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Homework Help: Up Counter Question

  1. Nov 27, 2012 #1

    I got this question on midterm. the correct answer is 20 MHz.

    But I am getting 10 MHz. I attached a text file which shows all the work I done.

    Can someone please explain this question and tell me where I am doing it wrong.


    Attached Files:

  2. jcsd
  3. Nov 28, 2012 #2


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    Homework Helper
    Gold Member

    Your state diagram, and sequence are correct. :approve:
    Look at the problem statement once again (and Figure 12). You need to calculate the frequency of signal z. (The signal z is the same thing as Q1.) How many periods does signal z have in one complete sequence? :wink:
  4. Nov 28, 2012 #3
    so now if I was to write Z I get
    1 1 0 1 1 0

    therefore Z is repeating 110 thus,

    60/3 gives 20 MHz

    am I on right track?
  5. Nov 28, 2012 #4


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    Homework Helper
    Gold Member

    Yes, you are absolutely on the right track. :approve: But you'll need to be a little more detailed about where that '3' came from. (I think you already have it, but you should be prepared spell it out for the sake of your instructor).

    There are 6 clock cycles per sequence (as you have already figured out in your original post). How many periods of z exist per sequence? How many clock cycles exist in one period of z? And thus, what's the frequency of z?
    Last edited: Nov 28, 2012
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