Author:
Xi Zhang
Affiliation:
The University of Electro-Communications, Japan
Keyword(s):
IIR allpass filter, Flatness, Equiripple approximation, Remez exchange algorithm.
Related
Ontology
Subjects/Areas/Topics:
Design and Implementation of Signal Processing Systems
;
Multidimensional Signal Processing
;
Multimedia
;
Multimedia Signal Processing
;
Multimedia Systems and Applications
;
Telecommunications
Abstract:
This paper proposes a new method for designing allpass filters having the specified degrees of flatness at the specified frequency point(s) and equiripple phase responses in the approximation band(s). First, a system of linear equations are derived from the flatness conditions. Then, the Remez exchange algorithm is used to approximate the equiripple phase responses in the approximation band(s). By incorporating the linear equations from the flatness conditions into the equiripple approximation, the design problem is formulated as a generalized eigenvalue problem. Therefore, we can solve the eigenvalue problem to obtain the filter coefficients, which have the equiripple phase response and satisfy the specified degrees of flatness simultaneously. Furthermore, a class of IIR filters composed of allpass filters are introduced as one of its applications, and it is shown that IIR filters with flat passband (or stopband) and equiripple stopband (or passband) can be designed by using the pro
posed method. Finally, some examples are presented to demonstrate the effectiveness of the proposed design method.
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