[Eeglablist] Downsampling while collecting data

[robert lawson]

Thanks Makoto

Good thought- I low pass at 70hz in the amp firmware so any noise that
would get removed by that averaging would be faster than the amp's low
pass.

On Fri, May 20, 2016, 6:11 PM Makoto Miyakoshi <mmiyakoshi at ucsd.edu> wrote:

> Dear Robert,
>
>
> > I am considering averaging 4 samples instead because it seems like it
> would reduce random noise.
>
> Intuitively, I doubt if it works with noise under 1000/4=250 Hz. And you
> need to apply antialiasing filter at or below 1000/4/2=125 Hz. So the
> smoothing effect, if ever, would be negligible in the end anyway. So I'll
> bet there is no difference.
>
> Makoto
>
> On Mon, May 16, 2016 at 3:26 PM, robert lawson <robert at sherab.net> wrote:
>
>> I have an amp with 1000 sps sampling rate. I want to downsample to 250
>> sps. The amp firmware has a filter to low pass the data before
>> downsampling. I currently take every 4th sample. I am considering averaging
>> 4 samples instead because it seems like it would reduce random noise. What
>> are the advantages disadvantages of these 2 methods?
>>
>>
>> _______________________________________________
>> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
>> To unsubscribe, send an empty email to
>> 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
>>
>
>
>
> --
> Makoto Miyakoshi
> Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
>
-- 

Sent from my phone 425.765.1324
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sccn.ucsd.edu/pipermail/eeglablist/attachments/20160521/0fe601cd/attachment.html>