In this experiment a scilab code was developed to design a digital butterworth filter by accepting the following specifications
- Pass band attenuation(Ap<3dB)
- Pass band frequency(Fp in Hz)
- Stop band attenuation(As>40dB)
- Stop band frequency(Fs in Hz)
- Sampling frequency(Fs in Hz)
The analog filter was first designed using the input specifications. After designing the analog filter, digital was designed using BLT method. The values of Ap and As were verified from the obtained magnitude response. It was also observed that the magnitude response had a smooth monotonous curve.
The poles zero plot of analog and digital filter was also plotted. It was observed that for LPF the analog filter poles were on the LHS of the imaginary axis whereas the digital filter poles were on the RHS of the imaginary axis
PS: It took almost 3 weeks to learn Scilab and its functions. We tried to do all the computations by writing equations only to realize later that there are functions already available to directly calculate the transfer function of the filter by providing necessary inputs.
PS: It took almost 3 weeks to learn Scilab and its functions. We tried to do all the computations by writing equations only to realize later that there are functions already available to directly calculate the transfer function of the filter by providing necessary inputs.
Yeah , the inbuilt functions like "butt" and "cheby" were really easy but we didnt find them till out program was almost done
ReplyDeletei know the feel.. but i hope this post turns out to be helpful having same issues
Deleteyes!!! scilab was supposed to be used because it has all these inbuilt functions. though calculating all parameters didnt go waste as we could verify the answers of design problems solved in class or given for assignment
ReplyDeletewow!! you surely made the full use of the software... Thanks for the comment.. I'll do the same next time onwards.. :p
DeleteIn-built are not always useful, like in case if you wanted to calculate the intermediate values, but have used the buttmag function. It becomes redundant to use the function any way.
ReplyDeleteThanks KTK for teaching me Scilab. You could also mention the HPF that you designed.
ReplyDeleteYou did help us with the algo.. so i guess we're even now :p
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