What Does "Linear Phase" Mean?

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  • Опубликовано: 28 окт 2024

Комментарии • 61

  • @ChrisWhoLikesGrapes
    @ChrisWhoLikesGrapes 2 года назад +10

    I’m blown away by the quality of this video. Thank you for your work, you’ve helped me understand a topic i’ve had on my mind for months!

    • @iain_explains
      @iain_explains  2 года назад

      Glad it was helpful! Have you seen that there are lots more videos on the channel too? Check out this web link for a full categorised listing: iaincollings.com

  • @shithsu
    @shithsu Год назад +1

    Appreciations from Taiwan😊 the most understandable video explaining linear phase

  • @payman_azari
    @payman_azari 4 месяца назад

    These videos are heaven-sent resources for engineers. Thanks, Professor Iain!

  • @dmitrikazantsev3692
    @dmitrikazantsev3692 Год назад

    This was good, something was new, something was not, but never seen on one page before for sure. Thanks!

  • @jfyt2114
    @jfyt2114 2 года назад

    IIR filters and optical fibres have non linear phase and non linear phase occurs when two signals of different frequencies and diffrent delays are there.

  • @aryamallick5426
    @aryamallick5426 Год назад +2

    great concept sir

  • @malashis
    @malashis 2 года назад

    The way you explain things is truly amazing! I wish I could watch all your videos !!! Thanks for sharing.

    • @iain_explains
      @iain_explains  2 года назад

      Glad you like the video! Hopefully you'll get time to watch some of my other videos too. There's a categorised list at this website: iaincollings.com

  • @subhashishbarik4319
    @subhashishbarik4319 2 года назад +1

    Nice videos, please keep up the good work.
    I have one question:
    On the top right figure why have you already chosen tau to be pi/2 (isn’t it supposed to be generic)? I mean, when you have extended the plot to the left (from where t = tau), you could have crossed the y-axis at a different point then -1.

    • @iain_explains
      @iain_explains  2 года назад

      I chose tau to be 1/4 of the wavelength for the sinusoid at frequency f_1 as an example (this corresponds to pi/2), so I could show the plot clearly and explain the concept of how a time shift of a sinusoidal waveform is equivalent to a phase shift.

  • @abidurrahman6195
    @abidurrahman6195 2 года назад

    This is too good. Can you please provide a video on The Goertzel Algorithm for specific DFT points? That would be much appreciated.

    • @iain_explains
      @iain_explains  2 года назад +1

      Thanks for the suggestion. I've put it on my "to do" list (although I should warn you it's getting to be a long list ...)

  • @M0XYM
    @M0XYM 2 года назад +1

    This is teaching at its finest - thank you. I have just finished the "Basic Signal Concepts" and am wondering which playlist I should next follow - do you have a recommendation? My motivation for learning DSP is that I am an amateur radio enthusiast and would like to understand more about SDR (software defined radio) and eventually process signals from a SDR with python/matlab/gnuradio - but that's after I understand the basics! So - can you recommend a playlist order please? Thanks again Kevin M0XYM.

    • @iain_explains
      @iain_explains  2 года назад +2

      Hi Kevin, I'm glad you like the videos. The usual topic order would be: Convolution; Fourier Transform; Delta Functions and Sampling; Sampling Continuous Time Signals; Communication System Fundamentals.

  • @sanjayd411
    @sanjayd411 3 года назад +2

    Excellent explanation 👍👍

  • @gavishkasenanayake8943
    @gavishkasenanayake8943 2 года назад

    Wow! Thank you. Straight to the point and very clear explanation.

  • @jhtongamer3151
    @jhtongamer3151 8 месяцев назад

    FL1: (Fixed minimum phase fast roll-off)
    FL2: (Linear slow roll-off)
    FL3: (Apodizing Apodization Filter)
    FL4: (Minimum phase fast roll-off)
    FL5: (Minimum phase slow roll-off)
    FL6: (Linear fast roll-off)
    FL7: (Brickwall Mixing Filter
    what would be the best for gaming to hear foot steps ?

  • @gangsclooney9737
    @gangsclooney9737 2 года назад

    I am not able to understand why in your case when you consider a time delay, the linearity is positive with respect to change in frequency and in the textbook Oppenheim and Wilsky, Signals and Systems, 2nd edition, Chapter 6, pg 428 the linear phase for time delay in frequency response is

    • @iain_explains
      @iain_explains  2 года назад +1

      Sorry, I should have made that clearer. It can be confusing. I defined the phase, theta, to equal (2 pi f tau). Which means the formula for a shifted sinusoid is sin(2 pi f t - theta). Other people prefer to write a phase-shifted sinusoid as sin(2 pi f t + theta). The only difference is that their "theta" would be the negative of my "theta" (ie. their "theta" would equal -(2 pi f tau) ).

    • @iain_explains
      @iain_explains  2 года назад +1

      Here's a video where I included the negative into my definition of "theta", and the phase has a corresponding negative slope: "Is Phase important in the Fourier Transform?" ruclips.net/video/WyFO6yBQ0Cg/видео.html

  • @MrFab0117
    @MrFab0117 3 года назад +1

    Very good Thanks ! I should be very interesting by an presentation of hilbert filtering ( constant phase at pi/2 for every frequencies) ; for example to creat I/Q values with a mixer. Thanks in advance 🙏😊

    • @iain_explains
      @iain_explains  3 года назад

      Thanks for the suggestion. I'll have to think a bit about that one. I always like to give intuitive insights in my videos, and the Hilbert transform is certainly one of the less-intuitive transforms. I'll put it on my "to do" list.

    • @MrFab0117
      @MrFab0117 3 года назад

      @@iain_explains You’re right, I have no doubt you’ll find the good way to explain us this particular transform. Thanks again 🙏😌

  • @bran_rx
    @bran_rx Год назад +1

    I swear my professor assumes we know all this stuff straight off the bat... thanks

    • @iain_explains
      @iain_explains  Год назад

      I'm glad the video was helpful. Have you seen my webpage, which lists all the videos in categorised order? It might help to fill the gaps that your professor assumes you already know. iaincollings.com

  • @mnada72
    @mnada72 Год назад

    Thank you for the explanation. For a system, is linear phase good or bad ?

    • @iain_explains
      @iain_explains  Год назад +1

      This video should help: "When is Linear Phase Important?" ruclips.net/video/6EkfAKT5oSg/видео.html

    • @mnada72
      @mnada72 Год назад

      @@iain_explains Thank you. It seems that in most cases it's good 👍. Is there a situation where linear phase is bad ?

    • @iain_explains
      @iain_explains  Год назад +2

      It's bad if you're trying to design a distorting amplifier, to create odd/interesting sounds. Like a sound-effects foot-pedal of an electric guitar, for example.

  • @tranhuuthong07
    @tranhuuthong07 Год назад

    Great tutorial, thank you!!!

  • @hyggeligt007
    @hyggeligt007 2 года назад

    Hi Iain, thanks for the intuitive explanation.
    What could be the benefit of having linear phase? Is it simply to avoid communication delays (if any), in real time applications. Are there times where having a linear phase brings no tangible benefits to the table?

    • @iain_explains
      @iain_explains  2 года назад +1

      An example of when it's important to have a linear phase response is in Bandpass Filtering. The aim is to pass the signals in the frequency band of interest (unchanged - apart from an unavoidable time delay), while also completely suppressing any signals that are not in that frequency band. In this case you want to have a flat amplitude spectrum and linear phase response across the frequency band of interest, and have a zero-amplitude response across the rest of the frequency spectrum. Thanks for raising this question. I think I might add this topic to my "to do" list for a future video.

    • @hyggeligt007
      @hyggeligt007 2 года назад

      @@iain_explains Noted, I'll read up a bit more on the theory as well.
      As an example, phone lines can have a pass band between 200 Hz to 8 kHz (focused on speech and syllable information). If the filter is designed to have non-linear phase, the speech frequencies lying between that could probably cause unintended interference at the receiver's position, making the caller sound different. Mainly because linear phase implies a constant delay between input and output, whereas the delay would not be constant for non-linear phase (?)
      Perhaps a better example could be in diagnosis of patient data with some monitoring tool (like cardiogram or ECG), where the interference could lead to erroneous interpretation by the doctor.

    • @iain_explains
      @iain_explains  2 года назад

      Yes that's right.

  • @alisharafi1225
    @alisharafi1225 2 года назад

    Great tutorials. But I would be grateful if u help me with explanation of difference between generalized linear phase and linear phase. However I know their equation are different!

    • @iain_explains
      @iain_explains  2 года назад

      Systems with generalized linear phase have an additional frequency-independent constant added to the phase.

  • @edebevictor9221
    @edebevictor9221 Год назад

    Thank you, sir. I understood it at 7:20 .

  • @Youshisu
    @Youshisu Год назад

    2:58, where have you lost f param? with tau? and how did that pi end up there? 1/(4f) = T/4, and T is 1, so why -pi/2

    • @Youshisu
      @Youshisu Год назад

      nvm im dum, did not saw other part and though its coma :D

  • @stephenflatham1122
    @stephenflatham1122 2 года назад

    what is the condition for the wireless system to be a nonlinear phase system??
    and what if the same copies of the frequency is delayed by different amount does in that case the system becomes non linear phase

    • @iain_explains
      @iain_explains  2 года назад +1

      Wireless channels are generally modelled as being linear (with linear phase). I'm not sure what you mean when you say "the same copies of the frequency". I think you are referring to multi path propagation. In this case, it's still a linear channel. This video might help: "What is Intersymbol Interference ISI?" ruclips.net/video/I087FUvW2ys/видео.html

  • @ihya1129
    @ihya1129 3 года назад

    Sir, can you explain about Sine PWM : Triangle wave compare with sine wave, and Related Bessel Function for Harmonic

    • @iain_explains
      @iain_explains  3 года назад +1

      Thanks for the suggestion. I've added it to my "to do" list.

  • @Anonymous____________A721
    @Anonymous____________A721 11 месяцев назад +1

    Oh my god, u are my god, excellent ❤

    • @iain_explains
      @iain_explains  11 месяцев назад

      I'm so glad to hear that the videos are helpful to you.

  • @ashilpasha6867
    @ashilpasha6867 3 года назад

    Sir please make video on AGC working on OFDMA.

    • @iain_explains
      @iain_explains  3 года назад

      Thanks for the suggestion, I'll add it to my "to do" list. The topic is covered to an extent (for single user OFDM) in the video "What is PAPR? and its relationship to OFDM" ruclips.net/video/F4LAZTdm_b8/видео.html

  • @abhishekpratap7744
    @abhishekpratap7744 Год назад

    Nice thank you

  • @jfyt2114
    @jfyt2114 2 года назад

    Can you please explain what happen if the phase is non linear?

    • @iain_explains
      @iain_explains  2 года назад +2

      Then the signal will be distorted. It won't just be a time-delayed version of the input signal.