scramble also can decrease EMI. i was testing the HDMI 2.0 UD60 signals. Before sending, the data was scrambled for decreasing EMI 2014-09-04 5:27 GMT+08:00 Chen, Sherman <sherman.chen@xxxxxxx>: > Understood. That's why we've been keeping SSC off. Thanks. > Best Regards, > > Sherman Chen > Signal Integrity > EMC Global Hardware Engineering > Tel: +86 21 60951100-3329 > > From: Scott McMorrow [mailto:scott@xxxxxxxxxxxxx] > Sent: Wednesday, September 03, 2014 9:31 PM > To: Chen, Sherman > Cc: weirsi@xxxxxxxxxx; si-list@xxxxxxxxxxxxx > Subject: Re: [SI-LIST] Re: options for reducing EMI > > Chen > > You can certainly do that, but it's a band aid for whatever the actual > problem is. You should just not be radiating at 8 GHz. > > Regards, > > Scott > > > Scott McMorrow > Teraspeed(r) Consulting - A Division of Samtec > 16 Stormy Brook Rd > Falmouth, ME 04105 > (401) 284-1827 Business > http://www.teraspeed.com > > On Wed, Sep 3, 2014 at 9:20 AM, Chen, Sherman <sherman.chen@xxxxxxx > <mailto:sherman.chen@xxxxxxx>> wrote: > 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> > [mailto: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<mailto: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<mailto: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<mailto: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<http://www.ipblox.com> > > (775) 299-4236 Business > (866) 675-4630 Toll-free > (707) 780-1951 Fax > > All contents Copyright (c)2013 IPBLOX, LLC. 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