オーバラップFFTに関する一考察 (信号処理)  [in Japanese] Performance Evaluation of a Generalized Overlapped-FFT Scheme  [in Japanese]

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Author(s)

    • 山崎 悟史 YAMAZAKI Satoshi
    • 沼津工業高等専門学校制御情報工学科 Dept. of Control and Computer Engineering, Numazu National College of Technology

Abstract

近年,コグニティブ無線システムにおいて,信号検出確率の改善を目的として,ノイズ分散の低減に効果を有するオーバーラップ(Overlapped)FFT法が活用されている.また従来から,音声分野においてフレーム内両端の減衰低減を目的とした,ハーフ・オーバラップ(Half-Overlapped)FFT法が利用されている.これらにおいて,特にオーバラップ率の設定がシステム性能に影響を与える.しかし,これまでOverlapped FFT法を一般化し,定量的評価がなされているものは見当たらない.そこで本論文では,従来のHalf-Overlapped FFT法に対して,窓関数形状とオーバラップ率を可変とした一般化オーバラップFFT法を提案,評価している.具体的には,原信号と出力信号に対する相互相関および新たに窓掛け回数の概念を導入し,窓関数形状やオーバラップ率による類似度の影響,また,演算量や分解能などについて定量的に考察している.

Recently, in various cognitive wireless systems, to improve signal detection probability, the overlapped FFT scheme has been utilized. Also, in acoustics the half-overlapped FFT scheme has been utilized to reduce the attenuation of both ends of a frame. In these schemes, in particular, the value of the overlap ratio influences the performance of the system. However, the generalized Overlapped-FFT Scheme has not been evaluated quantitatively. In this report, l propose and evaluate the generalized overlapped-FFT Scheme, which has a variable window function form and overlap ratio. Specifically, l introduce the cross correlation of the original signal and the output signal and a new concept, the number of window multiplications. Also, l evaluate and consider the influence of the similarity due to the window function shape and overlap ratio, and the computational costs and resolution.

Journal

  • IEICE technical report. Signal processing

    IEICE technical report. Signal processing 112(485), 241-246, 2013-03-14

    The Institute of Electronics, Information and Communication Engineers

Codes

  • NII Article ID (NAID)
    110009703115
  • NII NACSIS-CAT ID (NCID)
    AA11943613
  • Text Lang
    JPN
  • ISSN
    0913-5685
  • NDL Article ID
    024419198
  • NDL Call No.
    Z16-940
  • Data Source
    NDL  NII-ELS 
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