• Title/Summary/Keyword: 잡음 검출기

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IR Signal Analysis and Band Selection for Two-color Seeker (Two-color 탐색기를 위한 적외선 신호 분석 및 대역 선정)

  • 오정수;서동선;최종수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.1B
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    • pp.112-119
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    • 2000
  • A two-color infrared (IR) seeker employs two detection-bands for efficient target tracking under countermeasures and background noises. This paper describes a study on the detection-band selections for the two-color seeker. To select the detection-bands, we analysis infrared radiation characteristics of a target, a flare, and background noises and then other characteristics closely related with the received power, such as the atmospheric transmission, acquisition range, background noise effect, and signal-to-noises. The analysis shows that the pertinent bands of two-color IR seeker are 3 um~5 um for target detection and 1.5 um~l.7 um for counter-countermeasures. The results of our study will play a significant role in the further study of two-color seekers.

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Noise Cancellation and Detection of Heartbeat using A New Adaptive Noise Canceller Based on ALE(Adaptive Line Enhancer) in the CW Bio-radar (CW 바이오 레이더에서 ALE(Adaptive Line Enhancer) 기반의 새로운 적응형 잡음제거기를 이용한 잡음제거 및 심장박동 검출)

  • Seo, Myung-Hwan;Kim, Jae-Joong
    • Journal of Advanced Navigation Technology
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    • v.13 no.4
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    • pp.482-489
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    • 2009
  • This paper proposes a CW(Continuous-Wave) bio-radar applying a new adaptive noise canceller based on ALE(Adaptive Line Enhancer) which can remove the Gaussian noise and system noise. Recently the research works on this CW bio-radar which can be used to detect heartbeat and respiration are advanced by the university and research facility. Although the researches describe CW bio-radar not only is vulnerable for the Gaussian noise but also has a disadvantage of decreasing the heart-rate accuracy due to the noise, the researches do not demonstrate the effective method for removing the noise component in a baseband signal. In this paper, a CW bio-radar applying the new adaptive noise canceller based on ALE which can remove the noise component is proposed. This paper compares and analyzes the performance for increasing the heart-rate accuracy according to removing the Gaussian noise and system noise in the baseband signal through the quadrature receiver which can alleviate the demodulation sensitivity to target position.

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A Study on a Robust Voice Activity Detector Under the Noise Environment in the G,723.1 Vocoder (G.723.1 보코더에서 잡음환경에 강인한 음성활동구간 검출기에 관한 연구)

  • 이희원;장경아;배명진
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.2
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    • pp.173-181
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    • 2002
  • Generally the one of serious problems in Voice Activity Detection (VAD) is speech region detection in noise environment. Therefore, this paper propose the new method using energy, lsp varation. As a result of processing time and speech quality of the proposed algorithm, the processing time is reduced due to the accurate detection of inactive period, and there is almot no difference in the subjective quality test. As a result of bit rate, proposed algorithm measures the number of VAD=1 and the result shows predominant reduction of bit rate as SNR of noisy speech is low (about 5∼10 dB).

Time-Frequency Domain Impulsive Noise Detection System in Speech Signal (음성 신호에서의 시간-주파수 축 충격 잡음 검출 시스템)

  • Choi, Min-Seok;Shin, Ho-Seon;Hwang, Young-Soo;Kang, Hong-Goo
    • The Journal of the Acoustical Society of Korea
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    • v.30 no.2
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    • pp.73-79
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    • 2011
  • This paper presents a new impulsive noise detection algorithm in speech signal. The proposed method employs the frequency domain characteristic of the impulsive noise to improve the detection accuracy while avoiding the false-alarm problem by the pitch of the speech signal. Furthermore, we proposed time-frequency domain impulsive noise detector that utilizes both the time and frequency domain parameters which minimizes the false-alarm problem by mutually complementing each other. As the result, the proposed time-frequency domain detector shows the best performance with 99.33 % of detection accuracy and 1.49 % of false-alarm rate.

Performance of the Recursive Systematic Convolutional Code with Turbo-Equalization Method for PMR Channel (수직자기기록 채널에서 터보등화기 구조를 이용한 순환 구조적 길쌈 부호의 성능)

  • Park, Dong-Hyuk;Lee, Jae-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.1C
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    • pp.15-20
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    • 2009
  • For perpendicular magnetic recording (PMR) channels, noise-predictive maximum likelihood (NPML) detection method has been used. But, it is hard to expect improving the performance when the bit density is increased. Hence, we exploit the coding methods which has good performance. In this paper, we show the performance of the recursive systematic convolutional (RSC) codes with turbo-equalization method with different channel bit densities. The noise model is 80% jitter noise and 20% AWGN.

SNR Improvement in A Wireless Optical Differential Detector Using Plastic Fibers (플라스틱 광섬유를 이용한 무선광 차동검출기의 신호대잡음비 개선)

  • Lee Seong-Ho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.4 s.95
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    • pp.410-417
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    • 2005
  • In this paper, optical noise is reduced by a differential detector with a plastic optical fiber bundle in a wireless optical interconnection. A plastic optical fiber bundle divides the received optical signal equally and connects it to two photodiodes. In this configuration two photodiodes effectively detect the optical signal at one point, and the output voltage variation due to the abrupt change of optical noise distribution in space disappears. The signal to noise ratio in a differential detector with a fiber bundle was improved to be $10\;\cal{dB}$ higher than in a single photodiode with an optical filter.

A Study on Double Talk Detector of Acoustic Echo Canceller Using A Correlation Function (상관도를 이용한 음향 반향 제거기의 동시통화 검출기에 대한 연구)

  • 이영호;김대경;박장식;손경식
    • Proceedings of the Korea Multimedia Society Conference
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    • 2000.04a
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    • pp.129-132
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    • 2000
  • 본 논문에서는 음향 반향 제거기의 새로운 동시 통화 검출기를 제안하여 근단화자신호에 의한 적응 필터의 계수 오조정을 줄이고자 하였다. 제안한 동시 통화 검출기는 마이크 입력 신호의전력과 추정 오차 신호와 마이크 입력 신호간의 상호 상관의 비를 이용하여 동시 통화를 검출하는 방법이다. 제안한 동시 통화 검출기는 주변 잡음이 없는 상황에서는 다른 동시 통화 검출기와 비교하여 우수한 성능을 보였다. 그리고 전체적인 음향 반향 제거기의 향상을 가져왔다.

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LO power effect on the performance of the 4-port BPSK receiver (4 포트 BPSK 수신기에서 LO 전력의 수신 성능에 대한 영향)

  • Jo, Ik-Kyun;Lee, Moon-Que
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1397-1398
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    • 2008
  • 본 논문에서는 BPSK 수신을 위한 덧셈(sum) 방식의 4-port 직접 변환 수신기를 제안하고, 국부 발진기(LO) 전력의 크기에 대한 수신기의 성능을 분석하였다. 수신 성능 분석에는 열잡음, 전력 검출기의 산탄(shot) 잡음, LO의 위상 잡음을 고려하였다. 수신 성능 분석 결과 최적의 신호대 잡음비를 보이는 최적의 LO 전력이 존재할 수 있음을 보였다.

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Signal Detection for Pattern Dependent Noise Channel (신호패턴 종속잡음 채널을 위한 신호검출)

  • Jeon, Tae-Hyun
    • Journal of the Korean Institute of Intelligent Systems
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    • v.14 no.5
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    • pp.583-586
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    • 2004
  • Transition jitter noise is one of major sources of detection errors in high density recording channels. Implementation complexity of the optimal detector for such channels is high due to the data dependency and correlated nature of the jitter noise. In this paper, two types of hardware efficient sub-optimal detectors are derived by modifying branch metric of Viterbi algorithm and applied to partial response (PR) channels combined with run length limited modulation coding. The additional complexity over the conventional Viterbi algorithm to incorporate the modified branch metric is either a multiplication or an addition for each branch metric in the Viterbi trellis.

Boll's Spectral Subtraction Algorithm by New Voice Activity Detection (새로운 음성 활동 검출법에 의한 Boll의 스펙트럼 차감 알고리즘)

  • 류종훈;김대경;박장식;손경식
    • Journal of Korea Multimedia Society
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    • v.4 no.1
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    • pp.46-55
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    • 2001
  • In this paper, a new voice activity detection method estimating SNR of enhanced speech with extended spectral subtraction (ESS) is proposed. Voice activity detection is performed by putting an second Wiener filter behind an Wiener filter used in the ESS to estimate speech and noise power of output signal of first Wiener filter. The proposed voice activity detection method does not require many computational loads and performs well under severe input SNR. Boll's spectral substraction algorithm with proposed voice activity detection was compared to ESS under several noise environment having different time-frequency distributions. During speech and non-speech activity, performance of Boll's spectral substraction algorithm with proposed voice activity detection is superior to that of ESS.

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