Prev: Overlapping Circular Area Problem
Next: Reading and modifying XML file using MATLAB
From: nethaji anandhavalli on 14 Apr 2010 13:14
hai,
regarding filtering tech, i have made low pass filtering, followed by high pass too. but for ecg wave, i need to find the peakness,is there any specialised functions? and also, in high pass filter function, i need to specify the gain? pls help me
From: TideMan on 14 Apr 2010 16:12
On Mar 4, 1:00 am, Rune Allnor <all...(a)tele.ntnu.no> wrote:
> On 3 Mar, 13:25, Ruben <rubenregtersc...(a)hotmail.com> wrote:
>
> > Thanks for reply. So filtering leads to a changed amplitude of the signal. I think that's OK, because it removes the frequencies that camouflage the signal (ca. 15 Hz) were I am looking for. I expected that it would be possible to determine the amplitude of this specific signal. But if I understand it well than this is not possible? Or is there another way to remove the disturbance frequencies and to determine the amplitude of this specific signal? Many thanks for help!
>
> There are very, very few applications - I am not aware of a single
> one - where determining the amplitude of a sinusoidal makes any
> sort of sense.
>
> > My problem in short: I would like to determine the amplitude of a signal
>
> I would like to win the lottery.
>
> The fact that one would like to do something, does not mean it
> is neither useful, wise, or even possible.
>
> Rune

Bunkum, balderdash, poppycock and hooey!!

We do this all the time in tidal analysis.
That's how tide forecasting works. From the constituents calculated
by fitting cosine waves.
I can give papers from Lord Kelvin through to the present on various
techniques that do this.

There is even a Matlab toolbox:
http://www.eos.ubc.ca/~rich/#T_Tide

From: Rune Allnor on 14 Apr 2010 16:47
On 14 apr, 22:12, TideMan <mul...(a)gmail.com> wrote:
> On Mar 4, 1:00 am, Rune Allnor <all...(a)tele.ntnu.no> wrote:
>
>
>
>
>
> > On 3 Mar, 13:25, Ruben <rubenregtersc...(a)hotmail.com> wrote:
>
> > > Thanks for reply. So filtering leads to a changed amplitude of the signal. I think that's OK, because it removes the frequencies that camouflage the signal (ca. 15 Hz) were I am looking for. I expected that it would be possible to determine the amplitude of this specific signal. But if I understand it well than this is not possible? Or is there another way to remove the disturbance frequencies and to determine the amplitude of this specific signal? Many thanks for help!
>
> > There are very, very few applications - I am not aware of a single
> > one - where determining the amplitude of a sinusoidal makes any
> > sort of sense.
>
> > > My problem in short: I would like to determine the amplitude of a signal
>
> > I would like to win the lottery.
>
> > The fact that one would like to do something, does not mean it
> > is neither useful, wise, or even possible.
>
> > Rune
>
> Bunkum, balderdash, poppycock and hooey!!

What is? I stated facts: I was not aware of any such applications.

> We do this all the time in tidal analysis.

OK, I have been enlightened. I was not aware of that
application until reading your post; it even makes sense
to use those kinds of techniques in that particular
application.

But are you aware of any other applications where
sinusoidal parameter estimation is useful?

> That's how tide forecasting works.  From the constituents calculated
> by fitting cosine waves.
> I can give papers from Lord Kelvin through to the present on various
> techniques that do this.

No one cares what have been published. I know of papers
where equations of the type

L(x,y) = 1 + e

where L is an arbitrary operator, are 'solved' for both x and
y by a trial'n error kind of approach. The idea is that for
some pairs of (x,y) the error e is particularly small, so those
(x,y) are the solutions.

Seriously.

Rune
 | 
Pages: 1
Prev: Overlapping Circular Area Problem
Next: Reading and modifying XML file using MATLAB