From: bill.sloman@ieee.org
On 30/11/2025 6:17 am, Joerg wrote:
> On 11/29/25 3:38 AM, Bill Sloman wrote:
>> On 29/11/2025 8:56 am, Joerg wrote:
>>> On 11/28/25 1:32 PM, Joe Gwinn wrote:
>>>> On Fri, 28 Nov 2025 12:52:07 -0800, Joerg
>>>> wrote:
>>>>
>>>>> On 11/28/25 12:45 PM, Joerg wrote:
>>>
>>> [...]
>>>
>>>>>> To the surprise of my clients it's the contrary. The most
>>>>>> client-shocking redesign was an auto-align circuit for ganged
>>>>>> ADC-channels. High speed, high phase accuracy and all that. They
>>>>>> had an
>>>>>> elaborate time domain method with a fat DSP, lots of code and very
>>>>>
>>>>> I meant they used a frequency domain method.
>>>>>
>>>>>> expensive chips used as programmable delay chips. The NRE alone
>>>>>> had been
>>>>>> humongous. It never reliably converged so the system hung a lot. I
>>>>>> suggested to ditch all that and use time domain. This caused an
>>>>>> uproar
>>>>>> because I had rocked the boat a lot and usually consultants aren't
>>>>>> supposed to do that. "I don't think this can possibly work", "It
>>>>>> won't
>>>>>> deliver the accuracy", "It won't converge either" and all that.
>>>>>>
>>>>>> Yet the boss let me do it. In the end the whole thing dropped from
>>>>>> three-digit dollars in HW to under 10 bucks. Instead of expensive
>>>>>> discrete-step time delay chips I used inductors, caps and varicap
>>>>>> diodes
>>>>>> for almost infinite granularity. The DSP became unemployed because
>>>>>> the
>>>>>> connected PC could easily handle the computations. It converged in
>>>>>> less
>>>>>> than a second, always. The NRE was low because it took less than two
>>>>>> weeks of my time and less than a day for the programmer, and we
>>>>>> didn't
>>>>>> need an expensive DSP programmer.
>>>>
>>>> Embarrassing. Were any of the customers design team later
>>>> defenstrated?
>>>
>>> No, they were pretty good. It's the usual phenomenon where, in an old
>>> German saying, you can't see the forest because of all the trees.
>>
>> Brainstorming is designed to get around that to some extent, but if
>> you aren't used to thinking outside the box it's difficult to step
>> back far enough to get outside the box.
>>
>
> My experience with brainstorm sessions is not good. The results are
> often encouraging but then hardly anything of it gets documented and
> typically none of itv is implemented. All I need is a large whiteboard
> or a large piece of paper. Plus coffee or mate (having a mate right now).
>
>
>>> Frequency domain, FFT and all that is the classical approach but
>>> consultants can help companies see other more unorthodox methods.
>>
>> Frequently poached from other companies that the consultants have
>> helped. ...
>
>
> That I make darn sure won't happen here. All client files are strictly
> separated and each client's stuff has its own shelf. No crossings allowed.
>
>
>> ... It's not about stealing industrial secrets - just starting off
>> from a different place.
>>
>>> Most of my design jobs boil down to that. The other jobs are more
>>> boring, failed EMC tests and such.
>>
>> There's nothing boring about EMC.
>
> After a dozen times of telling people not to use anodized aluminum for
> gear that needs to shield and they did it anyhow it does become boring.
> Then, explaining for the umpteenth time that split grounds do not work
> and that pigtail ground connections have close to zero effect at VHF and
> up.
That's not EMC - that's just human stupidity. You need to hire a primary
school teacher (albeit one with electronics skills) and let them handle
those kinds of jobs.
--
Bill Sloman, Sydney
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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