[IBIS-Users] RE: AMI Cable EQ using QFB/AGC

Hi Eric,

I'm wondering if you'd consider an alternate to hand coding in C? Specifically, our ESL tool (SystemVue) can automatically generate such blocks of C code and an AMI wrapper for you. If this approach might be of interest, here is a point of contact for further info/discussion:
http://www.agilent.com/find/eesof-ami-model-gen

Best regards,

-- Colin Warwick
High Speed Digital Design Flow Manager, Agilent EEsof EDA
Blog http://signal-integrity.tm.agilent.com
Information Exchange for IBIS Model Users http://www.ibis-user.org

-----Original Message-----
From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf Of Eric Monteiro
Sent: Wednesday, June 09, 2010 11:14 AM
To: si-list@freelists.org; ibis-users@eda.org
Subject: [IBIS-Users] AMI Cable EQ using QFB/AGC

Hello Everyone

I was wondering if anyone out there has implemented (or tied to) an IBIS AMI model of an AGC feedback loop. If so (and you are willing to share), I am having some speed issues that I could use help solving.

In short, does anyone have experience using fft sample by sample using internal states(e.g. choosing how many samples to track)? I.e. similar to how veriloga does it. Note: I am doing this in C, not Matlab.

Details:
Right now my loop updates the AGC coeffients ( 3 to be exact, for 3 EQ stages ) 1 per sample (maybe I should do once per bit?). This means that the 2nd and 3rd stage inputs change if the 1st AGC coeff changes, meaning I have to revaluate the outputs of the 2nd and 3rd linear stages using fft in AMI GetWave instead of AMI init. To help speed this up, I am opting for convolution for simple low pass filters, however I still need the fft for the linear EQ.

Source for any fucntion is avaible at any time for review or re-use (though I wouldn't ever consider myself a software engineer).

Best Regards,
Eric

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