I obviously can't speak for the Italian or Norwegian companies you
mention, but I do have the direct experience of 17 years of circuit
design and project engineering management at Tektronix. It's hard to
imagine experiences like yours happening with Tek equipment.

During the time I worked there, and presumably up to the present, Tek
had what they called the "phase" system. The engineers would do their
very best to design the product to meet all the advertised
specifications, plus additional non-advertised in-house specs. These
included temperature, vibration, shock, humidity and other environmental
specs; certification by various safety agencies; and EMC requirements,
in addition to detailed electrical performance specs.

When this design was complete, a meeting was held. Attendees included
representatives from design engineering, marketing, product safety,
component and evaluation engineering, and others. Only by consensus of
this group was the milestone declared to have been completed.

This was just the beginning, though, of the first phase, called "A
Phase". A number of instruments were built, typically around 25 to 50.
Some were sent to the environmental lab to test performance over the
range of specified environmental conditions. Others were shaken and
shocked. Others were studded with temperature probes and tested for
excessive temperature at many internal points. A few were put on
accelerated long-term reliability testing at a greatly elevated
temperature. Some were cycled on and off at high temperature. The design
was carefully analyzed by the evaluation engineering group, looking for
overstressed components. And many of the units were tested against the
full specification list, to insure that they fully met every spec.

During this phase, many problems were of course found and fixed. The
engineers would generate change orders describing the fixes, and the
test units were modified accordingly.

When it was believed that the units all met the many requirements,
another milestone meeting was held. Again if the attendees agreed, the
milestone was declared met, and "B Phase" began.

B Phase was largely a re-run of A Phase. Again, a sizeable number of
instruments were built and fully tested. Problems which were found were
corrected. Only at the end of this phase was production started.

Production often started with a pilot build. The first hundred or so
instruments were given extra scrutiny, temperature cycled, and otherwise
tested in a way to overstress them. These instruments normally became
demo units for the sales force, and some were retained by engineering
for internal use.

After pilot production, volume shipment finally commenced. Some large
companies required an incoming inspection test where every one of the
electrical performance specifications was checked, and the instrument
rejected if any failed. I once had the job of collecting test equipment
and writing a procedure for customers to use for testing our 50 GHz
bandwidth sampling head to specification, and it was very difficult to
find equipment capable of verifying the performance. We weren't able to
claim 60 GHz bandwidth even though we were pretty sure our units would
do it, because we couldn't find a way for us or the customer to verify
it at the time.

After the units were in production, each field service center kept
records of repairs, and which components failed. They were sorted by
circuit number (e.g. Q123) and part number, as well as by instrument and
board. If any part showed a high failure rate, the design was modified
and future instruments were built using the new design.

I know that other quality manufacturers have similar development systems.

That's why a Tektronix instrument costs a lot more than some others. The
existence of companies putting out the shoddy sort of stuff you mention
shows that some people are willing to trade quality for price. That's
their choice.

But the environment I described is the one I, and Wes, are accustomed
to, and it's what our designs had to get through.

Roy Lewallen, W7EL
(formerly Principal Engineer, Tektronix)

J M Noeding wrote:
On Sat, 16 Oct 2004 15:17:47 -0700, Roy Lewallen
wrote:

When amateur constructors are mentioned, it is not only those who do
strange things. While many large telecommunication and instrument
factories like HP, Tektronic, Siemens, Wandel&Goltermann,
Rohde&Schwartz, LME, Philips, Telettra seem to have certain rules to
follow and you may even see certain ways the different factory solves
the problems, it is some very large companies in Norway, Great
Brittain and elsewhere who make rather strange solutions.

One Italian company forgot to put transient protection over a relay,
and the driver transistor was damaged ever so often. I've maintained
many different transmitters which were almost impossible to tune up
after replacing parts because the impedances changed a lot, adding a
resistor in the base circuit improved on this. A wellknown Norwegian
radiolink manufacturer designed local oscillators in 6-8GHz using
2N3866 with over 1.5W power consumption, a buffer with the same and
operated in class C, the next doubler to 200MHz in class C and a
2N3866 as well, and a 2N3375 in class C. The first and third
transistors were critical and had to be replaced every two years, and
the signal on 6cm was so noisy that SM6ESG couldn't find any beat
note. He modified the stages to class A, reduced the drive level on
all stages and the heat was considerable lower, and at least the
oscillator noise very much improved

So, one shouldn't only blame the amateurs for bad constructors, but
sometime the manufacturers may even be worse

73,
Jan-Martin
---
J. M. Noeding, LA8AK, N-4623 Kristiansand
http://home.online.no/~la8ak/c.htm

And what happened when the management/sales team decided they were
going to deliver anyway, and asked you in a _meaningful_ manner
whether you thought that your objections to the milestone being declared
were really in the company's best interests or in your own personal
best interests?

"Roy Lewallen" wrote in message
...
When this design was complete, a meeting was held. Attendees included
representatives from design engineering, marketing, product safety,
component and evaluation engineering, and others. Only by consensus of
this group was the milestone declared to have been completed.

On Sun, 17 Oct 2004 13:55:15 +0100, "Airy R. Bean"
wrote:

And what happened when the management/sales team decided they were
going to deliver anyway, and asked you in a _meaningful_ manner
whether you thought that your objections to the milestone being declared
were really in the company's best interests or in your own personal
best interests?

"Roy Lewallen" wrote in message
...
When this design was complete, a meeting was held. Attendees included
representatives from design engineering, marketing, product safety,
component and evaluation engineering, and others. Only by consensus of
this group was the milestone declared to have been completed.


apart from Tek and certain others which Roy describes, I believe that
some economists look at the balance between number of components used
and trade-off in production, so much more equipment would pass the
control if certain components were added.

What I actually meant, but perhaps didn't fully express was that you
may study the circuit diagrams and have a feeling which manufacturer
has designed it, they follow certain techniques and technical
management.

On the other hand one may experience that HP and Tek uses some extra
components which are difficult for the average constructor to explain
or understand the function for, and one may experience that even among
the amateurs somebody manage some technique which almost nobody else
can copy - not even very experienced persons, may I mention SM5BZR
Leif's techniques, it is many constructions, they may look so easy,
but one often need some more deeper understanding to succeed, what
say's G3SEK?

73
Jan-Martin
---
J. M. Noeding, LA8AK, N-4623 Kristiansand
http://home.online.no/~la8ak/c.htm

J M Noeding wrote:
On the other hand one may experience that HP and Tek uses some extra
components which are difficult for the average constructor to explain
or understand the function for,

They don't have a legal obligation to explain their detailed circuit
design... but you can learn a lot by trying to work it out for yourself.

and one may experience that even among the amateurs somebody manage
some technique which almost nobody else can copy - not even very
experienced persons, may I mention SM5BZR Leif's techniques, it is many
constructions, they may look so easy, but one often need some more
deeper understanding to succeed, what say's G3SEK?

I don't have any personal experience of copying Leif's designs (assuming
this is SM5BSZ we're talking about) but they have been widely copied. It
just takes everyone else a whole lot longer... so he's still way out
ahead.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

This is to be expected. The engineers who work at the job all day, every
day, know and understand a lot more about the circuits they're designing
than someone to whom it's only a hobby.

And, considering the incredible time and effort that goes into the
design of each product, Tektronix and similar companies can't afford to
be making instruments that can be perfectly copied within days. I never
saw any conscious effort to obscure a design, but the normal process of
developing state-of-the-art equipment required use of techniques out of
the reach of amateurs or even most manufacturing companies. Let me give
you just a few examples.

1. Circuit board layout becomes critical for many high performance
circuits, and sometimes several iterations are required before all
problems are solved. There are also mechanical considerations such as
maintaining necessary air flow. In a product I worked on, we had to
solder the turns of a delay line together to reduce coupling from a CRT
deflection circuit. In another, the ground was broken in a critical
point to interrupt ground current flow.

2. Design techniques are used which aren't well known outside the
industry. For example, look at the schematic of the vertical amplifiers
in older Tek analog scopes. You'll find series RC combinations,
sometimes with a thermistor as the R, between the emitters of the
differential stage transistors. These served two functions. One was to
compensate for the delay line loss which increases as the square root of
frequency. The other is to compensate for thermals -- the fact that a
common-emitter stage gain changes as the transistor heats up in response
to a signal voltage change. This can usually be ignored in a time-domain
application, but can cause serious distortion of a voltage step or other
time-domain waveform. Changing the transistor type or sometimes even its
package type changes the compensation requirements.

3. Component selection and design are often critical, as is material
selection. As an example, some high impedance attenuators are built on
special circuit board material such as polysulfone, because of a
nonlinear property of FR4 and other materials called "hook" which causes
signal distortion.

4. Manufacturing techniques. The list of these is almost endless. It
becomes a major determining factor in circuit performance particularly
at very high frequencies, such as the 20 - 50 GHz sampling heads I
helped design.

I recall showing a photomicrograph of a new sampling head to a company
which was very sensitive to security, and telling the surprised
engineers that I'd be happy to give them a copy. I also told them
truthfully that even if I gave them the schematic and parts list, they
still wouldn't be able to build it. I'd guess that a competing company
with world-class engineers might be able to do so in about a year. There
were just too many special and selected components and manufacturing tricks.

So it's wishful thinking to believe that you can duplicate one of these
high-performance circuits by soldering parts together from a circuit
diagram. There's a very lot that goes into these products that most
people have no idea of.

Roy Lewallen, W7EL

J M Noeding wrote:
. . .
On the other hand one may experience that HP and Tek uses some extra
components which are difficult for the average constructor to explain
or understand the function for, and one may experience that even among
the amateurs somebody manage some technique which almost nobody else
can copy - not even very experienced persons, may I mention SM5BZR
Leif's techniques, it is many constructions, they may look so easy,
but one often need some more deeper understanding to succeed, what
say's G3SEK?

73
Jan-Martin
---
J. M. Noeding, LA8AK, N-4623 Kristiansand
http://home.online.no/~la8ak/c.htm

In my experience, never. And I never heard of it happening, ever.

When the heat got turned up, everyone worked nights and weekends until
the goal was met. If we couldn't do it, the project was canceled.

Roy Lewallen, W7EL

Airy R. Bean wrote:
And what happened when the management/sales team decided they were
going to deliver anyway, and asked you in a _meaningful_ manner
whether you thought that your objections to the milestone being declared
were really in the company's best interests or in your own personal
best interests?

"Roy Lewallen" wrote in message
...

When this design was complete, a meeting was held. Attendees included
representatives from design engineering, marketing, product safety,
component and evaluation engineering, and others. Only by consensus of
this group was the milestone declared to have been completed.