You can use the DCM architecture wizard to calculate the CLKFX jitter. The
number in ps is correct and ignore the number in UI.

HTH,
Jim
(jimwu88NOOOSPAM@yahoo.com remove capital letters)

"RobJ" <rsefton@abc.net> wrote in message
news:tKYPf.9561$e1.2509@tornado.socal.rr.com...
> The data sheet refers you to the Xilinx web site, but I can't find
anything
> there for Virtex-4. Does the Virtex-II CLKFX jitter calculator also work
for
> Virtex-4?
>
> Thanks,
> Rob
>
>

Robj,

You can do that to get an estimate.  It will be different, but not by 
that much.

I believe the FAEs have the latest jitter predictor, and I am pretty 
sure that it is built into the latest software release as well.

One of the concerns we have had is since the DCM is digital, why would 
the jitter ever be different from one technology to the next?

But, the delay lines are different each time, and the control system 
gets more sophisticated as we improve the features of the DCM, so the 
jitter is slightly different.

Austin

RobJ wrote:

> The data sheet refers you to the Xilinx web site, but I can't find anything 
> there for Virtex-4. Does the Virtex-II CLKFX jitter calculator also work for 
> Virtex-4?
> 
> Thanks,
> Rob 
> 
> 

The data sheet refers you to the Xilinx web site, but I can't find anything 
there for Virtex-4. Does the Virtex-II CLKFX jitter calculator also work for 
Virtex-4?

Thanks,
Rob