On Dec 10, 5:18*am, Bruce L. Bergman
wrote:
On Wed, 9 Dec 2009 23:41:31 -0800 (PST), Andrew VK3BFA
On Nov 29, 10:50 am, "John R. Carroll" wrote:
Jim Wilkins wrote:
On Nov 28, 5:54 pm, Wes wrote:

Sorta correct - theres a large lot of electronics (digital) devoted to
getting the software decoded digital signal onto the screen, either
LCD or plasma. Has to map and address the screen in an X-Y plane -

The digital radios I worked on sometimes had hardware Matched Filters
between the A/D converter and the DSP.
http://en.wikipedia.org/wiki/Matched_filter

The too-far-ahead-of-its-time color ink jet printer used custom ASICs
to remap linear images onto the multiple ink jets.
http://en.wikipedia.org/wiki/VLSI_Technology

These functions could be done in either hardware or software, the
choice sometimes depending on the skills available on the development
team. Twice I was temporarily promoted from lab tech to custom IC
designer to help.

* The Manufacturers of all electronics should be REQUIRED to release
full schematics into the public domain when the unit is out of
production and no longer supported, and the replacement circuit boards
are no longer available. *Because old gear sometimes must be repaired
when there are no new replacements available for them, and you need
the old gear to read the old media.
...
* And without the board schematics and the realignment procedures, and
the Super Seekrit conversion list of proprietary chip numbers to the
industry-standard chips they had relabeled, it can be almost
impossible to fix the unit - unless you were the engineer who built it
in the first place.

-- Bruce ---

When circuits include a PIC or other programmable device the schematic
isn't enough. Little stubs of circuity stick out of it with no hint of
when or how they are active. Once a member of the original design team
leaves some faults in the product can become impossible to diagnose
and repair even in-house.

Companies don't release unpatented "trade secrets" hidden in the
software.

Devices like these are an extreme example.
http://www.xilinx.com/products/devices.htm
The compiler includes a randomizer so that for instance it won't
repeat a compilation that assigns a critical clock signal to an
excessively long path. This means that the very same schematic may
work perfectly one time its compiled and not the next. I spent quite a
while driving between my CAD room and the radio site, through the snow
and wolves, trying to get every function working.

If you want to pursue this line ask Microsoft to release operating
systems into the public domain after they stop supporting them.

How is all this a Primitive Tool???

jsw

In article
,
Jim Wilkins wrote:

[snip]

When circuits include a PIC or other programmable device the schematic
isn't enough. Little stubs of circuity stick out of it with no hint of
when or how they are active. Once a member of the original design team
leaves some faults in the product can become impossible to diagnose
and repair even in-house.

Companies don't release unpatented "trade secrets" hidden in the
software.

Devices like these are an extreme example.
http://www.xilinx.com/products/devices.htm
The compiler includes a randomizer so that for instance it won't
repeat a compilation that assigns a critical clock signal to an
excessively long path. This means that the very same schematic may
work perfectly one time its compiled and not the next. I spent quite a
while driving between my CAD room and the radio site, through the snow
and wolves, trying to get every function working.

A subcontractor had exactly this problem in the 1990s. Drove them nuts
because while the compiler was randomizing paths and pinouts, the
artwork on the prototype board strangely didn't automatically rearrange
itself to follow.

Completely stopped integration until the engineer broke the undocumented
proprietary CAD file format and figured out how to force the pinouts to
remain stable.

I don't see how randomizing paths and pinouts helps their sales or
protects anybody's intellectual property. I bet this comes under the
heading of "don't ascribe to malice that which can be adequately
explained by incompetence".

Joe Gwinn

On Dec 10, 9:17*am, Joseph Gwinn wrote:
In article
,
*Jim Wilkins wrote:

[snip]







When circuits include a PIC or other programmable device the schematic
isn't enough. Little stubs of circuity stick out of it with no hint of
when or how they are active. Once a member of the original design team
leaves some faults in the product can become impossible to diagnose
and repair even in-house.

Companies don't release unpatented "trade secrets" hidden in the
software.

Devices like these are an extreme example.
http://www.xilinx.com/products/devices.htm
The compiler includes a randomizer so that for instance it won't
repeat a compilation that assigns a critical clock signal to an
excessively long path. This means that the very same schematic may
work perfectly one time its compiled and not the next. I spent quite a
while driving between my CAD room and the radio site, through the snow
and wolves, trying to get every function working.

A subcontractor had exactly this problem in the 1990s. *Drove them nuts
because while the compiler was randomizing paths and pinouts, the
artwork on the prototype board strangely didn't automatically rearrange
itself to follow. *

Completely stopped integration until the engineer broke the undocumented
proprietary CAD file format and figured out how to force the pinouts to
remain stable.

I don't see how randomizing paths and pinouts helps their sales or
protects anybody's intellectual property. *I bet this comes under the
heading of "don't ascribe to malice that which can be adequately
explained by incompetence".

Joe Gwinn-

Auto-routing is something like chess, a pattern-recognition problems
that a human can sometimes do better than a machine. As I understand
it randomizing prevents the tightest routing channels from filling up
and blocking completion the same way each time. The PADS autorouter I
used in the 90's would jam in ways I could easily see how to fix by
moving components, since I could evaluate the effect of lengthening
their interconnections.

I never met another PC board layout person who understood the circuit,
let alone had designed it, so the tool had to be able to fix its
problems automatically.

Xilinx explained their randomizing algorithm in the thermodynamic
terms of metastability, the peaks and valleys of activation energy,
which I followed from knowing chemistry but won't try to explain here.

jsw

Andrew VK3BFA wrote:
And back in the Old Days - why, I remember when I had to walk 10 miles
to school, barefoot, through the snow with nothing but a pointy stick
to protect myself from wolves. And this was after I had got up at 5am
to milk the cows and do my chores, breaking ice in the well to draw up
water for my mother. And if I hadn't taken a bundle of firewood with
me for the school heater, I was whipped and made to go out in a raging
blizzard and find some.....

And you tell the young people this, and they don't believe you.

Andrew VK3BFA.

You forgot, It was UP-Hill both ways.
...lew...

On Wed, 9 Dec 2009 23:41:31 -0800 (PST), Andrew VK3BFA
wrote:

On Nov 29, 10:50 am, "John R. Carroll" wrote:
Jim Wilkins wrote:
On Nov 28, 5:54 pm, Wes wrote:

Outside of a RF reciever, most televisions don't work the same as
they did when I was a kid.

They did go digital recently.

Downconvert, digitize, the rest is software.

I'd be interested in hearing about that.
I've gone from 30 decent channels to six poor ones.

--
John R. Carroll

Sorta correct - theres a large lot of electronics (digital) devoted to
getting the software decoded digital signal onto the screen, either
LCD or plasma. Has to map and address the screen in an X-Y plane -
most of this is build into the panel at manufacture, so replacement is
costly . With plasmas, its the high power/high voltage driver boards
that die, with LCD its the back light inverters....haven't had a
chance to pull one of the newer LED backlight panels to pieces yet....

The real issue with digital TV's is you cannot look at the screen and
get some idea of where the fault is, unlike analogue. They either
work, or they don't. No schematics available, fix by board
replacement. Totally uneconomic (except as a "interesting problem") to
reverse engineer to component level.

But thats true of most modern goods, except for Old Farts like us who
will spend a day machining a 10c part to fix a $20 machine....its not
economic, but we do it becaause it annoys the hell out of us that
"spare parts" is nowadays an oxymoron.

And back in the Old Days - why, I remember when I had to walk 10 miles
to school, barefoot, through the snow with nothing but a pointy stick
to protect myself from wolves. And this was after I had got up at 5am
to milk the cows and do my chores, breaking ice in the well to draw up
water for my mother. And if I hadn't taken a bundle of firewood with
me for the school heater, I was whipped and made to go out in a raging
blizzard and find some.....

And you tell the young people this, and they don't believe you.

Andrew VK3BFA.

On a cool spring day I was sent down to stoke the wood furnace just
after lunch, by 2 PM we were sent outside because the classroom was
too hot to stay inside. I never got asked to stoke the furnace again!
Gerry :-)}
London, Canada

In article
,
Jim Wilkins wrote:

On Dec 10, 9:17*am, Joseph Gwinn wrote:
In article
,
*Jim Wilkins wrote:

[snip]







When circuits include a PIC or other programmable device the schematic
isn't enough. Little stubs of circuity stick out of it with no hint of
when or how they are active. Once a member of the original design team
leaves some faults in the product can become impossible to diagnose
and repair even in-house.

Companies don't release unpatented "trade secrets" hidden in the
software.

Devices like these are an extreme example.
http://www.xilinx.com/products/devices.htm
The compiler includes a randomizer so that for instance it won't
repeat a compilation that assigns a critical clock signal to an
excessively long path. This means that the very same schematic may
work perfectly one time its compiled and not the next. I spent quite a
while driving between my CAD room and the radio site, through the snow
and wolves, trying to get every function working.

A subcontractor had exactly this problem in the 1990s. *Drove them nuts
because while the compiler was randomizing paths and pinouts, the
artwork on the prototype board strangely didn't automatically rearrange
itself to follow. *

Completely stopped integration until the engineer broke the undocumented
proprietary CAD file format and figured out how to force the pinouts to
remain stable.

I don't see how randomizing paths and pinouts helps their sales or
protects anybody's intellectual property. *I bet this comes under the
heading of "don't ascribe to malice that which can be adequately
explained by incompetence".

Joe Gwinn-

Auto-routing is something like chess, a pattern-recognition problems
that a human can sometimes do better than a machine. As I understand
it randomizing prevents the tightest routing channels from filling up
and blocking completion the same way each time. The PADS autorouter I
used in the 90's would jam in ways I could easily see how to fix by
moving components, since I could evaluate the effect of lengthening
their interconnections.

That makes sense.

This is OK for the paths between the in and out pins, but not for the
pinout.


I never met another PC board layout person who understood the circuit,
let alone had designed it, so the tool had to be able to fix its
problems automatically.

Xilinx explained their randomizing algorithm in the thermodynamic
terms of metastability, the peaks and valleys of activation energy,
which I followed from knowing chemistry but won't try to explain here.

I do understand. They are using simulated annealing in hope of finding
the global optimum without becoming stuck in some local optimum.


Joe Gwinn

On 2009-12-10, Andrew VK3BFA wrote:

[ ... ]

Bloody Hell Bruce - I have trouble remembering what I did 6 months ago

[ ... ]

BUT - the REALLY NICE old gear had beautiful manuals , old HP , Tek
test gear, even till the 70's radio gear - again, its the Old Fart
syndrome, we remember (I think) when such things as manuals and spare
parts were routine.

Not only that -- but Tektronix, at least, had a sense of humour.
Look in the schematics for something from the period of the 454 and you
will find, somewhere in there, a joke. In one of them, there was a
railroad train running along the ground rail on one page, complete with
puffs of smoke and steam. :-)

I forget what the other devices had, but there was one schematic
for each device which had an "Easter egg" like that.

Enjoy,
DoN.

--
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