Tuesday, 26 April 2016

Analog and Digital Butterworth Design

This was the first experiment implemented on scilab. The objective of this experiment was to design a digital Butterworthfilter from analog filter.

The Butterworth filter was designed using Transfer Domain Method - Bilinear Transformation (BLT).

The user had to just enter input values like Attenuation in Stop band (As) and Pass band (Ap) as well as Pass band frequency, Stop band frequency and sampling frequency.  
The order of the filter was calculated along with the cut-off frequency. Then the normalised H(s) and denormalised H(s) was calculated. From this the transfer function H[z] was calculated for both low pass and high pass filter design.

We observed the magnitude and frequency graphs and learnt that the graph in monotonic and without any ripple for both low pass and high pass designs.

https://drive.google.com/open?id=0B2dvoOHjY9tfLUF2UVNtSDIyMHM

6 comments:

  1. Poles lie inside the unit circle which shows that filter is stable.

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  2. Poles lie inside the unit circle which shows that filter is stable.

    ReplyDelete
  3. As poles are within unit circle, the filter is stable

    ReplyDelete
  4. poles lies on circle in butterworth filter

    ReplyDelete