[Diy_efi] Re: Minimalist micro based EFI ?

[Bevan Weiss]

----- Original Message -----
From: "Erik Jacobs" <emj14 at columbia.edu>
To: "List for general do-it-yourself EFI talk" <diy_efi at diy-efi.org>
Sent: Wednesday, March 12, 2003 2:33 AM
Subject: RE: [Diy_efi] Re: Minimalist micro based EFI ?


> > I agree that 10bits should be adequate.  That gives 1024 codes...
> > which means on a 0->5V sensor, that's 4.8mV or similar.  I would imagine
> > that noise on the line would be greater than this, and hence the only
real
> > way to remove it would be to oversample, which is not worth it in
> > this kind of environment anyway.
>
> Couldn't you just apply some filtering on the input signal?  The noise in
an
> automotive system has got to be at far higher frequencies than any delta
> signal you'd get, wouldn't it?

What rate do your spark plugs fire???
And what's the first harmonic, second harmonic, third harmonic??

What's the signal frequency of interest??

This is one of the main problems.  Adding resolution is not the correct
answer, but filtering won't remove all the noise that we'll get.  Better
sheilding would help, as would amplifying the signal closer to it's
measurement.  But that's getting a little complicated...

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