• Title, Summary, Keyword: Signal to Noise Ratio

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Effects of Radio Interference from Digital Phase Modulation(PSK) System on Analog Frequency Modulation(FM) System (아나로그 주파수변조(FM) 무선통신 시스템에 미치는 디지탈 위상변조(PSK) 무선통신 시스템의 간섭 영향)

  • 조성준
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.8 no.2
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    • pp.63-75
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    • 1983
  • This paper has investigated and discussed the effects of multiple PSK signals upon an wideband FM signal in an intersystem interference environment between analog and digital radios. Using the derived approximate equation for the output haseband interference noise, the signal-to-interference noise power ratio(SNR) in the top channel baseband signal has been numerically calculated. The results are plotted in graphs as the functions of carrier-to-noise ratio(CNR), carrier-to interfer power ratio(CIR), and normalized carrier separation. From the results in this paper, one can know some optimu, or suitable, operating conditions(frequency allocation, bandwidth, and power, etc.) for an FM channel in the intersystemn interferences from digital PSK channels.

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The Signal-to-Noise Ratio Enhancement of the Satellite Electro-Optical Imager using Noise Analysis Methods (영상센서신호의 잡음분석을 이용한 위성용 전자광학탑재체의 신호대잡음비 개선 방법)

  • Park, Jong-Euk;Lee, Kijun
    • Korean Journal of Remote Sensing
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    • v.33 no.2
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    • pp.159-169
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    • 2017
  • The Satellite Electro-Optic Payload System needsspecial requirements with the conditions of limited power consumption and the space environment of solar radiation. The acquired image quality should be mainly depend on the GSD (Ground Sampled Distance), SNR (Signal to Noise Ratio), and MTF (Modulation Transfer Function). On the well-manufactured sensor level, the thermal noise is removed on ASP (Analog Signal Processing) using the CDS (Corrective Double Sampling); the noise signal from the image sensor can be reduced from the offset signals based on the pre-pixels and the dark-pixels. The non-uniformity shall be corrected with gain, offset, and correction parameter of the image sensor pixel characteristic on the sensor control system. This paper describes the SNR enhancement method of the satellite EOS payload using the mentioned noise remove processes on the system design and operation, which is verified by tests and simulations.

Application of Instantaneous Frequency Analysis(I) -Algorithm Performance and Noise Effects- (순간주파수 분석기법의 응용 (1) -알고리즘간의 성능비교 및 잡음영향-)

  • 김정태;임병덕
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.4
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    • pp.1050-1056
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    • 1994
  • When a vibration data for a rotating machine such as a pump or a compressor is concerned, the frequency fluctuation of the energy contents at an instant time may provide useful information on understanding the vibration characteristics of the rotating machinery, rather than the averaged energy distribution along the frequency axis. Especially, when a periodic signal has different spectral contents, the approach to use the averaged frequency distribution, called the normal frequency analysis, may not be appropriate to extract vibration source characteristics of the structure. This paper introduces a way to analyze the signal based on an instant time. In order to evaluate the performance of the various approach, the investigatation compares three different algorithms which are frequently implemented in the instantaneous frequency analysis. Also for the noise effect embodied in the true signal, various cases for different SN ratio have been examined. The result shows that the noise level is crucial to evalute the instantaneous frequency analysis. In order to implement the instantaneous frequency analysis, the extraction of the relevant information from the measured signal should have the high S/N ratio, i, e., 40 dB or above.

A Comparison of C/No Estimation Techniques for Commercial GPS Receivers under Jamming Environments (전파방해환경에서 상용 GPS 수신기의 C/No 추정기법 성능분석)

  • Baek, Jeehyeon;Yoo, Seungsoo;Kim, Sun Yong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.11
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    • pp.973-975
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    • 2013
  • In this paper, the carrier-to-noise power ratio estimation performances for commercial GPS receiver are shown by simulation and are analyzed under weak signal reception, high sensitivity signal reception, and the matched spectrum jamming signal reception environments.

Output SINR Analysis of GPS Adaptive Interference Canceler Based on Modified Despreader (변형된 역확산기 기반의 GPS 적응 간섭제거기의 출력 SINR 해석)

  • Hwang, Suk-Seung
    • The Journal of the Korea institute of electronic communication sciences
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    • v.9 no.2
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    • pp.195-202
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    • 2014
  • The Global Positioning System (GPS), which has various military and commercial applications, is designed to estimate the location of the specific user or object. In order to accurately estimate the location, GPS requires at least four satellite signals. The GPS receiver operates on extremely low signal-to-noise ratio (SNR) environment and it may suffer from various interference signals with the extremely high power. In this paper, we introduce a blind adaptive receiver based on the modified despreader, which suppress interference signals and detect GPS signals of interest without requiring explicit angle-of-arrival (AOA) information. We, also, provide the mathematical analysis for the signal-to-interference and noise ratio (SINR) of the modified despeader beamformer output. A representative computer simulation example is presented to illustrate the interference suppression performance of the considered GPS receiver and mathematical analysis of the SINR.

An Acoustic Analysis of Noise Environments during Mobile Device Usage

  • Park, Hyung Woo
    • International journal of advanced smart convergence
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    • v.6 no.2
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    • pp.16-23
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    • 2017
  • In contemporary modern society, people are constantly exposed to many kinds of noise, such as that from machinery, aircraft, construction sites, or road traffic. Noise is considered one of the most indispensable and influential parts of human life. This study investigates the acoustic characteristics of noise transfer from external sources to the human ear. For this study, we measured and analyzed various types of noise environments, installed monitoring speakers in a semi-anechoic room, and conducted intentional noise-filled experiments. In this environment, the size of the sounds generated by use of a portable device was also measured and the SNR (signal to noise ratio) calculated to study the influence of the noise. As sound is transmitted to the ear and the human body, it affects not only auditory damage but also other parts of the body. In this paper, we propose a proper SNR for noise emitted by portable IT equipment to prevent hearing loss when IT equipment is used.

Soft Combination Schemes for Cooperative Spectrum Sensing in Cognitive Radio Networks

  • Shen, Bin;Kwak, Kyung-Sup
    • ETRI Journal
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    • v.31 no.3
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    • pp.263-270
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    • 2009
  • This paper investigates linear soft combination schemes for cooperative spectrum sensing in cognitive radio networks. We propose two weight-setting strategies under different basic optimality criteria to improve the overall sensing performance in the network. The corresponding optimal weights are derived, which are determined by the noise power levels and the received primary user signal energies of multiple cooperative secondary users in the network. However, to obtain the instantaneous measurement of these noise power levels and primary user signal energies with high accuracy is extremely challenging. It can even be infeasible in practical implementations under a low signal-to-noise ratio regime. We therefore propose reference data matrices to scavenge the indispensable information of primary user signal energies and noise power levels for setting the proposed combining weights adaptively by keeping records of the most recent spectrum observations. Analyses and simulation results demonstrate that the proposed linear soft combination schemes outperform the conventional maximal ratio combination and equal gain combination schemes and yield significant performance improvements in spectrum sensing.

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SLNR-Based Precoder Design for Multiuser MIMO in Distributed Antenna Systems (분산 안테나 시스템에서 다중 사용자 MIMO를 위한 SLNR 기반의 프리코더 설계)

  • Seo, Bangwon
    • The Journal of The Institute of Internet, Broadcasting and Communication
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    • v.18 no.6
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    • pp.75-82
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    • 2018
  • In this paper, we consider a precoder design for downlink multiuser multiple-input multiple-output (MU-MIMO) in distributed antenna systems (DAS). In DAS, remote radio heads (RRHs) are placed at geographically different locations within a cell area. Three different precoder design schemes are proposed to maximize the separate or joint signal-to-leakage-plus-noise ratio (SLNR) metrics by considering RRH sum power or per-RRH power constraints. The analytical closed-form form solution for each optimization problem is presented. Through computer simulation, we show that the joint SLNR based precoding schemes have better signal-to-interference-plus-noise ratio (SINR) and bit error rate (BER) performances than the separate SLNR based schemes. Also, it is shown that the precoding scheme with RRH sum power constraint has better performance than the precoding scheme with per-RRH power constraint.

The Characteristics of Signal versus Noise SST Variability in the North Pacific and the Tropical Pacific Ocean

  • Yeh, Sang-Wook;Kirtman, Ben P.
    • Ocean Science Journal
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    • v.41 no.1
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    • pp.1-10
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    • 2006
  • Total sea surface temperature (SST) in a coupled GCM is diagnosed by separating the variability into signal variance and noise variance. The signal and the noise is calculated from multi-decadal simulations from the COLA anomaly coupled GCM and the interactive ensemble model by assuming both simulations have a similar signal variance. The interactive ensemble model is a new coupling strategy that is designed to increase signal to noise ratio by using an ensemble of atmospheric realizations coupled to a single ocean model. The procedure for separating the signal and the noise variability presented here does not rely on any ad hoc temporal or spatial filter. Based on these simulations, we find that the signal versus the noise of SST variability in the North Pacific is significantly different from that in the equatorial Pacific. The noise SST variability explains the majority of the total variability in the North Pacific, whereas the signal dominates in the deep tropics. It is also found that the spatial characteristics of the signal and the noise are also distinct in the North Pacific and equatorial Pacific.

Improvement of Sound Quality of Voice Transmission by Finger

  • Park, Hyungwoo
    • International Journal of Advanced Culture Technology
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    • v.7 no.2
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    • pp.218-226
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    • 2019
  • In modern society, people live in an environment with artificial or natural noise. Especially, the sound that corresponds to the artificial noise makes the noise itself and affects each other because many people live and work in the city. Sounds are generated by the activities and causes of various people, such as construction sites, aircraft, production machinery, or road traffic. These sounds are essential elements in human life and are recognized and judged by human auditory organs. Noise is a sound that you do not want to hear by subjective evaluation, and it is a loud sound that gives hearing damage or a sound that causes physical and mental harm. In this study, we introduce the method of stimulating the human hearing by finger vibration and explain the advantages of the proposed method in various kinds of a noise environment. And how to improve the sound quality to improve efficiency. In this paper, we propose a method to prevent the loss of hearing loss and the transmission of sound information based on proper signal to noise ratio when using portable IT equipment in various noise environments.