=C7=C1=B8=AE=C3=A7=B8=DE=C0=CF =09 =09 In my case, If any system has 16 bit data= , I do simulation for current profile. For worst case, I make spice = circuit all 16 bit driver and receiver and do simulation such SSN , = then measure the current profile via time domain. V(t)*ripple tolera= nce =3D Z(target) I(profile) I set the "output variable" lice Z(targ= et) =3D V(t) * ripple tolerance/I(profile) Someone use the stimulus = as random source. Good luck. ---------- =BF=F8=BA=BB =C6=ED=C1=F6 ---------- =BA=B8=B3=BD=BB=E7= =B6=F7: Steve Waldstein =BA=B8=B3=BD=B3=AF=C2=A5: 2008/5/24 1= 9:47:59 =B9=DE=C0=BA=BB=E7=B6=F7: "'ZHENGGANG CHENG'";si-list@xxxxxxxxxxxxx =C1=A6=B8=F1: [SI-LIST] Re:= target impedance profile Zhengang,We took v(t) =3D = Inverse FFT (Z(f) x I(f)) to look at the time domain noise.Remember to have= both the real and imaginary (or magnitude and phase)portions of Z(f) and I= (f) so the coherency of the noise components add orsubtract properly when t= he Inverse FFT is performed.Steve-----Original Message-----From: si-list-bo= unce@xxxxxxxxxxxxx[mailto:si-list-bounce@xxxxxxxxxxxxx] OnBehalf Of ZHENGG= ANG CHENGSent: Saturday, May 24, 2008 5:27 PMTo: si-list@xxxxxxxxxxxxxxxxxx= ct: [SI-LIST] target impedance profileHi all,It seems many SI engineers are= using the method described below to definethe target impedance profile for= PSD:Z(f) =3D 0.05*V_DC/I(f) or Z_target=3D0.05*V_DC/Ima= x(f)Z(f)---target impedance profile at freq f;Z_target---target impedanace = at all freq;0.05---allowed tolerance;V_DC---power raill;I(f) ---current pro= file;Imax(f)---max I(f)---generallt 0.5Imax(t).But this setup does not guar= antee the overall noise is 5%. All it does ismaking sure noise at each of = the frequency of interest is less than 5%. Intime domain, the combined con= tent has the possibility of bigger than 5%.So is there a better way to defi= ne target impedance profile?Thanks,Zhenggang Cheng-------------------------= -----------------------------------------To unsubscribe from si-list:si-lis= t-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject fieldor to admini= ster your membership from a web page, go to://www.freelists.org/webpag= e/si-listFor help:si-list-request@xxxxxxxxxxxxx with 'help' in the Subject = fieldList technical documents are available at: http://www.s= i-list.netList archives are viewable at: =09=09//www.freelists.org= /archives/si-listorat our remote archives:=09=09http://groups.yahoo.com/gr= oup/si-list/messagesOld (prior to June 6, 2001) list archives are viewable = at: =09=09http://www.qsl.net/wb6tpu --------------------------------------= ----------------------------To unsubscribe from si-list:si-list-request@fre= elists.org with 'unsubscribe' in the Subject fieldor to administer your mem= bership from a web page, go to://www.freelists.org/webpage/si-listFor = help:si-list-request@xxxxxxxxxxxxx with 'help' in the Subject fieldList tec= hnical documents are available at: http://www.si-list.netLis= t archives are viewable at: =09=09//www.freelists.org/archives/si-= listor at our remote archives:=09=09http://groups.yahoo.com/group/si-list/m= essagesOld (prior to June 6, 2001) list archives are viewable at: =09=09htt= p://www.qsl.net/wb6tpu =09 = =C3=DF=C3=B5=B5=BF=BF=B5=BB=F3 =09=09=09 =09 =09[IMG][1] =C7=DA=B5=E5=C6=F9=C0=C7 =BA=AF=C3=B5=BB=E7.. =09[IMG][3] =B9=DA=C1=F6=BC=BA =B1=CD=B1=B9! =BA=B8=B0=ED= =BD=CD=BE=FA=BE=EE!![4] =09[5] =BB=C7=BA=FC=C0=CC.. =B1=D7=B4=C2 =BD=C7=C1=B8= =C0=CE=B9=B0=C0=CC..[6] =09[7] =B5=BF=BD=C3=BF=A1 =BB=E7=B6=F3=C1=F6=B4=C2 = =B5=CE=B0=B3=C0=C7 =BA=F4..[8] =09[IMG][9] =BE=EE=B8=A5=B8=B8=BA=B8=BC=BC=BF=E4[10] =09 =09=09=09 =09 --- Links --- 1 3D 2 3D"http://qtv.freechal.com/movie/QTVMovieView.asp?docid= 3 3D 4 3D"http://qtv.freechal.com/movie/QTVMovieView.asp?docid= 5 3D 6 3D"http://qtv.freechal.com/movie/QTVMovieView.asp?docid= 7 3D 8 3D"http://qtv.freechal.com/movie/QTVMovieView.asp?docid= 9 3D 10 3D"http://19.qtv.freechal.com/"; ------------------------------------------------------------------ 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