On 5/24/2022 9:51 PM, Tony wrote:
There is of course, some reasonable level of RFI that can not be
corrected if the system is next door to you
That does seem logical Dave.
It does NOT seem reasonable to me. The engineering principles needed to
do it right are well known, and have been since I graduated as an EE in
1964. One major problem is that some of us, including me, had to
re-learn them 30 years later; another is that, thanks to the
Balkanization of the teaching of EE in multiple specialties, the
education of those specializing in digital systems didn't include many
of those fundamentals, or they were "not important" in the context of
their applications. For example, the analog I/O of the K3 is a train
wreck because the digital guy designed it.
Here's an example of engineers with a very broad EE technical background
get the big picture. In 2004, I took a 3-day seminar from EMC guru Henry
Ott, retired from AT&T Bell Labs, the premier engineering entity on the
planet for most of the 20th century. One of MANY jewels that were almost
"asides" was that multilayer circuit boards that included "ground"
layers above and/or below a circuit trace formed a transmission line,
which confined fields from current on those traces to a VERY narrow
region in the insulation between those traces, AND, here's the Jewell --
that the time it takes the signal to traverse that transmission line on
practical board layouts places a fundamental limit on how fast these
systems can run!
In the context of this discussion, Henry recommended two EE books by
Johnson and Graham, which he described as fundamentally transmission
lines books, that addressed these concepts in the context of traces on
circuit boards. The seminar was in Palo Alto, and on the way to a
restaurant after dinner, several of us stopped at the Stanford
engineering bookstore, where I bought both books.
Henry worked as a consultant to many major corporations, including the
giants of Si Valley, which gave him a great perspective, and caused him
to think about technical things in the context of everything from
physical implementation to cost to ongoing development of
microprocessors to all sorts of applications, as well as fundamental
limitations noted above. In that workshop were engineers working in a
dozen or so specialties, and Henry's answers to their questions made it
obvious to me that he had thought these questions through in ALL of
those contexts, and many more.
Systems engineering and design in today's world requires expertise in
MANY areas, and few of us can learn everything we need to solve any
given problem that includes many of these disciplines. In my
professional life, I was regularly a part of design teams with nearly a
dozen different engineering disciplines, each of us addressing our own
areas of expertise, and working interactively with those working in
other disciplines so that all the bases were covered.
In that process, we asked a lot of "what if?" questions. What if in that
Fukushima nuclear power plant, a tidal wave flooded the generators,
which were in the basement, protecting the reactors? What if there's
someone next door who cares about the emissions of the system I'm designing?
73, Jim K9YC
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