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Homework Help: Desperate for help on how to produce triangle wave in excle using harmonics in post .

  1. Jan 11, 2010 #1
    1. The problem statement, all variables and given/known data
    A triangular wave is produced by the following combination of harmonics


    iosoifns.jpg

    Using Microsoft© Excel, synthesise a triangular wave. Start with a plot of the first term and gradually add the next term. Print out the graph produced after adding each term.
    (P)

    Describe in your own words what affect was produced by adding each term. (M)

    Give a detailed description with examples on how you would create a square wave using a similar method. (D)


    I do not have a clue where to even start with this. Could some one point me in the right direction or ever possibly talk me through it?

    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jan 11, 2010 #2

    berkeman

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    Re: Desperate for help on how to produce triangle wave in excle using harmonics in po

    Have you graphed functions using Excel before? It's pretty straightforward. Set up some columns with time t in the first column. You should estimate what frequency you want to use, and set the time increment at something appropriate to give you a number of samples per cycle. So for a 1kHz signal, choose your delta-t to be a fraction of a ms. I like to put my constants in some Excel worksheet locations near the top of the page, and use absolute addressing to refer to them in the rows down in the body of the worksheet.

    So, the top box in your time column is 0, and the next box below it is a pointer to the 0 entry, plus the delta-t absolute cell address. Then use Fill-Down to copy that formula into the next few dozen rows or more below. That gives you the time base for the spreadsheet.

    Then in the columns to the right of the time base, construct the formula for the triangular wave, and use Fill-Down to give you the column with the function that you want to plot.

    Have you plotted columns in Excel before? The plotting wizard is pretty helpful. What experience do you have with Excel? Your instructor must be offering some help on using it, or else you are assumed to have a basic working knowledge of it.
     
  4. Jan 12, 2010 #3
    Re: Desperate for help on how to produce triangle wave in excle using harmonics in po

    Would anyone be able to plot this for me please it would be massively appreciated?
     
  5. Jan 12, 2010 #4

    berkeman

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    Re: Desperate for help on how to produce triangle wave in excle using harmonics in po

    No. It's your homework, and we don't do your homework for you here.

    Try plotting something simpler at first, to get the hang of using Excel. Something like y = 2*x + 5, for x=1..5, in steps of 0.1
     
  6. Jan 12, 2010 #5

    berkeman

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  7. Jan 15, 2011 #6
    Re: Desperate for help on how to produce triangle wave in excle using harmonics in po

    Small world, I have exactly the same questions to answer, (word for word) as the original problem posted here.
    I have read through the suggestions but I'm still a little confused.
    I am assuming that V=Voltage, w=Angular Frequency, t=time ?
    If this is the case then how do you know what initial values to use for each to produce a triangular wave in excel.
    I.e. let’s say I start with a 5V circuit at 50Hz how do you know what (w) to use and what (t) to use.
    Also by how much do you increase these values for the next section of the formula?
    Any help would be greatly appreciated.
     
  8. Jan 15, 2011 #7

    gneill

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    Re: Desperate for help on how to produce triangle wave in excle using harmonics in po

    What's the relationship between frequency (Hz) and angular frequency (rad/sec)?
     
  9. Jan 15, 2011 #8
    Re: Desperate for help on how to produce triangle wave in excle using harmonics in po

    I'm not sure, new to all this electrical engineering. I could be wrong, the w may not stand for angular frequency.
    I'll just wait to see if any one comes back with some help.
     
  10. Jan 15, 2011 #9

    gneill

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    Re: Desperate for help on how to produce triangle wave in excle using harmonics in po

    The [tex] \omega [/tex] stands for angular frequency.
     
  11. Jan 15, 2011 #10
    Re: Desperate for help on how to produce triangle wave in excle using harmonics in po

    Still need some help here :)
     
  12. Jan 15, 2011 #11

    gneill

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    Re: Desperate for help on how to produce triangle wave in excle using harmonics in po

    Help with what? What have you tried?
     
  13. Jan 16, 2011 #12

    gneill

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    Re: Desperate for help on how to produce triangle wave in excle using harmonics in po

    There is only one variable in the formula, t. The amplitude V remains constant. The fundamental angular frequency [tex]\omega[/tex] doesn't change

    How is frequency related to angular frequency?
    How is the period related to the frequency?
    Can you draw one cycle of a sinewave of a given frequency?

    Does it matter what frequency you choose to start with? Is f=1Hz, V=1Volt a perfectly good choice?
     
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