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Topic: find meeting point
Replies: 11   Last Post: Oct 4, 2009 7:03 PM

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joe

Posts: 19
Registered: 9/24/09
Re: find meeting point
Posted: Oct 3, 2009 4:47 PM
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ImageAnalyst <imageanalyst@mailinator.com> wrote in message <4c956101-5398-43e8-92f0-de3935501613@a6g2000vbp.googlegroups.com>...
> On Oct 3, 3:07?pm, "joe " <courstele...@yahoo.fr> wrote:
> > "joe " <courstele...@yahoo.fr> wrote in message <ha80mt$9t...@fred.mathworks.com>...
> > > Hi
> > > I have to find the time (point ) where the signal (sinus) and the axis (i.e y=10)...

> >
> > > thx
> >
> > Hi
> > Here a example about this point
> > t=0:0.001:5;
> > S=sin(2*pi*t)+sin(20*pi*t); my signal
> > y=4; ? ? ? ? ? ?the point
> > plot(t,s,t,y,'k')
> > I want to know the point the different time where y meet S...
> >
> > thanks

> ----------------------------------------------------------------
> That's easy. The answer is "never" since s never exceeds 2.
> Next time post code that will run. I had to fix three errors in your
> code to get it to run. In general you might look for something like
> aboveElements = (s > y);
> if you want to find those elements where s is above y. Most likely it
> will never exactly be equal so you have to know what you want.
> Realize here that you're dealing with quantized arrays. If you really
> want to know where y = s then you'll have to find the roots of the
> equation s-y=0 and it the answer(s) may not lie exactly on array
> elements - it may lie in between elements.


Hi
Thanks for your Help and I undertstand your point of view.
A problem is , I want to the point on the Time Axis , not just the solution of this equation.

Thanks



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