[SI-LIST] Re: AC Coupled Signals
- From: ronald miller <ron@xxxxxxxxxxx>
- To: scott@xxxxxxxxxxxxx
- Date: Tue, 25 Sep 2007 12:27:01 -0700
All
Steve did a very nice job of making a complex subject easy to understand..
Ron
Scott McMorrow wrote:
>Steve,
>Steve Weir and I are in absolute agreement.
>
>"The only time position matters is in the face of discontinuities."
>
>
>We have tens of 1000's of hours of simulation time utilizing a multitude
>of 2D, 3D, quasi-static, and full wave time and frequency domain
>modeling and simulation techniques, and "real world" designs for 3,6, 12
>and 40 Gbps channels for our customers, with backplane and cabled
>connectivity, with associated time and frequency domain measurements,
>which bear this out. All of our modeling methods have been correlated
>with measurements, in some cases out to 40 GHz. This is not conjecture
>or theory. This is the way the physical real world works.
>
>You conflate two phenomena into the term "lossy" and do everyone a
>disservice. In my world, loss is a physical mechanism whereby energy
>is dissipated in an interconnect by either the resistance of a
>conductor, the polarization of a dielectric, or radiated energy. This
>is distinct from resonances which move energy around, but do not in any
>way dissipate the energy. When energy is displaced through resonance,
>it sometimes appears to look like "loss" and may be measured as "loss",
>but no energy is dissipated. It has just been moved to another place,
>often as reflected energy or crosstalk.
>
>If you move a capacitor's location across an interconnect and it
>provides a measurable change in S12, then you can rest assured that the
>problem is a resonance between it and another discontinuity in the
>channel, which is moving energy around in a "Wack-a-Mole^TM " fashion.
>If you do not correlate your modeled and simulated behavior with
>measurements, you may find that you may be experiencing an electronic
>hallucination, which can be satisfying, but may have no connection to
>the real world.
>
>
>Scott McMorrow
>Teraspeed Consulting Group LLC
>121 North River Drive
>Narragansett, RI 02882
>(401) 284-1827 Business
>(401) 284-1840 Fax
>
>http://www.teraspeed.com
>
>Teraspeed® is the registered service mark of
>Teraspeed Consulting Group LLC
>
>
>
>Stephen Zinck wrote:
>
>
>>Hi Steve,
>>
>>I understand your point but I actually thought Scott and I were getting
>>close. I guess I still need him to explain his statement:
>>"The only time position matters is in the face of discontinuities." because
>>this runs counter to your assertion.
>>
>>It would be good to have some concrete lab measurement results to back
>>either of our points up. I am sorry I don't have any.
>>
>>We agree on TDR/VNA characteristics...
>>
>>Steve
>>
>>Stephen P. Zinck
>>Interconnect Engineering Inc.
>>P.O. Box 577
>>South Berwick, ME 03908
>>Phone - (207) 384-8280
>>Email - szinck@xxxxxxxxxxxxxxxxxxxxxxxxxxx
>>Web - www.interconnectengineering.com
>>
>>----- Original Message -----
>>From: "steve weir" <weirsi@xxxxxxxxxx>
>>To: <signalintegrity@xxxxxxxxxxx>
>>Cc: "Scott McMorrow" <scott@xxxxxxxxxxxxx>; <jory_mckinley@xxxxxxxxx>;
>><leeritchey@xxxxxxxxxxxxx>; <npatel@xxxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
>>Sent: Tuesday, September 25, 2007 12:24 PM
>>Subject: [SI-LIST] Re: AC Coupled Signals
>>
>>
>>
>>
>>
>>>Stephen, OK so when you say "lossy" or "nonlinear" you mean=20
>>>discontinuous. Discontinuities aggravate resonances based on specific=20
>>>structure material and geometries, in other words the distance on a=20
>>>centimeter or millimeter scale between discontinuities. We have=20
>>>essentially the same opportunities for channel discontinuities at and in =
>>>
>>>the vicinity of the transmitter as the receiver. So I still do not see=20
>>>a defensible basis for the offered position: that placing a capacitor at =
>>>
>>>one end of the line versus the other changes the end to end loss. What=20
>>>matters is if wherever I place one discontinuity that it sets up a sharp =
>>>
>>>resonance with another discontinuity. That can happen equally well at=20
>>>either end of the line.
>>>
>>>If one looks at a channel with only a TDR I might understand the=20
>>>erroneous perception that placing a discontinuity down the line is=20
>>>better than up front. But that is an illusion. TDR resolution falls=20
>>>with interconnect distance. This ia a result of the inherent loss of=20
>>>the interconnect that shelves bandwidth and hence resolution versus=20
>>>distance for the instrument. This is one of the big limitations of a=20
>>>TDR for channel evaluation. A through measurement with a TDT or VNA=20
>>>does not suffer that limitation, give true measure of S21 and so report=20
>>>the real channel performance. Eric Bogatin spends some time on the=20
>>>issue of bandwidth versus interconnect length in his book.
>>>
>>>Regards,
>>>
>>>
>>>Steve.
>>>Stephen Zinck wrote:
>>>
>>>
>>>
>>>>Scott,
>>>>We may have some nomenclature issues here...=20
>>>>
>>>>When I say "lossy interface to the capacitor" I mean with impedance dis=
>>>>
>>>>
>>>>
>>>continuities. So I think we are on a similar page given your statement:
>>>
>>>
>>>
>>>>"The only time position matters is in the face of discontinuities."
>>>>
>>>>Again, most often, my role is to simulate the customers system at the 1=
>>>>
>>>>
>>>>
>>>1th hour. I don't recommend this, I just work within the customer's needs=
>>>/requirements. I make real world recommendations from simulation results =
>>>for designs where these discontinuities you mention are a fact of life. G=
>>>ranted my customers are not doing 5+ Gbit/s designs (right now ;-).
>>>
>>>
>>>
>>>>Above these data-rates, all you mention, capacitor transition (pad, via=
>>>>
>>>>
>>>>
>>>s, etc) are of the utmost importance. And I would absolutely agree that t=
>>>he more perfect you make these transitions, the less it matters where the=
>>>y are placed...
>>>
>>>
>>>
>>>>So I do believe AC coupling capacitor position does matter, as you stat=
>>>>
>>>>
>>>>
>>>e, for the bulk of the designs occurring these days where component footp=
>>>rint and via optimization, etc. is NOT occurring...
>>>
>>>
>>>
>>>>Steve
>>>>
>>>>Stephen P. Zinck
>>>>Interconnect Engineering Inc.
>>>>P.O. Box 577
>>>>South Berwick, ME 03908
>>>>Phone - (207) 384-8280
>>>>Email - szinck@xxxxxxxxxxxxxxxxxxxxxxxxxxx
>>>>Web - www.interconnectengineering.com
>>>>
>>>> ----- Original Message -----=20
>>>> From: Scott McMorrow=20
>>>> To: Stephen Zinck=20
>>>> Cc: jory_mckinley@xxxxxxxxx ; leeritchey@xxxxxxxxxxxxx ; npatel@micro=
>>>>
>>>>
>>>>
>>>n.com ; si-list@xxxxxxxxxxxxx=20
>>>
>>>
>>>
>>>> Sent: Tuesday, September 25, 2007 11:08 AM
>>>> Subject: Re: [SI-LIST] Re: AC Coupled Signals
>>>>
>>>>
>>>> Steven,
>>>>
>>>> I would not agree with your following statements.
>>>>
>>>> "I agree in theory with all you state. Assuming a lossless interface =
>>>>
>>>>
>>>>
>>>to the capacitor, it shouldn't matter where you place it, given a purely =
>>>linear system. But the real world is lossy, even when one makes great 3D =
>>>solved structures. Manufacturing and other tolerances tend to take the tr=
>>>ek towards perfection to task."
>>>
>>>
>>>
>>>> "Would either of you agree that AC coupling capacitor location may ma=
>>>>
>>>>
>>>>
>>>tter with a lossy interface to the capacitor?"
>>>
>>>
>>>
>>>> Insertion loss in a flat impedance linear lossy system will be indepe=
>>>>
>>>>
>>>>
>>>ndent of capacitor location. Run the math and see. The only time positi=
>>>on matters is in the face of discontinuities. In fact, given a low loss=
>>>interconnect with discontinuities and a high loss interconnect with disc=
>>>ontinuities, the low loss system, with it's higher Q, will often have wor=
>>>se behavior.
>>>
>>>
>>>
>>>> An improperly designed 0402 capacitor transition for a 50 ohm line ca=
>>>>
>>>>
>>>>
>>>n easily exhibit a discontinuity of 35 ohms for 50 ps. If attached to po=
>>>orly designed via transitions, the discontinuity will be even worse. Whe=
>>>n this is coupled closely to a high capacitance receiver input, a high ca=
>>>pacitance transmitter output, a low impedance via stub discontinuity, or =
>>>a low impedance connector discontinuity, it can form a 1/2 wave resonant =
>>>circuit. This is most likely the problem you are seeing. =20
>>>
>>>
>>>
>>>> If the interconnect has essentially flat impedance, position does not=
>>>>
>>>>
>>>>
>>>matter. If the capacitor transition is properly designed, position does=
>>>not matter. All of the data we have on this is proprietary at this time=
>>>=2E Our understanding of the physics has been verified by full wave mode=
>>>ling, simulation and measurement.
>>>
>>>
>>>
>>>> regards,
>>>>
>>>> Scott
>>>>
>>>>
>>>>
>>>>Scott McMorrow
>>>>Teraspeed Consulting Group LLC
>>>>121 North River Drive
>>>>Narragansett, RI 02882
>>>>(401) 284-1827 Business
>>>>(401) 284-1840 Fax
>>>>
>>>>http://www.teraspeed.com
>>>>
>>>>Teraspeed=AE is the registered service mark of
>>>>Teraspeed Consulting Group LLC
>>>>
>>>>
>>>> Stephen Zinck wrote:=20
>>>> Hi Scott and Steve,
>>>>
>>>> To answer both of your questions, it is the resulting Hspice (with =
>>>>
>>>>
>>>>
>>>S-parameters) differential eye patterns, as viewed at the receiver die, t=
>>>hat were used to make a comparison of source versus destination AC coupli=
>>>ng capacitor locations. The system was excited with a string of ones, fol=
>>>lowed by a single zero, followed by a string of ones.=20
>>>
>>>
>>>
>>>> I have not specifically designed a test board that varies the AC co=
>>>>
>>>>
>>>>
>>>upling capacitor location along a trace.
>>>
>>>
>>>
>>>> I understand the "shades of gray" here and agree that one can't mak=
>>>>
>>>>
>>>>
>>>e a "rule of thumb" generalization in our line of work these days.=20
>>>
>>>
>>>
>>>> I agree in theory with all you state. Assuming a lossless interface=
>>>>
>>>>
>>>>
>>>to the capacitor, it shouldn't matter where you place it, given a purely=
>>>linear system. But the real world is lossy, even when one makes great 3D=
>>>solved structures. Manufacturing and other tolerances tend to take the t=
>>>rek towards perfection to task.=20
>>>
>>>
>>>
>>>> Do either of you have real world measured results, that you could s=
>>>>
>>>>
>>>>
>>>hare, that show no marked difference in received signal characteristics w=
>>>hen the AC coupling capacitor position is varied through a 30 inch backpl=
>>>ane system (or similar)?
>>>
>>>
>>>
>>>> I believe my experience with capacitor location may prove true if t=
>>>>
>>>>
>>>>
>>>he capacitor interface is lossy (which is the case). A lot of my customer=
>>>s are just looking for quick ways to maximize performance using standard =
>>>component packages and standard layout practices (in the end, I don't lik=
>>>e to give anything away that is low lying fruit). Most of the time I am d=
>>>oing my analysis after the board is in layout, where I have limited abili=
>>>ty to change the design (unless it is really broken). In a perfect world,=
>>>where I am involved early, the package optimization and layout structure=
>>>s can be optimized as you state, but only if the margins warrant it (syst=
>>>em performance issues are expected after initial "what-if" simulations ha=
>>>ve occurred). The right tool for the right job rules the day...
>>>
>>>
>>>
>>>> Would either of you agree that AC coupling capacitor location may m=
>>>>
>>>>
>>>>
>>>atter with a lossy interface to the capacitor?
>>>
>>>
>>>
>>>> All the best,
>>>> Steve
>>>>
>>>> Stephen P. Zinck
>>>> Interconnect Engineering Inc.
>>>> P.O. Box 577
>>>> South Berwick, ME 03908
>>>> Phone - (207) 384-8280
>>>> Email - szinck@xxxxxxxxxxxxxxxxxxxxxxxxxxx
>>>> Web - www.interconnectengineering.com
>>>>
>>>> ----- Original Message -----=20
>>>> From: Scott McMorrow=20
>>>> To: Stephen Zinck=20
>>>> Cc: jory_mckinley@xxxxxxxxx ; leeritchey@xxxxxxxxxxxxx ; npatel@m=
>>>>
>>>>
>>>>
>>>icron.com ; si-list@xxxxxxxxxxxxx=20
>>>
>>>
>>>
>>>> Sent: Tuesday, September 25, 2007 9:44 AM
>>>> Subject: Re: [SI-LIST] Re: AC Coupled Signals
>>>>
>>>>
>>>> Stephen
>>>>
>>>> Define "better" and then relate your simulations and conclusions =
>>>>
>>>>
>>>>
>>>to linear system theory and measurements. =20
>>>
>>>
>>>
>>>> I contend that the only difference an AC coupling capacitor can p=
>>>>
>>>>
>>>>
>>>ossibly have due to position in a linear interconnect is a result of impe=
>>>dance mismatch. I contend that the capacitor will form a 1/2 wave resona=
>>>nt circuit with other interconnect discontinuities (connectors, vias stub=
>>>s, packages, Tx die, Rx die ... etc) and that this interaction is system,=
>>>chip, connector and package design dependent. I contend that it is this=
>>>1/2 resonance that can cause differences that can be measured, but that =
>>>there is no "rule of thumb", since the position and magnitude of disconti=
>>>nuities are different in every system. In some systems the receiver cons=
>>>titutes a larger discontinuity than the transmitter. In other systems th=
>>>is is reversed. In yet other systems, connectors and vias represent larg=
>>>er discontinuites than do either the transmitters or receivers. It all "j=
>>>ust depends". To state a specific rule is just plain incorrect.
>>>
>>>
>>>
>>>> I contend that once you remove the magic and myths surrounding AC=
>>>>
>>>>
>>>>
>>>coupling capacitors, analysis of the 3D structure shows that by reducing=
>>>the signal path discontinuity through the capacitor, you will necessaril=
>>>y improve performance. An AC coupling capacitor, with it's associated vi=
>>>a and pad transition design, can be viewed as a black box which has inser=
>>>tion loss and return loss, and can be modeled quite well using either lum=
>>>ped element approximations or (my favorite) S-parameters. As such it wil=
>>>l cascade in a simulation model just like any other linear element. If w=
>>>e start with a system with flat 50 ohm impedance from end to end, it can =
>>>be easily shown that no matter what the position of the capacitor along t=
>>>he interconnect is, the insertion loss of the system is identical. It is=
>>>only the return loss, as seen from each end that changes.
>>>
>>>
>>>
>>>> I've been designing AC coupling capacitor mounting transitions pr=
>>>>
>>>>
>>>>
>>>operly for quite a few years now and have some 0402 designs that keep S12=
>>>above -0.2 dB up to 7.5 GHz, S12 below -20 dB @ 5 GHz, and below -15 dB =
>>>@ 10 GHz. For all practical purposes, these designs are transparent and =
>>>may be placed anywhere in an interconnect design where there is space, si=
>>>nce there is little resonance interaction with other devices and structur=
>>>es.
>>>
>>>
>>>
>>>> Scott
>>>>
>>>>
>>>>Scott McMorrow
>>>>Teraspeed Consulting Group LLC
>>>>121 North River Drive
>>>>Narragansett, RI 02882
>>>>(401) 284-1827 Business
>>>>(401) 284-1840 Fax
>>>>
>>>>http://www.teraspeed.com
>>>>
>>>>Teraspeed=AE is the registered service mark of
>>>>Teraspeed Consulting Group LLC
>>>> =20
>>>>
>>>> Stephen Zinck wrote:=20
>>>> Hi Scott,
>>>>
>>>> My simulations show that the capacitor is best placed at the re=
>>>>
>>>>
>>>>
>>>ceiver end of the transmission-line. Do you disagree? If so, why?
>>>
>>>
>>>
>>>> Steve
>>>>
>>>> Stephen P. Zinck
>>>> Interconnect Engineering Inc.
>>>> P.O. Box 577
>>>> South Berwick, ME 03908
>>>> Phone - (207) 384-8280
>>>> Email - szinck@xxxxxxxxxxxxxxxxxxxxxxxxxxx
>>>> Web - www.interconnectengineering.com
>>>>
>>>> ----- Original Message -----=20
>>>> From: Scott McMorrow=20
>>>> To: signalintegrity@xxxxxxxxxxx=20
>>>> Cc: jory_mckinley@xxxxxxxxx ; leeritchey@xxxxxxxxxxxxx ; npat=
>>>>
>>>>
>>>>
>>>el@xxxxxxxxxx ; si-list@xxxxxxxxxxxxx=20
>>>
>>>
>>>
>>>> Sent: Tuesday, September 25, 2007 8:30 AM
>>>> Subject: Re: [SI-LIST] Re: AC Coupled Signals
>>>>
>>>>
>>>> Stephen,
>>>>
>>>> I'm sorry, this is a linear system. Except for possible reso=
>>>>
>>>>
>>>>
>>>nances that are created by discontinuities and modal conversion (which ha=
>>>ve absolutely zero to do with signal rise time), there is no difference i=
>>>n the attenuation of a capacitor placed at the Tx as opposed at the Rx. =
>>>W.R.T. the receiver, if it is "lost in the rise-time degradation of the =
>>>system", it will be lost wherever it is placed.
>>>
>>>
>>>
>>>>Scott McMorrow
>>>>Teraspeed Consulting Group LLC
>>>>121 North River Drive
>>>>Narragansett, RI 02882
>>>>(401) 284-1827 Business
>>>>(401) 284-1840 Fax
>>>>
>>>>http://www.teraspeed.com
>>>>
>>>>Teraspeed=AE is the registered service mark of
>>>>Teraspeed Consulting Group LLC
>>>> =20
>>>>
>>>> Stephen Zinck wrote:=20
>>>>Hi Jory,
>>>>
>>>>I have simulated this at length and concur with your experience that th=
>>>>
>>>>
>>>>
>>>e=20
>>>
>>>
>>>
>>>>capacitor is best placed at the receiver...
>>>>
>>>>In effect, the attenuation associated with the capacitor placement at t=
>>>>
>>>>
>>>>
>>>he=20
>>>
>>>
>>>
>>>>receiver (parasitics/pads/vias) is lost in the rise-time degradation of=
>>>>
>>>>
>>>>
>>>the=20
>>>
>>>
>>>
>>>>system.
>>>>The classic "don't break it until you have to" rule is applicable... OK=
>>>>
>>>>
>>>>
>>>this=20
>>>
>>>
>>>
>>>>is my rule... :-)
>>>>
>>>>All the best,
>>>>Steve
>>>>
>>>>Stephen P. Zinck
>>>>Interconnect Engineering Inc.
>>>>P.O. Box 577
>>>>South Berwick, ME 03908
>>>>Phone - (207) 384-8280
>>>>Email - szinck@xxxxxxxxxxxxxxxxxxxxxxxxxxx
>>>>Web - www.interconnectengineering.com
>>>>
>>>>----- Original Message -----=20
>>>>From: "Jory McKinley" <jory_mckinley@xxxxxxxxx>
>>>>To: <leeritchey@xxxxxxxxxxxxx>; <npatel@xxxxxxxxxx>; <si-list@freelists=
>>>>
>>>>
>>>>
>>>=2Eorg>
>>>
>>>
>>>
>>>>Sent: Monday, September 24, 2007 5:31 PM
>>>>Subject: [SI-LIST] Re: AC Coupled Signals
>>>>
>>>>
>>>> I will elaborate a bit on what I have seen. I have measured (time dom=
>>>>
>>>>
>>>>
>>>ain)=20
>>>
>>>
>>>
>>>>in the lab some effects that appears to be location specific in the=20
>>>>placement of the AC coupling caps at the rcvr. Now this may be due in =
>>>>
>>>>
>>>>
>>>part=20
>>>
>>>
>>>
>>>>to the fact that I am using 50-ohm resistor termination in each lead as=
>>>>
>>>>
>>>>
>>>=20
>>>
>>>
>>>
>>>>well and the combination (cap plus rcvr reflection) is giving some=20
>>>>imbalance depending on distance. The best rcvr eye that I am seeing is=
>>>>
>>>>
>>>>
>>>=20
>>>
>>>
>>>
>>>>when I can move the AC/term as close to the rcvr as I can. By the way =
>>>>
>>>>these are 5Gb/s signals.
>>>>If I have time I will try and isolate what I am seeing and even simulat=
>>>>
>>>>
>>>>
>>>e=20
>>>
>>>
>>>
>>>>it, has anyone else seen or simulated this?
>>>>-Jory
>>>>
>>>>----- Original Message ----
>>>>From: Lee Ritchey <leeritchey@xxxxxxxxxxxxx>
>>>>To: "npatel@xxxxxxxxxx" <npatel@xxxxxxxxxx>; si-list@xxxxxxxxxxxxx
>>>>Sent: Monday, September 24, 2007 1:06:06 PM
>>>>Subject: [SI-LIST] Re: AC Coupled Signals
>>>>
>>>>Nikil,
>>>>
>>>>I have made measurements on test PCBs and the location is not all that
>>>>important. In identical pairs, one with AC coupling capacitors and the=
>>>>
>>>>other without, the loss vs. frequency is virtually identical at leas ou=
>>>>
>>>>
>>>>
>>>t=20
>>>
>>>
>>>
>>>>to
>>>>6 GHz. That would be 12 Mb/S.
>>>>
>>>>Lee Ritchey
>>>>
>>>>
>>>> [Original Message]
>>>>From: <npatel@xxxxxxxxxx>
>>>>To: <si-list@xxxxxxxxxxxxx>
>>>>Date: 9/24/2007 10:21:37 AM
>>>>Subject: [SI-LIST] AC Coupled Signals
>>>>
>>>>Hi all,
>>>>In case of AC coupled signals does anyone know of an optimum placement
>>>>for the caps? I mean should they be placed near the source, receiver,
>>>>middle of the transmission line?
>>>>How much difference does it make in the opening of the eye?
>>>>The signals are differential CML running at 3.0Gbps
>>>>
>>>>Thanks,
>>>>Nikhil
>>>>
>>>>
>>>>------------------------------------------------------------------
>>>>To unsubscribe from si-list:
>>>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>>>
>>>>or to administer your membership from a web page, go to:
>>>>//www.freelists.org/webpage/si-list
>>>>
>>>>For help:
>>>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>>>
>>>>
>>>>List technical documents are available at:
>>>> http://www.si-list.net
>>>>
>>>>List archives are viewable at:
>>>> //www.freelists.org/archives/si-list
>>>>or at our remote archives:
>>>> http://groups.yahoo.com/group/si-list/messages
>>>>Old (prior to June 6, 2001) list archives are viewable at:
>>>> http://www.qsl.net/wb6tpu
>>>>
>>>> -----------------------------------------------------------------=
>>>>
>>>>
>>>>
>>>-
>>>
>>>
>>>
>>>>To unsubscribe from si-list:
>>>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>>>
>>>>or to administer your membership from a web page, go to:
>>>>//www.freelists.org/webpage/si-list
>>>>
>>>>For help:
>>>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>>>
>>>>
>>>>List technical documents are available at:
>>>> http://www.si-list.net
>>>>
>>>>List archives are viewable at:
>>>> //www.freelists.org/archives/si-list
>>>>or at our remote archives:
>>>> http://groups.yahoo.com/group/si-list/messages
>>>>Old (prior to June 6, 2001) list archives are viewable at:
>>>> http://www.qsl.net/wb6tpu
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>_______________________________________________________________________=
>>>>
>>>>
>>>>
>>>_____________
>>>
>>>
>>>
>>>>Moody friends. Drama queens. Your life? Nope! - their life, your story.=
>>>>
>>>>
>>>>
>>>=20
>>>
>>>
>>>
>>>>Play Sims Stories at Yahoo! Games.
>>>>http://sims.yahoo.com/
>>>>------------------------------------------------------------------
>>>>To unsubscribe from si-list:
>>>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>>>
>>>>or to administer your membership from a web page, go to:
>>>>//www.freelists.org/webpage/si-list
>>>>
>>>>For help:
>>>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>>>
>>>>
>>>>List technical documents are available at:
>>>> http://www.si-list.net
>>>>
>>>>List archives are viewable at:
>>>>//www.freelists.org/archives/si-list
>>>>or at our remote archives:
>>>>http://groups.yahoo.com/group/si-list/messages
>>>>Old (prior to June 6, 2001) list archives are viewable at:
>>>> http://www.qsl.net/wb6tpu
>>>>
>>>>
>>>>
>>>> =20
>>>>
>>>>------------------------------------------------------------------
>>>>To unsubscribe from si-list:
>>>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>>>
>>>>or to administer your membership from a web page, go to:
>>>>//www.freelists.org/webpage/si-list
>>>>
>>>>For help:
>>>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>>>
>>>>
>>>>List technical documents are available at:
>>>> http://www.si-list.net
>>>>
>>>>List archives are viewable at: =20
>>>>//www.freelists.org/archives/si-list
>>>>or at our remote archives:
>>>>http://groups.yahoo.com/group/si-list/messages
>>>>Old (prior to June 6, 2001) list archives are viewable at:
>>>> http://www.qsl.net/wb6tpu
>>>> =20
>>>>
>>>>
>>>> =20
>>>>------------------------------------------------------------------
>>>>To unsubscribe from si-list:
>>>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>>>
>>>>or to administer your membership from a web page, go to:
>>>>//www.freelists.org/webpage/si-list
>>>>
>>>>For help:
>>>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>>>
>>>>
>>>>List technical documents are available at:
>>>> http://www.si-list.net
>>>>
>>>>List archives are viewable at: =20
>>>>//www.freelists.org/archives/si-list
>>>>or at our remote archives:
>>>>http://groups.yahoo.com/group/si-list/messages
>>>>Old (prior to June 6, 2001) list archives are viewable at:
>>>> http://www.qsl.net/wb6tpu
>>>> =20
>>>>
>>>>
>>>>
>>>> =20
>>>>
>>>>
>>>>
>>>--=20
>>>Steve Weir
>>>Teraspeed Consulting Group LLC=20
>>>121 North River Drive=20
>>>Narragansett, RI 02882=20
>>>
>>>California office
>>>(408) 884-3985 Business
>>>(707) 780-1951 Fax
>>>
>>>Main office
>>>(401) 284-1827 Business=20
>>>(401) 284-1840 Fax=20
>>>
>>>Oregon office
>>>(503) 430-1065 Business
>>>(503) 430-1285 Fax
>>>
>>>http://www.teraspeed.com
>>>This e-mail contains proprietary and confidential intellectual property o=
>>>f Teraspeed Consulting Group LLC
>>>-------------------------------------------------------------------------=
>>>-----------------------------
>>>Teraspeed(R) is the registered service mark of Teraspeed Consulting Group=
>>>LLC
>>>
>>>
>>>------------------------------------------------------------------
>>>To unsubscribe from si-list:
>>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>>
>>>or to administer your membership from a web page, go to:
>>>//www.freelists.org/webpage/si-list
>>>
>>>For help:
>>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>>
>>>
>>>List technical documents are available at:
>>> http://www.si-list.net
>>>
>>>List archives are viewable at:
>>>//www.freelists.org/archives/si-list
>>>or at our remote archives:
>>>http://groups.yahoo.com/group/si-list/messages
>>>Old (prior to June 6, 2001) list archives are viewable at:
>>> http://www.qsl.net/wb6tpu
>>>
>>>
>>>
>>>
>>>
>>>
>>------------------------------------------------------------------
>>To unsubscribe from si-list:
>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>
>>or to administer your membership from a web page, go to:
>>//www.freelists.org/webpage/si-list
>>
>>For help:
>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>
>>
>>List technical documents are available at:
>> http://www.si-list.net
>>
>>List archives are viewable at:
>> //www.freelists.org/archives/si-list
>>or at our remote archives:
>> http://groups.yahoo.com/group/si-list/messages
>>Old (prior to June 6, 2001) list archives are viewable at:
>> http://www.qsl.net/wb6tpu
>>
>>
>>
>>
>>
>>
>
>
>------------------------------------------------------------------
>To unsubscribe from si-list:
>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
>or to administer your membership from a web page, go to:
>//www.freelists.org/webpage/si-list
>
>For help:
>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>
>List technical documents are available at:
> http://www.si-list.net
>
>List archives are viewable at:
> //www.freelists.org/archives/si-list
>or at our remote archives:
> http://groups.yahoo.com/group/si-list/messages
>Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
>
>
>
>
--
Ronald Miller
Ghz Data, Signal Integrity Consulting
7721 Sunset Ave.
Newark CA 94560
tel 510-793-4744
cell 510-377-9380
fax 510-742-6686
www.ghzdata.com
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
