GSM-noise "buzz" issue
joerg at openmoko.org
Mon Sep 22 01:33:59 CEST 2008
[oops, sorry for delayed post]
Am So 21. September 2008 schrieb Werner Almesberger:
> Joerg Reisenweber wrote:
> > Clock-harmonics and the like are a completely different story, and also
> > clock frequency itself could create noise if a clocked component is placed
> > inside audio can, not only it's harmonics.
> Yes, that's what I meant: noise we generate in the CPU can sneaking
> out and, say, hitting GPS. Given the current poor RF design, this is
> probably already happening, it's just not bad enough that it would
> lead to something clearly visible as a failure.
> We could actually test this: rework a device such that only GPS is
> powered and communicate with GPS
[editor: create a link from a GPS-app on an auxiliary device to chipset on
> from a remote system (over a
> properly exorcised cable). Then compare the performance between this
> system and a regular device.
...in a way I mentioned xx times, named A/B-double-blind test
> Ah, so many ideas, so little time ... and so few devices to
> slaughter ;-)
> - Werner
a brilliant idea, even better than (or as good as) doing a plot of emitted
(rogue) frequencies in a RF-clean room (Faraday-room), in the range from 1MHz
to 2500. (exactly what I recently asked a German guy to do, in one of my last
Werner, we're not short on devices to gain decent results (the type of results
we couldn't gain knowledge about from simple reading of ABS.MAX.Ratings in
datasheets). Argentina customs is a different issue.
Tell me what you like to do exactly and I'll see whether I can set up a test
environment :-). Actually got some spare devices.
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