Steve, yes that sounds reasonable, when looking thru PCI-SIG presentations, it's clear that the fixed -3.5 dB de-emphasis for PCI Express Gen 1, was made as an trade-off, with respect to target channels where it is supposed to be used. Are there any other SerDes interface standards besides PCI Express Gen 1 & 2, that has default tap settings? 2014-09-02 22:22 GMT+02:00 steve weir <weirsi@xxxxxxxxxx>: > You may find that for consistently built short links that fixed EQ is > fine. And you may even find that the default coefficients are > adequate. But I don't know how you get there without doing the homework > at least once. > > Steve > > On 9/2/2014 1:06 PM, Mario Antolos wrote: > > For SerDes transceivers with high equalization capabilites and many > > different tap combinations, when it's "good enough" to use default > > settings, instead of performing extensive optimal tap settings search? > > I know that it should boil down to how much margin (losses, receiver > > sensitivty, etc) we have, but for example in cheap consumer electronics, > > it's cheaper to have fixed default tap setting then to have programmable > > tap settings. > > > > > > Also what are default tap settings? > > > > For example in PCI Express where we have: > > > > -3.5 dB de-emphasis, for 2.5 Gbps & 5 Gbps > > > > -6.0 dB de-emphasis, for 5 Gbps > > > > > > Thanks, Mario > > > > > > ------------------------------------------------------------------ > > 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