• Title, Summary, Keyword: wideband

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Designing of efficient super-wide bandwidth extension system using enhanced parameter estimation in time domain (시간 영역에서 개선된 파라미터 추론을 통한 효율적인 초광대역 확장 시스템 설계)

  • Jeon, Jong-jeon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.431-433
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    • 2018
  • This paper proposes the system that offer super-wideband speech which is made by artificial bandwidth extension technique using wideband speech signal in time-domain. wideband excitation signal and line spectrum pair(LSP) are extracted based on source-filter model in time-domain. Two parameters are extended by each bandwidth extension algorithms, and then, super-wideband speech parameters are estimated. and synthesized. Subjective test shows super-wideband speech is better speech quality than wideband speech signal.

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A Study on the Architecture of Narrowband/Wideband Switching Networks (협대역/중대역 스위치망의 구성 방안)

  • Sung, Dan-Keun;Kim, Seung-Hwan
    • Proceedings of the KIEE Conference
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    • pp.497-501
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    • 1988
  • In this study we consider three types of accomodation methods of narrowband/wideband services. The fully integrated accomodation method is sufficient to accomodate the relatively low wideband traffic and the partially integrated method is required to meet the specification of blocking probability as the wideband traffic increases. The segregated accomodation method is required expecilly in case of the high wideband traffic demand.

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Compact and Wideband Fylfot-Shaped Planar Monopole Antenna

  • Shim, Jae-Ruen
    • Journal of information and communication convergence engineering
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    • v.7 no.4
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    • pp.449-452
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    • 2009
  • In this paper, a novel compact and wideband fylfot-shaped planar monopole antenna is proposed. The fylfot-shaped is suggested to reduce the volume of a general crossed planar monopole antenna. The volume of the proposed antenna is about 1/4 of a general crossed planar monopole antenna under the conditions where the wideband characteristics are maintained. This technique is suitable for the design of wideband planar monopole antenna which needed a small volume.

A Dynamic QoS Model for improving the throughput of Wideband Spectrum Sharing in Cognitive Radio Networks

  • Manivannan, K.;Ravichandran, C.G.;Durai, B. Sakthi Karthi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.11
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    • pp.3731-3750
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    • 2014
  • This paper considers a wideband cognitive radio network (WCRN) which can simultaneously sense multiple narrowband channels and thus aggregate the detected available channels for transmission and studies the ergodic throughput of the WCRN that operated under: the wideband sensing-based spectrum sharing (WSSS) scheme and the wideband opportunistic spectrum access (WOSA) scheme. In our analysis, besides the average interference power constraint at PU, the average transmit power constraint of SU is also considered for the two schemes and a novel cognitive radio sensing frame that allows data transmission and spectrum sensing at the same time is utilized, and then the maximization throughput problem is solved by developing a gradient projection method. Finally, numerical simulations are presented to verify the performance of the two proposed schemes.

Efficient Codebook Search Method for AMR Wideband Speech Codec (광대역 AMR 음성 압축기를 위한 효율적인 코드북 검색 방법)

  • 김윤희;박호종
    • The Journal of the Acoustical Society of Korea
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    • v.22 no.4
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    • pp.308-314
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    • 2003
  • Wideband speech communications with 7㎑ bandwidth can provide high-quality speech services that are almost impossible with current narrow-band speech communications with 3.4 ㎑ bandwidth, and AMR wideband codec was recently developed for these services. The performance of AMR wideband codec is excellent due to its wideband information and partially to ACELP structure, but it requires high computational complexity especially in codebook search. In this paper, to solve this problem, an efficient codebook search method for AMR wideband codec is proposed. The proposed method first determines the coarse initial codevector, then improves the performance of codevector by replacing a poor pulse in codevector with better one iteratively. Simulations show that AMR wideband codec with proposed codebook search method has higher performance with much less computational cost than conventional AMR wideband codec.

Interference Evaluation between competiting Wideband CDMA systems

  • Kwon, Dong-Seung;Han, Jin-Kyu;Park, Han-Kyu
    • Proceedings of the IEEK Conference
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    • pp.121-124
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    • 2000
  • In this paper, we evaluate the interference statistics between the competiting wideband CDMA systems, and optimize the frequency coordination between Wideband-CDMA systems by the Monte-Carlo methodology. We develop the simulator to analyze the radio interference between CDMA systems. It can calculate or estimate the probability of interference from adjacent frequency band, which is also power controlled. We simulate the interference effects between two Wideband CDMA systems. We present the required carrier distance and zone for two operators to meet the required coverage efficiency and outage probability of Signal to interference plus noise ration (SINR).

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design of wideband MMIC LNA using ETRI MMIC Library (ETRI MMIC 라이브러리를 이용한 Wideband MMIC LNA의 설계)

  • An, D.;Chae, Y.S.;Rhee, J.K.
    • Proceedings of the IEEK Conference
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    • pp.641-644
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    • 1998
  • In this paper, wideband MMIC LNA's were designed using low Q matching network. gains of 23.6~25.4dB $(24.5\pm0.9dB),$ noise figures of 0.9~2.8 dB were obtained from the designed wideband MMIC LNA in the frequency ranges of 1.2~2.8㎓. And, P1dB of 10.13 dBm, IP3 of 12.25 dB were obtained at the center frequency of 2 ㎓. A chip size of the designed wideband MMIC LNA is 1.4mm$\times$1.4mm.

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Polymer-Based Devices for Optical Communications

  • Lee, Myung-Hyun;Ju, Jung-Jin;Park, Sun-Tak;Do, Jung-Yun;Park, Seung-Koo
    • ETRI Journal
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    • v.24 no.4
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    • pp.259-269
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    • 2002
  • Polymers are emerging as new alternative materials for optical communication devices. We developed two types of polymer-based devices for optical communications. One type is for ultra high-speed signal processing that uses nonlinear optical (NLO) polymers in such devices as electro-optic (EO) Mach-Z${\ddot{e}} $ hnder (MZ) modulators and EO 2${\times}$2 switches. The other is for WDM optical communications that use low-loss optical polymers in such devices as 1${\times}$2, 2${\times}$2, 4-arrayed 2${\times}$2 digital optical switches (DOSs) and 16${\times}$16 arrayed waveguide grating (AWG) routers. For these devices, we synthesized a polyetherimide-disperse red 1 (PEI-DR1) side chain NLO polymer and a low-loss optical polymer known as fluorinated polyaryleneethers (FPAE). This paper presents the details of our development of these polymeric photonic devices considering all aspects from materials to packaging.

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Quickest Spectrum Sensing Approaches for Wideband Cognitive Radio Based On STFT and CS

  • Zhao, Qi;Qiu, Wei;Zhang, Boxue;Wang, Bingqian
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.3
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    • pp.1199-1212
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    • 2019
  • This paper proposes two wideband spectrum sensing approaches: (i) method A, the cumulative sum (CUSUM) algorithm with short-time Fourier transform, taking advantage of the time-frequency analysis for wideband spectrum. (ii)method B, the quickest spectrum sensing with short-time Fourier transform and compressed sensing, shortening the time of perception and improving the speed of spectrum access or exit. Moreover, method B can take advantage of the sparsity of wideband signals, sampling in the sub-Nyquist rate, and it is more suitable for wideband spectrum sensing. Simulation results show that method A significantly outperforms the single serial CUSUM detection for small SNRs, while method B is substantially better than the block detection based spectrum sensing in small probability of the false alarm.

Wideband propagation characteristics analysis of a microstrip transmission line on FR-4 composite substrate (FR-4 composite 기판을 이용한 microstrip 전송선의 광대역 전송 특성 해석)

  • 홍정기;김영국;이해영
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.2
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    • pp.69-77
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    • 1996
  • We analyzed wideband propagation characteristics of a microstrip transmission line based on FR-4 composite substrate using the wideband complex dielectric constant model and the phenomenological loss equivalence method. The loss calculated by constant relative permittivity and loss tangent is greatly overestimatd compared to that calculated by the frequency-dependent complex relative permittivity. This wideband analysis can be helpful to characterize high-speed and high-density transmission lines associated with the wideband dielectric characteristics and shows that the FR-4 composite substrate has high potential of high frequency circuit applications in terms o fthe propagation loss.

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