The sensitivity issue could be addressed via a pre-amplifier, or possible cascade of a couple pre-amplifiers. So that isn't a show-stopper.
The F-65 current probe transfer impedance is flat with respect to frequency over its 1 M - 1 GHz range, so there is no problem there, either. But the o'scope gives you time domain info, and your 40 dBuA limit is in the frequency domain. So you need to get from the time domain to the frequency domain. I'm not familiar with the o'scope models cited but some scopes have built-in FFT capability, and even if that doesn't exist, there should be some way to get the scope data into a PC and perform the FFT there. > From: [email protected] > Date: Fri, 22 Jun 2007 11:50:32 +0530 > To: [email protected] > Cc: [email protected] > Subject: Using Common mode current probe with an oscilloscope > > Dear Experts, > > 1. With a current probe (similar to the Fischer Custom Communication Inc. > make model 'F - 65') connected to the oscilloscope (similar to the model > 'TDS 7145' & 'TDS 7404' of Tektronix) will it be possible to measure / > identify common mode emissions in signal cables like UTP ethernet cable, > USB cable used for high bus powered (about 500 mA) device, USB cable used > for low bus powered (about 100 mA) device, D.C power cable (both shielded > and unshielded) with about 1 amps etc. > > 2. What are the issues / short comings that one can expect while using such > a common mode current probe connected to a digital storage oscilloscope > (1.5 / 4.0 GHz bandwidth). > > We have scopes & an impedance analyser but do not have a spectrum > analyser. We have Agilent make '4294A' model precision impedance analyser. > Is it possible to interface through some hardware the common mode current > probes with this analyser and measure cable common mode emission? > > Bruce L. Harlacher of Fischer highlighted issues like poor > sensitivity of scopes for the 0.1 milli volts output of F - 65 for 40 dBuA > current and like things. I started discussing with Tek engineers and to > start discussion with Agilent. I always found experts advise / inputs from > this forum very useful. > > Sincerely > > K.Balasubramanian > Manager - Hardware Support. > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. Website: http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to [email protected] > > Instructions: http://listserv.ieee.org/request/user-guide.html > > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > > Scott Douglas [email protected] > Mike Cantwell [email protected] > > For policy questions, send mail to: > > Jim Bacher: [email protected] > David Heald: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
