I'm really thankful for this video because I finally can do my essay about digital filter in real world with real life numbers n such (my lecturer asked for it, can you imagine?). I cant really do it by myself because my lecturer only teaches thru an 11-page essay explaining his ppt....... 😥😥😥😥😥 now I know city Blackbirds has freq range between 1.5 kHz and 3.5 kHz HAHAHA! Thank you though!!!
hi Luke.. l was wondering if you applied the binary transform directly to the T(s) you obtained at 11:58 or did you have to backtrack in order to apply pre warping OMEGA as you explain on video No. 14 of this series.. thank you for these awesome tutorials!
Hey Ric, First up thanks, I’m glad that it’s helping you. I have a video about using the filter we make in this video in my python signal processing tutorial :) You can find the implementation and demonstration of the filter here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wJgBB4EsUHw.html
@@TutorialsWithGary thank you for your reply! yes, l've watched the python implementation videos, although the coefficients have already been calculated by then.. but l think I've already sorted my question from the low pass video.. assuming prewarping works the same for low pass and band pass
Ric Vega ah yes sorry mate, and we calculated the digital filter coefficients from this video in my next video ‘digital filter from frequency response’
Hey Taylor, for this video we used MATLAB due to the complex transfer function but this is very achievable if you aren't scared by a bit of algebra :) In MATLAB we used the bilinear function, we go through an example of how to manually apply a bilinear transform here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-rOjHIbevWXM.html And go through how this is actually working in another video here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-1HBpbagZtrc.html Hope this helps :)
9:32 What happened to the +1 in the denominator? Wouldn't it become S^2 since you multiplied each term on the top and bottom by s^2? Edit: I see now that it was added into the 24 to make 25, my bad.
Did you input: fs = 1000 [numd,dend] = bilinear([0,0,1.579e8,0,0],[1,17740,3.95e9,3.369e13,3.59e18],fs) into Matlab on 13:17? I got a different output than you. What did you set the sampling frequency as? EDIT: Oops, I wrote 395e9 instead of 3.95e9!, but it's still wrong
Hey Twabourne, In this video here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wJgBB4EsUHw.html we implement this filter, and test it with multiple input frequencies to demonstrate how the filter attenuates various frequencies. Hope this helps
Hey, Luke I just wanted to do the bilinear transform from s-space to z-space as you did at 13:17 in this video. I just wonder how you found H(z) from T(s) in Matlab as you mentioned in your video?
Oh sorry about that :) misread your comment! Yes that's almost what I used :) It was a while ago now, but your numerator and denominator look good, I just used a 48KHz sampling frequency
Sorry mate, I can't have a look at it as unfortunately my MATLAB licence has expired. (Not a student anymore unfortunately) but I'll try to find a way to check for you tomorrow
Hey, Luke, I managed to replicate your answer by writing the following code in MATLAB: fs = 48000; Ts = 1/48000.0 h = tf([0,0,1.579e8,0,0],[1.0,17740,3.95e9,3.369e13,3.59e18],'variable','s'); hd = c2d(h,Ts,'tustin') and then multiply numerator and denominator with z^(-4)
+David Helmuth there sure is, Octave: www.gnu.org/software/octave/ Open source, a lot of the same functionality and free! If that's not your style, Python has some really useful tools such as MatPlotLib which is quite simple to use.
Thank you Luke. RU-vid never sent me a notification in regards to your response. I was just revisiting your video and there it was. Anyway, thank you for the recommendation ☺️
Hey Santiago, A band reject - or band stop - filter can be calculated exactly as we have done above here, but instead, using the band stop translation. This site here lists all the major translations and explains how they work (including the band stop) www.rfcafe.com/references/electrical/filters.htm
