Hi everybody, is there any further progress on this issue? How can we help to solve this issue?
Greetings Torsten On Wednesday 01 October 2008 05:34:24 Joerg Reisenweber wrote: > Am So 21. September 2008 schrieb Uwe Klein: > > On 9/21/08, Werner Almesberger <[EMAIL PROTECTED]> wrote: > > > Andy Green wrote: > > > > One interesting thing would be stick a tracking generator on the GSM > > > > antenna, put it near the headphone socket in a repeatable way, stick > > > > spectrum analyzer probe on the victim net, and sweep them to get a > > > > display of coupling efficiency vs frequency. > > > > > > Do you think this will work ? I thought of using a tracking generator > > > when I wrote that mail lamenting that Joerg didn't have a signal > > > source, but then I realized that almost all tracking generators have > > > their maximum output at about 0dBm, while our troublemaker should be > > > more like 30dBm. > > > > I had thought about using the FR as an energy sink. > > Using a 4pole networkanalyzer and a pair of antenna > > in a grid dip meter style arrangement. > > This should indicate all absorbtive elements. > > A very cute test setup. > Anyway I don't exactly see what we have learnt once we know all dips by > name, err frequency and dB. I'd guess we get a lot of dips, and we can't > tell what element caused them, and especially we don't learn anything about > audio contamination path. Even less we learn something *new*. > Werner's original proposal seems somewhat more result oriented, alas all > this fails when attaching probe to the "victim net", due to total change of > RF-properties (probe has some pF! need to open can, etc). So probably the > most helpful test would be to use a +36dBm generator at 850/900/.... and > "record" buzz by arecord piped to ssh-stdout to external PC, so you can > level up generator and see what dBm you need at different frequencies to > start buzz. Basically exactly the tests I already did in TPE, though I had > to use a second phone for generator purpose, and this was rather clumsy and > not very reproduceable. > > Also direct coupling of RF to JK4401:4 at a moderate level might be a way > to go, then check with scope/spectralizer all the pins and pads inside can, > and get an idea of where RF jumps to from primary path (if any). Again we > won't learn anything about how we could improve things, other than KEEP RF > OUT of CAN, i.e. away from non-linear audio-circuits. > > Anyway, I'm looking forward to read your report on test results. > > cheers > jOERG _______________________________________________ hardware mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/hardware
