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19th May 2017, 05:36 #1
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Major Understanding Issue in DiscreteTime Signals
Last edited by dzafar; 19th May 2017 at 05:55.

19th May 2017, 05:36

19th May 2017, 11:47 #2
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Re: Major Understanding Issue in DiscreteTime Signals
A is amplitude and yeas your interpretation is correct.
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19th May 2017, 11:47

19th May 2017, 13:03 #3
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Re: Major Understanding Issue in DiscreteTime Signals
Thanks nomigoraya! What about the question in the second image? Thanks

19th May 2017, 13:03

19th May 2017, 17:08 #4
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Re: Major Understanding Issue in DiscreteTime Signals
You have already answered that simple question.
u[5]= 0+0+0+0.....+1+0+0+0+0+0 = 1 Where is the problem ?
u[12454352]=0+0+0+0+0+....1+0+0+0+0+0+0.... = 1
u[1324583425893245738984237441394]=0+0+0+0+0+....1+0+0+0+0+0+0.... = 1
Do you see it now ?
What you have written in the question is wrong because it is a sum of values i.e. it is 0+0+0+.....+1+0+0+0.... that "1" at delta[0]=1 makes the sum to be "1".

19th May 2017, 17:28 #5
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Re: Major Understanding Issue in DiscreteTime Signals
Umm.. okay! The problem that I am having is that at n = 5, u[5] = 1 whereas, impulse[5] = 0!
So for n = 5, they are not equal!
I understand that impulse function is with a summation. But that just means it's 1 at n = 0.
Q1: So does it not matter what the impulse is at n = 5?!
Q2: If so, we can then just remove the summation and say:
u[n] = impulse[0] for any index n?!
Also, if they just mean the maginitude of u[n] equals the magnitude of the summation of impulses,
Q3: Why don't they use the magnitude symbol:
u[n] = summation of impulses?
Q4: Also, why does the summation stop at n?! We can easily have it upto positive infinity (as the magnitude will still be 1)?!
Thanks! I hope someone can answer my doubts in the same order (of questions asked) so that I have a better understanding.
Thanks :)Last edited by dzafar; 19th May 2017 at 17:41. Reason: Extra detail

19th May 2017, 17:28

19th May 2017, 18:36 #6
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Re: Major Understanding Issue in DiscreteTime Signals
No, it does not.
Q2: If so, we can then just remove the summation and say:
u[n] = impulse[0] for any index n?!
Also, if they just mean the maginitude of u[n] equals the magnitude of the summation of impulses,
Q3: Why don't they use the magnitude symbol:
u[n] = summation of impulses?
The author simply gave good mathematical definition. You can remember it however you want e.g. as I have answered to Q2 but it would be useless when applying demonstrations of formulas or transforms because correct mathematical definitions can be used to prove other stuff.
Q4: Also, why does the summation stop at n?! We can easily have it upto positive infinity (as the magnitude will still be 1)?!Last edited by CataM; 19th May 2017 at 18:49.
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