Chris, There are so many ways to skin a cat! High-speed chip makers do specify Tx RJ and DJ (jitter generation) numbers and also Rx jitter tolerance numbers. As a matter of fact, various high-speed interface standards call for the specification of those jitter characteristics. System designers use those numbers while evaluating the performance over their links. The jitter tolerance number is a measure of the Rx performance. An HSPICE simulation may not easily give you a BER number but it gives you an eye-pattern at the end of the link which you can use to determine if it meets the far-end eye-pattern expected by the receiver. Best regards. Hassan. On Feb 15, "Chris Cheng" <Chris.Cheng@xxxxxxxxxxxx> wrote: > > I am a firm believer of divide and conquer. The same reason you don't = > simulate your Tx/Rx PLL jitter while you are doing your prop delay = > analysis. They are separate components of a BERT budget. You are asking = > for trouble and unnecessary complexity if you try to do it all in the = > same time in SPICE or IBIS. > Besides, who really knows what his Tx Rj is anyways ? > Further more, without knowing your CDR jitter transfer, how do you know = > the BERT is really that bad AFTER your CDR recover the clock that is = > used to capture your data ? > > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx > [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Hassan O. Ali > Sent: Wednesday, February 15, 2006 3:05 PM > To: si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] Re: HSPICE - adding jitter to ethernet serial link > > > > I don't know how the two methods would compare. What do you think? > > Best regards. > > Hassan. > > > On Feb 15, "Chris Cheng" <Chris.Cheng@xxxxxxxxxxxx> wrote: > >=20 > > If the channel is indeed linear, what's the difference between not = > doing =3D > > Rj at all and simulate your PRBS, get the minium eye opening (Dj) then = > =3D > > add a seperate Rj convoluted with impulse response ?=3D20 > >=20 > > -----Original Message----- > > From: si-list-bounce@xxxxxxxxxxxxx > > [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Hassan O. Ali > > Sent: Wednesday, February 15, 2006 2:18 PM > > To: si-list@xxxxxxxxxxxxx > > Subject: [SI-LIST] Re: HSPICE - adding jitter to ethernet serial link > >=20 > >=20 > > Chris, > >=20 > > The HSPICE approach allows you to see the effect of source RJ as well = > as =3D > > both source and=3D20 > > channel-induced DJ. I think the convolution you're referring to = > doesn't =3D > > consider source=3D20 > > DJ. > >=20 > > I'm thinking out loud here, but I think in simulation, if the input = > =3D > > pattern is known, it=3D20 > > doesn't need many bits to simulate a case of worst-case jitter (or =3D > > eye-opening) for a=3D20 > > particular BER requirement.=3D20 > >=20 > > For example, for a BER of 10E-14, the max pk-to-pk RJ is approx. 15.3 = > =3D > > times RJ(rms). To=3D20 > > simulate the worst-case total jitter, In the PWL source you could use = > =3D > > that amount of max=3D20 > > pk-to-pk RJ right at the bit where you expect the worst-case ISI e.g. = > at =3D > > a lone "1" that=3D20 > > follows a long run of 0's. In other words, I think you can = > strategically =3D > > define source=3D20 > > RJ and DJ amounts along your bit stream and cover the entire = > eye-pattern =3D > > voltage/time=3D20 > > bounds in just a few bits. Anyone out there has done this? > >=20 > > Best regards. > >=20 > > Hassan. > >=20 > >=20 > >=20 > > On Feb 15, "Chris Cheng" <Chris.Cheng@xxxxxxxxxxxx> wrote: > > >=3D20 > > > If your channel response is linear. How does a separate analysis = > with =3D > > Rj only=3D20 > > convoluted with the impulse response of the channel different from = > what =3D > > you are doing ?=3D20 > > How many bit do you think is need to simulate in SPICE a BERT of = > 10e-14 =3D > > or -18 ? > > > =3D20 > > > ________________________________ > > >=3D20 > > > From: si-list-bounce@xxxxxxxxxxxxx on behalf of Hassan O. Ali > > > Sent: Wed 2/15/2006 9:02 AM > > > To: si-list@xxxxxxxxxxxxx > > > Subject: [SI-LIST] Re: HSPICE - adding jitter to ethernet serial = > link > > >=3D20 > > >=3D20 > > >=3D20 > > > A piece-wise linear (PWL) source implemented as below in an HSPICE = > =3D > > subcircuit may be > > > used to simulate RJ and DJ effects on the output. > > >=3D20 > > > The total jitter (J) factors (e.g. 0.512, 0.221, etc.) in this case = > =3D > > were generated with > > > a random number generator. The bit pattern is random but is supposed = > =3D > > to mimic an 8B/10B > > > encoding where the maximum run-length (maximum number of consecutive = > =3D > > 1's or 0's) is 5. > > > The pattern length was arbitrarily chosen as 160 bits. > > >=3D20 > > > Mind you, this is just one arbitrary way of including DJ and RJ =3D > > effects. I'm sure more > > > elaborate ways exist. > > >=3D20 > > > Best regards. > > >=3D20 > > > Hassan. > > >=3D20 > > >=3D20 > > > ************************************************ > > > * HSPICE PWL voltage source > > > * Parameter description: > > > * TR - Rise/Fall time of the PWL source > > > * UI - Unit Interval time (Bit width =3D3D 1/BitRate) > > > * HI - Voltage value representing bit "1" > > > * LO - Voltage value representing bit "0" > > > * JD - Peak-to-peak deterministic jitter > > > * JR - Peak-to-peak random jitter > > > ************************************************ > > > .SUBCKT pwl_source node1 node2 > > > +TR=3D3DTRval UI=3D3DUIval HI=3D3DHIval LO=3D3DLOval > > > +JD=3D3DJDval JR=3D3DJRval > > > .param J=3D3D'(JD+JR/2)' > > > vsrc node1 node2 PWL > > > + 0.0 'HI', '0.512*J+UI*1' 'HI', > > > + '0.512*J+UI*1+TR' 'LO', '0.221*J+UI*2' 'LO', > > > + '0.221*J+UI*2+TR' 'LO', '0.868*J+UI*3' 'LO', > > > + '0.868*J+UI*3+TR' 'LO', '0.358*J+UI*4' 'LO', > > > + '0.358*J+UI*4+TR' 'LO', '0.379*J+UI*5' 'LO', > > > + '0.379*J+UI*5+TR' 'HI', '-0.003*J+UI*6' 'HI', > > > + '-0.003*J+UI*6+TR' 'LO', '0.2*J+UI*7' 'LO', > > > + '0.2*J+UI*7+TR' 'LO', '0.238*J+UI*8' 'LO', > > > + '0.238*J+UI*8+TR' 'LO', '0.197*J+UI*9' 'LO', > > > + '0.197*J+UI*9+TR' 'LO', '-0.424*J+UI*10' 'LO', > > > + '-0.424*J+UI*10+TR' 'HI', '-0.608*J+UI*11' 'HI', > > > + '-0.608*J+UI*11+TR' 'HI', '-0.47*J+UI*12' 'HI', > > > + '-0.47*J+UI*12+TR' 'LO', '-0.124*J+UI*13' 'LO', > > > + '-0.124*J+UI*13+TR' 'LO', '-0.094*J+UI*14' 'LO', > > > + '-0.094*J+UI*14+TR' 'LO', '-0.657*J+UI*15' 'LO', > > > + '-0.657*J+UI*15+TR' 'HI', '0.48*J+UI*16' 'HI', > > > + '0.48*J+UI*16+TR' 'LO', '-0.052*J+UI*17' 'LO', > > > + '-0.052*J+UI*17+TR' 'LO', '0.208*J+UI*18' 'LO', > > > + '0.208*J+UI*18+TR' 'HI', '-0.15*J+UI*19' 'HI', > > > + '-0.15*J+UI*19+TR' 'HI', '-0.097*J+UI*20' 'HI', > > > + '-0.097*J+UI*20+TR' 'LO', '0.089*J+UI*21' 'LO', > > > + '0.089*J+UI*21+TR' 'LO', '-0.535*J+UI*22' 'LO', > > > + '-0.535*J+UI*22+TR' 'LO', '0.096*J+UI*23' 'LO', > > > + '0.096*J+UI*23+TR' 'LO', '-0.433*J+UI*24' 'LO', > > > + '-0.433*J+UI*24+TR' 'LO', '0.603*J+UI*25' 'LO', > > > + '0.603*J+UI*25+TR' 'LO', '-0.119*J+UI*26' 'LO', > > > + '-0.119*J+UI*26+TR' 'HI', '-0.847*J+UI*27' 'HI', > > > + '-0.847*J+UI*27+TR' 'HI', '-0.234*J+UI*28' 'HI', > > > + '-0.234*J+UI*28+TR' 'HI', '-0.056*J+UI*29' 'HI', > > > + '-0.056*J+UI*29+TR' 'LO', '-0.535*J+UI*30' 'LO', > > > + '-0.535*J+UI*30+TR' 'LO', '-0.564*J+UI*31' 'LO', > > > + '-0.564*J+UI*31+TR' 'HI', '-0.191*J+UI*32' 'HI', > > > + '-0.191*J+UI*32+TR' 'LO', '0.16*J+UI*33' 'LO', > > > + '0.16*J+UI*33+TR' 'LO', '-0.552*J+UI*34' 'LO', > > > + '-0.552*J+UI*34+TR' 'LO', '0.277*J+UI*35' 'LO', > > > + '0.277*J+UI*35+TR' 'HI', '-0.491*J+UI*36' 'HI', > > > + '-0.491*J+UI*36+TR' 'LO', '0.463*J+UI*37' 'LO', > > > + '0.463*J+UI*37+TR' 'LO', '-0.166*J+UI*38' 'LO', > > > + '-0.166*J+UI*38+TR' 'HI', '-0.592*J+UI*39' 'HI', > > > + '-0.592*J+UI*39+TR' 'HI', '0.667*J+UI*40' 'HI', > > > + '0.667*J+UI*40+TR' 'LO', '-0.296*J+UI*41' 'LO', > > > + '-0.296*J+UI*41+TR' 'LO', '-0.11*J+UI*42' 'LO', > > > + '-0.11*J+UI*42+TR' 'HI', '-0.608*J+UI*43' 'HI', > > > + '-0.608*J+UI*43+TR' 'HI', '-0.351*J+UI*44' 'HI', > > > + '-0.351*J+UI*44+TR' 'LO', '0.818*J+UI*45' 'LO', > > > + '0.818*J+UI*45+TR' 'HI', '-0.365*J+UI*46' 'HI', > > > + '-0.365*J+UI*46+TR' 'LO', '0.201*J+UI*47' 'LO', > > > + '0.201*J+UI*47+TR' 'LO', '-0.247*J+UI*48' 'LO', > > > + '-0.247*J+UI*48+TR' 'LO', '0.446*J+UI*49' 'LO', > > > + '0.446*J+UI*49+TR' 'HI', '0.329*J+UI*50' 'HI', > > > + '0.329*J+UI*50+TR' 'LO', '0.706*J+UI*51' 'LO', > > > + '0.706*J+UI*51+TR' 'HI', '-0.165*J+UI*52' 'HI', > > > + '-0.165*J+UI*52+TR' 'LO', '0.302*J+UI*53' 'LO', > > > + '0.302*J+UI*53+TR' 'LO', '0.03*J+UI*54' 'LO', > > > + '0.03*J+UI*54+TR' 'HI', '0.152*J+UI*55' 'HI', > > > + '0.152*J+UI*55+TR' 'LO', '-0.255*J+UI*56' 'LO', > > > + '-0.255*J+UI*56+TR' 'HI', '-0.237*J+UI*57' 'HI', > > > + '-0.237*J+UI*57+TR' 'LO', '0.014*J+UI*58' 'LO', > > > + '0.014*J+UI*58+TR' 'LO', '0.64*J+UI*59' 'LO', > > > + '0.64*J+UI*59+TR' 'LO', '-0.162*J+UI*60' 'LO', > > > + '-0.162*J+UI*60+TR' 'LO', '0.311*J+UI*61' 'LO', > > > + '0.311*J+UI*61+TR' 'LO', '0.33*J+UI*62' 'LO', > > > + '0.33*J+UI*62+TR' 'LO', '-0.301*J+UI*63' 'LO', > > > + '-0.301*J+UI*63+TR' 'HI', '-0.513*J+UI*64' 'HI', > > > + '-0.513*J+UI*64+TR' 'LO', '0.102*J+UI*65' 'LO', > > > + '0.102*J+UI*65+TR' 'LO', '-0.695*J+UI*66' 'LO', > > > + '-0.695*J+UI*66+TR' 'LO', '-0.308*J+UI*67' 'LO', > > > + '-0.308*J+UI*67+TR' 'LO', '-0.444*J+UI*68' 'LO', > > > + '-0.444*J+UI*68+TR' 'LO', '0.387*J+UI*69' 'LO', > > > + '0.387*J+UI*69+TR' 'LO', '-0.031*J+UI*70' 'LO', > > > + '-0.031*J+UI*70+TR' 'HI', '-0.599*J+UI*71' 'HI', > > > + '-0.599*J+UI*71+TR' 'LO', '-0.071*J+UI*72' 'LO', > > > + '-0.071*J+UI*72+TR' 'LO', '0.077*J+UI*73' 'LO', > > > + '0.077*J+UI*73+TR' 'HI', '0.663*J+UI*74' 'HI', > > > + '0.663*J+UI*74+TR' 'HI', '-0.526*J+UI*75' 'HI', > > > + '-0.526*J+UI*75+TR' 'LO', '0*J+UI*76' 'LO', > > > + '0*J+UI*76+TR' 'LO', '0.193*J+UI*77' 'LO', > > > + '0.193*J+UI*77+TR' 'LO', '0.479*J+UI*78' 'LO', > > > + '0.479*J+UI*78+TR' 'LO', '-0.055*J+UI*79' 'LO', > > > + '-0.055*J+UI*79+TR' 'HI', '0.161*J+UI*80' 'HI', > > > + '0.161*J+UI*80+TR' 'LO', '0.404*J+UI*81' 'LO', > > > + '0.404*J+UI*81+TR' 'LO', '-0.249*J+UI*82' 'LO', > > > + '-0.249*J+UI*82+TR' 'HI', '-0.255*J+UI*83' 'HI', > > > + '-0.255*J+UI*83+TR' 'LO', '-0.668*J+UI*84' 'LO', > > > + '-0.668*J+UI*84+TR' 'HI', '-0.481*J+UI*85' 'HI', > > > + '-0.481*J+UI*85+TR' 'LO', '0.553*J+UI*86' 'LO', > > > + '0.553*J+UI*86+TR' 'LO', '0.16*J+UI*87' 'LO', > > > + '0.16*J+UI*87+TR' 'HI', '0.392*J+UI*88' 'HI', > > > + '0.392*J+UI*88+TR' 'LO', '-0.056*J+UI*89' 'LO', > > > + '-0.056*J+UI*89+TR' 'LO', '0.267*J+UI*90' 'LO', > > > + '0.267*J+UI*90+TR' 'LO', '0.384*J+UI*91' 'LO', > > > + '0.384*J+UI*91+TR' 'LO', '0.79*J+UI*92' 'LO', > > > + '0.79*J+UI*92+TR' 'LO', '-0.734*J+UI*93' 'LO', > > > + '-0.734*J+UI*93+TR' 'LO', '-0.006*J+UI*94' 'LO', > > > + '-0.006*J+UI*94+TR' 'HI', '-0.01*J+UI*95' 'HI', > > > + '-0.01*J+UI*95+TR' 'HI', '-0.039*J+UI*96' 'HI', > > > + '-0.039*J+UI*96+TR' 'LO', '0.648*J+UI*97' 'LO', > > > + '0.648*J+UI*97+TR' 'HI', '0.099*J+UI*98' 'HI', > > > + '0.099*J+UI*98+TR' 'LO', '0.409*J+UI*99' 'LO', > > > + '0.409*J+UI*99+TR' 'HI', '0.808*J+UI*100' 'HI', > > > + '0.808*J+UI*100+TR' 'HI', '0.458*J+UI*101' 'HI', > > > + '0.458*J+UI*101+TR' 'LO', '0.709*J+UI*102' 'LO', > > > + '0.709*J+UI*102+TR' 'LO', '0.489*J+UI*103' 'LO', > > > + '0.489*J+UI*103+TR' 'HI', '0.309*J+UI*104' 'HI', > > > + '0.309*J+UI*104+TR' 'LO', '0.637*J+UI*105' 'LO', > > > + '0.637*J+UI*105+TR' 'LO', '0.225*J+UI*106' 'LO', > > > + '0.225*J+UI*106+TR' 'LO', '-0.052*J+UI*107' 'LO', > > > + '-0.052*J+UI*107+TR' 'HI', '-0.1*J+UI*108' 'HI', > > > + '-0.1*J+UI*108+TR' 'HI', '0.288*J+UI*109' 'HI', > > > + '0.288*J+UI*109+TR' 'LO', '-0.219*J+UI*110' 'LO', > > > + '-0.219*J+UI*110+TR' 'LO', '-0.129*J+UI*111' 'LO', > > > + '-0.129*J+UI*111+TR' 'LO', '0.035*J+UI*112' 'LO', > > > + '0.035*J+UI*112+TR' 'LO', '0.131*J+UI*113' 'LO', > > > + '0.131*J+UI*113+TR' 'HI', '-0.23*J+UI*114' 'HI', > > > + '-0.23*J+UI*114+TR' 'LO', '0.24*J+UI*115' 'LO', > > > + '0.24*J+UI*115+TR' 'LO', '0.684*J+UI*116' 'LO', > > > + '0.684*J+UI*116+TR' 'LO', '0.027*J+UI*117' 'LO', > > > + '0.027*J+UI*117+TR' 'HI', '0.351*J+UI*118' 'HI', > > > + '0.351*J+UI*118+TR' 'LO', '-0.562*J+UI*119' 'LO', > > > + '-0.562*J+UI*119+TR' 'LO', '0.831*J+UI*120' 'LO', > > > + '0.831*J+UI*120+TR' 'LO', '-0.524*J+UI*121' 'LO', > > > + '-0.524*J+UI*121+TR' 'HI', '-0.041*J+UI*122' 'HI', > > > + '-0.041*J+UI*122+TR' 'HI', '0.675*J+UI*123' 'HI', > > > + '0.675*J+UI*123+TR' 'HI', '-0.035*J+UI*124' 'HI', > > > + '-0.035*J+UI*124+TR' 'HI', '0.083*J+UI*125' 'HI', > > > + '0.083*J+UI*125+TR' 'LO', '-0.247*J+UI*126' 'LO', > > > + '-0.247*J+UI*126+TR' 'HI', '-0.372*J+UI*127' 'HI', > > > + '-0.372*J+UI*127+TR' 'LO', '-0.44*J+UI*128' 'LO', > > > + '-0.44*J+UI*128+TR' 'HI', '-0.861*J+UI*129' 'HI', > > > + '-0.861*J+UI*129+TR' 'LO', '0.162*J+UI*130' 'LO', > > > + '0.162*J+UI*130+TR' 'HI', '-0.228*J+UI*131' 'HI', > > > + '-0.228*J+UI*131+TR' 'HI', '0.606*J+UI*132' 'HI', > > > + '0.606*J+UI*132+TR' 'HI', '-0.002*J+UI*133' 'HI', > > > + '-0.002*J+UI*133+TR' 'LO', '0.385*J+UI*134' 'LO', > > > + '0.385*J+UI*134+TR' 'HI', '0.012*J+UI*135' 'HI', > > > + '0.012*J+UI*135+TR' 'LO', '0.14*J+UI*136' 'LO', > > > + '0.14*J+UI*136+TR' 'LO', '-0.286*J+UI*137' 'LO', > > > + '-0.286*J+UI*137+TR' 'HI', '-0.124*J+UI*138' 'HI', > > > + '-0.124*J+UI*138+TR' 'HI', '0.132*J+UI*139' 'HI', > > > + '0.132*J+UI*139+TR' 'HI', '0.65*J+UI*140' 'HI', > > > + '0.65*J+UI*140+TR' 'LO', '0.422*J+UI*141' 'LO', > > > + '0.422*J+UI*141+TR' 'HI', '-0.173*J+UI*142' 'HI', > > > + '-0.173*J+UI*142+TR' 'HI', '-0.701*J+UI*143' 'HI', > > > + '-0.701*J+UI*143+TR' 'HI', '0.674*J+UI*144' 'HI', > > > + '0.674*J+UI*144+TR' 'LO', '-0.063*J+UI*145' 'LO', > > > + '-0.063*J+UI*145+TR' 'LO', '0.697*J+UI*146' 'LO', > > > + '0.697*J+UI*146+TR' 'HI', '-0.464*J+UI*147' 'HI', > > > + '-0.464*J+UI*147+TR' 'HI', '0.241*J+UI*148' 'HI', > > > + '0.241*J+UI*148+TR' 'LO', '0.158*J+UI*149' 'LO', > > > + '0.158*J+UI*149+TR' 'HI', '0.725*J+UI*150' 'HI', > > > + '0.725*J+UI*150+TR' 'LO', '-0.715*J+UI*151' 'LO', > > > + '-0.715*J+UI*151+TR' 'HI', '0.379*J+UI*152' 'HI', > > > + '0.379*J+UI*152+TR' 'HI', '-0.341*J+UI*153' 'HI', > > > + '-0.341*J+UI*153+TR' 'LO', '0.387*J+UI*154' 'LO', > > > + '0.387*J+UI*154+TR' 'HI', '-0.158*J+UI*155' 'HI', > > > + '-0.158*J+UI*155+TR' 'LO', '0.637*J+UI*156' 'LO', > > > + '0.637*J+UI*156+TR' 'LO', '-0.883*J+UI*157' 'LO', > > > + '-0.883*J+UI*157+TR' 'LO', '-0.083*J+UI*158' 'LO', > > > + '-0.083*J+UI*158+TR' 'HI', '-0.087*J+UI*159' 'HI', > > > + '-0.087*J+UI*159+TR' 'HI', '0.573*J+UI*160' 'HI', > > > .ends > > >=3D20 > > >=3D20 > > >=3D20 > > >=3D20 > > >=3D20 > > > On Feb 15, "Chris Cheng" <Chris.Cheng@xxxxxxxxxxxx> wrote: > > > > > > > > May be its just me but Rj only makes sense when you are trying to = > =3D > > extract a BERT=3D20 > > curve > > > which seems to be a MATLAB job. > > > > If you have your Tx Rj, channel model and jitter transfer of your = > =3D > > CDR, the rest of=3D20 > > the > > > work is straight forward. > > > > > > > > > > > > > > > At 10:40 AM 2/7/2006 -0800, Ali Burney wrote: > > > > >=3D20 > > > > >> Hi, > > > > >> > > > > >> > > > > >> I am running gigabit Ethernet link simulation using HSPICE and = > =3D > > have a=3D3D20 > > > > >> question on adding jitter to the transmitted data. Is there any = > =3D > > way to=3D3D20 > > > > >> add Gaussian jitter to the transmitted data? I know that tools = > =3D > > such as > > > > >> =3D20 > > > > > > > > > >=3D20 > > > > >> Hyperlynx allow you to add transmit jitter. > > > > >> > > > > >> > > > > >> > > > > >> Thanks and best regards, > > > > >> > > > > >> > > > > >> > > > > >> A Burney > > > ------------------------------------------------------------------ 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