> -----Original Message----- > From: [email protected] > [mailto:[email protected]]On Behalf Of Scott Douglas > Sent: Monday, October 26, 1998 10:50 AM > To: [email protected] > Subject: Required Margin for EMI? > > > Hello all, > > When doing EMI scans of ITE, I have always worked with a margin of 2 dB > less than the actual limit. No test house I have ever been to will give a > "meets the requirements..." without having this margin. Can anyone point > out if this is an actual requirement built into any of the standards, i.e. > EN 55022 or FCC Part 15, etc. and if so, where is it in writing? > > I understand about measurement errors, product to product differences and > repeatability of testing issues. Just want to know if the 2dB margin is > actually written into law. > > Thanks for your comments. > Scott > [email protected]
It is not written into EU law. The old VDE "f" mark required 2dB margin. My former employer, TUV Product Service, _would_ issue a passing report on any result zero dB or greater margin. Of course there was also a prominent statement of the measurement uncertainty of plus or minus 5.4 dB. From a practical standpoint, I wouldn't expect my customer to have much faith in my product if it had a one dB margin in that uncertainty margin. Best regards, Brent G DeWitt Datex-Ohmeda Medical Louisville, CO --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
