Understanding the Z-Transform

Ғылым және технология

This intuitive introduction shows the mathematics behind the Z-transform and compares it to its similar cousin, the discrete-time Fourier transform. Mathematically, the Z-transform is straightforward-it’s just a bunch of multiplications and additions, and you’ll learn how to solve an equation for a few different signals. However, understanding how to solve a Z-transform equation isn’t as important as understanding why the math is the way it is. Therefore, the majority of this tech talk discusses what you are actually doing when you take the Z-transform of a signal.
Want to see all of the references in a nice, organized list? Check out this journey on Resourcium: bit.ly/3DeS8DX
Check out these links to learn more about Z-transform:
- DTFT visualization MATLAB App: bit.ly/DTFT_MATLAB_App
- MATLAB Documentation: Discrete Fourier Transform: bit.ly/3NfFtGV
- MATLAB Function, ztrans: bit.ly/40MSnjy
- Creating Discrete-Time Models: bit.ly/438xsZZ
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Пікірлер: 115

  • @BrianBDouglas
    @BrianBDouglas9 ай бұрын

    If you want to play around with the DTFT MATLAB App from this video, you can find it here: github.com/aerojunkie/control-tools/tree/master/DTFT%20MATLAB%20App

  • @fahimrahman5196

    @fahimrahman5196

    7 ай бұрын

    Thanks Brian

  • @ShahadetHosenPolash

    @ShahadetHosenPolash

    Ай бұрын

    How you design those matlab app? How can i learn this? any tutorial video?

  • @nurahmedomar
    @nurahmedomar Жыл бұрын

    In university, we were taught how to do the DFT and Z-transform, but never taught why. And this video explains them in crystal clear. Great Job!

  • @HansScharler

    @HansScharler

    9 ай бұрын

    Thanks for the feedback!

  • @harrytsai0420
    @harrytsai0420 Жыл бұрын

    OMG! I've been waiting for the series of discrete-time control for nearly 5 years!

  • @BrianBDouglas

    @BrianBDouglas

    Жыл бұрын

    Hopefully, it's worth the wait!

  • @xptransformation3564

    @xptransformation3564

    10 ай бұрын

    ​@@BrianBDouglashow did you get such a perfect understanding for all this?

  • @erickappel4120
    @erickappel4120 Жыл бұрын

    I was blown away by the clearness of the explanation! Looking forward to more!

  • @diegoperezromero6610
    @diegoperezromero6610 Жыл бұрын

    This is by far the best video about the dtft and z transform i've ever seen. Very good and very detailed explanation.

  • @erickappel4120
    @erickappel41209 ай бұрын

    Excelllent explanation! It is the first time someone made the DFT's relation to finite length input clear to me! Thankyou!!!

  • @MarkNewmanEducation
    @MarkNewmanEducation Жыл бұрын

    Amazing explanation. Thanks so much for explaining things in a more intuitive way.

  • @Michael-ze6oz
    @Michael-ze6oz6 ай бұрын

    Your explanations and teachings are awesome. This opens my eyes to so many things, and in just 1 video!. Brain, you have been blessed with an amazing gift. Thank you for sharing this with us.

  • @DRAMBgo
    @DRAMBgo Жыл бұрын

    Crazy explanation Brian, thank you!

  • @wellid2087
    @wellid20877 ай бұрын

    One of the best introductions I have ever watched

  • @jmanius1
    @jmanius1 Жыл бұрын

    Brian is basically my mentor at this point

  • @BrianBDouglas

    @BrianBDouglas

    Жыл бұрын

    🤓 aww thanks!

  • @jmanius1

    @jmanius1

    Жыл бұрын

    @@BrianBDouglas You responding has literally made my day. Thank you for your awesome videos!

  • @martinsanchez-hw4fi

    @martinsanchez-hw4fi

    Жыл бұрын

    Is there a list of the Matlab videos made by Brian?

  • @MATLAB

    @MATLAB

    4 ай бұрын

    Hi @martinsanchez-hw4fi, You can find all of our Tech Talks on this page: bit.ly/MATLAB-Tech-Talks

  • @Adhithya2003
    @Adhithya20038 ай бұрын

    The most intutive and lucid explanation of DTFT and Z transform I have ever seen 💖

  • @BrianBDouglas

    @BrianBDouglas

    8 ай бұрын

    I'm glad you liked it!

  • @teebee3881
    @teebee3881 Жыл бұрын

    This helps so much, please make more of these

  • @terrycrews2281
    @terrycrews2281 Жыл бұрын

    been watching ur vids since 2014 ty so much for this ,brian

  • @user-pn6qx1vu3q
    @user-pn6qx1vu3q Жыл бұрын

    please make more of this ! it really really help !!!!

  • @grxoxl
    @grxoxl4 ай бұрын

    Honestly, the best explanation of the DFT I've ever seen)

  • @MrRaghunar
    @MrRaghunar8 ай бұрын

    Excellent explanation, great job!

  • @222_Official
    @222_Official3 ай бұрын

    Amazing and very intuitive video, thanks!

  • @PrestonRogersJPL
    @PrestonRogersJPL5 ай бұрын

    This was the best explanation on DTFT I have ever seen! Bravo!

  • @BrianBDouglas

    @BrianBDouglas

    5 ай бұрын

    I appreciate that!

  • @clarklau1292
    @clarklau12922 ай бұрын

    I learned about DFT and z-transform many years ago, but it wasn't until I watched this video that I truly understood what the 'e' and 'z' in these two transformations actually do.

  • @giantbee9763
    @giantbee97632 ай бұрын

    Brian is amazing! This video is extremely clear :) One note on time delay [n-1] implying z^-1, it wasn't clear to me at first how the first example with a pulse function translated to all general cases, but it later occured to me that y^0, which in a delayed sequence matched z^-1, and every term afterward matches the original function, so hence it is the case for the general case. Such that time delay [n-2] does not imply z^-2, and so on. If I have understood correctly.

  • @hamedmajidian4451
    @hamedmajidian4451 Жыл бұрын

    You are the best looking forward to watching more and more!

  • @BingtheLizard
    @BingtheLizard5 ай бұрын

    I've been able to solve a Fourier Transform in analytical form back at uni, without understanding what it was for. I've been able to implement a Discrete Fourier Transform algorithm in code to do simple frequency analysis of a signal, without understanding why the algorithm was the way it is. With your explanation, I think I finally get the "why" of the Discrete Fourier Transform, the way it uses correlation. Thanks for this explanation; I feel like one more thing is clicking into place.

  • @BrianBDouglas

    @BrianBDouglas

    5 ай бұрын

    Glad it helped!

  • @philipprottweiler2924
    @philipprottweiler2924 Жыл бұрын

    Awesome explanation! When will the video on the Z-Domain be published? Really looking forward to it

  • @BrianBDouglas

    @BrianBDouglas

    9 ай бұрын

    I hope before the end of the year. I have 4-5 more videos in my queue before it though :(

  • @franciskimonge1851
    @franciskimonge185110 ай бұрын

    my guy just made fourier transforms, laplace transorm and z transform all make sense , thank you

  • @BrianBDouglas

    @BrianBDouglas

    9 ай бұрын

    Good to hear! Thanks!

  • @vincentjupiterayuste2358
    @vincentjupiterayuste2358 Жыл бұрын

    Thank you Sir Brian

  • @Eta_Carinae__
    @Eta_Carinae__ Жыл бұрын

    We know that we can use FT on account of e^{i /omega n} forming an orthogonal basis for all n. I'm wondering, since z^{-n} spans all complex exponentials (assuming no limit like n>0), if there are any non-zero inner products between differently-based exponential functions. I mean, just by definition you're sweeping over scalar multiples of a basis, making all elements (r e^{i /omega})^{-n} LD on (e^{i /omega})^{-n}, right?

  • @emiliomartineziii2980
    @emiliomartineziii29804 ай бұрын

    This was truly amazing! This guy has MIT level brainpower. Like woah, his ability to explain and efficiently articulate this stuff is unreal. This channel will be my saving grace in dsp for sure! Already subscribed too. He's a legend for sure!

  • @BrianBDouglas

    @BrianBDouglas

    4 ай бұрын

    🤓 haha thanks so much!

  • @yinkaleoogundiran1171

    @yinkaleoogundiran1171

    4 ай бұрын

    Or MIT has Brian Douglas’ level brainpower? 😊

  • @joez9162
    @joez9162 Жыл бұрын

    @Brian I’d love to see you do an explanation of ADRC controllers!

  • @Pedritox0953
    @Pedritox0953 Жыл бұрын

    Great video!

  • @ernstuzhansky
    @ernstuzhansky Жыл бұрын

    Many thanks Brian!

  • @mixguru9669
    @mixguru9669 Жыл бұрын

    My control systems professor should watch this video.

  • @sukursukur3617

    @sukursukur3617

    Жыл бұрын

    I am very sure he didnt learn the background of the concept. That is why he cant convey its knowledge properly.

  • @Amine-gz7gq

    @Amine-gz7gq

    10 ай бұрын

    @@sukursukur3617 KZread FTW

  • @j.fkamaldeen
    @j.fkamaldeen Жыл бұрын

    Thanks alot Brian 🎉

  • @joelevi9823
    @joelevi982325 күн бұрын

    I can't find the link to the video about the Z domain.. will be happy to get it

  • @user-pn6qx1vu3q
    @user-pn6qx1vu3q Жыл бұрын

    I never understand why we use complex number to do the transform, until now !! TO CONSIDER THE PHASE !!

  • @em2129
    @em2129Ай бұрын

    You are a wizard. Thank you!

  • @Neuromante73
    @Neuromante73 Жыл бұрын

    Hi Brian, since I am studying how to develop MATLAB apps, would it be possible for you to share the app that you have used during the discussion on the DTFT? Thanks

  • @Amine-gz7gq

    @Amine-gz7gq

    Ай бұрын

    he put the github link in the description

  • @martinsanchez-hw4fi
    @martinsanchez-hw4fi Жыл бұрын

    Thanks for te awesome content. Where can I find the list with Brian videos for this Channel?

  • @BrianBDouglas

    @BrianBDouglas

    9 ай бұрын

    I organize all of my MATLAB videos here: engineeringmedia.com/videos

  • @Volticymo
    @Volticymo7 ай бұрын

    Can’t wait for z domain video

  • @user-xq6dq7xe5e
    @user-xq6dq7xe5e8 ай бұрын

    is there any open source on the internet about detail on z domain

  • @BalajiSankar
    @BalajiSankar Жыл бұрын

    Thank you.

  • @user-iu7qg9lo7y
    @user-iu7qg9lo7y Жыл бұрын

    this is teaching at its finest

  • @khanhtruong3254
    @khanhtruong32549 ай бұрын

    Hi Brian, thanks for great explanation. At your DTFT demo 10:10, your input data signal clearly has magnitude of 1, so you choose the probing signals also have magnitude of 1 so it fits perfectly in your "dot product". If the input data signal is a combination of many frequencies with different magnitudes, it seems that we still keep the magnitude of probing signals (sine and cosine) as 1. I wonder why that still works? Shouldn't we adjust magnitude of probing signals according to the input signal?

  • @BrianBDouglas

    @BrianBDouglas

    8 ай бұрын

    I think I understand your question, but I might be off a bit. Let me give it a try. If a particular frequency in the input signal had an amplitude that wasn't 1 there would still be correlation between it and the probing signal with an amplitude of 1. Since we're multiplying the two signals, having a larger amplitude in one is just like multiplying the product of the two signals by a gain. So that frequency would have a larger value in the lower plot. Which is exactly what you want because you want to see "how much" of each frequency there is in the original signal. For example, if the signal is 5*sin(t) and the probing signal is sin(t), then the product of the two is 5*sin^2(t) and so the summation would be 5 times larger. Was that your question and did my answer make sense?

  • @binhnguyenquoc3249

    @binhnguyenquoc3249

    8 ай бұрын

    This is how I see it, lets assume the input signal is a sum of many sinusoidal signals like x1.sin(w1.t) + x2.sin(w2.t) + x3.sin(w3.t) + .... When you have infinite data point, you can prove mathematically that with each probing signal, ONLY the exact probing signal that have the same frequency as one of the input's frequency components would have a NON-ZERO dot product (you can intuitively understand the reason why this happen by taking the integration of the product of two sinusoidal signals with different frequencies, the value would be 0), so the value of x1, x2, x3 or any amplitude of the input's frequency component is not that important (except when you need to know the amplitude of the component frequency) since the output plot would only have pulses at those exact frequencies (when you have infinite data point).

  • @franciscorainero8673
    @franciscorainero867311 ай бұрын

    Is the shown Matlab application available on any link? (The one that calculates the FFT in min 7:50)

  • @BrianBDouglas

    @BrianBDouglas

    9 ай бұрын

    I just put it on GitHub. Check the pinned comment above!

  • @user-yy5vg3mf6m
    @user-yy5vg3mf6m22 күн бұрын

    Common man I had math exam yesterday, where were you 😢

  • @braedenlarson9122
    @braedenlarson91223 ай бұрын

    So cool!

  • @gradientenfeld
    @gradientenfeld Жыл бұрын

    Is this tool you showed for the DTFT somewhere available?

  • @BrianBDouglas

    @BrianBDouglas

    9 ай бұрын

    I just put it on GitHub. Check the pinned comment above!

  • @blessingshenjere484
    @blessingshenjere484Ай бұрын

    Like how he explains. Like a documentary

  • @PankajSingh-dc2qp
    @PankajSingh-dc2qpАй бұрын

    The input signal at @ 1:31 is delta[n] and not u[n].

  • @martinsanchez-hw4fi
    @martinsanchez-hw4fi Жыл бұрын

    Why an impulse would be integrated to a constant value of 1?

  • @heitorabreu3045
    @heitorabreu30452 ай бұрын

    love you Brian

  • @5vart5ol
    @5vart5ol8 ай бұрын

    I love this, Im only 9 min in and it is all so clear to me now! Thank you. (Unless the next 10 min gives me dementia).

  • @BrianBDouglas

    @BrianBDouglas

    8 ай бұрын

    Did it stick? :)

  • @5vart5ol

    @5vart5ol

    8 ай бұрын

    It has indeed. Thank you.

  • @briancoon308
    @briancoon3084 ай бұрын

    Did that z domain video ever get published?

  • @BrianBDouglas

    @BrianBDouglas

    3 ай бұрын

    I'm almost done with it! I had to change what I'm going to cover in it because I found a video by Youngmoo Kim that covers pretty much what I wanted to and it's brilliantly done. I'm going to call it out in my video and cover a few different things now. I'd put the link but my comment will be removed but search KZread for "Applied DSP No. 9: The z-Domain and Parametric Filter Design"

  • @tim110-handle
    @tim110-handle5 ай бұрын

    when will the z domain video come out?

  • @BrianBDouglas

    @BrianBDouglas

    5 ай бұрын

    I was hoping by now! But the video got pushed for a bit to get other work done. It will be here one day though. Sorry!

  • @borisbvt5473
    @borisbvt54738 ай бұрын

    So, is z-transform kind of discreet Laplace Transform?

  • @BrianBDouglas

    @BrianBDouglas

    8 ай бұрын

    Yep!

  • @LokeKS
    @LokeKS14 сағат бұрын

    brilliant

  • @rob9756
    @rob9756 Жыл бұрын

    Is z transform discrete Laplace transform?

  • @matwiz20xx

    @matwiz20xx

    Жыл бұрын

    Yes, that's right. This is why you have to see what is the application for which you are going to choose certain transform. For instance, z-transform is used in digital filter design, whereas the Laplace transform is mainly used in applications such as AC circuit analysis, and so on.

  • @manfredbogner9799
    @manfredbogner97995 ай бұрын

    Very good

  • @BrianBDouglas

    @BrianBDouglas

    5 ай бұрын

    Thanks!

  • @PankajSingh-dc2qp
    @PankajSingh-dc2qpАй бұрын

    There is no integrator in discrete time. Discrete time has "accumulator".

  • @reviewchan9806
    @reviewchan9806Ай бұрын

    If the components have both exponential and periodic signals, wouldn't that just the the Laplace transform?

  • @BrianBDouglas

    @BrianBDouglas

    Ай бұрын

    The Laplace transform is for continuous signals, the Z-transform is the discrete equivalent.

  • @hamedhojatian3539
    @hamedhojatian35397 ай бұрын

    Could it BE any more simpler to explain DFT?

  • @pijnappel03
    @pijnappel035 ай бұрын

    DTFT: 5:28

  • @eduardojreis
    @eduardojreis5 ай бұрын

    16:50 - Where is the Z-Domain video?

  • @BrianBDouglas

    @BrianBDouglas

    4 ай бұрын

    I'm just starting it now ☺ It took a while to get to it. Any particular questions you'd like answered in it while you're thinking about it? Thanks!

  • @eduardojreis

    @eduardojreis

    4 ай бұрын

    @@BrianBDouglas Thank you so much for the feedback. Very much appreciated you asking! Yes! I do have questions that, if possible, I'd love to see them answers. 1) Can you give a couple more examples of how to go from the zero+poles representation to the filter equation? 2) Can you explain butter filters design and their relation to the Z-transform? What does the butter function does? 3) Can you explain `sos` for filter design? Why `sos` is more stable than the `butter` function in some cases? These are some topics I came across when first watching this video. I would find very helpful to have them addressed, but if you consider a bit out of scope for the next video you're planning that is fine. I looking forward to it anyways, your videos are great and I've learned a lot! Thank you for all the effort and quality put into them!

  • @user-xq6dq7xe5e
    @user-xq6dq7xe5e8 ай бұрын

    when the video on the z domain will be made and published

  • @BrianBDouglas

    @BrianBDouglas

    8 ай бұрын

    I don't know, it keeps getting pushed back :( But I'll get it out eventually.

  • @kenakackrmn3898
    @kenakackrmn3898Ай бұрын

    5:25 sampai 12:09

  • @KingBhoomie
    @KingBhoomie Жыл бұрын

    1:27 Input u[n] generally refers to unit step function. And Unit impulse is represented by δ[n]

  • @40NoNameFound-100-years-ago
    @40NoNameFound-100-years-ago Жыл бұрын

    I am wondering why Mathworks took so long time to make such videos? We are in 2023 and version 2023 has been released. These control methods were introduced and had been modified since version 2006 .

  • @tidin_tss
    @tidin_tss2 ай бұрын

    респект авторам, но ничего не понятно для чего его использовать вообще

  • @SRIGHT0
    @SRIGHT0Ай бұрын

    Halo saa disuru bu guru njelasin

  • @Amine-gz7gq
    @Amine-gz7gq10 ай бұрын

    Thank you very much Brian. I love you man (I'm not gay 😂). I have a master degree in CS and system control but I never really understood system control and that's why when I have free time I enjoy watching your videos. software engineering sucks, I spend my day refactoring complex, buggy programs written by idiots and unconscious people. I'd like to do something more meaningful and intellectually stimulating like systems controls. Unfortunately, I wasn't taught the latter and maths very well, and thanks to some books and youtube videos, I'm in the process of fixing that. I have a question : Why don't we use exponential functions based on 'e' to scan/probe the sampled signal ? Is it because the signal is sampled and it doesn't make sense to use a function that expresses continuous growth/decay ? after all we can pose r = e^something.

  • @BrianBDouglas

    @BrianBDouglas

    9 ай бұрын

    The middle of page 608 here: www.dspguide.com/CH33.PDF explains why we use r instead of e. Hope that helps!

  • @jimapost1496
    @jimapost14964 ай бұрын

    respect to matlab

  • @Amine-gz7gq

    @Amine-gz7gq

    Ай бұрын

    For the videos, yes, but not for their software, which should be free for home users.

  • @kdre76
    @kdre764 ай бұрын

    L 1

  • @mightyparry
    @mightyparry7 ай бұрын

    in cre di ble

  • @BrianBDouglas

    @BrianBDouglas

    7 ай бұрын

    Glad you liked it!

  • @Alexis-ym9ph
    @Alexis-ym9ph8 ай бұрын

    This explanation is actually pretty bad in comparison to explanation of other authors on KZread)

  • @youtube-username-placeholder

    @youtube-username-placeholder

    8 ай бұрын

    I respectfully disagree😅

  • @Amine-gz7gq

    @Amine-gz7gq

    Ай бұрын

    This subject (like many others) is so complex that a single video is not enough to explain it in depth. You need to watch several videos by different people to improve your understanding of the subject.

  • @marcinmartke2960
    @marcinmartke2960 Жыл бұрын

    boring, but not for me :)

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