• Title/Summary/Keyword: Multi-band frequency

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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.

A Pair Dipole Antenna with Double Tapered Microstrip Balun for Wireless Communications

  • Lee, Hyeonjin
    • Journal of Electrical Engineering and Technology
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    • v.10 no.3
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    • pp.1081-1085
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    • 2015
  • In this paper a printed pair dipole antenna with double tapered microstrip balun for wireless communications is proposed. The proposed antenna consists of a pair arm of different sizes that is branched microstrip line and microstrip line with the ground plane on opposite side of the dielectric substrate plane. The proposed antenna is matched between the ground plane to the microstrip line by double tapered microstrip balun. This antenna obtains multi-band radiation frequency band. The impedance bandwidths for a reflection coefficient of VSWR ≤ 2 are about 1.01 GHz (2.35~3.336 GHz), 1.56 GHz (4.7~6.26 GHz) and 1.15GHz (6.85~8.0[GHz]). Additionally, the measurement peak gain is about 3.6 dBi. The proposed antenna is able to support wireless communication applications.

A Wideband ${\Delta}{\Sigma}$ Frequency Synthesizer for T-DMB/DAB/FM Applications in $0.13{\mu}m$ CMOS (T-DMB/DAB/FM 수신기를 위한 광대역 델타시그마 분수분주형 주파수합성기)

  • Shin, Jae-Wook;Shin, Hyun-Chol
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.12
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    • pp.75-82
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    • 2010
  • This paper presents a wideband ${\Delta}{\Sigma}$ fractional-N frequency synthesizer for a multi-band single chip CMOS RFIC transceivers. A wideband VCO utilizes a 6-bit switched capacitor array bank for 2340~3940 MHz frequency range. VCO frequency calibration circuit is designed for optimal capacitor bank code selection before phase locking process. It finishes the calibration process in $2{\mu}s$ over the whole frequency band. The LO generation block has selectable multiple division ratios of ${\div}2$, ${\div}16$, and ${\div}32$ to generate LO I/Q signals for T-DMB/DAB/FM Radio systems in L-Band (1173~1973 MHz), VHF-III (147~246 MHz), VFH-II (74~123 MHz), respectively. The measured integrated phase noise is quite low as it is lower than 0.8 degree RMS over the whole frequency band. Total locking time of the ${\Delta}{\Sigma}$ frequency synthesizer including VCO frequency calibration time is less than $50{\mu}s$. The wideband ${\Delta}{\Sigma}$ fractional-N frequency synthesizer is fabricated in $0.13{\mu}m$ CMOS technology, and it consumes 15.8 mA from 1.2 V DC supply.