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 Message Boards » » ece420 problem 1-9b Page [1]  
Ann
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Hi,

Has anyone done this problem yet??? I got it down to 1exp((-j*pi*k*15)/8) + 1exp((-j*pi*k)/8), but Dr. Alexander told me that I need to combine the exponential, but I have no idea how you can combine the exponential, any idea?

Thanks,
Ann

1/17/2006 8:26:01 PM

teh_toch
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Quote :
"Dr. Alexander told me"


lol you went to his office hours

exp(-j*2*pi*k/16 + 2*pi) + exp(-j*2*pi*k*15/8)
exp(j*2*pi*k*15/8) + exp(-j*2*pi*k*15/8)
2cos(15*pi*k/8)

1/17/2006 9:54:26 PM

Quinn
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nice work

i was just working on typing up the answer

looks like my boy swoops in for the kill

gg

1/17/2006 9:55:37 PM

Ann
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Did any of you also get an answer for 1-10???? My answer doesn't match the matlab answer, that's why i am asking. I have 48delta[k-2] + 48delta[k-14], but matlab gives 48delta[k-1] + 48delta[k-7], which one do you have? Thanks.

1/17/2006 10:10:55 PM

Quinn
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what is your t vector?

1/17/2006 10:13:38 PM

Ann
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M = 16;
delta_t = 125e-6;
m = 0:1:15;
t = delta_t*m;

1/17/2006 10:16:46 PM

Quinn
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1/17/2006 10:18:56 PM

Ann
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for 9b)
I got this 1exp((-j*pi*k)/8) + 1exp((-j*pi*k*15)/8)

and you got: exp(-j*2*pi*k/16 + 2*pi) + exp(-j*2*pi*k*15/8)

So for the second term in the numerator, where is the 2pi coming from, i only got pi

1/17/2006 10:28:17 PM

Ann
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oh nm...i figured it out

1/17/2006 10:32:17 PM

jakis
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i get the same as you got at first for 9-b Ann. What am I doing wrong?

1/17/2006 11:14:51 PM

virga
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this is going to be a fun semester

1/18/2006 12:26:04 AM

teh_toch
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^^ What you are doing wrong is being in a 400 level ECE class when you cannot do basic trigonometry.

[Edited on January 18, 2006 at 12:26 AM. Reason : ^]

1/18/2006 12:26:16 AM

cosgrove
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ohmed

1/18/2006 7:40:43 AM

Probasesteal
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bahaha

1/19/2006 3:26:03 PM

ncsu_engr
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For MATLAB questions, do we turn in just the plots, or the code as well?

1/19/2006 6:49:52 PM

jakis
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just plots

1/19/2006 7:30:41 PM

statepkt
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^^Just read the format sheet he put up.

1/19/2006 7:33:33 PM

ncsu_engr
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^^ thanks
^ he does not say anything about turning in or not turning in the code in the format sheet. also, of the problems assigned, only 1.16 mentions not to turn in the code.

[Edited on January 19, 2006 at 7:39 PM. Reason : ]

1/19/2006 7:39:04 PM

statepkt
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He says in problem:
Quote :
"Turn in your Matlab plot(s), but not your Matlab code."

We would assume he means all of them.

[Edited on January 19, 2006 at 7:42 PM. Reason : .]

1/19/2006 7:41:32 PM

ncsu_engr
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^ read my post carefully
Quote :
"only 1.16 mentions not to turn in the code.
"

1/19/2006 8:06:50 PM

statepkt
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No I realize that he only mentions it in that one problem.....but he says Matlab plot(s), and I would have to assume he means all the problems.

But if you don't want to risk it just print out the code, its not much more work.

Plus he never mentions how he wants the coding to be formated.....and as anal as he is he should have definitely specified what formating your code should be.

[Edited on January 19, 2006 at 8:50 PM. Reason : .]

1/19/2006 8:48:16 PM

virga
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he could care less about the code

put your name in your plot titles

that is all

[Edited on January 19, 2006 at 11:45 PM. Reason : b->p]

1/19/2006 11:45:10 PM

vonjordan3
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What if I told you that I had all the homework answers for 420 since the year 2000?

1/20/2006 1:55:09 PM

teh_toch
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lol

1/20/2006 2:02:13 PM

virga
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some of us want to LEARN by DOING


(l-o-l)

1/20/2006 5:22:32 PM

statepkt
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I still can't believe we have 2 HW's due every week....or so the assignments say.

1/20/2006 6:00:05 PM

virga
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^ you haven't had him before, have you?

1/21/2006 1:16:28 AM

vonjordan3
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I thought like that too...a long time ago, trust me on this though, you will never use all of that stuff when you are out, I was never asked about school, only about my previous job. The most important thing you can do is find a summer job or an internship. But I really do have all of the answers to most ece classes.

1/23/2006 9:20:02 AM

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