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## RE: [Tftb-help] finding the energy in a certain time and frequency inter

 From: Hallgrímur Th . Björnsson Subject: RE: [Tftb-help] finding the energy in a certain time and frequency interval in a TF plot Date: Mon, 14 May 2007 23:29:54 +0200

```Hi.

Thanks for the help, although it wasn't exactly what I meant. I was a little
confused on how to map the "frequency bins" to specific frequencies, but now
I have that figured out. I originally made the mistake of using the full
sampling rate as the highest frequency.

I am Icelandic, currently studying in Sweden (Lund).

Thanks again.

> -----Original Message-----
> Sent: 14. maí 2007 00:31
> To: Hallgrímur Th. Björnsson; address@hidden
> Subject: Re: [Tftb-help] finding the energy in a certain time and
> frequency interval in a TF plot
>
> Dear Hallgrímur,
> In a TFR matrix, the time is in columns, and the frequency bins are in
> lines
> (The first line is the zero frequency (DC), and the last one is the
> highest
> (one half of the sampling frequency).
> Best regards,
>
> To select the area between the 10th and the 50th time sample, and the
> frequency between the 60th and the 80th frequency bin, use
> TFR(10:50,60:80)
>
> By the way, where on earth are you living ?
>
> best regards,
>
> At 22:50 09/05/2007, Hallgrímur Th. Björnsson wrote:
> >Content-Type: multipart/alternative;
> >         boundary="----=_NextPart_000_0049_01C7928C.6A56F930"
> >Content-Language: is
> >
> >Hi.
> >
> >I am using the Time Frequency Toolbox in Matlab
> >for my Masters thesis. It is working very well
> >and I have been using the Choi Williams
> >Distribution to great effect working on EEG signals.
> >
> >What I like to do is to find the total energy in
> >a certain part of the plot (for ex. All energy
> >in 10-12 Hz from time 0 to 1 sec).
> >I have been trying to use integ2d.m to do this,
> >but what confuses me is how I interact with the
> >TFR variable returned from tfrcw. How do I only select a subspace of
> TFR?
> >
> >Thanks.
>
> Francois Auger,  http://www.univ-nantes.fr/auger-f
>
> Chef du departement Mesures Physiques de l'IUT de Saint-Nazaire
> tel : 02 40 17 81 21, internet : http://www.univ-nantes.fr/iutsn/mp
>
> Laboratoire Ireena, Crtt, bureau 272
> tel : 02 40 17 26 35, internet : http://www.polytech.univ-
> nantes.fr/ireena
>
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```