Phase Frequency Detector in PLL theory ?

Discussion in 'General Electronics Chat' started by nqchanh, Feb 6, 2013.

  1. nqchanh

    Thread Starter New Member

    Dec 5, 2012
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    i'm studying about Phase Frequency Detector (PFD) as a part of Phase Locked Loop (PLL) theory, but after viewing the textbook, i've got some questions.here is the link from which you can download a part of my textbook about PFD:
    http://www.mediafire.com/view/?2qst60ke29ci44i
    i haven't been clear why we can get equation (2.24) ?
    In my opinion, from figure 2.11, ud can get only two value Ub and zero, so the average signal can not get a negative value! However, according to textbook, the opposite's still right ! hope someone can give me an explaination ! ^~^
     
  2. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    How about, instead of downloading a copyrighted book, you reference something that isn't illegal to distribute?
    Maybe like this?
    Or this?
     
  3. nqchanh

    Thread Starter New Member

    Dec 5, 2012
    18
    0
    Tshuck, sorry but i don't think it does matter! i've downloaded the book for free, but when extracting a part of it , i used a software that hasn't got a valid license so that may be the reason you thought it invalid!
    My problem here is that i'd like to know how the author can get equation 2.24 ? i've thought about it for a quite long period but haing no idea, so i hope someone here can help me ! ^~^
    thanks for your links but i don't think they're really effective for me! it's great if you answer directly on my problem , instead of giving a link that does not concentrate on my problem!
     
  4. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
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    How about you post the equation? I don't think anyone is going to download your link...
     
  5. nqchanh

    Thread Starter New Member

    Dec 5, 2012
    18
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    thanks, Tshuck!because that equation is related to some figures in the posted material, so if i only just posted the equation, it's not enough for everyone to view it! ^~^
     
  6. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    I tried....well, good luck!
     
  7. w2aew

    Member

    Jan 3, 2012
    219
    64
    You might want to watch this video that I made a few months ago on the basics of PLL circuits. I spend about 10 minutes or more discussing PFD circuits and showing their characteristics on an oscilloscope:
    http://www.youtube.com/watch?v=SS7z8WsXPMk
     
  8. nqchanh

    Thread Starter New Member

    Dec 5, 2012
    18
    0
    w2aew, i'm studying PLL theory and my final purpose is to create a printed circuit board (PCB) that is based on the PFD in order to control motor! that's the content of my very important project on this semester at my university.Have you ever done a real board based on PLL theory ?
     
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