|
Okay, that's what I was after ... an eye derived from the combination
of the waveform and clock ticks returned by RX_Getwave. I'm going to echo what Mike Steinberger said ... when you apply an eye mask to a problem, you need to be clear about what assumptions went into the mask, and what it's supposed to be compared to. For example, I would expect a PCIe Gen 1 RX mask to specify the required eye opening at the RX pin. One would determine compliance by plotting the RX pin eye contour at the target probability level and seeing if the mask fit inside of it (in this case, anywhere). My point is: clock recovery and data noise are built into the mask in this case, and simulation of the clock recovery behavior isn't actually required. In the strictest sense, the case you outlined - combining the data and clock ticks from the RX model - shouldn't require a mask. If the eye opening clears the Rx_Receiver_Sensitivity level at the clock point, the latch should be able to sample the data successfully. That being the case, I realize that people will still insist on eye masks ... which is why I agree with Mike: understand what assumptions are in the mask and what it means to apply it. Todd. Todd Westerhoff VP, Software Products SiSoft 6 Clock Tower Place, Suite 250 Maynard, MA 01754 (978) 461-0449 x24 twesterh@xxxxxxxxxx www.sisoft.com Muranyi, Arpad wrote: --------------------------------------------------------------------- IBIS Macro website : http://www.eda.org/pub/ibis/macromodel_wip/ IBIS Macro reflector: //www.freelists.org/list/ibis-macro To unsubscribe send an email: To: ibis-macro-request@xxxxxxxxxxxxx Subject: unsubscribeSorry for my poor problem statement... I mean the output of Rx (as it comes back from Rx GetWave), used together with the clock ticks from Rx GetWave to formulate the eye. Arpad ================================================ -----Original Message----- From: Todd Westerhoff [mailto:twesterh@xxxxxxxxxx] Sent: Tuesday, December 08, 2009 12:40 PM To: Muranyi, Arpad Cc: IBIS-ATM Subject: Re: [ibis-macro] Eye mask question Arpad, Not meaning to be enigmatic here, but what signal(s) are you thinking get used to generate the eye diagram, and how? Todd. Todd Westerhoff VP, Software Products SiSoft 6 Clock Tower Place, Suite 250 Maynard, MA 01754 (978) 461-0449 x24 twesterh@xxxxxxxxxx www.sisoft.com Muranyi, Arpad wrote:Hello IBIS-AMI experts, This is a question regarding the analysis/evaluation of the results we get back from an AMI simulation. How does the user decide whether the eye is good or bad? Naturally we have this thing called eye mask (template) which we would all be able to drop into the eye without touching any of the waveforms. But where are we trying to position it? Anywhere it fits the best way? Or is it supposed to be positioned at a certain location? Thanks for any feedback in advance, Arpad ========================================================= --------------------------------------------------------------------- IBIS Macro website : http://www.eda.org/pub/ibis/macromodel_wip/ IBIS Macro reflector: //www.freelists.org/list/ibis-macro To unsubscribe send an email: To: ibis-macro-request@xxxxxxxxxxxxx Subject: unsubscribe--------------------------------------------------------------------- IBIS Macro website : http://www.eda.org/pub/ibis/macromodel_wip/ IBIS Macro reflector: //www.freelists.org/list/ibis-macro To unsubscribe send an email: To: ibis-macro-request@xxxxxxxxxxxxx Subject: unsubscribe |
