Yes - Meeting Class B with a USB cable attached IS feasible. First things first... Have you followed all the USB guidelines (such as adding a CM choke in the signal lines)? Best Regards Charles Grasso Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: 3032042974@xxxxxxxxx Email: charles.grasso@xxxxxxxxxxxx -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Bharathkumar Raju Sent: Thursday, January 17, 2008 6:03 PM To: Signal Integrity Subject: [SI-LIST] High speed USB cable What charecteristics the high speed USB cable must have to pass FCC Class B radiated emissions? We cannot add a ferrite core to the cable to supress the emissions. The device is a self powered high speed (480 MHz) USB device. From various testings it is established that the CM curent flowing through the D+ & D- conductors of the USB cable causing the failures in the radiated emission testing. The tests also established that the CM current flowing through the 5.0 volts +ve & -ve conductors of the USB cable is not at all contributing for the emissions. Is it feasible to have a high speed USB bus powered device with 1.5 m long USB cable to meet FCC / CISPR ClassB radiated emission limits (without a ferrite core attached to it).=20 Bharath PS : I hope this question is appropriate for this forum.. Get the freedom to save as many mails as you wish. To know how, go to http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu