Put a current probe around the bundle. What you measure is common mode (a good current probe should have close to 50 dB of dm rejection). In the case of power, the current probe goes around feeder and return. Alternatively, for power you may use a 3-port device such as LISNMATE device which hooks up to each LISN and to your spectrum analyzer and attenuates dm emissions by 50 dB below 30 MHz. The advantage of LISNMATE is that you may compare spectrum analyzer reading directly to the CE limit.
---------- >From: rehel...@mmm.com >To: emc-p...@majordomo.ieee.org >Subject: Common Mode or Differential Mode >Date: Tue, Jan 4, 2000, 2:20 AM > > > > > Are there "rules of thumb" or a "quick and dirty" means of determining > whether conducted emission noise (or radiated) is common mode or > differential mode? > > Thanks and have a great new year. > > Bob Heller > 3M Company > > > > --------- > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to majord...@ieee.org > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to ed.pr...@cubic.com, > jim_bac...@monarch.com, ri...@sdd.hp.com, or > roger.volgst...@compaq.com (the list administrators). > > --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
