Jon, I may be in the minority but I have to disagree with your comment ' don't take the 0dB's into account ' While every attempt is made to design well below the limit, a pass is still a pass. It is my opinion that the standards bodies build in a 'measurement uncertainty' when creating the requirements. This is probably one of the factors contributing to their long incubation period. In fact one lab in particular in the UK speaks about a +2, -3dB. limit. If everybody chooses to move the goal posts by creating de-facto requirements, then the game becomes very dull indeed.
Best regards Barry Singleton Approvals Specialist email:[email protected] Securicor 3net Limited Ringway House Bell Road Daneshill Basingstoke Hants RG24 8FB UK Tel: 44 (0)1256 792174 ------------- Original Text From: Jon Griver <[email protected]>, on 15/10/96 22:41: Doug McKean wrote: (Taken out of context) >6dB would be comfortable. >Unfortunately, I have been in a lab that passed at only 0.5dB. There has been some confusion in this discussion between the test lab's responsibilities and the manufacturer's responsibilities. The test lab tests the sample(s) the manufacturer submits. The lab's responsibility is to test the product in a professional manner according to the standards requested by the manufacturer. A margin of 0dB is a pass and the manufacturer has the right to expect the test lab to issue a pass test report. The manufacturer's responsibility is to comply with the EMC Directive (or other regulations around the world). If the manufacturer does not realise it, the lab should explain to him that a 0dB margin means that most likely a large percentage of his production will be over the limit, and that he should be aiming for a margin of xdB to give him a particular level of confidence that his production complies. Cynthia, when you do your statisitics, don't take the 0dB's into account, as these do not refer to confidence margin, but to the test results of an individual sample submitted to a test lab. Jon Griver ITL (Product Testing) Ltd. [email protected]
