Finally Fun
Hi
I want to thank Larry for all his worries, he is beginning to De-bore me.
and would appreciate any inputs or concern that we can address
to make the next meeting worthwhile for everyone and tackle the issues.
I got some of Larry's feedback down here to keep the email resonable.
between the "--"
Larry's input on the MLT3 with/without power:
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Well, actually, here is an area where I think that just using a normal
signal is inadequate. I don't seem to be alone in this, beause IEEE 802.3d
(MAU Conformance Test Suite, on your CD) was deemed necessary to test for
proper implementation, and it was for this reason that I put in in my List
Of Requirements (Have You Looked).
To put it in a nutshell, these tests look at the ability of a an Ethernet
link to deal with bursts of out-of-band interference, minimum-level signals
and the like. Having magnetics operating near saturation may affect the
ability of the system to cope with such things.
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>> Larry, why would we run the magnetic near saturation to start with ?
>> please specify where in your list this concern has risen so it won't be
>> guess work on my part- thank's.
Larry's input on the Magnetic department
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When you are running 100TX you have 20 mA signals, but up to 8 mA of
allowed DC unbalance. 10BASE-T is DC balanced, but you have 50 mA signals.
So the two schemes sort of help each other out in the magnetics department,
but is that still true with a big DC bias present? (I don't know-- but this
is the kind of thing that will have to be sorted out, as well as the prior
Ethernet clauses that deal with such things.)
>well Larry I can measure this, but given that the current is balanced to
>a decent level, we expect the unbalance to chew away at the 8ma margin,
>how was the 8ma number chosen?, and if the OCL (open circuit inductance), is way above the 350uh
>to start, you are not on the edge of saturation, and your phy is doing BWL (base line
>wander correction) would this still be a problem. Will try to address this issue. (you gonna tip me
>-laughs)
Larry's input on Detection Pulses:
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I was talking about the detection pulses, not what you get after the power
is on. I do not think you have shown anything of that, at least not yet, or
I missed it. My reason for asking is that there seems to be a certain
amount of filter de-Q'ing in your differential scheme, similar to what we
found in the common mode scheme because of the low load impedance on the
filter output.
And I think that a digital filter would be a damned clever solution to this!
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For the detection pulses, we control them, their amplitude, frequency- even
polarity, they are differential and much lower in frequency, the filter is a low pass
filter I remind everyone, so ok, it shaves off 100mv that I designed for.... why
is any filter mismatch a worry at this point?. Also as promised 90% the
filter will be gone- you gotta start somewhere....
Finally, here I am again on the playing fields, could you tell us a little more
about your approach so we can share our worries about it with you, for we have been
to two meetings so far, and your concerns toward our approach never made it
to me so they can be addressed.
regards,
roger