• Title/Summary/Keyword: 잡음분석

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Analysis of Phase Noise Effects in OFDM Transmit Diversity Systems (OFDM 송신 다이버시티 시스템에서의 위상잡음 영향 분석)

  • Lee, Jong-Gil
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.2
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    • pp.243-249
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    • 2006
  • In this paper, the phase noise effects of OFDM transmission diversity systems were analyzed. Since OFDM communication system is very sensitive to phase noise, the system performance may degrade seriously due to the increase of subcarrier interferences and system noise. Therefore, The phase noise model was suggested and its distribution and power were varied to investigate the effects of phase noise on the system performance. The degree of the system performance degradation depends on the specific diversity structures of transmission systems. Here, the performances of OFDM systems with two and three antennas transmission diversity were analyzed and compared with that of systems without transmission diversity as the phase noise characteristics varied.

An Analysis of the Noise Influence on the Cross-well Travel-time Tomography to Detect a Small Scale Low Velocity Body (소규모 저속도 이상대 탐지를 위한 시추공 주시 토모그래피에서 잡음 영향 분석)

  • Lee, Doo-Sung
    • Geophysics and Geophysical Exploration
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    • v.14 no.2
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    • pp.140-145
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    • 2011
  • In order to analyze the influence of the noise on a cross-well traveltime tomography to detect a small scale low velocity body in a homogeneous medium, the first arrival travel times were computed one a tunnel model by a finite-difference ray tracing scheme. Three different types and four different intensity levels of white noises were added to the computed first arrival travel times, and velocity tomograms were constructed using an iterative inversion method (SIRT). Tomograms with the noise intensity up to 10% of the maximum traveltime delay in the tunnel model, showed the exact location of the tunnel. However, the velocity shown at the tunnel location was not close to air velocity but only slightly less than the velocity of the background medium. The additive random noise showed significantly less degree of influence on the resulting tomogram than the source- and receiver consistent noise.

The study about efficient process of disable By Analyzing spectrum signals category in HFC net (HFC 망에서 스펙트럼 신호 유형 분석을 통한 효율적 장애 처리에 관한 연구)

  • Im, Byong-Kwang;Jeong, Yeon-Man
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2010.07a
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    • pp.191-194
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    • 2010
  • 본 논문에서는 HFC 망에서 상향 대역의 잡음신호를 중심으로, 잡음신호 및 스펙트럼을 분석하여 HFC 전송망의 효율적 장애처리 방안을 제시한다. HFC망은 빠른 속도로 다양한 멀티미디어 서비스를 제공하는 장점에도 불구하고 동축 구간이 외부의 환경적 영향을 많이 받을 가능성과 상향 잡음의 유입으로 디지털 전송망에 비교하여 상대적으로 어려움이 있다. 따라서 본 연구는 유입잡음을 스펙트럼 분석하여 유형화함으로서 잡음신호의 원인에 따른 신속한 대처와 인적, 물적 자원 투입요소 최소화가 기대된다.

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Analysis and Optimization of Cross-Modulation Noise in CDMA Cellular RF System (CDMA 셀룰러 RF 시스템에서 교차변조 잡음 레벨 분석 및 최적화)

  • 곽준호;김학선
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.6A
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    • pp.397-404
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    • 2003
  • In this paper, we have analyzed the level of cross-modulation noise required for CDMA mobile station and proposed a guideline for optimum design. From the analysis, the level of cross-modulation noise is determined by the system's noise figure(NF) and VCO's phase noise and there is a trade-off relationships between them. In addition, we have determined the value of LNA's IIP3 and duplexer's isolation to satisfy the above level in designing the system. Therefore, this paper will give a guideline for a selection of components in designing cdma2000 mobile station.

Performance of DS/SSMA Communications over Nonselective Fading Channels with Gaussian and Impulsive Noise Channels (가우스 잡음과 임펄스 잡음이 혼합된 비선택적 페이딩 채널에서의 DS/SSMA 통신의 성능 분석)

  • 진익수;김은묵;박용석;황금찬
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.16 no.9
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    • pp.838-849
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    • 1991
  • An accurate approximation based on the integration of the characteristic function of the multiple access interference which consists of specular and scatter components is obtained for the average probability of error for asynchronous binary PSK direct sequence spread spectrum multiple access(DS/SSMA) communications system operating over nonselective fading channels with additive white Gaussian and impulsive noise channels.

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Analysis of Noise Influence on a Chaotic Series and Application of Filtering Techniques (카오스 시계열에 대한 잡음영향 분석과 필터링 기법의 적용)

  • Choi, Min Ho;Lee, Eun Tae;Kim, Hung Soo;Kim, Soo Jun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.1B
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    • pp.37-45
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    • 2011
  • We studied noise influence on nonlinear chaotic system by using Logistic data series which is known as a typical nonlinear chaotic system. We regenerated Logistic data series by the method of adding noise according to noise level. And, we performed some analyses such as phase space reconstruction, correlation dimension, BDS statistics, and DVS Algorithms which are known as the methods of nonlinear deterministic or chaotic analysis. If we see the results of analysis, the characteristics of data series are gradually changed from nonlinear chaotic data series to random stochastic data series according to increasing noise level. We applied Low Pass Filter (LPF) and Kalman Filter techniques for the investigation of removing effect of the added noise to data series. Typical nonparametric method cannot distinguish nonlinear random series but the BDS statistic can distinguish the nonlinear randomness of the time series. Therefore this study used the BDS statistic which is well known as nonlinear statistical method for the investigation of randomness of time series for the effect of removing noise of data series. We found that Kalman filter is better method to remove the noise of chaotic data series even for high noise level.

Noise Analysis and Measurement for a CW Bio-Radar System for Non-Contact Measurement of Heart and Respiration Rate (호흡 및 심박수 측정을 위한 비접촉 방식의 CW 바이오 레이더 시스템의 잡음 분석 및 측정)

  • Jang, Byung-Jun;Yook, Jong-Gwan;Na, Won;Lee, Moon-Que
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.9
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    • pp.1010-1019
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    • 2008
  • In this paper, we present a noise analysis and measurement results of a bio-radar system that can detect human heartbeat and respiration signals. The noise analysis including various phase noise effects is very important in designing the bio-radar system, since the frequency difference between the received signal and local oscillator is very small and the received power is very low. All of the noise components in a bio-radar system are considered from the point of view of SNR. From this analysis, it can be concluded that the phase noise due to antenna leakage is a dominant factor and is a function of range correlation. Therefore, the phase noise component with range correlation effect, which is the most important noise contribution, is measured using the measurement setup and compared with the calculated results. From the measurement results, our measurement setup can measure a closed-in phase noise of a free-running oscillator. Based on these results, it is possible to design a 2.4 GHz bio-radar system quantitatively which has a detection range of 50 cm and low power of 1 mW without additional PLL circuits.

Design of the Noise Suppressor Using Wavelet Transform (웨이블릿 변환을 이용한 잡음제거기 설계)

  • 원호진;김종학;이인성
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.7
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    • pp.37-46
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    • 2001
  • This paper proposes a new noise suppression method using the Wavelet transform analysis. The noise suppressor using the Wavelet transform shows the more effective advantages in a babble noise than one using the short-time Fourier transform. We designed a new channel structure based on spectral subtraction of Wavelet transform coefficients and used the Wavelet mask pattern with more higher time resolution in high frequency. It showed a good adaptation capability for babble noise with a non-stationary property. To evaluate the performance of proposed noise canceller, the informal subjective listening tests (Mos tests) were performed in background noise environments (car noise, street noise, babble noise) of mobile communication. The proposed noise suppression algorithm showed about MOS 0.2 performance improvements than the suppression algorithm of EVRC in informal listening tests. The noise reduction by the proposed method was shown in spectrogram of speech signal.

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The Effect of Phase Noise from PLL Frequency Synthesizer (PLL 주파수 합성기에서 발생하는 위상잡음의 영향)

  • 조형래;최정수
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.6
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    • pp.865-870
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    • 2001
  • In this paper, we analyse the effect of phase noise from PLL frequency synthesizer on 64 QAM when detecting corrupted signals. To predict the phase noise of an oscillator very accurately, we assume that the oscillator is linearly time-varying when the input impulsive current to the oscillator is small. The performance of the detector which detects the corrupted signal by oscillator phase noise is compared with that when the detector is only affected by AWGN and then analyse how much the phase noise degrades the system performance for 64 QAM.

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A Study on Low Phase Noise Frequency Synthesizer Design for Satellite Terminal (위성통신 단말용 저 위상잡음 주파수 합성기 설계에 관한 연구)

  • Ryu, Joon-Gyu;Oh, Deock-Gil;Hong, Sung-Yong
    • Journal of Satellite, Information and Communications
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    • v.6 no.1
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    • pp.45-49
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    • 2011
  • In this paper, we present the high resolution and low phase noise frequency synthesizer for satellite terminal. To improve the phase noise of frequency synthesizer, we analyze how the configuration of frequency synthesizer affect the phase noise. The implemented frequency synthesizer reduce the phase noise and show the high resolution. The output power of this frequency synthesizer is over -2dBm in 950~1450MHz and the phase noise of the -101dBc/Hz at 10kHz frequency offset.