Abstract:
The Bilinear z-transform (BZT) can be very efficiently used in the study and design of classical analog filters, such as Butterworth, Chebyshev and elliptical. Generally, the Infinite Impulse Response (IIR) filter design for lowpass and bandpass filters is carried out using approximation of derivatives or the impulse invariant method. These techniques are not suitable for highpass or band-reject filters. This limitation is overcome in the mapping technique called bilinear z-transformation. This transformation is a one-to-one mapping from the s-domain to the z-domain. The BZT is a conformal mapping technique that transforms the j-axis into the unit circle in the z-plane only once, thus avoiding aliasing of frequency components. In this paper the authors will present designing methods of IIR filters containing Butterworth structures. First the lowpass prototype filter is considered in detail, followed by highpass, bandpass and bandstop filters. Design procedures for each of these methods are presented in length. In order to render comprehensibility to this research paper, some useful basics of these filters are also clearly outlined.
Page(s):
29-40
DOI:
DOI not available
Published:
Journal: New Horizons: Journal of the Institution of Electrical & Electronics Engineers Pakistan, Volume: 50, Issue: 0, Year: 2005