[Scilab-users] Envelop of a noisy curve

[Tim Wescott]

I think you need to think hard about what you mean by "envelope".  It's
not necessarily a well-defined quantity if you're talking about baseband
data.

As an example, if you're starting with x you might want to take it's
absolute xa = abs(x), then process it with a difference equation
something like:

a = <something between 0 and 1>;
xe = zeros(x);
xa = abs(x);
state = 0;
for ix = 1:prod(size(xa))
    if (state < xa(ix))
        state = xa(ix);
    else
        state = state * (1 - a);
    end

    xe(ix) = state;
end

This will certainly give you something that adheres to one
interpretation of the word "envelope", but I absolutely positively can't
guarantee that it's what you want.  It'll also not take good advantage
of Scilab's capabilities -- I don't know that anything will in this
case, at any rate.

On Fri, 2015-04-24 at 14:05 +0200, paul.carrico at free.fr wrote:
> Dear All,
> 
> I am absolutly not familiar with "signal processing" field, so my question is probably naïve: how can I proceed to get the envelop curve (maximum values) of a non periodic noisy signal ?
> 
> Thanks for any suggestion
> 
> Have a good WE
> 
> Paul
> _______________________________________________
> users mailing list
> users at lists.scilab.org
> http://lists.scilab.org/mailman/listinfo/users

-- 

Tim Wescott
www.wescottdesign.com
Control & Communications systems, circuit & software design.
Phone: 503.631.7815
Cell:  503.349.8432