[wineeg] Re: Time clock error suspected in WinEEG1.4

  • From: "David E. Myer, Sr." <damyer@xxxxxxx>
  • To: wineeg@xxxxxxxxxxxxx
  • Date: Sat, 15 Mar 2003 13:21:33 -0500

Hi, Joe.

Naturally, our old Dell laptop (W98) advances its "paper" at exactly 1 sec=
per major division of the scrolling scale. So, seconds on a real clock=20
correspond with "seconds" on the glass strip chart.  Same thing on=20
batteries or on AC (200 MHz vs 500 MHz).

Now, the newer, much faster, more modern desktop system (W2000Pro) exhibits=
a consistent error. It shows one "paper second" for every 2.2 clock=20
seconds, resulting in quite significant errors within a 5-minute recording.=
This value seems consistent, but I have't had a chance to look for normal=20
spectrum components yet. The only client I have used the new computer on,=20
proved to be highly unusual. So, in his brain, I have no sure benchmarks to=
trust or to measure with a different machine.

I will check for a newer Microsoft Service Pack for W2000Pro . . . more=


At 05:59 PM 3/15/03 +0100, you wrote:

>Looks like it just is the epochs that are labeled incorrectly, while
>the spectral analysis looks correct. The individual peak alfas (eyes
>closed) have been around 9-11Hz in our qEEGs of normal subjects,
>which is what one would expect.
>Maybe the labeling actually shows paper length? 500 seconds at 30
>mm/s =3D3D 15000 mm paper =3D3D 1500 cm =3D3D150 desimeters (which is close=
>the no. "157". The labeling doesn=3DB4t seem to change when one changes
>the paper speed value though...
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