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ragabs
Joined: 28 Jun 2005
Posts: 99
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 16 May 2006 9:22 how to get sine from cosine |
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dear all
in a reciver of fm signal i have
rx=cos(wc+kf*∫m(t) dt).
i need to get
sin(wc+kf*∫m(t) dt)
can u suggest algorithm
thanx for help
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nathan80
Joined: 23 Feb 2006
Posts: 68
Helped: 5
Location: Malaysia
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| 17 May 2006 4:45 Re: how to get sine from cosine |
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well, i am not sure whether it is correct but will like to suggest to you;
go back to basic trigonometric.
just subtract with 90degrees or equivalent in radian. cos can convert to sin
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Blilix
Joined: 28 Feb 2006
Posts: 30
Helped: 2
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| 17 May 2006 5:02 Re: how to get sine from cosine |
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| I think you should look at some communication textbook. There should be the algorithm about FM signal. As I remember, it should be a building block diagram called "delay". However, in trigonometry, you just add or subtract angle of 90 or pi/2 radian.
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sidra
Joined: 05 Apr 2006
Posts: 107
Helped: 12
Location: see in yr heart...found it?
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| 17 May 2006 7:26 Re: how to get sine from cosine |
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| well the basic theme of algorithm is certaily to add or subtract 90' from the present value of the angle...sidra_maheen84(at)yahoo.com
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ragabs
Joined: 28 Jun 2005
Posts: 99
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| 17 May 2006 10:11 Re: how to get sine from cosine |
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ok
now the question is how to make a delay equalls pi/2 in digital domain?
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Sal
Joined: 29 Nov 2005
Posts: 288
Helped: 36
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| 25 May 2006 20:29 how to get sine from cosine |
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Hi
I dont know why you need such a signal, analgously you just need a delay line and digitally just remember that the derivative of sin(x) = cos(x). then you just need to integrate your signal
cheers
Sal
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pakitos
Joined: 14 Nov 2005
Posts: 310
Helped: 38
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| 26 May 2006 8:02 Re: how to get sine from cosine |
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you are using software or hardware?
if hardware use an integrator with no gain using opamps or even rc
if software you can do the same .
wich software you are using?
matlab ....
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Roshdy
Joined: 23 Nov 2005
Posts: 444
Helped: 7
Location: Egypt
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| 27 May 2006 23:35 Re: how to get sine from cosine |
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I think it will be better it you explained mre details about the problem you need to do this for, it will be great if you explained the whole problem
Roshdy
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