Thanks, Steve. The freq. exceeding the EMI margin is 8GHz. Enabling SSC should help on that I think. Any impact & precaution for turning SSC on? Looks there would be no big issue since all our chip vendors claims their products work fairly well with SSC on... Best Regards, Sherman Chen Signal Integrity EMC Global Hardware Engineering Tel: +86 21 60951100-3329 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of steve weir Sent: Tuesday, September 02, 2014 7:04 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: options for reducing EMI This is another infamous: "It depends". First: Will any combination of anticipated measures yield a solution that meets both your SI and EMC requirements? Second: Do you prioritize margin to SI or EMC, or split them? It sounds like you have a design that has failed EMC. Before twiddling anything that you can look at where you are failing and how badly. TX swing can only reduce noise in the best case dB for dB. So, if you just need a couple of dB to squeak by and have the link budget, it is an option. SSC can buy up to 10dB on the clock and harmonics. Edge rate could help if you have resonance issues. Otherwise, it is similar to fiddling with the Tx swing. Steve On 9/1/2014 1:43 PM, Chen, Sherman wrote: > Hi SI Gurus, > We are considering the following options in order to reduce the EMI of one of > our boards, which is mainly caused by the PCIe Gen3 link: > > 1. Reducing TX swing. > > 2. Turn on SSC. > > 3. Slowing down edge rate. > While we are running test to verify which option will bring us the best > result & least impact, any comments or suggestions from those who had > experiences on this matter? > > Best Regards, > > Sherman Chen > Signal Integrity > EMC Global Hardware Engineering > Tel: +86 21 60951100-3329 > > > ------------------------------------------------------------------ > 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 forum is accessible at: > http://tech.groups.yahoo.com/group/si-list > > List archives are viewable at: > //www.freelists.org/archives/si-list > > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > -- Steve Weir IPBLOX, LLC 1580 Grand Point Way MS 34689 Reno, NV 89523-9998 www.ipblox.com (775) 299-4236 Business (866) 675-4630 Toll-free (707) 780-1951 Fax All contents Copyright (c)2013 IPBLOX, LLC. All Rights Reserved. This e-mail may contain confidential material. If you are not the intended recipient, please destroy all records and notify the sender. ------------------------------------------------------------------ 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 forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ 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 forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu