[SI-LIST] Re: DC-blocking transmission-line
- From: <Aubrey_Sparkman@xxxxxxxx>
- To: <wdowsley@xxxxxxxxx>, <tfox@xxxxxxxxx>, <gkorony@xxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
- Date: Thu, 28 Jun 2007 17:23:10 -0500
WRT "a discussion in the list count as a technical disclosure and thus
prevents a subsequent patent?"
IMHO, which is not a legal opinion... For the initial discloser who can
show prior effort, it can serve two purposes: 1) the start of the 1 year
time limit and 2) a Defensive Publication such that no one else can
patent the concept. =20
Unless, of course, someone else can show prior work...
Aubrey Sparkman=20
Enterprise Engineering Signal Integrity Team
Dell, Inc.=20
Aubrey_Sparkman@xxxxxxxx=20
(512) 723-3592
The Greatest Pleasure in Life is Doing what People say can't be done...
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of Bill Owsley
Sent: Thursday, June 28, 2007 4:07 PM
To: tfox@xxxxxxxxx; gkorony@xxxxxxxxx; Si-List
Subject: [SI-LIST] Re: DC-blocking transmission-line
The original Q'er still want to AC couple the T-line instead of a
transformer coupled DC-block. And in one package no less. With more
information, this might not be as easy as the first impression.
ps. Does a discussion in the list count as a technical disclosure and
thus prevents a subsequent patent?
Terry Fox <tfox@xxxxxxxxx> wrote:
At risk of being stoned...the "differential impedance" has very
little to do with anything.
The key issues is the impedance of the individual lines to their
reference.
As long as the individual lines above are confined to a PCB or other
structure that contains a reference? Let's not include a twisted pair
floating in space for this discussion, unless the reference is the other
line?
=20
The number "differential impedance" comes from 2 X Z0 which is the
characteristic impedance of each of the individual lines.
If these lines are balanced mirror images, the current through each of
the
That indeed is a really big if. These balance mirror images exist in
simulation software and textbooks, but in an actual circuit???
=20
two Z0 50 ohm resistors cancels and there is no net current out the
reference...hence you can use a single 100ohm resistor rather than two
50 ohm resistors.
For DC analysis or short transmission lines? =20
For long lines, The edge that 'sees' the Z0 has not yet arrived at the
50 ohm terminations, or 100 ohm one, and is using either the reference
plane/s or the other line to 'use' Z0?
=20
The out fall of this is that everyone thinks differential imp[edance is
some magical thing.
ElectroMagicalCompatibility of course!=20
In my experience it is not.
He has touched the holy thing...let us now begin the stoning.
TFox
At 07:59 AM 6/28/2007, George Korony wrote:
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>BlankHi All,
>I am not a board designer, but I do design parts that other people put=20
>on boards. We are working on a new (patent protected) concept: the "
>DC-blocking transmission-line".
>Basically the idea is to build a pair of capacitors that can be=20
>intercalated on the differential signal traces, having a controlled=20
>characteristic impedance between the two capacitors, the obvious scope=20
>is to reduce the reflections that may show up due the DC-blocking
capacitors.
>One request, we have, is that the characteristic impedance between the=20
>two capacitors (treated as a simple transmission line) should be 100
Ohm.
>Of course things are not so simple; and my question is: does anyone=20
>have a different approach to this problem?
>Thanks for any suggestion, George.
>
>
>
>
>
>------=3D_NextPart_002_0008_01C7B973.5B78CED0
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> charset=3D"iso-8859-1"
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>
>Hi All,
>I am not a board designer, but I =3D do design=3D20 parts that other =
people
>put on boards. We are working on =3D a new =3D20 (patent protected)
concept:
>the " DC-blocking =3D transmission-line".
>Basically the idea is to build a =3D pair of=3D20 capacitors that can =
be=20
>intercalated on the differential signal =3D traces,=3D20 having a=20
>controlled characteristic impedance between the two capacitors, =3D=20
>the=3D20 obvious scope is to reduce the reflections that may show up =
due=20
>the =3D DC-blocking capacitors.
>One request, we have, is that the=3D20 characteristic impedance between =
>the two capacitors (treated as a simple =3D transmission line) should =
be
100 Ohm.
>Of course things are not so =3D simple; and my=3D20 question is: does=20
>anyone have a different approach to this =3D problem?
>Thanks for any suggestion,=3D20 George.
>
>
>
>
>------=3D_NextPart_002_0008_01C7B973.5B78CED0--
>
>
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>
>-- Binary/unsupported file stripped by Ecartis --
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>
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