• Title/Summary/Keyword: Channel Array

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Time-reversal Channel Capacity in Rayleigh and Ricean Environment (Rayleigh와 Ricean 채널 환경에서 동작하는 시역전 통신 채널 용량)

  • Koh, Il-Suek
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.3C
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    • pp.243-250
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    • 2009
  • In this paper, a closed-form expression of the ergodic channel capacity for a narrow-band time-reversal communication scheme is analytically formulated. In the time-reversal communication scenario, a transmitter sends a signal and a so-called time-reversal array receives the signal. Then, the received signal is reversed in the time do main and resent to the original transmitter. Here, one transmitter and an antenna array for the time-reversal array are assumed. Since the spacing between the array elements is large, the signals received by each antenna element can be considered independent. For simplicity, the communication channel is assumed stationary, whose properties are not changed for the time-reversal process. Based on the obtained formulation, the channel capacities for the time-reversal and the conventional channels are compared.

Characteristics of 2-Channel TDM fiber-optic sensor array (TDM 방식의 2채널 광섬유 센서 배열 특성 연구)

  • Lee, Jong-Kil
    • Journal of Sensor Science and Technology
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    • v.7 no.5
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    • pp.306-312
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    • 1998
  • To develop the multi-channel fiber-optic sensor array system, two-channel TDM(Time Division Multiplexing) fiber-optic sensor array was constructed and characterized. The sensor array topology was Mach-Zehender ladder type and PMDI(Phase-Matched Differential Interferometer) technique was used to exploit the efficiency of the array signal processing. By using a synthetic heterodyne demodulation technique, outputs of the two channels were monitored simultaneously. The sensitivities of channel #1 and #2 were measured ${\sim}60{\mu}rad/\sqrt{Hz}$ and ${\sim}80{\mu}rad/\sqrt{Hz}$, respectively. Crosstalk of sensors in the array was found to be approximately -36dB. Based on the results, we could conclude that TDM Mach-Zehnder ladder type sensor array can be used to detect the acoustic signal with stability and efficiency of the sensor array.

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Performance Analysis of DS-CDMA Communication Systems with Array Antenna and CCI Canceller (Array 안테나와 간섭제거기에 의한 DS-CDMA 통신 시스템의 성능분석)

  • 최충열;오창헌;김봉철;조성준
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.9 no.4
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    • pp.439-449
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    • 1998
  • In this paper, error performance of DS-CDMA communication system has been analyzed in a radio channel which is characterized by multi-user interference (MUI). Also, performance improvement has been obtained by both numerical analysis and simulation techniques when 3-element array antenna and co-channel interference (CCI) canceller are employed as a means for overcoming an MUI effect. The MUI was modelled as a gaussian random process. In array antenna scheme we only considered a directivity of antennal. The results show that there is a substantial enhancement in performance by employing an array antenna or a CCI canceller. CCI canceller gives better improvement in performance than the array antenna with D=2.67. Additional improvement can be obtained when the array antenna and the CCI canceller are adopted in cascade form. In this case the error performance approaches that of AWGN environment.

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4-Channel Patch Array Antennas for Home Network System

  • Min Kyeong-Sik;Kim Dong-Jin
    • Journal of electromagnetic engineering and science
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    • v.5 no.3
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    • pp.122-125
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    • 2005
  • This paper describes a design of a miniature patch antenna and its 4-channle array for 5.25 GHz wireless LAN band. Each patch element is designed for the low mutual coupling between each element and for the small size of the array antenna. The size of the each element is $7 mm{\times}14.5 mm{\times}5.6 mm$ and it satisfy IEEE 802.11a frequency band. It is arrayed for independent 4-channel operation. The total size of the array antenna is $35.6 mm{\times}52.5 mm{\times}5.6 mm$. The measured reflection coefficients and the radiation patterns of the fabricated antennas show the reasonable agreements with prediction.

Microphone Array Based Speech Enhancement Using Independent Vector Analysis (마이크로폰 배열에서 독립벡터분석 기법을 이용한 잡음음성의 음질 개선)

  • Wang, Xingyang;Quan, Xingri;Bae, Keunsung
    • Phonetics and Speech Sciences
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    • v.4 no.4
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    • pp.87-92
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    • 2012
  • Speech enhancement aims to improve speech quality by removing background noise from noisy speech. Independent vector analysis is a type of frequency-domain independent component analysis method that is known to be free from the frequency bin permutation problem in the process of blind source separation from multi-channel inputs. This paper proposed a new method of microphone array based speech enhancement that combines independent vector analysis and beamforming techniques. Independent vector analysis is used to separate speech and noise components from multi-channel noisy speech, and delay-sum beamforming is used to determine the enhanced speech among the separated signals. To verify the effectiveness of the proposed method, experiments for computer simulated multi-channel noisy speech with various signal-to-noise ratios were carried out, and both PESQ and output signal-to-noise ratio were obtained as objective speech quality measures. Experimental results have shown that the proposed method is superior to the conventional microphone array based noise removal approach like GSC beamforming in the speech enhancement.

A Desired Signal Estimation using Sub-Array Algorithm of Adaptive Array Antenna in Correlation Channel Environment (상관성 채널 환경에서의 적응배열안테나의 부배열 알고리즘을 이용한 관심신호 추정)

  • Lee, Kwanhyeong;Cho, Taejun
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.13 no.3
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    • pp.75-81
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    • 2017
  • This paper estimate a desired signal in a correlation wireless communication. The transmitted signal is mixed with the information signal, interference, and noise in wireless channel, and it is incident on the receiver. In this paper, we apply MUSIC algorithm and sub-array method to recover the total rank of the correlation matrix in order to estimation a desired signal among receiving signals. Through simulation, we analyze to compare the proposed method with the classical MUSIC algorithm. As a result of the simulation, the proposed method improved the resolution about 10degrees compared to the conventional MUSIC algorithm. We prove the superiority of the proposed method for the desired signal estimation in correlation channel.

Ku band Linear Active phased Array Antenna Design and Fabrication (Ku 대역 선형 능동 위상 배열 안테나 설계 및 제작)

  • Ryu, Sung-Wook;Eom, Soon-Young;Kim, Nam
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.215-216
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    • 2006
  • In this paper, the antenna the with linear active phased array of $1{\times}16$ operated in DBS band was designed. The antenna was composed of sixteen radiating elements, sixteen active channels and five Wilkinson power combiners with 4-channel inputs, a digital control board and a stabilizing DC bias board. The radiating element of the array has the structure of a microstrip stack patch with a left-hand circular polarization. And, each active channel consists of a low noise ampilifier, a 3-bit digital phase shifter and a variable analog attenuator. The breadboard of linear active phased array antenna was also fabricated to test the electrical performances. The radiation patterns of the antenna were measured after correcting initial phases of each active channel in aechoic chamber. And also, the beam scanning chracteristcs of $10^{\circ}$, $20^{\circ}$, $30^{\circ}$ were measured.

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An Array Antenna Calibration Algorithm Using LTE Downlink Zadoff-Chu Sequence (LTE 하향링크의 Zadoff-Chu 시퀀스를 이용한 배열 안테나 Calibration 알고리즘)

  • Sun, Tiefeng;Jang, Jae Hyun;Yang, Hyun Wook;Choi, Seung Won
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.9 no.4
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    • pp.51-57
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    • 2013
  • Research on calibration of array antenna has become a hot spot in the area of signal processing and it is necessary to obtain the phase mismatch of each antenna channel. This paper presents a new calibration method for an array antenna system. In order to calibrate the phase mismatch of each antenna channel, we used primary synchronization signal (PSS) which exists in LTE downlink frame. Primary synchronization signal (PSS) is based on a Zadoff-Chu sequence which has a good correlation characteristic. By using correlation calculation, we can extract primary synchronization signal (PSS). After extracting primary synchronization signal (PSS), we use it to calibrate and reduce the phase errors of each antenna channel. In order to verify the new array antenna calibration algorithm which is proposed in this paper, we have simulated the proposed algorithm by using MATLAB. The array antenna system consists of two antenna elements. The phase mismatch of first antenna and second antenna is calculated accurately by proposed algorithm in the experiment test. Theory analysis and MATLAB simulation results are shown to verify the calibration algorithm.

10-GHz band 2 × 2 phased-array radio frequency receiver with 8-bit linear phase control and 15-dB gain control range using 65-nm complementary metal-oxide-semiconductor technology

  • Seon-Ho Han;Bon-Tae Koo
    • ETRI Journal
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    • v.46 no.4
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    • pp.708-715
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    • 2024
  • We propose a 10-GHz 2 × 2 phased-array radio frequency (RF) receiver with an 8-bit linear phase and 15-dB gain control range using 65-nm complementary metal-oxide-semiconductor technology. An 8 × 8 phased-array receiver module is implemented using 16 2 × 2 RF phased-array integrated circuits. The receiver chip has four single-to-differential low-noise amplifier and gain-controlled phase-shifter (GCPS) channels, four channel combiners, and a 50-Ω driver. Using a novel complementary bias technique in a phase-shifting core circuit and an equivalent resistance-controlled resistor-inductor-capacitor load, the GCPS based on vector-sum structure increases the phase resolution with weighting-factor controllability, enabling the vector-sum phase-shifting circuit to require a low current and small area due to its small 1.2-V supply. The 2 × 2 phased-array RF receiver chip has a power gain of 21 dB per channel and a 5.7-dB maximum single-channel noise-figure gain. The chip shows 8-bit phase states with a 2.39° root mean-square (RMS) phase error and a 0.4-dB RMS gain error with a 15-dB gain control range for a 2.5° RMS phase error over the 10 to10.5-GHz band.

A Compact Active Channel Module Design for Active Phased Array Antenna System

  • Jung, Young-Bae
    • Journal of IKEEE
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    • v.17 no.4
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    • pp.393-397
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    • 2013
  • This paper introduces the T/RX combined compact active channel module which is a key unit of the active phased array antenna(APAA) system. This module is mainly compoased of two parts for TX and RX fabricated on both sides of the active module for size reduction. The TX-part is primarily composed of a 3-stage amplifier, a microstrip phase shifter, a thermal compensation and a power detection circuit. The RX-part is composed of LNAs a microstrip phase shifter and BPFs for TX power rejection. Using the proposed design structure we can realized a compact active channel module having high performance.