If the power supply noise is affecting your PLLs I suggest you look at your decoupling and/or filtering appropriate VCC pins. 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 Mikhail Matusov Sent: Friday, July 06, 2007 1:40 PM To: Istvan.Novak@xxxxxxx Cc: Christian D'Souza; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Mixed digital/RF board with switching power supplies ----- Original Message -----=20 From: "Istvan Novak" <Istvan.Novak@xxxxxxx> >=20 > It might be worth checking to see if the spurious signal that pops up is > a ringing on the switching edge rather than the harmonic of the > switching frequency. If it is ringing, you may be able to reduce it > substantially either by using an appropriate second source of changing > the converter layout (in case it is your embedded design). >=20 Thank you Istvan. That's an interesting idea. I'll see into it... /Mikhail ------------------------------------------------------------------ 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