Math and electrical desgin

On Sun, 29 Mar 2020 10:26:54 +0100, Tom Gardner
<spamjunk@blueyonder.co.uk> wrote:

On 29/03/20 04:09, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 00:49:57 +0000, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 28/03/20 22:08, Joerg wrote:
On 2020-03-28 13:38, blocher@columbus.rr.com wrote:
On Friday, March 27, 2020 at 6:00:10 PM UTC-4, Rick C wrote:

[...]


So your work is not so much circuit design as it is system design?

I like to think I straddle circuits and systems.  I am decent at both
but certainly not an expert at analog.  The problem in my company is
that there is not enough work in circuit design to keep one always
busy.  I also think that most circuit problems are better solved
through a system approach.  If you get the system concept wrong, then
the circuit is going to be wrong.  If you know what you want at the
high level, it is easier to tell if your circuit design is adequate.


Amen!

Top-down is generally the only approach that really works. Now we'll have to
explain that to the next generations. All the ones who have served in the
military don't need to be told, they know this already.

You need top-down and bottom-up simultaneously.

It's best to be fluid and confused for a while before getting
rigorous. Bottom-level thinking about a new problem can create
insights that can affect top-level architectures and requirements, and
specs. How can you create requirements if you don't know what's
possible?


Bottom-up allows you to reuse known working
components, processes and concepts.

Or invent new ones.


Top-down on its own can lead to requiring
impossible components.


Top-level requirements documents are very difficult to change in some
organizations. They require signoff by too many managers. Important or
just sensible changes can go into a swirl of management approvals and
disappear in the process.

Yes to all the above.

The response to such "waterfall" processes is are the
various "agile" processes. The agile processes do have
some real advantages w.r.t. waterfall, but the zealous
acolytes are too dumb to realise that they have different
disadvantages.

A key issue is the absolute reliance on test-driven
design and a bottom-up approach.

TDD is great for ensuring your last low-level tweak
didn't change things - but it is of little use in
getting the right design. Too many people think "it
works because it passes the tests", without giving
any thought to the comprehensiveness of the tests.

As old timers know, "you can't test quality into a
product".


I recently discovered a semiconductor processing system that has four
expensive energy metrology subsystems that never worked but have been
installed in all systems since 2003. My gear collects useless data
from them and sends it to a computer that ignores it. It would be
impossible to move enough management to fix this. Figure roughly a
million dollars a year wasted for 17 years now.

When creating a new plant, Intel duplicates absolutely
everything, down to the ridiculous last detail (e.g.
exact type of obsolete PC). They know how fragile
semiconductor plants are, and want to remove all
possible variables.

That's the Intel "copy exact." I guess it's good for them, in building
fabs all around the world, but locks in dumb stuff, theoretically down
to the brand of soap in the bathrooms.

Bottom-level things, at the board level, are easier to fix. Just do
it. Management can't read schematics.

Such low-level fixes can have "unintended consequences"
at the system level.

Like improved reliability. All it takes is some people with
intelligence and guts to look over a change and decide that it's an
improvement. I guess there aren't enough such people around. The
original designers of things are often gone a few years later.

I'd love to ask the guys who designed that metrology thing why they
integrated a fast edge twice, and buried it in noise, before handing
it to us to time stamp. Nobody even knows who designed it.

We create a design notes file for all our products, and we don't lose
it. If you might consider changing a bottom-level design, it helps to
know the original intent.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

On Sun, 29 Mar 2020 07:39:16 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-03-28 23:31, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 00:55:47 +0000, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 28/03/20 22:48, Phil Hobbs wrote:
Instinct is super useful for generating ideas.  We come up with some scheme by
instinct, but then test it by math.  The math involved is super familiar--what's
the noise floor, the bandwidth, the settling time, and so on.  It's the
familiarity that makes that seem like it's the same as design instinct, but it
isn't.

Very true, IMNSHO.

Practice without theory is blind fumbling.

It built aqueducts, ships, roads, cathedrals, all sorts of stuff.

Not by fiddling, though--experience accumulates. Even a pyramid will
fall down if you build it too steep.
https://en.wikipedia.org/wiki/Meidum_Pyramid

Cheers

Phil Hobbs

Sure, fiddling evolved and techniques were passed down and evolved.
But as long as we don't already know everything, some occasional
fiddling can discover stuff.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Tom Gardner]

On 29/03/20 16:16, jlarkin@highlandsniptechnology.com wrote:

On Sun, 29 Mar 2020 10:26:54 +0100, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 29/03/20 04:09, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 00:49:57 +0000, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 28/03/20 22:08, Joerg wrote:
On 2020-03-28 13:38, blocher@columbus.rr.com wrote:
On Friday, March 27, 2020 at 6:00:10 PM UTC-4, Rick C wrote:

[...]


So your work is not so much circuit design as it is system design?

I like to think I straddle circuits and systems.  I am decent at both
but certainly not an expert at analog.  The problem in my company is
that there is not enough work in circuit design to keep one always
busy.  I also think that most circuit problems are better solved
through a system approach.  If you get the system concept wrong, then
the circuit is going to be wrong.  If you know what you want at the
high level, it is easier to tell if your circuit design is adequate.


Amen!

Top-down is generally the only approach that really works. Now we'll have to
explain that to the next generations. All the ones who have served in the
military don't need to be told, they know this already.

You need top-down and bottom-up simultaneously.

It's best to be fluid and confused for a while before getting
rigorous. Bottom-level thinking about a new problem can create
insights that can affect top-level architectures and requirements, and
specs. How can you create requirements if you don't know what's
possible?


Bottom-up allows you to reuse known working
components, processes and concepts.

Or invent new ones.


Top-down on its own can lead to requiring
impossible components.


Top-level requirements documents are very difficult to change in some
organizations. They require signoff by too many managers. Important or
just sensible changes can go into a swirl of management approvals and
disappear in the process.

Yes to all the above.

The response to such "waterfall" processes is are the
various "agile" processes. The agile processes do have
some real advantages w.r.t. waterfall, but the zealous
acolytes are too dumb to realise that they have different
disadvantages.

A key issue is the absolute reliance on test-driven
design and a bottom-up approach.

TDD is great for ensuring your last low-level tweak
didn't change things - but it is of little use in
getting the right design. Too many people think "it
works because it passes the tests", without giving
any thought to the comprehensiveness of the tests.

As old timers know, "you can't test quality into a
product".


I recently discovered a semiconductor processing system that has four
expensive energy metrology subsystems that never worked but have been
installed in all systems since 2003. My gear collects useless data
from them and sends it to a computer that ignores it. It would be
impossible to move enough management to fix this. Figure roughly a
million dollars a year wasted for 17 years now.

When creating a new plant, Intel duplicates absolutely
everything, down to the ridiculous last detail (e.g.
exact type of obsolete PC). They know how fragile
semiconductor plants are, and want to remove all
possible variables.

That's the Intel "copy exact." I guess it's good for them, in building
fabs all around the world, but locks in dumb stuff, theoretically down
to the brand of soap in the bathrooms.

Just so. It smacks of "here there be magick".

Bottom-level things, at the board level, are easier to fix. Just do
it. Management can't read schematics.

Such low-level fixes can have "unintended consequences"
at the system level.

Like improved reliability.

Or not.

All it takes is some people with
intelligence and guts to look over a change and decide that it's an
improvement. I guess there aren't enough such people around. The
original designers of things are often gone a few years later.

A slightly different case with different causes, but
the 737-max debacle indicates how a low-level tweak by
inexperienced people can cause unintended consequences
in a domain outside their experience.

I'd love to ask the guys who designed that metrology thing why they
integrated a fast edge twice, and buried it in noise, before handing
it to us to time stamp. Nobody even knows who designed it.

As someone who likes to believe in cause and effect,
the cockup theory of history is usually the case and
the conspiracy theory of history is less often the case.

We create a design notes file for all our products, and we don't lose
it. If you might consider changing a bottom-level design, it helps to
know the original intent.

Now get taken over a few times, have the faceless
MBAs do some "rationalisation", and see the end
result

 

On Sun, 29 Mar 2020 08:47:23 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-03-29 07:59, DecadentLinuxUserNumeroUno@decadence.org wrote:
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:fd467d02-06d6-78e5-bd05-d420a9f8948f@electrooptical.net:

On 2020-03-28 23:12, DecadentLinuxUserNumeroUno@decadence.org
wrote:
George Herold <ggherold@gmail.com> wrote in
news:494f975a-54da-46d1-bdfb-9eaeb783919b@googlegroups.com:

Designing something cool with a few smart people at a whiteboard
is the

most fun you can have standing up.
Amen,
George H.

Barefoot water skiing.

Running off a whole rack at pool.


You've apparently never done it.

Cheers

Phil Hobbs


Going over my design ideas with supportive co-engineers is one
thing. Having one or more unable to see what you've come up with
'providing' stupid input is entirely another, and therefore is not a
favorite thing to do. I'll design it, they'll do their pieces. No
need for a white board discussion, just a white board project
declaration, and any issues they have can be brought up while they
are doing their assigned part.

Which is not what I was referring to, at all, and sounds boring, I agree.

Collaborative design at a whiteboard may go something like this example
of a phase-sensitive laser microscope. Somebody says, "How about using
a heterodyne interferometer with an acousto-optic cell and a Wollaston
prism to recombine the beams? That way we can make the whole thing
common-path so we can use normal galvo scanning." (A real example from
long ago--an English guy improving on an idea of mine.)

Then everybody chimes in with questions such as the following.

"You'll need at least a milliwatt of laser power to get to the shot
noise in that bandwidth. That's about 200 kilowatts per square
centimetre--will your sample stand that?" (Leading to a discussion about
3-D heat conduction in solids.)

"The topological phase shift in the galvo scanner will screw up the beam
recombination in the return path, won't it?" (This is a real issue that
constrains the scan range.)

This isn't rock-throwing at all--everybody wants the thing to work, and
ideally they're all friends. After half an hour or so, everybody has a
much better idea of whether the scheme can be made to work, and the
final version probably doesn't look much like the initial proposal.

It's better if there are two or three schemes being discussed, along
with lots of ideas for improvements. You also need a few harebrained
notions tossed in. (*)

It only works if nobody minds having their pet ideas demolished, because
that's definitely going to happen. Personally I'm very glad when it
happens to me, because it may save a lot of wasted work. I have lots of
ideas, so I'm not at all attached to the bad ones.

You've apparently moved toward the Larkin attitude of presumimg
things which you know no facts regarding as it relates to me. That
is a character and integrity hit you do not want. But you live as
you like.


Not intending to be insulting at all, but as your first paragraph
suggests, you've probably never done what I'm attempting to describe.
(Or perhaps I just didn't describe it well enough initially.)

Cheers

Phil Hobbs

(*) The use of helicopter propwash to knock ice off high-tension wires
allegedly came out of a discussion like that.

We did a brainstorm session once, with DR, about reflections off a
liquid metal sphere. That was wonderful. You and DR did, in about 20
minutes, astounding math. My function was just to make a lot of random
noise that could be filtered.

Old cars, like MGs, and old Honda motorcycles, had carburetors that
obviously couldn't work. There was way too much static friction for a
little bit of differential air pressure to move the needle valve. But
there was a lot of engine vibration too.




--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

On Sun, 29 Mar 2020 10:54:52 +0100, Tom Gardner
<spamjunk@blueyonder.co.uk> wrote:

On 29/03/20 04:31, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 00:55:47 +0000, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 28/03/20 22:48, Phil Hobbs wrote:
Instinct is super useful for generating ideas.  We come up with some scheme by
instinct, but then test it by math.  The math involved is super familiar--what's
the noise floor, the bandwidth, the settling time, and so on.  It's the
familiarity that makes that seem like it's the same as design instinct, but it
isn't.

Very true, IMNSHO.

Practice without theory is blind fumbling.

It built aqueducts, ships, roads, cathedrals, all sorts of stuff.

Er, no.

Wells cathedral is near me. There are strange additions
that became necessary because it rapidly started falling
down.

It took a long time for architects to understand the finer
points (literally!) of flying buttresses and why they are
necessary. Lots of trial and error (i.e. blind fumbling)
before that.

Exactly. Fumbling is not as efficient as using math, but it built a
lot of stuff. The structures usually came before, and inspired (and
paid for) the math.

And there is still stuff that gets done by guided fumbling. A lot of
biology and medicine are still like that. Some very valuable medicines
were discovered by brute-force testing of hundreds of improbable
things.

I've seen the Wasa, and ought to see the Mary Rose.
Both were high-prestige warships that sank on their
first voyage.

And the Tacoma narrows bridge is near you.


Theory without practice is mental masturbation.

Well, maybe less useful.

I exaggerate, of course.

--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Tom Gardner]

On 29/03/20 16:33, jlarkin@highlandsniptechnology.com wrote:

On Sun, 29 Mar 2020 10:54:52 +0100, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 29/03/20 04:31, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 00:55:47 +0000, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 28/03/20 22:48, Phil Hobbs wrote:
Instinct is super useful for generating ideas.  We come up with some scheme by
instinct, but then test it by math.  The math involved is super familiar--what's
the noise floor, the bandwidth, the settling time, and so on.  It's the
familiarity that makes that seem like it's the same as design instinct, but it
isn't.

Very true, IMNSHO.

Practice without theory is blind fumbling.

It built aqueducts, ships, roads, cathedrals, all sorts of stuff.

Er, no.

Wells cathedral is near me. There are strange additions
that became necessary because it rapidly started falling
down.

It took a long time for architects to understand the finer
points (literally!) of flying buttresses and why they are
necessary. Lots of trial and error (i.e. blind fumbling)
before that.

Exactly. Fumbling is not as efficient as using math, but it built a
lot of stuff. The structures usually came before, and inspired (and
paid for) the math.

And there is still stuff that gets done by guided fumbling. A lot of
biology and medicine are still like that. Some very valuable medicines
were discovered by brute-force testing of hundreds of improbable
things.

That's one reason I chose to drop biology and chemistry
after school. Too much like stamp collecting.

A real problem with the brute force arithmetic design
strategies (a.k.a. machine learning) is that you don't
know how close to the edge of the envelope you are.

That doesn't matter if you can then test a design output
exhaustively by other means e.g. a drug.

It really does matter where that isn't the case,
e.g. trivial changes to pictures convert 35mph into
85mph, or stop into go. Such "designs" are and always
will be flaky.

 

[Tom Gardner]

On 29/03/20 16:36, jlarkin@highlandsniptechnology.com wrote:

On Sun, 29 Mar 2020 07:39:16 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-03-28 23:31, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 00:55:47 +0000, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 28/03/20 22:48, Phil Hobbs wrote:
Instinct is super useful for generating ideas.  We come up with some scheme by
instinct, but then test it by math.  The math involved is super familiar--what's
the noise floor, the bandwidth, the settling time, and so on.  It's the
familiarity that makes that seem like it's the same as design instinct, but it
isn't.

Very true, IMNSHO.

Practice without theory is blind fumbling.

It built aqueducts, ships, roads, cathedrals, all sorts of stuff.

Not by fiddling, though--experience accumulates. Even a pyramid will
fall down if you build it too steep.
https://en.wikipedia.org/wiki/Meidum_Pyramid

Cheers

Phil Hobbs

Sure, fiddling evolved and techniques were passed down and evolved.
But as long as we don't already know everything, some occasional
fiddling can discover stuff.

It is often said that the most exciting sound in science
isn't "eureka", but is "that's strange".

That's as good a design strategy as inserting "fundamental
advance occurs here" into a plan. Infamously that didn't
work for the HP Itanium processor's compilers, as those
that were knowledgeable predicted.

 

On Sun, 29 Mar 2020 16:27:54 +0100, Tom Gardner
<spamjunk@blueyonder.co.uk> wrote:

As someone who likes to believe in cause and effect,
the cockup theory of history is usually the case and
the conspiracy theory of history is less often the case.

Conspiracy is the harder thing to do.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Lasse Langwadt Christense]

søndag den 29. marts 2020 kl. 21.14.13 UTC+2 skrev Joerg:

On 2020-03-29 02:54, Tom Gardner wrote:
On 29/03/20 04:31, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 00:55:47 +0000, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 28/03/20 22:48, Phil Hobbs wrote:
Instinct is super useful for generating ideas. We come up with some
scheme by
instinct, but then test it by math. The math involved is super
familiar--what's
the noise floor, the bandwidth, the settling time, and so on. It's the
familiarity that makes that seem like it's the same as design
instinct, but it
isn't.

Very true, IMNSHO.

Practice without theory is blind fumbling.

It built aqueducts, ships, roads, cathedrals, all sorts of stuff.

Er, no.

Wells cathedral is near me. There are strange additions
that became necessary because it rapidly started falling
down.


Check out some of the Roman structures in Germany. I lived there and
participated in events in some. Amazing. 1500+ years old, rock-solid,
where "modern" buildings are generally gone in less than 200 years.

https://en.wikipedia.org/wiki/Survivorship_bias#In_architecture_and_construction

 

On Sun, 29 Mar 2020 12:10:06 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2020-03-28 15:47, Clifford Heath wrote:
On 29/3/20 7:23 am, Joerg wrote:
On 2020-03-27 12:29, blocher@columbus.rr.com wrote:
A topic to elicit some thoughts....
How important is mathematics to you as an engineer?
It ranks surprisingly low on the pecking order.
... Do you consider yourself an applied mathematician? ...
Definitely not. My sister (has a mathematics degree) is razzing me
about that all the time but that's just how I am. IMO engineering is
mostly instinct. People who don't have them can't be good engineers.
Instinct comes with practice, lots of practice.


By definition, anything that only comes with practice is *not* instinct.


You are correct, though it is rather muddled in scientific literature:

https://www.edge.org/response-detail/11453

Great article. Mo is a speech pathologist and bird lover, and I'll
send it to her.




--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

On Sun, 29 Mar 2020 15:09:08 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-03-29 11:26, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 08:47:23 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-03-29 07:59, DecadentLinuxUserNumeroUno@decadence.org wrote:
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:fd467d02-06d6-78e5-bd05-d420a9f8948f@electrooptical.net:

On 2020-03-28 23:12, DecadentLinuxUserNumeroUno@decadence.org
wrote:
George Herold <ggherold@gmail.com> wrote in
news:494f975a-54da-46d1-bdfb-9eaeb783919b@googlegroups.com:

Designing something cool with a few smart people at a whiteboard
is the

most fun you can have standing up.
Amen,
George H.

Barefoot water skiing.

Running off a whole rack at pool.


You've apparently never done it.

Cheers

Phil Hobbs


Going over my design ideas with supportive co-engineers is one
thing. Having one or more unable to see what you've come up with
'providing' stupid input is entirely another, and therefore is not a
favorite thing to do. I'll design it, they'll do their pieces. No
need for a white board discussion, just a white board project
declaration, and any issues they have can be brought up while they
are doing their assigned part.

Which is not what I was referring to, at all, and sounds boring, I agree.

Collaborative design at a whiteboard may go something like this example
of a phase-sensitive laser microscope. Somebody says, "How about using
a heterodyne interferometer with an acousto-optic cell and a Wollaston
prism to recombine the beams? That way we can make the whole thing
common-path so we can use normal galvo scanning." (A real example from
long ago--an English guy improving on an idea of mine.)

Then everybody chimes in with questions such as the following.

"You'll need at least a milliwatt of laser power to get to the shot
noise in that bandwidth. That's about 200 kilowatts per square
centimetre--will your sample stand that?" (Leading to a discussion about
3-D heat conduction in solids.)

"The topological phase shift in the galvo scanner will screw up the beam
recombination in the return path, won't it?" (This is a real issue that
constrains the scan range.)

This isn't rock-throwing at all--everybody wants the thing to work, and
ideally they're all friends. After half an hour or so, everybody has a
much better idea of whether the scheme can be made to work, and the
final version probably doesn't look much like the initial proposal.

It's better if there are two or three schemes being discussed, along
with lots of ideas for improvements. You also need a few harebrained
notions tossed in. (*)

It only works if nobody minds having their pet ideas demolished, because
that's definitely going to happen. Personally I'm very glad when it
happens to me, because it may save a lot of wasted work. I have lots of
ideas, so I'm not at all attached to the bad ones.

You've apparently moved toward the Larkin attitude of presumimg
things which you know no facts regarding as it relates to me. That
is a character and integrity hit you do not want. But you live as
you like.


Not intending to be insulting at all, but as your first paragraph
suggests, you've probably never done what I'm attempting to describe.
(Or perhaps I just didn't describe it well enough initially.)

Cheers

Phil Hobbs

(*) The use of helicopter propwash to knock ice off high-tension wires
allegedly came out of a discussion like that.

We did a brainstorm session once, with DR, about reflections off a
liquid metal sphere. That was wonderful. You and DR did, in about 20
minutes, astounding math. My function was just to make a lot of random
noise that could be filtered.

Pretty good quality noise, that.

I have a really big bag of tricks for doing those sorts of calculations,
mostly consisting of amusing facts, such as that in the ray model, a
shiny sphere scatters parallel light exactly equally into 4 pi
steradians, and that the scattering cross section is twice its projected
area.

No, that's impossible. It defies all common sense.




(This is easy to show for a plane obstruction--the hole it

punches into the plane wave scatters just like the obstruction, except
180 degrees out of phase. Add them back together and you get the
original beam.)

That's how I do photon budgets for instruments all the time, but it's
way more fun doing it live.

How's DR doing? Have they started paying him what he's worth?

He is sort of a systems architect and futurist, looking ahead at where
semiconductor fab may go. I think his pay is OK now. It would be cool
to repeat the fun we had. There is maybe a 5% chance that we will.

Old cars, like MGs, and old Honda motorcycles, had carburetors that
obviously couldn't work. There was way too much static friction for a
little bit of differential air pressure to move the needle valve. But
there was a lot of engine vibration too.

There's a recent physics coinage for that: "stochastic resonance". Like
that famous remark of Voltaire's about the Holy Roman Empire, of course
stochastic resonance is neither stochastic nor resonance.

Any time you need a little chaos, I'm available.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Phil Hobbs]

On 2020-03-29 11:26, jlarkin@highlandsniptechnology.com wrote:

On Sun, 29 Mar 2020 08:47:23 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-03-29 07:59, DecadentLinuxUserNumeroUno@decadence.org wrote:
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:fd467d02-06d6-78e5-bd05-d420a9f8948f@electrooptical.net:

On 2020-03-28 23:12, DecadentLinuxUserNumeroUno@decadence.org
wrote:
George Herold <ggherold@gmail.com> wrote in
news:494f975a-54da-46d1-bdfb-9eaeb783919b@googlegroups.com:

Designing something cool with a few smart people at a whiteboard
is the

most fun you can have standing up.
Amen,
George H.

Barefoot water skiing.

Running off a whole rack at pool.


You've apparently never done it.

Cheers

Phil Hobbs


Going over my design ideas with supportive co-engineers is one
thing. Having one or more unable to see what you've come up with
'providing' stupid input is entirely another, and therefore is not a
favorite thing to do. I'll design it, they'll do their pieces. No
need for a white board discussion, just a white board project
declaration, and any issues they have can be brought up while they
are doing their assigned part.

Which is not what I was referring to, at all, and sounds boring, I agree.

Collaborative design at a whiteboard may go something like this example
of a phase-sensitive laser microscope. Somebody says, "How about using
a heterodyne interferometer with an acousto-optic cell and a Wollaston
prism to recombine the beams? That way we can make the whole thing
common-path so we can use normal galvo scanning." (A real example from
long ago--an English guy improving on an idea of mine.)

Then everybody chimes in with questions such as the following.

"You'll need at least a milliwatt of laser power to get to the shot
noise in that bandwidth. That's about 200 kilowatts per square
centimetre--will your sample stand that?" (Leading to a discussion about
3-D heat conduction in solids.)

"The topological phase shift in the galvo scanner will screw up the beam
recombination in the return path, won't it?" (This is a real issue that
constrains the scan range.)

This isn't rock-throwing at all--everybody wants the thing to work, and
ideally they're all friends. After half an hour or so, everybody has a
much better idea of whether the scheme can be made to work, and the
final version probably doesn't look much like the initial proposal.

It's better if there are two or three schemes being discussed, along
with lots of ideas for improvements. You also need a few harebrained
notions tossed in. (*)

It only works if nobody minds having their pet ideas demolished, because
that's definitely going to happen. Personally I'm very glad when it
happens to me, because it may save a lot of wasted work. I have lots of
ideas, so I'm not at all attached to the bad ones.

You've apparently moved toward the Larkin attitude of presumimg
things which you know no facts regarding as it relates to me. That
is a character and integrity hit you do not want. But you live as
you like.


Not intending to be insulting at all, but as your first paragraph
suggests, you've probably never done what I'm attempting to describe.
(Or perhaps I just didn't describe it well enough initially.)

Cheers

Phil Hobbs

(*) The use of helicopter propwash to knock ice off high-tension wires
allegedly came out of a discussion like that.

We did a brainstorm session once, with DR, about reflections off a
liquid metal sphere. That was wonderful. You and DR did, in about 20
minutes, astounding math. My function was just to make a lot of random
noise that could be filtered.

Pretty good quality noise, that.

I have a really big bag of tricks for doing those sorts of calculations,
mostly consisting of amusing facts, such as that in the ray model, a
shiny sphere scatters parallel light exactly equally into 4 pi
steradians, and that the scattering cross section is twice its projected
area. (This is easy to show for a plane obstruction--the hole it
punches into the plane wave scatters just like the obstruction, except
180 degrees out of phase. Add them back together and you get the
original beam.)

That's how I do photon budgets for instruments all the time, but it's
way more fun doing it live.

How's DR doing? Have they started paying him what he's worth?

Old cars, like MGs, and old Honda motorcycles, had carburetors that
obviously couldn't work. There was way too much static friction for a
little bit of differential air pressure to move the needle valve. But
there was a lot of engine vibration too.

There's a recent physics coinage for that: "stochastic resonance". Like
that famous remark of Voltaire's about the Holy Roman Empire, of course
stochastic resonance is neither stochastic nor resonance.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Joerg]

On 2020-03-28 15:47, Clifford Heath wrote:

On 29/3/20 7:23 am, Joerg wrote:
On 2020-03-27 12:29, blocher@columbus.rr.com wrote:
A topic to elicit some thoughts....
How important is mathematics to you as an engineer?
It ranks surprisingly low on the pecking order.
... Do you consider yourself an applied mathematician? ...
Definitely not. My sister (has a mathematics degree) is razzing me
about that all the time but that's just how I am. IMO engineering is
mostly instinct. People who don't have them can't be good engineers.
Instinct comes with practice, lots of practice.


By definition, anything that only comes with practice is *not* instinct.

You are correct, though it is rather muddled in scientific literature:

https://www.edge.org/response-detail/11453

I think you mean intuition. Intuition comes with practice. It's just a
cognitive habit, and habits come with practice.

Ok, intuition. That's super-important in engineering.

... Theoretical EMAG is important, but you can go a long
way without being super proficient at maxwells equations.
True ... but ... one must have a very good gut feel of how Maxwell
applies to stuff. Otherwise the whole design could turn into a
nightmare at the EMC lab.

Students are taught to think of electrons flowing inside wires. Is it
any wonder they have trouble with RF, where they have to visualise
everything as a field, with wires to guide the field?

That's where the right feel for Maxwell's stuff needs to come in. If
someone can't develop an understanding of electrical, magnetic and
electromagnetic fields it may be better to pick another career. Maybe
sales, makes more money anyhow

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 2020-03-29 02:54, Tom Gardner wrote:

On 29/03/20 04:31, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 00:55:47 +0000, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 28/03/20 22:48, Phil Hobbs wrote:
Instinct is super useful for generating ideas. We come up with some
scheme by
instinct, but then test it by math. The math involved is super
familiar--what's
the noise floor, the bandwidth, the settling time, and so on. It's the
familiarity that makes that seem like it's the same as design
instinct, but it
isn't.

Very true, IMNSHO.

Practice without theory is blind fumbling.

It built aqueducts, ships, roads, cathedrals, all sorts of stuff.

Er, no.

Wells cathedral is near me. There are strange additions
that became necessary because it rapidly started falling
down.

Check out some of the Roman structures in Germany. I lived there and
participated in events in some. Amazing. 1500+ years old, rock-solid,
where "modern" buildings are generally gone in less than 200 years.

As a side note, some of the best engineers I worked with have no formal
academic education.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 2020-03-29 09:17, Tom Gardner wrote:

On 29/03/20 16:36, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 07:39:16 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-03-28 23:31, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 00:55:47 +0000, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 28/03/20 22:48, Phil Hobbs wrote:
Instinct is super useful for generating ideas. We come up with
some scheme by
instinct, but then test it by math. The math involved is super
familiar--what's
the noise floor, the bandwidth, the settling time, and so on.
It's the
familiarity that makes that seem like it's the same as design
instinct, but it
isn't.

Very true, IMNSHO.

Practice without theory is blind fumbling.

It built aqueducts, ships, roads, cathedrals, all sorts of stuff.

Not by fiddling, though--experience accumulates. Even a pyramid will
fall down if you build it too steep.
https://en.wikipedia.org/wiki/Meidum_Pyramid

Cheers

Phil Hobbs

Sure, fiddling evolved and techniques were passed down and evolved.
But as long as we don't already know everything, some occasional
fiddling can discover stuff.

It is often said that the most exciting sound in science
isn't "eureka", but is "that's strange".

Or "Shazam!"

An example was a weird EMI case.

"The processor hangs it up once in a while, mostly every few seconds,
but never if we close the blinds on the windows. We can't understand how
this can have anything to do with daylight."

"Hey, what's that thing there in the distance, on the mountain top, that
glistens every few seconds?"

"That? Well, that's just a military radar .. oh, OH! DANG!"

(the blinds were aluminum)

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Phil Hobbs]

On 2020-03-29 15:24, Joerg wrote:

On 2020-03-29 09:17, Tom Gardner wrote:
On 29/03/20 16:36, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 07:39:16 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-03-28 23:31, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 00:55:47 +0000, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 28/03/20 22:48, Phil Hobbs wrote:
Instinct is super useful for generating ideas.  We come up with
some scheme by
instinct, but then test it by math.  The math involved is super
familiar--what's
the noise floor, the bandwidth, the settling time, and so on.
It's the
familiarity that makes that seem like it's the same as design
instinct, but it
isn't.

Very true, IMNSHO.

Practice without theory is blind fumbling.

It built aqueducts, ships, roads, cathedrals, all sorts of stuff.

Not by fiddling, though--experience accumulates.  Even a pyramid will
fall down if you build it too steep.
https://en.wikipedia.org/wiki/Meidum_Pyramid

Cheers

Phil Hobbs

Sure, fiddling evolved and techniques were passed down and evolved.
But as long as we don't already know everything, some occasional
fiddling can discover stuff.

It is often said that the most exciting sound in science
isn't "eureka", but is "that's strange".


Or "Shazam!"

An example was a weird EMI case.

"The processor hangs it up once in a while, mostly every few seconds,
but never if we close the blinds on the windows. We can't understand how
this can have anything to do with daylight."

"Hey, what's that thing there in the distance, on the mountain top, that
glistens every few seconds?"

"That? Well, that's just a military radar .. oh, OH! DANG!"

(the blinds were aluminum)

[...]

Speaking of fiddling, when I was a postdoc, a good friend named David
Abraham came into my lab to ask me to make him a notch filter to knock
down the 30-kHz resonance of the piezo tube in his tunnelling microscope.

As a first try, I pulled out a largish Pulse Engineering transformer
from my drawer, put a 100 nF monocap across each side, and (iirc) wired
the windings in series. (I might have used just one side, but
definitely resonated both.)

Then I stuck it between a sweep generator and an HP diode detector,
connected to a scope synced to the sweep. (The normal scalar network
analyzer setup.) It displayed a beautiful two-peaked notch response
centred exactly at 30 kHz, with a Q of about 20.

So I smiled sweetly, handed it to him, and refused to tell him how I did
that. Poor guy, I never did tell him that it was a total fluke.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

On 2020-03-29 15:34, jlarkin@highlandsniptechnology.com wrote:

On Sun, 29 Mar 2020 15:09:08 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-03-29 11:26, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 08:47:23 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-03-29 07:59, DecadentLinuxUserNumeroUno@decadence.org wrote:
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:fd467d02-06d6-78e5-bd05-d420a9f8948f@electrooptical.net:

On 2020-03-28 23:12, DecadentLinuxUserNumeroUno@decadence.org
wrote:
George Herold <ggherold@gmail.com> wrote in
news:494f975a-54da-46d1-bdfb-9eaeb783919b@googlegroups.com:

Designing something cool with a few smart people at a whiteboard
is the

most fun you can have standing up.
Amen,
George H.

Barefoot water skiing.

Running off a whole rack at pool.


You've apparently never done it.

Cheers

Phil Hobbs


Going over my design ideas with supportive co-engineers is one
thing. Having one or more unable to see what you've come up with
'providing' stupid input is entirely another, and therefore is not a
favorite thing to do. I'll design it, they'll do their pieces. No
need for a white board discussion, just a white board project
declaration, and any issues they have can be brought up while they
are doing their assigned part.

Which is not what I was referring to, at all, and sounds boring, I agree.

Collaborative design at a whiteboard may go something like this example
of a phase-sensitive laser microscope. Somebody says, "How about using
a heterodyne interferometer with an acousto-optic cell and a Wollaston
prism to recombine the beams? That way we can make the whole thing
common-path so we can use normal galvo scanning." (A real example from
long ago--an English guy improving on an idea of mine.)

Then everybody chimes in with questions such as the following.

"You'll need at least a milliwatt of laser power to get to the shot
noise in that bandwidth. That's about 200 kilowatts per square
centimetre--will your sample stand that?" (Leading to a discussion about
3-D heat conduction in solids.)

"The topological phase shift in the galvo scanner will screw up the beam
recombination in the return path, won't it?" (This is a real issue that
constrains the scan range.)

This isn't rock-throwing at all--everybody wants the thing to work, and
ideally they're all friends. After half an hour or so, everybody has a
much better idea of whether the scheme can be made to work, and the
final version probably doesn't look much like the initial proposal.

It's better if there are two or three schemes being discussed, along
with lots of ideas for improvements. You also need a few harebrained
notions tossed in. (*)

It only works if nobody minds having their pet ideas demolished, because
that's definitely going to happen. Personally I'm very glad when it
happens to me, because it may save a lot of wasted work. I have lots of
ideas, so I'm not at all attached to the bad ones.

You've apparently moved toward the Larkin attitude of presumimg
things which you know no facts regarding as it relates to me. That
is a character and integrity hit you do not want. But you live as
you like.


Not intending to be insulting at all, but as your first paragraph
suggests, you've probably never done what I'm attempting to describe.
(Or perhaps I just didn't describe it well enough initially.)

Cheers

Phil Hobbs

(*) The use of helicopter propwash to knock ice off high-tension wires
allegedly came out of a discussion like that.

We did a brainstorm session once, with DR, about reflections off a
liquid metal sphere. That was wonderful. You and DR did, in about 20
minutes, astounding math. My function was just to make a lot of random
noise that could be filtered.

Pretty good quality noise, that.

I have a really big bag of tricks for doing those sorts of calculations,
mostly consisting of amusing facts, such as that in the ray model, a
shiny sphere scatters parallel light exactly equally into 4 pi
steradians, and that the scattering cross section is twice its projected
area.

No, that's impossible. It defies all common sense.

That's why it's an amusing fact, and therefore memorable. The law of
reflection tells you that tipping a mirror by an angle theta steers the
beam by 2*theta, so going from the centre to the edge, the reflected
angle rotates through 180 degrees. So you do illuminate all 4 pi
steradians. The growth of the circumference with radius is exactly
balanced out by the obliquity of the surface and the solid angle vs.
deflection, so the illumination is uniform.

(This is easy to show for a plane obstruction--the hole it
punches into the plane wave scatters just like the obstruction, except
180 degrees out of phase. Add them back together and you get the
original beam.)

That's how I do photon budgets for instruments all the time, but it's
way more fun doing it live.

How's DR doing? Have they started paying him what he's worth?

He is sort of a systems architect and futurist, looking ahead at where
semiconductor fab may go. I think his pay is OK now. It would be cool
to repeat the fun we had. There is maybe a 5% chance that we will.

Here's hoping.

Old cars, like MGs, and old Honda motorcycles, had carburetors that
obviously couldn't work. There was way too much static friction for a
little bit of differential air pressure to move the needle valve. But
there was a lot of engine vibration too.

There's a recent physics coinage for that: "stochastic resonance". Like
that famous remark of Voltaire's about the Holy Roman Empire, of course
stochastic resonance is neither stochastic nor resonance.

Any time you need a little chaos, I'm available.

Sure, we should figure out something to do together again.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Rick C]

On Sunday, March 29, 2020 at 4:05:05 PM UTC-4, Phil Hobbs wrote:

On 2020-03-29 15:34, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 15:09:08 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

I have a really big bag of tricks for doing those sorts of calculations,
mostly consisting of amusing facts, such as that in the ray model, a
shiny sphere scatters parallel light exactly equally into 4 pi
steradians, and that the scattering cross section is twice its projected
area.

No, that's impossible. It defies all common sense.

That's why it's an amusing fact, and therefore memorable. The law of
reflection tells you that tipping a mirror by an angle theta steers the
beam by 2*theta, so going from the centre to the edge, the reflected
angle rotates through 180 degrees. So you do illuminate all 4 pi
steradians. The growth of the circumference with radius is exactly
balanced out by the obliquity of the surface and the solid angle vs.
deflection, so the illumination is uniform.

The moral of this story is to not trust Larkin's "common sense".

--

Rick C.

--- Get 1,000 miles of free Supercharging
--- Tesla referral code - https://ts.la/richard11209

 

[Phil Hobbs]

On 2020-03-29 16:15, Rick C wrote:

On Sunday, March 29, 2020 at 4:05:05 PM UTC-4, Phil Hobbs wrote:
On 2020-03-29 15:34, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 15:09:08 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

I have a really big bag of tricks for doing those sorts of calculations,
mostly consisting of amusing facts, such as that in the ray model, a
shiny sphere scatters parallel light exactly equally into 4 pi
steradians, and that the scattering cross section is twice its projected
area.

No, that's impossible. It defies all common sense.

That's why it's an amusing fact, and therefore memorable. The law of
reflection tells you that tipping a mirror by an angle theta steers the
beam by 2*theta, so going from the centre to the edge, the reflected
angle rotates through 180 degrees. So you do illuminate all 4 pi
steradians. The growth of the circumference with radius is exactly
balanced out by the obliquity of the surface and the solid angle vs.
deflection, so the illumination is uniform.

The moral of this story is to not trust Larkin's "common sense".

You're being a moron again.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Rick C]

On Sunday, March 29, 2020 at 4:24:10 PM UTC-4, Phil Hobbs wrote:

On 2020-03-29 16:15, Rick C wrote:
On Sunday, March 29, 2020 at 4:05:05 PM UTC-4, Phil Hobbs wrote:
On 2020-03-29 15:34, jlarkin@highlandsniptechnology.com wrote:
On Sun, 29 Mar 2020 15:09:08 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

I have a really big bag of tricks for doing those sorts of calculations,
mostly consisting of amusing facts, such as that in the ray model, a
shiny sphere scatters parallel light exactly equally into 4 pi
steradians, and that the scattering cross section is twice its projected
area.

No, that's impossible. It defies all common sense.

That's why it's an amusing fact, and therefore memorable. The law of
reflection tells you that tipping a mirror by an angle theta steers the
beam by 2*theta, so going from the centre to the edge, the reflected
angle rotates through 180 degrees. So you do illuminate all 4 pi
steradians. The growth of the circumference with radius is exactly
balanced out by the obliquity of the surface and the solid angle vs.
deflection, so the illumination is uniform.

The moral of this story is to not trust Larkin's "common sense".


You're being a moron again.

Hey, Larkin is the one who touts the value of "common sense". Then he gets it completely wrong because of it.

That is a valuable lesson which only some will appreciate. Certainly not Larkin and apparently not you.

--

Rick C.

-- Get 1,000 miles of free Supercharging
-- Tesla referral code - https://ts.la/richard11209