Re: Instead scopes

On Sat, 31 Aug 2024 17:59:04 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

john larkin <jlarkin_highland_tech> wrote:

On Thu, 29 Aug 2024 21:50:19 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
 

john larkin <jl@650pot.com> wrote:
 

On Thu, 29 Aug 2024 16:15:59 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
[...]

Calculators yes.

 

We weren't alowed to use a calculator on exams because it would give
an unfair advantage to the students that could afford one.

 
We were allowed mechanical calculators (Facits etc.) but there were only
enough for half the candidates.  Half of us were locked in a room with a
spare envigilator acting as a guard while the other half sat the exam
then we swapped places and the ones who had taken the exam were locked
in while the second group sat the exam.
 
Electronic calculators did not exist, but we did learn to program an
analogue computer where 100v = 1 Machine Unit.

 
A lot of current engineering practise is left over from the days when
computing was expensive or non-existant. Things like s-parameters and
Smith charts.

>
I’ve done a lot of lowish-power RF stuff, and mostly agree with you about
the practicality of using S parameters in hand calculations.
>
However, I cordially disagree with your sentiments regarding Smith charts.
>
For one thing, they’re super useful for designing optical coatings, but
that’s a minority interest on SED.
>
In RF work one runs into a lot of matching jobs involving modulated sine
waves.
>
One typical example from my work is coupling sine modulation into a diode
laser, for modulation-generated carrier interferometry.  (*)
 
A Smith chart makes it super easy to try out different schemes, such as
series/shunt stubs, lumped elements, or any combination thereof.
>
Useless for bandwidths of an octave or more, and so apt to be undervalued
by crass time-domain types. ;)

The interesting parts of the world are wideband and nonlinear. So are
we.

Sine waves are BORING.