> I am trying to accurately measure SSO noise. However > I am not sure my equipments are right for the job. Can anyone > comment on these setup? > Agilent 2Gsa/s (or 4Gsa/s) scope > 10:1 1MOhm Passive probe(comes with the scope) You might want to consider investing in active probes. Or making your own passive probes out of smaller valued resistors. The usual 10:1, 1Mohm passive probe is OK for signals below a few tens of MHz, or risetimes in the 5-10ns and up range. The ground clip is too long, resulting in a sizeable loop. Although the DC input resistance may be big, so is the capacitive loading. On many of these probes, the input resistance (real part of the impedance) itself falls way off as you go up in frequency, becoming a significant loss component. > (The rise time of my signal is 1ns.) Then you're only getting a couple scope samples in a risetime. You won't see the shape of the risetime, and might miss capacitive coupling that lasts only as long as the risetime. 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 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