• Title/Summary/Keyword: 광대역신호

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Design of Physical Layer and Performance Analysis for MX-S2X, Ship Centric Direct Communication with the Mitigation of Multi-path Fading on Sea Environment (해상 다중경로 페이딩 극복을 위한 선박중심 직접통신(MX-S2X) 물리계층 설계 및 성능 분석)

  • Ryu, Hyung-Jick;Yoo, Hae-Sun;Kim, Won-Yong;Kim, Bu-Young;Shim, Woo-Seong
    • Journal of Navigation and Port Research
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    • v.45 no.6
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    • pp.352-359
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    • 2021
  • This paper presents the definition and importance of ship-centric direct communication concerning ship safety of maritime autonomous and unmanned ships. It also proposes the concept of MX-S2X communication based on high frequency for wide-bandwidth technology and describes the design and simulation result for the physical layer of MX-S2X. It considered high-speed communication as well as overcoming maritime multi-path fading required to be resolved in the marine environment. The physical layer of MX-S2X communication was designed to overcome the occurrence of error-floor caused by multi-path fading even with receiving sufficient signal strength. To this purpose, a performance analysis was conducted on the physical layer by applying the channel model of the actual maritime communication environment. As a result of the performance analysis of the MX-S2X physical layer, it was confirmed that the BER error-floor observed in the VDE physical layer test was overcome, and it operated within the SNR 2dB degradation range compared to the AWGN channel. It is expected that this will show enough performance suitable for short-distance ship-centered direct communication and can be used for direct communication of maritime autonomous ships, unmanned ships, and group navigation of themshortly.

Wideband Receiver Module for LADAR Using Large Area InGaAs Avalanche Photodiode (대면적 APD를 이용한 LADAR용 광대역 광수신기)

  • Park, Chan-Yong;Kim, Dug-Bong;Kim, Chung-Hwan;Kwon, Yongjoon;Kang, EungCheol;Lee, Changjae;Choi, Soon-Gyu;La, Jongpil;Ko, Jin Sin
    • Korean Journal of Optics and Photonics
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    • v.24 no.1
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    • pp.1-8
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    • 2013
  • In this paper, we report design, fabrication and characterization of the WBRM (Wide Band Receiver Module) for LADAR (LAser Detection And Ranging) application. The WBRM has been designed and fabricated using self-made APD (Avalanche Photodiode) and TIA (Trans-impedance Amplifier). The APD and TIA chips have been integrated on 12-pin TO8 header using self-made ceramic submount and circuit. The WBRM module showed 450 ps of rise time, and corresponding 780 MHz bandwidth. Furthermore, it showed very low output noise less than 0.8 mV, and higher SNR than 15 for 150 nW of MDS(Minimum Detectable Signal). To the author's knowledge, this is the best performance of an optical receiver module for LIDAR fabricated by 200 um InGaAs APD.

Fabrication of Multiple-Frequency Exposure System for In Vitro Experiment (세포 실험용 다중 주파수 동시 노출 장치 제작)

  • Kim, Tae-Hong;Seo, Min-Gyeong;Mun, Ji-Yeon;Pack, Jeong-Ki
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.2
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    • pp.213-219
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    • 2012
  • Recently, we are simultaneously exposed by various electromagnetic sources due to an increase of mobile communication services. However, EMF(Electric, Magnetic and Electromagnetic Field) study has been performed mainly about only single frequency. The objective of this paper is to develop an multiple-frequency exposure system for in vitro experiment. The exposure unit for in vitro experiments was designed by radial transmission line type to get broadband characteristics to generate signals of CDMA at 836.5 MHz and WCDMA at 1950 MHz frequency simultaneously. The modulated signals were delivered to the conical antenna through amplifier, digital attenuator and RF combiner. SAR values were obtained by the averaged values of 3 measured values at 9 points in petri dish using the fiber optic temperature probe. The measured return loss was under -15 dB. For 1 W input power, the mean value and standard deviation of SAR were $0.105{\pm}0.019$ for the CDMA frequency and $0.262{\pm}0.055$ for the WCDMA frequency.

A Dual-Channel 6b 1GS/s 0.18um CMOS ADC for Ultra Wide-Band Communication Systems (초광대역 통신시스템 응용을 위한 이중채널 6b 1GS/s 0.18um CMOS ADC)

  • Cho, Young-Jae;Yoo, Si-Wook;Kim, Young-Lok;Lee, Seung-Hoon
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.43 no.12 s.354
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    • pp.47-54
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    • 2006
  • This work proposes a dual-channel 6b 1GS/s ADC for ultra wide-band communication system applications. The proposed ADC based on a 6b interpolated flash architecture employs wide-band open-loop track-and-hold amplifiers, comparators with a wide-range differential difference pre-amplifier, latches with reduced kickback noise, on-chip CMOS references, and digital bubble-code correction circuits to optimize power, chip area, and accuracy at 1GS/s. The ADC implemented in a 0.18um 1P6M CMOS technology shows a signal-to-noise-and-distortion ratio of 30dB and a spurious-free dynamic range of 39dB at 1GS/s. The measured differential and integral non-linearities of the prototype ADC are within 1.0LSB and 1.3LSB, respectively. The dual-channel ADC has an active area of $4.0mm^2$ and consumes 594mW at 1GS/s and 1.8V.

Size-Reduced Ring-Hybrid Coupler Using Phase-Inverting Ultra-Wideband Transitions and Its Frequency Doubler Application (초광대역 위상 역전 전이 구조를 이용한 소형화된 링 하이브리드 결합기 및 주파수 체배기 응용)

  • Song, Sun-Young;Kim, Young-Gon;Park, Jin-Hyun;Kim, Kang-Wook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.9
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    • pp.1037-1044
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    • 2010
  • In this paper, a new size-reduced, wideband ring-hybrid coupler is presented, and a design of a planar single-balanced doubler using the ring-hybrid is shown. This ring-hybrid coupler employs a pair of ultra-wideband transitions for phase inversion, which consists of in-phase and out of-phase transitions providing a good amplitude and phase balances for wide frequency ranges. The implemented ring-hybrid is 65 % smaller than conventional ring-hybrids, and provides 92.5 % and 81.3 % bandwidth at $\sum$ and $\Delta$ ports, respectively. Thanks to good amplitude and phase balances over wide bandwidth, the ring-hybrid can be applied to implement various balanced components. The implemented single-balanced doubler utilizing the ring-hybrid exhibits typical conversion loss of 10.5 dB for the output frequency range of 4~12 GHz with fundamental suppression level of 30 dB. The performance was also well-predicted with the nonlinear circuit simulation.

Study on Development of HDD Integrity Verification System using FirmOS (FirmOS를 이용한 HDD 무결성 검사 시스템 개발에 관한 연구)

  • Yeom, Jae-Hwan;Oh, Se-Jin;Roh, Duk-Gyoo;Jung, Dong-Kyu;Hwang, Ju-Yeon;Oh, Chungsik;Kim, Hyo-Ryoung;Shin, Jae-Sik
    • Journal of the Institute of Convergence Signal Processing
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    • v.18 no.2
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    • pp.55-61
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    • 2017
  • In radio astronomy, high-capacity HDDs are being used to save huge amounts of HDDs in order to record the observational data. For VLBI observations, observational speeds increase and huge amounts of observational data must be stored as they expand to broadband. As the HDD is frequently used, the number of failures occurred, and then it takes a lot of time to recover it. In addition, if a failed HDD is continuously used, observational data loss occurs. And it costs a lot of money to buy a new HDD. In this study, we developed the integrity verification system of the Serial ATA HDD using FirmOS. The FirmOS is an OS that has been developed to function exclusively for specific purposes on a system having a general server board and CPU. The developed system performs the process of writing and reading specific patterns of data in a physical area of the SATA HDD based on a FirmOS. In addition, we introduced a method to investigate the integrity of HDD integrity by comparing it with the stored pattern data from the HDD controller. Using the developed system, it was easy to determine whether the disk pack used in VLBI observations has error or not, and it is very useful to improve the observation efficiency. This paper introduces the detail for the design, configuration, testing, etc. of the SATA HDD integrity verification system developed.

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A Study on the Digital Filter Design using Software for Analysis of Observation Data in Radio Astronomy (전파천문 관측데이터 분석을 위해 소프트웨어를 이용한 디지털필터 설계에 관한 연구)

  • Yeom, Jae-Hwan;Oh, Se-Jin;Roh, Duk-Gyoo;Oh, Chung-Sik;Jung, Dong-Kyu;Shin, Jae-Sik;Kim, Hyo-Ryoung;Hwang, Ju-Yeon
    • Journal of the Institute of Convergence Signal Processing
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    • v.16 no.4
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    • pp.175-181
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    • 2015
  • In this paper, we propose a design method for a digital filter using software in order to analyze the radio astronomy observation data. Recently the analysis method for radio astronomy observing system is transferring from hardware to software by developing of state-of-the-art of computer system. The existing hardware system is not able to easily change the specification because it is implemented to meet special requirements and it takes a high cost and time. In case of software, however, it has an advantage to implement with small cost if open software is used, and flexibly changes to satisfy the desired specification. But, in order to analyze the massive data like radio astronomy with software, the good performance system is needed for computer. Therefore, this paper proposes a digital filter design method using software with the same performance as that of digital filter implemented with hardware in observation system which is operated by the KVN(Korean VLBI Network). To design a digital filter, the proposed method is performed with standard C language and the simulation is conducted with GNU(GNU's Not Unix) Octave and investigated to show its effectiveness. In addition, for the high speed operation of the designed digital filter, the SSE(Streaming SIMD Extensions) library is adopted for available parallel operation. By the proposed digital filter, the digital filtering is performed for the wide band observation data in the KVN observation mode, the filtering result of narrow band observation has no ripple inside of stop band, and confirmed the effectiveness of the proposed method.

The Comparison of Image Quality and Quantitative Indices by Wide Beam Reconstruction Method and Filtered Back Projection Method in Tl-201 Myocardial Perfusion SPECT (Tl-201 심근관류 SPECT 검사에서 광대역 재구성(Wide Beam Reconstruction: WBR) 방법과 여과 후 역투영법에 따른 영상의 질 및 정량적 지표 값 비교)

  • Yoon, Soon-Sang;Nam, Ki-Pyo;Shim, Dong-Oh;Kim, Dong-Seok
    • The Korean Journal of Nuclear Medicine Technology
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    • v.14 no.2
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    • pp.122-127
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    • 2010
  • Purpose: The Xpress3.$cardiac^{TM}$ which is a kind of wide beam reconstruction (WBR) method developed by UltraSPECT (Haifa, Israel) enables the acquisition of at quarter time while maintaining image quality. The purpose of this study is to investigate the usefulness of WBR method for decreasing scan times and to compare to it with filtered back projection (FBP), which is the method routinely used. Materials and Methods: Phantom and clinical studies were performed. The anthropomorphic torso phantom was made on an equality with counts from patient's body. The Tl-201 concentrations in the compartments were 74 kBq (2 ${\mu}Ci$)/cc in myocardium, 11.1 kBq (0.3 ${\mu}Ci$)/cc in soft tissue, and 2.59 kBq (0.07 ${\mu}Ci$)/cc in lung. The non-gated Tl-201 myocardial perfusion SPECT data were acquired with the phantom. The former study was scanned for 50 seconds per frame with FBP method, and the latter study was acquired for 13 seconds per frame with WBR method. Using the Xeleris ver. 2.0551, full width at half maximum (FWHM) and average image contrast were compared. In clinical studies, we analyzed the 30 patients who were examined by Tl-201 gated myocardial perfusion SPECT in department of nuclear medicine at Asan Medical Center from January to April 2010. The patients were imaged at full time (50 second per frame) with FBP algorithm and again quarter-time (13 second per frame) with the WBR algorithm. Using the 4D MSPECT (4DM), Quantitative Perfusion SPECT (QPS), and Quantitative Gated SPECT (QGS) software, the summed stress score (SSS), summed rest score (SRS), summed difference score, end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were analyzed for their correlations and statistical comparison by paired t-test. Results: As a result of the phantom study, the WBR method improved FWHM more than about 30% compared with FBP method (WBR data 5.47 mm, FBP data 7.07 mm). And the WBR method's average image contrast was also higher than FBP method's. However, in result of quantitative indices, SSS, SDS, SRS, EDV, ESV, EF, there were statistically significant differences from WBR and FBP(p<0.01). In the correlation of SSS, SDS, SRS, there were significant differences for WBR and FBP (0.18, 0.34, 0.08). But EDV, ESV, EF showed good correlation with WBR and FBP (0.88, 0.89, 0.71). Conclusion: From phantom study results, we confirmed that the WBR method reduces an acquisition time while improving an image quality compared with FBP method. However, we should consider significant differences in quantitative indices. And it needs to take an evaluation test to apply clinical study to find a cause of differences out between phantom and clinical results.

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MIMIC 94 GHz high isolation single balanced cascode mixer (94 GHz 대역의 높은 격리 특성의 MIMIC single balanced cascode 믹서)

  • Lee, Sang-Jin;An, Dan;Lee, Mun-Kyo;Moon, Sung-Woon;Bang, Suk-Ho;Baek, Tae-Jong;Kwon, Hyuk-Ja;Jun, Byoung-Chul;Yoon, Jin-Seob;Rhee, Jin-Koo
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.44 no.9
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    • pp.25-33
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    • 2007
  • In this paper, the high isolation and wideband 94 GHz MIMIC(Millimeter-wave Monolithic Integrated Circuit) single balanced cascode mixer was designed and fabricated. Also, we designed and fabricated a 3 dB tandem coupler which has a high isolation and wideband characteristic. The single balanced resistive mixer which does not require an external IF balun was designed using the 0.1 ${\mu}m$ InGaAs/InAlAs/GaAs metamorphic HEMT(High Electron Mobility Transistor). The DC characteristics of MHEMT's are 665 mA/mm of drain current density, 691 mS/mm of maximum transconductance. The current gain cut-off frequency($f_T$) is 189 GHz and the maximum oscillation frequency($f_{max}$) is 334 GHz. A 94 GHz single balanced cascode mixer was fabricated using our 0.1 ${\mu}m$ MHEMT MIMIC process. From the measurements, the fabricated couplers showed wideband characteristics. The conversion loss of single balanced cascode mixer was 9.8 dB at an LO power of 10.9 dBm. The LO to RF isolation of single balanced cascode mixer was 29.5 dB at 94 GHz. We obtained in this study a higher LO-RF isolation compared to some other single balanced mixers.

A Novel Idle Mode Operation in IEEE 802.11 WLANs: Prototype Implementation and Performance Evaluation (IEEE 802.11 WLAN을 위한 Idle Mode Operation: Prototype 구현 및 성능 측정)

  • Jin, Sung-Geun;Han, Kwang-Hun;Choi, Sung-Hyun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.2A
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    • pp.152-161
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    • 2007
  • IEEE 802.11 Wireless Local Area Network (WLAN) became a prevailing technology for the broadband wireless Internet access, and new applications such as Voice over WLAM (VoWLAN) are fast emerging today. For the battery-powered VoWLAN devices, the standby time extension is a key concern for the market acceptance while today's 802.11 is not optimized for such an operation. In this paper, we propose a novel Idle Mode operation, which comprises paging, idle handoff, and delayed handoff. Under the idle mode operation, a Mobile Host (MH) does not need to perform a handoff within a predefined Paging Area (PA). Only when the MH enters a new PA, an idle handoff is performed with a minimum level of signaling. Due to the absence of such an idle mode operation, both IP paging and Power Saving Mode (PSM) have been considered the alternatives so far even though they are not efficient approaches. We implement our proposed scheme in order to prove the feasibility. The implemented prototype demonstrates that the proposed scheme outperforms the legacy alternatives with respect to energy consumption, thus extending the standby time.