Liyaoshi, We have the same problem. I agree with what you mentioned. We checked If the RJ45 cable is not plugged in, but still failed the Radiated emissions test. What else we should look into? the RJ45 connector has the integrated magnetic.
Regards, Shu On Wednesday, May 14, 2014 at 9:52:10 PM UTC-5, liyaoshi wrote: > > 625M clock noise maybe from 125M clocksource， or 25M > This might be from ethernet > Do you use GIGA ethernet ? > And > Try to unplug the RJ45 cable > > > 2014-05-15 5:01 GMT+08:00 Gerald Coley <ger...@beagleboard.org > <javascript:>>: > >> OK. Understood. Different test equipment will yield different results. >> And it can be effected by the SW you are running. >> >> Gerald >> >> >> On Wed, May 14, 2014 at 3:59 PM, <l...@ansync.com <javascript:>> wrote: >> >>> It's not something unique to our board--a stock BBB has the same problem. >>> >>> >>> On Wednesday, May 14, 2014 1:41:29 PM UTC-7, Gerald wrote: >>> >>>> Sounds like you may have grounding issues or unterminated pin . Using a >>>> probe should let you be able to determine which side of the chip it is. >>>> >>>> Gerald >>>> >>>> >>>> >>>> On Wed, May 14, 2014 at 3:37 PM, <l...@ansync.com> wrote: >>>> >>>>> It seems to come from right around the processor, but we couldn't >>>>> pinpoint it any more precisely than that, or even to one side of the >>>>> board >>>>> or other. >>>>> >>>>> >>>>> On Wednesday, May 14, 2014 10:56:28 AM UTC-7, Gerald wrote: >>>>> >>>>>> In order to mitigate it you need to figure out where it >>>>>> is coming from. A probe test will help in that area. Have you run one? >>>>>> Using ferrites on all cables generally helps in these types of issues. >>>>>> >>>>>> Gerald >>>>>> >>>>>> >>>>>> >>>>>> On Wed, May 14, 2014 at 12:01 PM, <l...@ansync.com> wrote: >>>>>> >>>>>>> We have a BBB-based design currently undergoing FCC testing, and >>>>>>> they've found a bit of noise at 625 MHz. Has anyone else encountered >>>>>>> this, >>>>>>> or know what it might be, or how to mitigate it? >>>>>>> >>>>>>> -- >>>>>>> For more options, visit http://beagleboard.org/discuss >>>>>>> --- >>>>>>> You received this message because you are subscribed to the Google >>>>>>> Groups "BeagleBoard" group. >>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>> send an email to beagleboard...@googlegroups.com. >>>>>>> >>>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>>> >>>>>> >>>>>> -- >>>>> For more options, visit http://beagleboard.org/discuss >>>>> --- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "BeagleBoard" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to beagleboard...@googlegroups.com. >>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>> >>>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "BeagleBoard" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to beagleboard...@googlegroups.com <javascript:>. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to beagleboard...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
