[Eeglablist] Number of samples

[Samaneh Valipour]

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
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