[Eeglablist] Number of samples

Pål Gunnar Larsson pall at ous-hf.no
Sun May 25 23:50:08 PDT 2014


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<mailto: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<mailto: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<mailto: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<tel:%28%2B47%29%2023074407>
Mobile: (+47) 93429791<tel:%28%2B47%29%2093429791>
E-mail: pall at ous-hf.no<mailto: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<mailto: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> [mailto: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<mailto: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<mailto: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<mailto: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<tel:%2B91-20-25699841>,+91-20-25691256<tel:%2B91-20-25691256>,+91-20-25601419<tel:%2B91-20-25601419>


_______________________________________________
Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
To unsubscribe, send an empty email to eeglablist-unsubscribe at sccn.ucsd.edu<mailto:eeglablist-unsubscribe at sccn.ucsd.edu>
For digest mode, send an email with the subject "set digest mime" to eeglablist-request at sccn.ucsd.edu<mailto:eeglablist-request at sccn.ucsd.edu>



--
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<tel:%2B91-20-25699841>,+91-20-25691256<tel:%2B91-20-25691256>,+91-20-25601419<tel:%2B91-20-25601419>




--
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

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sccn.ucsd.edu/pipermail/eeglablist/attachments/20140526/da857c0f/attachment-0001.html>


More information about the eeglablist mailing list