• Title/Summary/Keyword: 차동검출기

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Optical Noise Reduction using a Digital Potentiometer in a Wireless Optical Differential Detector (무선광 차동검출기에서 디지털가변저항을 이용한 잡음광의 감소)

  • 이성호
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.6
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    • pp.599-604
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    • 2002
  • In this paper, a digital potentiometer is used as a load resistor of a wireless optical differential detector with a polarizer, to improve the noise reduction capability. In this structure, the noise voltages of the two photodiodes are made equal by controlling a digital potentiometer and the optical noise is cancelled out. With a digital potentiometer, the signal to noise ratio is enhanced by about 23 dB.

A Wireless Optical Differential Detector using a Beam Splitter (빔 분할기를 이용한 무선광 차동검출기)

  • 이성호
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.1
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    • pp.96-102
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    • 2004
  • In this paper, optical noise is reduced by a differential detector, which is composed of a beam splitter and two photodiodes whose spectral responses are different each other. In this configuration, the automatic gain control circuit is not required for noise cancellation because the noise intensities at the two photodiodes are kept equal by a beam splitter. The signal to noise ratio in a differential detector with a beam splitter was improved to be 14 ㏈ higher than in a single photodiode with optical filtering.

Signal to Noise Improvement in Optical Wireless Interconnection Using A Differential Detector (차동검출기를 이용한 무선광연결에서 신호대잡음비의 개선)

  • 이성호;강희창
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.1
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    • pp.54-62
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    • 1999
  • In this paper, we investigated the signal-to-noise ratio improvement in a differential detector, which is a function of the optical noise coupling ratio and the differential gain ratio. A differential detector consists of two photodiodes and a differential amplifier. The differential detector reduced the noise component and improved the signal-to-noise ratio by about 20 dB when the differential gain ratio equals to the optical noise coupling ratio. The differential detector is very effective in removing the environmental optical noise or interference from an adjacent optical channel. This method is also effective when the noise wavelength is similar to the signal.

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A VLSI Design for High-speed Data Processing of Differential Phase Detectors with Decision Feedback (결정 궤환 구조를 갖는 차동 위상 검출기의 고속 데이터 처리를 위한 VLSI 설계)

  • Kim, Chang-Gon;Jeong, Jeong-Hwa
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.39 no.5
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    • pp.74-86
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    • 2002
  • This paper proposes a VLSI architecture for high-speed data processing of the differential phase detectors with the decision feedback. To improve the BER performance of the conventional differential phase detection, DF-DPD, DPD-RGPR and DFDPD-SA have been proposed. These detection methods have the architecture feedbacking the detected phase to reduce the noise of the previous symbol as phase reference. However, the feedback of the detected phase results in lower data processing speed than that of the conventional differential phase detection. In this paper, the VLSI architecture was proposed for high-speed data processing of the differential phase detectors with decision feedback. The Proposed architecture has the pre-calculation method to previously calculate the results on 'N'th step at 'M-1'th step and the pre-decision feedback method to previously feedback the predicted phases at 'M-1'th step. The architecture proposed in this paper was implemented to RTL using VHDL. The simulation results show that the Proposed architecture obtains the high-speed data processing.

Optical Noise Reduction using a Solar Cell in a Wireless Optical Interconnection (무선광 연결에서 솔라 셀을 이용한 잡음광 소거)

  • 이성호
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.4
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    • pp.336-342
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    • 2003
  • In this paper, a new differential detector is introduced, in which a solar cell is used to reduce the low frequency interference from environmental optical noise. The solar cell also supplies electrical power to the detector circuit using the optical noise power. The DC voltage from the solar cell is used as a power supply to the detector, and the AC voltage is used to reduce the optical noise in a photodiode with the differential detection method. The signal to noise ratio was improved by about 20 dB.

Automatic Alignment of a Differential Detector to the Optical Signal in a Wireless Optical Interconnection (무선광연결에서 신호광에 자동 정렬하는 차동검출기)

  • 이성호
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.5
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    • pp.822-829
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    • 2000
  • In this paper, we introduce a differential detector that automatically aligns itself to the signal beam in order to prevent the voltage variation that may result from minute misalignment of the light source. In this system, a photodiode-array recognizes the central point of the signal beam, and drives motors that correspond to the x and y axes. The photodiode-array aligns itself to the central point of the signal beam, and eliminates the optical noise effect with differential detectioin method. It is very useful in wireless optical interconnections.

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Optical Noise Reduction in A Wireless Optical System using Two Orthogonal Polarizers (무선광시스템에서 직교편광기를 이용한 잡음광의 소거)

  • 이성호;이준호
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.8
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    • pp.891-897
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    • 2003
  • In this paper, a circular orthogonal polarizer is newly fabricated and used in a differential detector to reduce the optical noise in a wireless optical interconnection. The orthogonal polarizer is composed of two semicircular polarizers whose transmission axes are orthogonal each other, The orthogonal polarizer is driven by a motor and matched to the signal polarization in order to reduce the optical noise interference. The noise power was reduced by about 20 dB using a differential detector with the orthogonal polarizer.

결정궤환 복조에 근거한 차동 DPSK 시스템용 선형 등화기

  • 장동운;이용훈
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 1996.06a
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    • pp.23-26
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    • 1996
  • 본 논문에서는 선형궤환 등화방식과 결정궤환 복조방식을 결합하여 차동 PSK 신호검출에 필요한 등화기 구조를 제안한다. 이 등화기의 출력을 등화기의 궤환부로 입력하기 앞서, 결정궤환 복조방식에 근거하여 적절히 변형함으로써 제안된 구조는 마치 결정궤한 등화기처럼 동작한다. 모의 실험 결과는 실제로 제안된 등화기가 기존의 차동검파 방식의 등화기 보다 월등한 성능을 나타내고, 동기검파를 위한 결정궤환 등화기에 근접한 성능을 가짐을 보여준다.

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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.

Optical Noise Reduction Using Approximate Average Noise Detection in Wireless Optical Interconnection (무선광연결에서 근사적 평균잡음검출을 이용한 광잡음 감소)

  • 이성호
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.2
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    • pp.228-233
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    • 2000
  • In this paper, we introduce a differential detection method using approximate average noise detection, which improves the noise reduction efficiency in a wireless optical interconnection. Approximate average noise detection reduces the output voltage fluctuation that may result from the instantaneous change of the coupling coefficients with the movement of some objects or human beings. This method is very useful for noise reduction in an environment with optical noise whose spatial distribution varies instantaneously.

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