Minimum and Maximum Phase IIR Design (Digital Filter Design Toolkit)

You can use the Minimum Phase or Maximum Phase option of the filter type input if you want a minimum or maximum phase response or if the phase response is not important. When you use the Minimum Phase or Maximum Phase option, the DFD Least Pth Norm Design VI ignores the phase and group delay inputs.

For example, suppose you want to design a minimum phase IIR lowpass filter with a passband frequency range of [0, 0.2] and a stopband frequency range of [0.3, 0.5]. You can set the specifications as shown in the following figure:

The following figure shows the magnitude response of the designed filter.

The following figure shows the phase response of the designed filter.

Notice that the designed filter has greater stopband attenuation than the approximately linear phase IIR filter designed, but the passband phase response is now highly nonlinear.