Thread Subject: area under a curve

Hi everybody,
I'm a new matlab user and I'm trying to acquire an external pressure signal that I have to integrate in order to obtain the area under the pressure curve.
Actually I can acquire the signal but I don't know how to obtain the area under the trace.
I also knew that the same think I'm trying to realize can be made using simulink but I don't know if there are any advantages?

Thank you very much!

stepbike41 <stephan.caruso@unina.it> writes:

>Hi everybody,
>I'm a new matlab user and I'm trying to acquire an external pressure signal that I have to integrate in order to obtain the area under the pressure curve.
>Actually I can acquire the signal but I don't know how to obtain the area under the trace.
Try googling for
  matlab area under a curve

I found out that I can use the trapz function but I think that the integral of the curve is obtained with too much approximation....

stepbike41 wrote:
> I found out that I can use the trapz function but I think that the
> integral of the curve is obtained with too much approximation....

Well, you can sample faster to reduce the spacing or use other
integration techniques which in essence, do the interpolation behind the
scenes based on the particular choice.

You might look at

doc interp1

for a few alternatives; splines could be a reasonable choice perhaps...

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