GSM-noise "buzz" issue

Werner Almesberger werner at
Sat Sep 20 23:46:20 CEST 2008

Joerg Reisenweber wrote:
> YUP, long ago. Result: fix noise.

Excellent !

> Maybe you even 
> could visit me at Guantanamo then, which is more close to Argentina than 
> Germany is. :D

Heh, Joerg, the internationally wanted RF Cyberterrorist ;-)

But that's something you'll have to solve anyway. Otherwise, even
the nicest CMU200 will be of little use.

> > Basic guidelines:

Good principles for sure.

> > All connectors to outside of housing SHOULD have EMI-filters [[edit: as
> > close as possible to component]] on all lines

Shouldn't the EMI filters rather be where the signals enters the cage ?

> > *) that's one of the points why it's more reasonable to have a separate
> > cage.

Hmm, makes the mechanical setup more complex, though.

> > We don't want the need for EMI-block on lines that aren't related to
> > audio, but run to same cage.

Shouldn't they be filtered anyway, lest we contaminate other signal
paths, e.g., hyper-sensitive GPS ?

- Werner

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