Shekar, You are correct that the CM impedance is greater than 50 ohms - but not by much. Is it better to have no CM termination (rho = 1), or imperfect CM termination (rho ~~0) for CM signals? The single resistor provides the former, the split R with cap provides the latter. What is the CM range of your receiver? Can it tolerate a doubling of CM noise? Regards Mike shekhar sharma wrote: > Steve, > > Thanks for correction. Some mixing.... > Anyway, I think, this termination terminates the even > mode (AC termination) upto some extent, coz the the > resistance values are 50 ohm each with their common > point connected to a capacitor. Diff pair with 100 ohm > diff impedance will have common mode impedance more > than 50 ohm. > > > --- steve weir <weirsp@xxxxxxxxxx> wrote: > >>You are right that it terminates both modes. You >>just have the modes >>confused. Even is the common mode, odd is the diff. >>mode. The AC >>termination is to the even mode. >> >>Steve. >>At 11:37 AM 8/30/2004 +0100, shekhar sharma wrote: >> >>>Two resistor with centre tap capacitor termination >>>provides AC termination to odd-mode impedance which >>>terminates common mode signal. >>>May I right ??? >>> >>>Shekh >>> >>> >>> --- steve weir <weirsp@xxxxxxxxxx> wrote: >>> >>>>The two resistor termination is a double >>>>single-ended termination. The >>>>single resistor termination presumes a virtual >>>>ground at the center of the >>>>resistor. >>>> >>>>What noise sources do you think LVDS is trying >> >>to >> >>>>reject? >>>>What noise sources do you think LVDS can reject? >>>>What noise sources do you think LVDS cannot >> >>reject? >> >>>>Steve. >>>>At 03:34 PM 8/30/2004 +0530, Ummalaneni, Venu >> >>Babu >> >>>>(Venu) wrote: >>>> >>>>>Hi=20 >>>>> >>>>>This query is regarding termination schemes at >> >>the >> >>>>LVDS receiver inputs. >>>> >>>>>Can some one explain me the difference between >> >>a >> >>>>'single resistor >>>> >>>>>termination' and 'the two resistors with center >> >>tap >> >>>>capacitor' ? >>>> >>>>>I read some where that the 'center tap >> >>capacitor >> >>>>scheme' filter's the >>>> >>>>>common mode noise. My doubt is that even in >> >>'single >> >>>>resistor scheme' >>>> >>>>>also if we run the differential traces verly >>>> >>>>closely the common mode >>>> >>>>>noise pick-up by the two traces is equal and >> >>the >> >>>>Receiver can reject >>>> >>>>>this common mode part, right? So why we need to >> >>go >> >>>>for center tap >>>> >>>>>capacitor scheme? It unnecessarily increase the >>>> >>>>component count on the >>>> >>>>>board, right? >>>>> >>>>>Any inputs are appreciated. >>>>> >>>>>Best regards >>>>>Venu Babu. >>>>> >>>> >>------------------------------------------------------------------ >> >>>>>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 FAQ wiki page is located at: >>>>> >>>> >>>>http://si-list.org/wiki/wiki.pl?Si-List_FAQ >>>> >>>>>List technical documents are available at: >>>>> http://www.si-list.org >>>>> >>>>>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 >>>>> >>>> >>>> >>>> >>------------------------------------------------------------------ >> >>>>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 FAQ wiki page is located at: >>>> >>>>http://si-list.org/wiki/wiki.pl?Si-List_FAQ >>>> >>>>List technical documents are available at: >>>> http://www.si-list.org >>>> >>>>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 >>>> >>>> >>>> >>> >>________________________________________________________________________ >> >>>Yahoo! India Matrimony: Find your life partner >> >>online >> >>>Go to: http://yahoo.shaadi.com/india-matrimony >> >> >> > ------------------------------------------------------------------ > >>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 FAQ wiki page is located at: >> >>http://si-list.org/wiki/wiki.pl?Si-List_FAQ >> >>List technical documents are available at: >> http://www.si-list.org >> >>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 >> >> >> > > > ________________________________________________________________________ > Yahoo! India Matrimony: Find your life partner online > Go to: http://yahoo.shaadi.com/india-matrimony > ------------------------------------------------------------------ > 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 FAQ wiki page is located at: > http://si-list.org/wiki/wiki.pl?Si-List_FAQ > > List technical documents are available at: > http://www.si-list.org > > 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 > > > ------------------------------------------------------------------ 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 FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org 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