Degree of rational approximation in digital filter realization

  • Charles K. Chui
  • Xie-Chang Shen
Circuit Theory
Part of the Lecture Notes in Mathematics book series (LNM, volume 1105)


In recursive digital filter design, the amplitude characteristic of an ideal filter has to be translated into a rational function that is pole-free on the closed unit disk and preferably has real coefficients. This is possible through a causal transformation utilizing the tolerance allowance. In this paper we study the degree of uniform approximation by rational functions that fulfill the filter criteria and can be computed by interpolation or the method of least-squares inverses.


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Copyright information

© Springer-Verlag 1984

Authors and Affiliations

  • Charles K. Chui
    • 1
  • Xie-Chang Shen
    • 2
  1. 1.Department of MathematicsTexas A&M UniversityCollege StationUSA
  2. 2.Department of MathematicsPeking UniversityBeijingChina

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