/IIR-filter-py

Primary LanguagePython

Realtime IIR filter implementation and benchmark in Python

This is a project where you can create, test, evaluate IIR filters in Python 3.9. Besides, an IIR filter class is provided to perform realtime processing of a signal in your own computer withour own processor. It was designed to achieve efficiency but using only simple operations.

Real time Filtering implementation

In this repository, it is possible to create 5 different IIR filters: Butterworth, Bessel, Chebyshev type I, Chebyshev type II, Eliptic. The benchmark is prepared so that you can configure the filter order, the attenuation and rejection band for the filter design and other parameters. For the real time implementation of the system, an IIR class was designed and implemented.

Import

Use the command to import it:

  import iir

Calculate the coefficients

You can extract yout filter coefficients from the IIR filter design benchmark and design file:

sos = signal.butter(order, [cutoff(s)], '[filter type]', output='sos')

Instantiate the filter

You can create an instance of the IIR filter by calling it:

f = iir.IIR_filter(sos)

Filtering Flow

In the realtime script, a combination of sine waves can be created from the function provided. In the case of the example provided, a combination of a 1 and 50 Hz sine waves are provided.

For filtering sample by sample:

  y = np.zeros(SAMPLES)
    for i in range(SAMPLES):
       y[i] = myFilter.filter(mysignal[i])

And you obtain something like this:

Figure_2