Mike,
Yes, I was describing that scenario.
Thanks,
Arpad
=============================
From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] ;
On Behalf Of Mike Steinberger
Sent: Monday, November 6, 2017 12:19 PM
To: ibis-macro@xxxxxxxxxxxxx
Subject: [ibis-macro] Re: Question about "impulse response"
Arpad-
It appears that although I composed the message, I did not manage to send it.
My apologies.
If in your example what you mean by a 400mV swing in a differential Tx buffer
is that the True pin swings from a single ended voltage of Vref-200mV to a
single ended voltage of Vref+200mV, and similar for the Comp pin, then a logic
"0" would have a differential output voltage of -400mV, a logic "1" would have
a differential voltage of +400mV, and the differential voltage swing between
"0" and "1" would be 800mV, as you describe. Is this what you meant?
I'm afraid that when we're trying to track down factors of two, our best chance
of success is to be this pedantic.
Thanks.
Mike S.
On 11/06/2017 11:59 AM, Muranyi, Arpad wrote:
Mike,
I don't think I saw that response.
Could you please resend it?
Thanks,
Arpad
==========================
From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Steinberger
Sent: Monday, November 6, 2017 11:54 AM
To: ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>
Subject: [ibis-macro] Re: Question about "impulse response"
Arpad-
I responded to your e-mail will a clear and complete interpretation of your
example- an interpretation, by the way, which concluded that you were off by a
factor of two. I never did get any response to that e-mail, so maybe it somehow
didn't make it into your in-box.
Do I need to resend that e-mail?
Thanks.
Mike S.
On 11/6/2017 11:41 AM, Muranyi, Arpad wrote:
Mike,
I think I gave all that information in my illustration, which is now on
the bottom of this email. Please let me know if that is not clear and
I will try another way...
Thanks,
Arpad
=====================================================
From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Steinberger
Sent: Monday, November 6, 2017 11:31 AM
To: ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>
Subject: [ibis-macro] Re: Question about "impulse response"
Arpad-
Is the 800mV swing a single ended voltage swing or a differential voltage
swing? The input signal to the receiver is a differential voltage. If we
confuse single ended with differential, we'll be mixing apples and oranges, and
end up with a dog's breakfast.
I cannot agree to Todd's interpretation until I get your answer to this
question.
Thanks.
Mike Steinberger
On 11/6/2017 11:11 AM, Muranyi, Arpad wrote:
Todd,
Thanks for that clarification. Yes this is with the assumption that
the IR is derived from a step response, but all other methods
would need to provide equivalent results...
Would everyone on this email list agree with Todd's interpretation?
Thanks,
Arpad
====================================================
From: Todd Westerhoff [mailto:twesterh@xxxxxxxxxx]
Sent: Monday, November 6, 2017 10:33 AM
To: Muranyi, Arpad <Arpad_Muranyi@xxxxxxxxxx><mailto:Arpad_Muranyi@xxxxxxxxxx>;
ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>
Subject: RE: [ibis-macro] Re: Question about "impulse response"
Arpad,
My interpretation is that the channel impulse response passed to Tx_Init will
be the result of differentiating the 800 mV differential step response, as you
say.
That, of course, is assuming that the impulse response is derived from a step
response and not through some other method ...
Todd.
Todd Westerhoff
VP, Semiconductor Relations
Signal Integrity Software Inc. * www.sisoft.com<http://www.sisoft.com>
6 Clock Tower Place * Suite 250 * Maynard, MA 01754
(978) 461-0449<978-461-0449> x124 *
twesterh@xxxxxxxxxx<mailto:twesterh@xxxxxxxxxx>
"I want to live like that"
-Sidewalk Prophets
From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Thursday, November 2, 2017 2:27 PM
To: ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>
Subject: [ibis-macro] Re: Question about "impulse response"
Mike,
I am trying to apply what you are saying to IBIS-AMI. Let's use an example in
which
the differential Tx buffer has a 400 mV voltage swing on each of its outputs,
and as a
result, the difference step waveform at the Rx goes from -400 mV to +400 mV
(i.e.
the amplitude of the step waveform is 800 mV). The simulator will
differentiate this
step waveform and pass it into the AMI Tx Init function as the impulse response
of
the channel (or convolve with the output of the Tx GetWave function for the time
domain AMI simulation). Is this the correct interpretation of "impulse
response" in
the IBIS-AMI specification? Or should the 800 mV difference step waveform be
divided by 2 first before differentiating it to become the "impulse response"
for the
purposes if AMI simulations?
Thanks,
Arpad
===================================================================
