[Eeglablist] Number of samples

Samaneh Valipour samanehvalipour61 at gmail.com
Mon May 26 00:10:00 PDT 2014


Dear Pal,
Thanks again for your answer.


On Sun, May 25, 2014 at 11:50 PM, Pål Gunnar Larsson <pall at ous-hf.no> wrote:

>  Due to the dynamics of the signal, you could to some extent look at this
> as viewing a Mandelbrot set - you get different information with different
> "views". Tailor the window to suit your needs.
>
>
>
> Regards
>
>
>
> Pål
>
>
>
> Dr. philos. Pål G. Larsson
>
> Seksjonsleder Klinisk nevrofysiologi
>
> Nevrokirurgisk avdeling
>
> Oslo Universitetssykehus
>
> Postboks 4950 Nydalen
>
> 0424 Oslo
>
>
>
> Tlf.:  23074407
>
> Mobil: 93429791
>
>
>
> E-mail: pall at ous-hf.no <pal.gunnar.larsson at ous-hf.no>
>
>
>
> Denne meldingen innholder ikke sensitiv informasjon som bryter med OUS
> sine regler for taushetsplikt
>
>
>
> *Fra:* Samaneh Valipour [mailto:samanehvalipour61 at gmail.com]
> *Sendt:* 23. mai 2014 11:22
> *Til:* mmiyakoshi
> *Kopi:* Pål Gunnar Larsson; eeglablist at sccn.ucsd.edu
>
> *Emne:* Re: [Eeglablist] Number of samples
>
>
>
> Thanks Dear Makoto and Dear Pal,
>
> I think I couldn't to say my question clearly. I mean firstly whether
> number of samples in one window (or segment) will affect performance of FFT
> or WT of EEG signals?
> Secondly is there any standard for number of sample in one window for
> applying FFT or WT ?
>
> Thanks in advance.
>
>
>
> On Thu, May 22, 2014 at 11:31 AM, Makoto Miyakoshi <mmiyakoshi at ucsd.edu>
> wrote:
>
> I mean if you have more *trials *(in the case of ERP) for FFT, that is
> beneficial. If you have the same number of trials but longer analysis
> window it's not beneficial, as Pal pointed out.
>
>
>
> Makoto
>
>
>
> 2014-05-21 23:32 GMT-07:00 Pål Gunnar Larsson <pall at ous-hf.no>:
>
>
>
> Remember that EEG is a very dynamic signal. Hence, longer samples is not
> expected to give better information as the signal changes within the sample
> window. However, increasing the sampling rate, increases the information.
> According to Nyquist you will be able to reconstruct a signal if you sample
> faster than the double of the highest frequency in the signal. However,
> that is when the signal is stable (EEG is not) and the sample is infinite
> long. Practically you will often end up sampling 5-10 time the highest
> frequency in biological signals.
>
>
>
> Pål G. Larsson M.D., PhD.
>
> Head of Clinical Neurophysiology
>
> Department of Neurosurgery
>
> Division of Surgery and Clinical Neuroscience
>
>
>
> Oslo University Hospital
>
> Po.box 4950 Nydalen
>
> 0424 Oslo
>
> Norway
>
> Tel:  (+47) 23074407
>
> Mobile: (+47) 93429791
>
> E-mail: pall at ous-hf.no
>
> not sensitive
>
>
>
>
>
> Dr. philos. Pål G. Larsson
>
> Seksjonsleder Klinisk nevrofysiologi
>
> Nevrokirurgisk avdeling
>
> Oslo Universitetssykehus
>
> Postboks 4950 Nydalen
>
> 0424 Oslo
>
>
>
> Tlf.:  23074407
>
> Mobil: 93429791
>
>
>
> E-mail: pall at ous-hf.no <pal.gunnar.larsson at ous-hf.no>
>
>
>
> Denne meldingen innholder ikke sensitiv informasjon som bryter med OUS
> sine regler for taushetsplikt
>
>
>
> *Fra:* eeglablist-bounces at sccn.ucsd.edu [mailto:
> eeglablist-bounces at sccn.ucsd.edu] *På vegne av* Samaneh Valipour
> *Sendt:* 21. mai 2014 06:58
> *Til:* mmiyakoshi
> *Kopi:* eeglablist at sccn.ucsd.edu
> *Emne:* Re: [Eeglablist] Number of samples
>
>
>
> Thanks a lot Dear Makoto.
>
>
>
> On Tue, May 20, 2014 at 10:03 PM, Makoto Miyakoshi <mmiyakoshi at ucsd.edu>
> wrote:
>
> Dear Samaneh,
>
>
>
> Samples you mean sampling points? Yes of course. The more sampling points
> you have, the better (i.e. smoother and more reliable) the results are.
>
>
>
> Makoto
>
>
>
> 2014-05-19 21:31 GMT-07:00 Samaneh Valipour <samanehvalipour61 at gmail.com>:
>
> Dear EEGLAB users,
>
> I would like to be sure,whether the results of analysis of EEG using  FFT
> or DWT depend on the number of samples?If is so, what is best choice for
> number of samples?
>
> --
>
> *With very kind regards,*
>
> *Samaneh .Valipour*
>
> PhD research student: DOES_UOP_INDIA
> --------------------------------------------------------------------
> *Post address:  *University of Pune,
>                            Pune Ganeshkhind,
>                           Pune-411007 ,
>                            Maharashtra, (India) *
> Phone nos :*+91-20-25699841,+91-20-25691256,+91-20-25601419
>
>
>
>
>
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>
>
>
> --
>
> Makoto Miyakoshi
> Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
>
>
>
>
>
> --
>
> *With very kind regards,*
>
> *Samaneh .Valipour*
>
> PhD research student: DOES_UOP_INDIA
> --------------------------------------------------------------------
> *Post address:  *University of Pune,
>                            Pune Ganeshkhind,
>                           Pune-411007 ,
>                            Maharashtra, (India) *
> Phone nos :*+91-20-25699841,+91-20-25691256,+91-20-25601419
>
>
>
>
>
>
>
> --
>
> Makoto Miyakoshi
> Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
>
>
>
>
> --
>
> *With very kind regards,*
>
> *Samaneh .Valipour*
>
> PhD research student: DOES_UOP_INDIA
> --------------------------------------------------------------------
> *Post address:  *University of Pune,
>                            Pune Ganeshkhind,
>                           Pune-411007 ,
>                            Maharashtra, (India) *
> Phone nos :*+91-20-25699841,+91-20-25691256,+91-20-25601419
>
>
>



-- 
*With very kind regards,*

*Samaneh .Valipour*

PhD research student: DOES_UOP_INDIA
--------------------------------------------------------------------
*Post address:  *University of Pune,
                           Pune Ganeshkhind,
                          Pune-411007 ,
                           Maharashtra, (India) *
Phone nos :*+91-20-25699841,+91-20-25691256,+91-20-25601419
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