The H pattern was to increase monitor emissions; turning the electron beam on and off periodically was a surefire way to raise emissions. I've seen a monitor with H's make a computer _beside the EUT_ test fail conducted emissions even though turned OFF.
Nowadays a Windows (etc) halftone pattern is worse, though I saw that as far back as the '90's. Cortland KA5S > [Original Message] > From: Ken Javor <[email protected]> > To: <[email protected]> > Date: 6/7/2007 12:42:17 AM > Subject: Exercising test sample during emissions testing > > A long time ago, when DOS was the PC operating system, I seem to recall that > a PC undergoing emissions testing was supposed to continually write the > character "H" to the CRT display. > > What is the requirement today under CISPR or other emissions testing > requirements to ensure that the PC is being fully exercised? > > Thank you, > > Ken Javo - 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 ______________________________________________________________________
