[Eeglablist] What type of monitor gives less noise inthe neuropsychology experiment?

Margaret Mortz migsmortz at icehouse.net
Thu Jun 30 16:20:54 PDT 2005


 The LCD display produces little EMI (electromagnetic interference).  But
the computer itself produces EMI. 

A Faraday Cage  can reduce the computer emissions.  A improvised method is
to use copper screening and form a closed conducting "box", with the
computer and display inside.

Margaret Mortz
mmortz at wsu.edu

-----Original Message-----
From: eeglablist-bounces at sccn.ucsd.edu
[mailto:eeglablist-bounces at sccn.ucsd.edu] On Behalf Of GWMobile
Sent: Thursday, June 30, 2005 12:39 PM
To: morozov at mail.cplire.ru
Cc: eeglablist at sccn.ucsd.edu; geotransfer at mindspring.com
Subject: Re: [Eeglablist] What type of monitor gives less noise inthe
neuropsychology experiment?

CRT's give out TERRIBLE NOISE IN THE 60 and 30 HTZ RANGE. IF YOU DO ANY LOW
LEVEL RECORDING WITH THE MONITER ON IT WILL INTRODUCE SUCH A HUM INTO ANY
AMPLIFIED ELECTROMAGNETIC INPUT (including even microphones) AS TO MAKE IT
UNUSEABLE.


I have found I must turn the crt's off beofre recording and then back on
when finished.

Additionaly some cellphones such as sidekicks and blue tooth devices give
off loud intermittent bursts of signals. Balckberrys treo and sidekicks if
within 2 feet of a car radio with actually be easily heard in the car radio.

I think lcds are much lower however best is to eleimate all equipment 20ft
from the area and turn off what you can't eliminate.


On Thu, 30 Jun 2005 9:57 am, Alexei A. Morozov wrote:
> Dear colleagues,
>
> Could you please give me an advice.
> I am going to automate a neuropsychology experiment.
> The visual stimulus will be demonstrated on the computer monitor.
> So, the question is what type of computer monitor
> produces less noise – LCD of CRT?
> I have read that TFT (LCD) monitor produces less noise, but it has
> the vertical scanning frequency 56 – 75 Hz, that intersects with
> the Gamma frequencies that we want to measure.
> Well, could anybody tell me please what type of monitor
> gives less noise in the neuropsychology experiment?
> Have anybody compared various types of computer monitors?
>
> Thank you,
>
> Alexei
>  
>
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Typed from my mobile phone. Please excuse the typos!
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