From: yaniv_vi (yaniv_vi_at_yahoo.com)
Date: 2002-01-09 18:16:49
--- In buildcheapeeg_at_yahoogroups.com, "Joerg Hansmann" <info_at_jhansmann.de> wrote:
> Hi all,
>
> ----- Original Message -----
> From: Jim Meissner <jpmeissner_at_mindspring.com>
> To: <buildcheapeeg_at_yahoogroups.com>
> Sent: Wednesday, January 09, 2002 1:31 PM
> Subject: Re: [buildcheapeeg] New input stage
>
> ...
> > Check this out with the chief engineer Joerg Hansmann.
>
> I do not feel as a chief engineer at all, for this position
> I simply do not have enough experience and knowledge nor
> the required leading qualities ...
don't worry , you'll learn on the job :)
>
>
> [many important points snipped due to a lack of time]
>
> ...
> > Opinion: The U1 gain could be set much higher and U3 lower.
> > Also U1 has half the noise at a G = 100 vs. G = 10.
>
> For low noise high gain in the first stage is good, but not for
> electrode DC offsets. (saturation of the input stage)
>
> Therefore I have used INA114 with G=10 (according to the
application
> example in the INA114 datasheet for an ECG monitor ).
>
> At gain=10, the INA114 seems to be superior to the lt1167.
>
> Electrode offsets can easily result when combining different
electrodes
> (my electrode supplyer LAZINA told me, that some people really
> combine different types) or when the Chloride skin of AgCl type
> electrodes wears off.
>
> I have assumed that 100mV DC electrode offset should be handled by
the input
> stage. But maybe I was overly cautious.
>
> Some electrode experts here, who know about electrode offsets ?
>
>
>
> Regards,
>
> Joerg
This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:36 BST