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Báo cáo: Analysis and Properties of Time-Varying Modified DFT Filter Banks

Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2010, Article ID 342865, 15 pages doi:10.1155/2010/342865 Research Article Analysis and Properties of Time-Varying Modified DFT Filter Banks Guangyu Wang, Zufan Zhang, and Qianbin Chen Chongqing Key Lab of Mobile Communications, Chongqing University of Posts and Telecommunications (CQUPT), Chongqing 400065, China Correspondence should be addressed to Guangyu Wang, wangguangy@cqupt.edu.cn Received 24 September 2010; Revised 29 November 2010; Accepted 7 December 2010 Academic Editor: Magnus Jansson Copyright © 2010 Guangyu Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction. | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2010 Article ID 342865 15 pages doi 10.1155 2010 342865 Research Article Analysis and Properties of Time-Varying Modified DFT Filter Banks Guangyu Wang Zufan Zhang and Qianbin Chen Chongqing Key Lab of Mobile Communications Chongqing University of Posts and Telecommunications CQUPT Chongqing 400065 China Correspondence should be addressed to Guangyu Wang wangguangy@cqupt.edu.cn Received 24 September 2010 Revised 29 November 2010 Accepted 7 December 2010 Academic Editor Magnus Jansson Copyright 2010 Guangyu Wang et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. We provide a comprehensive analysis of the time-varying modified DFT MDFT filter bank based on the general time-varying filter bank theories Wang 2005 2006 2008 2009 in both the time domain and frequency domain. We give firstly the description of the time-invariant MDFT filter bank including its perfect reconstruction PR condition its mechanism of aliasing error cancellation and the relationship with the cosine-modulated filter bank in detail. Then the time-varying MDFT filter bank is analyzed according to the time-domain description. Finally the window switching method is introduced to design the prototype filter in the time-varying MDFT filter bank with examples. The error analysis shows that the introduced design approach is useful in practice. 1. Introduction Modified DFT filter banks MDFT and their applications are intensively studied in 1-5 . But all analyses are done in the frequency domain for the time-invariant modified DFT filter banks. In the literature we do not find any works for the time-varying MDFT filter bank. Subband coding is a widely used method in the digital signal processing and the telecommunication areas such as subband speech and .