MOS transistor was proposed.