🚀 go-pugleaf

On Wed, 11 Jan 2012 20:26:50 -0500, "krw@att.bizzzzzzzzzzzz"
<krw@att.bizzzzzzzzzzzz> wrote:

>On Wed, 11 Jan 2012 14:22:11 -0500, Phil Hobbs
><pcdhSpamMeSenseless@electrooptical.net> wrote:
>
>>On 01/11/2012 01:43 PM, John Larkin wrote:
>>> On Tue, 10 Jan 2012 18:02:50 -0800 (PST), Bill Sloman
>>> <bill.sloman@gmail.com>  wrote:
>>>
>>>> On Jan 10, 4:55 pm, John Devereux<j...@devereux.me.uk>  wrote:
>>>>> Robert Macy<robert.a.m...@gmail.com>  writes:
>>>>>> On Jan 10, 2:28 am,BillSloman<bill.slo...@ieee.org>  wrote:
>>>>>>> On Jan 10, 7:47 am, "David L. Jones"<altz...@gmail.com>  wrote:
>>>>>
>>>>>>>> Just thought some might be interested in hearing our recent guest on
>>>>>>>> our Amp Hour radio show, Dr Howard Johnson of "Handbook of Black
>>>>>>>> Magic" fame:http://www.theamphour.com/2012/01/10/the-amp-hour-77-winsome-waveform...
>>>>>
>>>>>>>> Lots of history of the book, signal integrity, Gigabit Ethernet
>>>>>>>> development, 90 degree PCB bends, audiophoolery, and a whole bunch of
>>>>>>>> other talk over almost 1 1/12 hours.
>>>>>
>>>>>>> "Black Magic" is more notorious than famous. I own both it and it's
>>>>>>> follow-up, and both have got some useful content but they are badly
>>>>>>> organised and what useful content they do contain is hard to find.
>>>>>
>>>>>>> The field is still waiting for a decent textbook on high speed circuit
>>>>>>> design and layout.
>>>>>
>>>>>>> This is one of the few matters on which John Larkin and I seem to
>>>>>>> agree.
>>>>>
>>>>>>> --
>>>>>>> BillSloman, Nijmegen
>>>>>
>>>>>> Perhaps, it is time for the first ever 'conference' book written by a
>>>>>> consortium of engineers/scientists.
>>>>>
>>>>>> Put my name in for proffreading.  :)
>>>>>
>>>>> Great idea. Perhaps John Larkin, Jim Thompson and Bill Sloman could
>>>>> collaborate on it.
>>>>>
>>>>> Sure that will work out well... :)
>>>>
>>>> I'm not sure what Jim Thompson might contribute. I've seen papers that
>>>> worry about the characteristic impedance of connections on the silicon
>>>> (or whatever) inside integrated circuits, but I don't have the feeling
>>>> that Jim designs stuff that's big enough and fast enough for him to
>>>> need to know much about it.
>>>
>>> I get the impression that most interconnects inside ICs are primarily
>>> distributed R-C things, not real transmission lines at all.
>>> Propagation speed of interconnects is a big deal in routing fast logic
>>> chips, but the speed of light isn't the issue.
>>>
>>>>
>>>> Motorola's ECL applications notes on board layout were rather useful,
>>>
>>> Just don't trust their microstrip equation!
>>>
>>> John
>>>
>>
>>Yup, all RC transmission lines with repeaters, speed roughly c/10.
>
>The routing delay scales roughly with the square of the length (not at all
>linear).  Yes, it's often faster to buffer the middle of a long line.  In the
>PPC970/G5, there were several nets with three and four repeaters.  Even
>numbers work better, though.  ;-)


Getcher inverter for free!

John