Polar coordinate based nonlinear function for frequency-domain blind source separation

Hiroshi Sawada*, Ryo Mukai, Shoko Araki, Shoji Makino

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

79 Citations (Scopus)


This paper discusses a nonlinear function for independent component analysis to process complex-valued signals in frequency-domain blind source separation. Conventionally, nonlinear functions based on the Cartesian coordinates are widely used. However, such functions have a convergence problem. In this paper, we propose a more appropriate nonlinear function that is based on the polar coordinates of a complex number. In addition, we show that the difference between the two types of functions arises from the assumed densities of independent components. Our discussion is supported by several experimental results for separating speech signals, which show that the polar type nonlinear functions behave better than the Cartesian type.

Original languageEnglish
Pages (from-to)590-596
Number of pages7
JournalIEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Issue number3
Publication statusPublished - 2003 Mar
Externally publishedYes


  • Cartesian coordinate
  • Complex-valued signal
  • Frequency domain
  • Independent component analysis
  • Polar coordinate

ASJC Scopus subject areas

  • Signal Processing
  • Computer Graphics and Computer-Aided Design
  • Electrical and Electronic Engineering
  • Applied Mathematics


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