Has anyone tried a ADC (analog to digital converter) to measure this noise? They come with fine granularity. Then one needs to allocate a clean / quiet ground and measure the noisy ground. Any critic to this idea? --- Andrew Ingraham <a.ingraham@xxxxxxxx> wrote: > > a) By using a 50Ù probe, did I create a > voltage divider? > > Adding a probe of any kind (except non-contact > optical, perhaps) always > affects the circuit. There is always some loading > (voltage divider), and > other things that affect what you see. > > > To check the sanity of my measurement, Instead of > my 50Ù probe, I used a > > standard 1MÙ probe and carried out the > measurement. > > Check the sanity check experiment by connecting both > probes at the same > time. > > You could also try experimenting with a passive > probe by inserting a small > series resistor between the pad and your coax cable. > For example, 450 ohms > gives you a pretty good 10:1 probe with 10 times the > input impedance, if > you're careful with the layout. > http://www.emcesd.com/1ghzprob.htm and > other places have tips on this. > > Use the scope (e.g., bandwidth controls) to see what > kind of noise you are > getting. > > Be careful about the maximum input voltage at the > scope. Some are rated for > less than 2V before damage may occur. > > Regards, > Andy > > > ------------------------------------------------------------------ > To unsubscribe from si-list: > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in > the Subject field > > or to administer your membership from a web page, go > to: > //www.freelists.org/webpage/si-list > > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the > Subject field > > List FAQ wiki page is located at: > > http://si-list.org/wiki/wiki.pl?Si-List_FAQ > > List technical documents are available at: > http://www.si-list.org > > List archives are viewable at: > //www.freelists.org/archives/si-list > or at our remote archives: > http://groups.yahoo.com/group/si-list/messages > Old (prior to June 6, 2001) list archives are > viewable at: > http://www.qsl.net/wb6tpu > > > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu