# Python scipy.signal IIR Filter Design Cont.

In the previous post the Python scipy.signal *iirdesign* function was disected. We reviewed the basics of filter specification and reviewed how to use the *iirdesign* function to design IIR filters. The previous post I only demonstrated low pass filter designs. The following are examples how to use the *iirdesign* function for highpass, bandpass, and stopband filters designs.

## Highpass Filter

The following is a highpass filter design for the different filter types. Refer to the previous post for information on the i*irdesign* function arguements and usage.

Again, similiar to the approach in the previous post tighter specifications can be given for the ellip and cheyb2 filter design.

## Bandpass Filter

As mentioned, a bandpass filter coefficients can be created with the *iirdesign* function as well. Since the *iirdesign *function is similiar for the different filter types we will only use the ellip and cheby2 for the rest of the examples.

## Stopband Filter

And lastely here is an example to create a stopband filter.

*iirdesign*function, similiar to other signal processing packages, is a flexible tool to design and generate filter coefficients for an IIR filter.

**Previous post by Christopher Felton:**

Python scipy.signal IIR Filter Design

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Python scipy.signal IIR Filtering: An Example

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w,H = signal.freqz(b,a) and plot(w, angle(H)) doesn't make sense there. How do you compute it?

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