• 제목/요약/키워드: Multi-band frequency

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A Study on Low Noise Frequency Synthesizer Design with Compact Size for Multi-Band (소형 다대역 저잡음 주파수 합성기 설계에 관한 연구)

  • Kim, Taeyoung;Han, Jonghoon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.20 no.5
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    • pp.673-680
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    • 2017
  • In the proposed paper, we designed low noise frequency synthesizer with compact size for Multi-Band. The proposed frequency synthesizer consists of fundamental frequency band(2 GHz) and harmonic frequency band(4 GHz). To improve the phase noise and spurious level of frequency synthesizer, we analyze how the configuration of frequency synthesizer affect the phase noise and design the multi-band's structure. The implemented frequency synthesizer reduce both the phase noise and spurious level. The phase noise is -92.17 dBc/Hz at 1 kHz frequency offset in 2 GHz and -90.50 dBc/Hz at 1 kHz frequency offset in 4 GHz. All spurious signals including fundamental frequency are suppressed at least 20 dBc than the second harmonic frequency.

Reconfigurable Multi-Band Mixer for SDR System

  • Kim, Jeong-Pyo;Choi, Jae-Hoon
    • Journal of electromagnetic engineering and science
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    • v.7 no.4
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    • pp.154-160
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    • 2007
  • A reconfigurable multi-band mixer for the SDR system is proposed. The proposed reconfigurable mixer is operated between $850\;MHz{\sim}2\;GHz$, which includes all commercial mobile communication service. Because the varactor diodes are used to select a specific frequency and to adjust the impedance characteristic of the selected frequency band, the proposed reconfigurable mixer can be achieved to similar performance across all of the tuning range. In addition, the designed reconfigurable mixer is applicable for the SDR system since it has a single signal path for the multi-band signals and wide band tuning range.

Earthquake detection based on convolutional neural network using multi-band frequency signals (다중 주파수 대역 convolutional neural network 기반 지진 신호 검출 기법)

  • Kim, Seung-Il;Kim, Dong-Hyun;Shin, Hyun-Hak;Ku, Bonhwa;Ko, Hanseok
    • The Journal of the Acoustical Society of Korea
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    • v.38 no.1
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    • pp.23-29
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    • 2019
  • In this paper, a deep learning-based detection and classification using multi-band frequency signals is presented for detecting earthquakes prevalent in Korea. Based on an analysis of the previous earthquakes in Korea, it is observed that multi-band signals are appropriate for classifying earthquake signals. Therefore, in this paper, we propose a deep CNN (Convolutional Neural Network) using multi-band signals as training data. The proposed algorithm extracts the multi-band signals (Low/Medium/High frequency) by applying band pass filters to mel-spectrum of earthquake signals. Then, we construct three CNN architecture pipelines for extracting features and classifying the earthquake signals by a late fusion of the three CNNs. We validate effectiveness of the proposed method by performing various experiments for classifying the domestic earthquake signals detected in 2018.

Design of Multi-Band VCO with Fast AFC Technique (광대역 고속 AFC 기법을 적용한 다중 대역 VCO의 설계)

  • Ahn, Tae-Won;Yoon, Chan-Geun;Lee, Won-Seok;Moon, Yong
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.983-984
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    • 2006
  • Multi-band VCO with fast response adaptive frequency calibration (AFC) technique is designed in 1.8V $0.18{\mu}m$ CMOS process. The possible operation is verified for 5.8GHz band, 5.2GHz band, and 2.4GHz band using the switchable L-C resonators for 802.11a/b/g WLAN applications. To linearize its frequency-voltage gain, optimized multiple MOS varactor biasing technique is used. In order to operate in each band frequency range with reduced VCO gain, 4-bit digitally controlled switched-capacitor bank is used and a wide-range digital logic quadricorrelator is implemented for fast frequency detector.

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Fractal Microstrip patch Antenna Design and Fabrication for WLAN/WiMax Applications (WLAN/WiMax용 프랙탈 마이크로스트립 패치 안테나설계 및 제작)

  • Kim, Kab-Ki
    • Journal of Advanced Navigation Technology
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    • v.15 no.6
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    • pp.1008-1014
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    • 2011
  • In this paper, multi-band fractal microstrip patch antenna which is possible for WLAN band and WiMax band is designed and made. For multi-resonance of developed antenna, resonance frequency, impedance matching, polarity and reflection pattern can mad perfectly, then to make satisfied multi-independent frequency three kind of half circle fractal patch is inserted. In the situation continuously happening half circle in designed structure, antennas one of half-circle band is shown.

Design Approach of Q-band Precision Subminiature Coaxial Adaptor Using 3D Simulator and Its Experimental Results (3D 시뮬레이션과 측정값을 이용한 Q-band 정밀 초소형 동축 어댑터의 설계)

  • Wang, Cong;Qian, Cheng;Cho, Won-Yong;Kim, Nam-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.387-388
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    • 2008
  • This paper presents the design approach and test results of the Q-band precision subminiature coaxial adaptor based on transmission line theory using multi-step impedance and air-holes to increase its cutoff frequency. In order to increase the frequency performance, the adaptor is designed with hooked structure, fixing step, multi-air-holes, and outer conductor. The return loss increments due to the hooked structure and multi air-holes are minimized to 2 dB and 1.5 dB, respectively. A VSWR(Voltage Standing Wave Ratio) of <1.2 is obtained from DC to 40 GHz, while guaranteeing the durability of the adaptor from room-temperature$(25^{\circ}C)$ to $120^{\circ}C$.

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Joint Estimation Schemes of Carrier and Sampling Frequency Offsets for MB-OFDM UWB Systems (MB-OFDM UWB 시스템을 위한 반송파 및 샘플링 주파수 오프셋 결합 추정 기법)

  • Cho, Chang-Hoon;Yang, Suck-Chel;Shin, Yo-An
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.10C
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    • pp.965-975
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    • 2005
  • In this paper, we propose and evaluate joint carrier and sampling frequency offset estimation schemes based on the channel estimation sequences in PLCP (Physical Layer Convergence Procedure) preamble for the proper and effcient synchronization of the MB-OFDM WB (Multi-Band Orthogonal Frequency Division Multiplexing Ultra Wide Band) systems which have recently drawn explosive attention for future W-PAN (Wireless Personal Area Network) applications. In the joint estimation schemes, we first estimate the sampling frequency offset, and then estimate the carrier frequency offset using the estimated sampling frequency offset. Moreover, to improve the reliability of the estimated offset values, each process uses a combination scheme based on weighting factors. Simulation results using IEEE 802.15 Task Group 3a UWB channel models reveal that the estimation scheme using the simple weighting factors based on easily-measurable received signal power of each sub-channel shows favorably comparable performance to the ideal scheme using the weighting factors based on the perfectly-estimated frequency response of the channel.

A Study on the RF performance analysis for Multi-band Ultra Wide Band Systems (멀티밴드 UWB 시스템의 무선성능 분석에 관한 연구)

  • Choi, Seok;Kim, Gil-Gyeom;Kwack, Jun-Ho;Kim, Hak-Sun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.12A
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    • pp.951-957
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    • 2003
  • The analysis of RF performance requirement conditions on communication system is critical indicator to predict the performance of system. UWB(Ultra Wide Band) system which the standard is not established yet is difficult to derive the precise system performance requirement condition. Also, there are differences between conventional UWB system and multi-band system about RF performance requirement condition. In this thesis, the differences are analyzed and performance requirement conditions of multi-band UWB system are described on the basis of the differences. Throughput, maximum transmit power, and sensitivity of multi-band UWB system is varied with respect to the number of Sub-Bands. In addition, because of Multi-path effect, if PRF(Pulse Repetition Frequency) is changed, the Multi-path link margin is happened to compensate for Multi-path Energy Loss which is contributed by increasing of the Link Margin. According to Multi-path Margin, the variation of the resistance with respect to sensitivity and interference signal is observed and analyzed through the simulation.

A study on architecture of channel estimation for multi-band OFDM UWB system (멀티밴드 OFDM UWB 시스템을 위한 채널추정 구조에 관한 연구)

  • Lee Yong-Bae;Jeong Jin-Doo;Chong Jong-Wha
    • Proceedings of the IEEK Conference
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    • 2004.06a
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    • pp.293-296
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    • 2004
  • This paper proposes an architecture of channel estimation for multi-band OFDM UWB systems presented to IEEE 802.15.3a by Multi-band OFDM alliance(MBOA). The multi-band OFDM (MB-OFDM) systems should have channel estimation for compensation of signal distortion by multi-band channel. The moving-averaging estimation algorithm and multi-band equalization architecture for MB-OFDM UWB systems proposed in this paper was verified by the simulation. Simulation results show that MB-OFDM system with the proposed architecture have the performance improved by about 3.4 dB compared to system with no channel estimation in 0.1$\pi$ phase-rotated channel.

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Decentralized Load-Frequency Control of Interconnected Power Systems with SMES Units and Governor Dead Band using Multi-Objective Evolutionary Algorithm

  • Ganapathy, S.;Velusami, S.
    • Journal of Electrical Engineering and Technology
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    • v.4 no.4
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    • pp.443-450
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    • 2009
  • This paper deals with the design of decentralized controller for load-frequency control of interconnected power systems with superconducting magnetic energy storage units and Governor Dead Band Nonlinearity using Multi-Objective Evolutionary Algorithm. The superconducting magnetic energy storage unit exhibits favourable damping effects by suppressing the frequency oscillations as well as stabilizing the inter-area oscillations effectively. The proposed control strategy is mainly based on a compromise between Integral Squared Error and Maximum Stability Margin criteria. Analysis on a two-area interconnected thermal power system reveals that the proposed controller improves the dynamic performance of the system and guarantees good closed-loop stability even in the presence of nonlinearities and with parameter changes.