Subband DFT - Part I: Definition, interpretation and extensions

O. V. Shentov, S. K. Mitra*, U. Heute, A. N. Hossen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


A new DFT computation method based on a subband decomposition is outlined for one- and two-dimensional (2-D) real-valued finite-length sequences. The two distinct parts of the algorithm, a preprocessing Hadamard-transform stage and a 'correction' stage are interpreted as a filter bank plus a recombination network, and are compared to the corresponding filter bank interpretation of the direct DFT and the classical FFT algorithms. The preprocessing stage decomposes the original sequence into a set of smaller length subsequences approximately separated in the spectral domain. The overall DFT is then given by a weighted sum of smaller length DFTs with the weights determined by the recombination network. The frequency-separation property of the subsequences permits elimination of the subsequences with negligible energy contribution from the DFT calculation thus resulting in a fast approximate DFT computation method. Various implementation schemes for the subband DFT computation method are outlined. As a first extension, adaptive versions are described, finding the band(s) of interest automatically. Furthermore, a generalized preprocessing stage as well as the extension to the 2-D case are addressed.

Original languageEnglish
Pages (from-to)261-277
Number of pages17
JournalSignal Processing
Issue number3
Publication statusPublished - Feb 1995
Externally publishedYes


  • Adaptive FFT
  • Approximate DFT computation
  • Discrete Fourier transform
  • Spectral analysis
  • Subband FFT

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Software
  • Signal Processing
  • Computer Vision and Pattern Recognition
  • Electrical and Electronic Engineering


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