Exactly. And, Ari, maybe we need to make this clearer in the next update to CISPR 22 and in CISPR 32 when we finally publish it (in our lifetimes?).
Ghery From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of ari.honk...@nsn.com Sent: Wednesday, February 20, 2008 12:00 PM To: emc-p...@ieee.org Subject: RE: CISPR 22 / ANSI C63.4 antenna-to-EUT distance I have the 2005 version of CISPR 22 in hand and it says: "The boundary of the EUT is defined by an imaginary straight-line periphery describing a simple geometric configuration encompassing the EUT. All ITE intersystem cables and connecting ITE shall be included within this boundary (see also Figure 2)". In other words, if the footprint of EUT, cables and used accessories is not a circle, the test distance varies when the table is rotated. This is indeed inconvenient, and what we usually do is that we take the closest distance available using such straight-line periphery and set that as the prescribed test distance. We penalise ourselves a bit since in some azimuths one EUT corner is too close but with typical EUT's the effect is not significant since we want anyhow some margin to the limits. regards, Ari Honkala Nokia Siemens Networks ________________________________ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of ext Bill Owsley Sent: 20. helmikuuta 2008 20:29 To: Pettit, Ghery; T.Sato; emc-p...@ieee.org Subject: RE: CISPR 22 / ANSI C63.4 antenna-to-EUT distance Ghery, I don't understand your desciption. I thought the original question was to find the 3 or 10 or 30 meter distance, numbers not actually mentioned, specified in the two standards given the interesting text in the standards. For example, Figure 3 of CISPR 22:2003 shows the circle surrounding the EUT system, and the two straight lines across the center. Then the distance L is indicated from the perimeter of the circle to the antenna center. This defines the specified measuring distance of antenna to EUT system. Then if one is interested in the "actual" distance from antenna to EUT, given that the EUT is setup along the edge of the table such the cables hang off, a measurement would have to be made, or if good at trigonometry - calculated. Thus, as the EUT is rotated during the survey, the measuring distance - "actual" antenna to EUT distance, changes as the turntable rotates. Figure 5 of C63.4:2003 seems to indicate much the same - a circle indicating the EUT on a turntable. Now there has been some debate of the definition of what's being tested. Is it just the EUT part of a system setup and then the distance measurement is made from just the EUT part and not encompassing system of accessories? Or does the system, which includes the EUT, become the whole of what is being tested and thus the distance is from the edge of the system, the outer most point of the various parts? "Pettit, Ghery" <ghery.pet...@intel.com> wrote: Actually, draw an outline of the EUT boxes on the table. Now draw a straight line between the outer edges of the boxes. As the turntable rotates the measurement distance is from the antenna to this outline. It is not a circle containing the EUT, the actual measurement point can be closer to the center of the table as it rotates. Ghery Pettit ________________________________ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Bill Owsley Sent: Wednesday, February 20, 2008 6:57 AM To: T.Sato; emc-p...@ieee.org Subject: Re: CISPR 22 / ANSI C63.4 antenna-to-EUT distance I understand it to be such when the system is assembled on a turntable, which is then rotated, the system can be contained within a circle described by the outer most device as the system rotates. Then the distance is from this circle to the antenna center, however the antenna center is defined. The straight line reference might be the tangent of the circle closest to the antenna. I get to have fun when one complete product is about 1 inch in size and the next is just over 12 feet in diameter. - Bill "T.Sato" <vef00...@nifty.ne.jp> wrote: Dear experts, I have a question about definition of antenna-to-EUT distance in CISPR 22 and ANSI C63.4. CISPR 22:2005 clause 10.3.1 ("Antenna-to-EUT distance") says that: Measurement of the radiated field shall be made with the antenna located at the horizontal distance from boundary of the EUT as specified in Clause 6. The boundary of the EUT is defined by an imaginary straight-line periphery describing a simple geometric configuration encompassing the EUT. This text is not very clear for me, but I think use of the "imaginary straight-line periphery" suggests that it is not intended to define the distance as the minimum distance between the antenna and boundary of the EUT when the EUT is rotated. I think that the Figure 2 suggests the same thing, and the figure also suggests that the distance is to be measured from front, or front or rear, of the EUT. Does anybody know clearer interpretation about this? And what about ANSI C63.4-2003, which simply says that: The specified distance is the distance between the horizontal projection onto the groundplane of the closest periphery of the EUT and the projection onto the groundplane of the center of the axis of the elements of the receiving antenna. in its clause 8.2.3? Regards, Tom Tomonori Sato URL: http://homepage3.nifty.com/tsato/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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Try it now. <http://us.rd.yahoo.com/evt=51733/*http:/mobile.yahoo.com/;_ylt=Ahu06i62 sR8HDtDypao8Wcj9tAcJ%20> - ---------------------------------------------------------------- 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 emc-p...@ieee.org 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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - Bill You can say what you want about the South, but you never hear of anyone retiring and moving North!!! ________________________________ Never miss a thing. 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