ABSTRACT
Bessel, etc.) lead to a normalized transfer function denoted low-pass prototype (LPP). The LPP is characterized by a passband frequency ΩP = 1.0 rad/s, a maximum passband ripple AP (or Amax), a minimum stopband attenuation As (or Amin), and a stopband frequency Ωs. Ap and As are usually specified in dB. Tolerance bounds (also called box constraints) for the magnitude response of an LPP are illustrated in
passband and stopband edge frequencies are defined as the maximum frequency with the maximum passband attenuation Ap and the minimum frequency with the minimum stopband attenuation As, respectively. The passband ripple and the minimum passband attenuation are expressed by
(3.1)
where K is the maximum value of the magnitude response in the passband (usually unity). Figure 3.1(b) shows the magnitude response of a Chebyshev LPP transfer function with specifications Ap = 2 dB, As = 45 dB, and Ωs = 1.6.
