FreeLists / si-list / [SI-LIST] Re: hspice questions

["Yang, Long" <long.0.yang@xxxxxxxxx>]

Hi, Kumar:
Here is Hspice code for generating Eye-diagram (you need to change some
parameters according to your req)
* .param eyefreq=625e6 per='1/eyefreq' $ max toggle lvds rate
 .param Tshift=1.55n
eT T 0 VOL='((TIME-Tshift)*(eyefreq/2))-int((TIME-Tshift)*(eyefreq/2))'
rT T 0 1k
.print tran v(t)*
On Wed, Mar 19, 2008 at 12:42 AM, Jim (James) Antonellis <
janton@xxxxxxxxxxxx> wrote:

>
> Hi Siva,
>
> Many ways to "skin the cat", here are a couple:
>
> If you have Cscope with your HSPICE (CosmosScope is a waveform viewer also
> a Synopsys product) you can easily plot Eye Diagrams and measure the
> zero-crossing of all transitions. Avanwaves is an older Synopsys waveform
> viewer that can alos plot Eye diagrams and give you the zero crossing
> measurement.
>
> In regards to "sweeping" multiple parameters, Using the ".Data" and
> ".ALTER" HSPICE constructs you can get any nested loop parameter sweep
> youdesire!
>
> For example (this is only psuedo code from memory):
>
> .tran STEP END sweep =3D foobar
> .DATA foobar
> param1  param2
> x               y
> m               n
> a               b
> .ENDDATA
>
> .ALTER
> .del lib SLOW_PVT
> .lib FAST_PVT
>
>
> This example will produce 6 runs. The inner loop (.DATA) provides 3
> sweeps=20 of param1 and param2. The outer loop (.ALTER) will add a second
> run with a change in my process lib.
>
> Jim Antonellis=20
>
> janton@xxxxxxxxxxxx
> Broadcom Corp www.broadcom.com
>
> Office: 978.689.1669
> Cell: 978.618.4745
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
> On Behalf Of Siva kumar
> Sent: Tuesday, March 18, 2008 11:50 AM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] hspice questions
>
> ladies and gentlemen,
>       i am a newbie to Hspice and i have few questions on it.
>
> 1. I have a differential clock output and i would like to measure the
> signal crossing points (the time at which the  clk_p and clk_n crossing
> event occurs.). I went thru the user manuals and tutorials. Though there are
> bunch of info on .MEASURE command, but i couldnt find a method to find the
> crossing of clk_p and clk_n. these values i need it to do the timing
> analysis.
>
> 2. My signals operates at 400mbps and i would like to generate the eye
> diagram. how to do that using hspice. can anybody give info on that?
>
> 3. I have one more question on Paramater sweep. I need to sweep
> twovariables in my circuit.=20
>
> For example,
>
> .tran 0.01ns 20ns sweep length1 100 1000 100 .tran 0.01ns 20ns sweep
> length2 500 1000 250
>
> i tried like above but always i am seeing only one variable in the
> waveform.( if i sweep var1 and var2 using the above method, tr1 and tr2
> results with var1 displayed but i dont know for which value of var2 the
> sweep happened..
>
> The objective is, i am doing the SI analysis and i want to sweep the
> tracelengths of the  topology. I want to try like the following for loop and
> print both length1 andlength2.=20
>
> for length1=3D100 to 1000 step 100
>  {
>   for length2=3D500 to 1000 step 25
> }
>
> thanking you in advance.
>
> Also i would appreciate if anybody can share any advanced / complex
> examples on SI analysis using hspice that helps to improve the efficiency
> and saves time.
>
> thanks,
> kumar
>


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