Another common signal processing technique is filtering. This is a big topic, and we could create all sorts of filters. We will only create a very basic filter here. Again, we will use the sunspot data as input.
The iirdesign function, as its name suggests, allows us to construct several types of analog and digital filters.
Design the filter with the iirdesign function of the scipy.signal module.
Note
IIR stands for Infinite Impulse Response; for more information, visit http://en.wikipedia.org/wiki/Infinite_impulse_response.
We are not going to go into all the details of the iirdesign function. Have a look at the documentation if necessary at http://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.iirdesign.html. In short, the following are the parameters we will set:
Frequencies normalized from 0 to 1.
Maximum loss.
Minimum attenuation.
Filter type.
Designing the filter can be done with the following code:
b,a = scipy.signal.iirdesign(wp=0.2, ws=0.1...
