IIR Filter Design Procedure

[@savinolupo2379]

I was born in the analog era and taught in terms of how to get a digital filter starting from the analog counterpart. This professor is teaching the other way around, meaning I got old :-)

[@lex_parsimoniae]

I watched a lot of your videos, thanks a lot. I love that you call the coefficients for the exponential that produces the decay d_k (dee-kay) :)

[@arlenalem]

Thanks for your videos, they are really helpful :D, could you recommend books that are focused on design? With examples? a so on? Please

[@allsignalprocessing]

:-) I suspect you are not trying to design an IIR filter, but rather to implement it in your 551 class. In that case you might find my video "Difference Equation Descriptions for Systems" (it is Lecture 10 in the Introduction and Background playlist) helpful.

[@dennispark9883]

Dear Barry Van Veen,Thank you for your informative video~ Can I ask you to open from 2nd to 4th video in this play list?It says "Private Video"... Would you allow me to watch those videos?

[@LilyHuss192]

sir, I'm doing a homework and I can't find the answer, can u help me? design filter using iir bandstop filter with cutoff frequency, fc1=10Hz and fc2=30Hz and lowpass filter with cutoff frequency, fc3=20Hz. what the type of formula or calculation i should used?

[@karimelmokhtari9559]

Thank you for this well explained video

[@anamemana]

Can you come and guest lecture for ECE 551 before we all fail on our projects?

[@TjipzPK]

b = h[n], and what is a equal to?

[@aleksagordic9593]

The capital omega symbol is usually used for discrete systems and the small one is used for continuous time systems. Just saying. :D Nice videos, thanks!

[@allsignalprocessing]

+Aleksa Gordic Thanks. Actually notation depends on where you look. For example, "Signals and Systems" by Oppenheim and Willsky follows the convention you mention. However, "Discrete-Time Signal Processing" by Oppenheim and Schafer uses the same notation as I do in the videos. In the end it is just notation and understanding the meaning is far more important.

[@aleksagordic9593]

+Barry Van Veen Wow, thanks for the quick response. :) Yeah I agree, but it's at times confusing because I'm used to this convention. One question, why can't I see 3 videos in this playlist (Infinite Impulse Response Filter Design)?

[@vasiq44]

If the goal is to design a discrete time filter, then why are we converting critical frequencies for the discrete time filter to critical frequencies for a continuous time filter (step 2 of the procedure)@9:19. I suspect it should be the other way round

[@georgeakaniro4112]

You are absolutely right. I heard the same too. It's a mistake he made I think, at least we know what he was trying to say.

[@afish3356]

@@georgeakaniro4112When we convert an analog filter to a discrete time filter (using a technique such as the Bilinear Transform), the cutoff frequency slightly changes between the analog and the discrete filter (so called "frequency warping"). Since the objective is to use an analog filter design process to first design an analog filter whose cutoff frequency will warp/change into the desired discrete filter cutoff frequency, then we need to work backwards from the desired discrete cutoff frequency to find the corresponding analog frequency which will 'warp' to the right extent to produce the discrete filter cutoff frequency that we want. This is called prewarping. Abstractly speaking, prewarping is a little bit like deducing how much sugar I should put in a cake if I want it to be just the right sweetness.

[@quitepernicious6041]

It's boring to hear CHE'-BEE-SHEV all the time and it's boring to tailor presentations of general interest to MATLAB.