Re: Fine Tuning Shifting

On 8/10/2024 4:56 PM, Jeff Liebermann wrote:

On Sat, 10 Aug 2024 19:53:16 GMT, Tom Kunich <cyclintom@yahoo.com>
wrote:
 

Liebermann cannot even envision WHY I would use PWM since he probably has never owned a good oscilloscope.

No one can envision why you would use PWM to measure cable length because no one uses PWM to measure cable length, including you.
The method you described wasn't PWM.
We're still at the same point we were when you made this ridiculous claim 3 years ago - you haven't shown any published white paper, tutorial, app note, test equipment, or any references to using PWM for testing cable length other than your description which was completely faulty - you can't use a PWM generator and one channel on an oscilloscope to align a returned pulse.

 50% true.
 You're correct that I can't envision why *YOU* would want to use PWM
to measure cable length.  You're also correct that I would need to
"envision" what you're doing.  You comment above was sufficiently
grammatically awkward that I had to use a grammar checker to decode
it.
 50% wrong.
I still have far too many oscilloscopes:
<https://www.learnbydestroying.com/jeffl/pics/home/test-equip-mess.jpg>
<https://www.learnbydestroying.com/jeffl/crud/scopes-to-be-fixed.jpg>
There are about 8 more scopes hidden in various corners or mounted in
a rack.  Nobody seems to want the older oscilloscopes at any price.  I
keep lusting after a nice new Rigol, but can't justify the expense.
 I'm cleaning house right now and plan to eventually give away most of
the oscilloscopes to hams, students, experimenters, builders and
masochists.
 I do own one LCD oscilloscope.  Something died inside and I haven't
had time to fix it.  It's an Owon PDS 5022S.
<https://www.google.com/search?q=owon+pds5022s&tbm=isch>
 These days, I tend to use a computer and a cheap USB sound dongle for
audio frequencies or something better for higher frequencies and more
features:
<https://www.google.com/search?q=usb+pc+oscilloscope&tbm=isch>
 

And in some cases, time delays have to be measured down to the microsecond.

 Huh?  Microsecond?  Light travels about 300 kilometers (186 miles) in
1 microsecond.  That's a rather large distance for measuring cable
length.  If your mythical "some cases" require precision, you might be
working in nanoseconds where light travels 30 cm (about 1 ft) in 1
nanosecond.  Picoseconds would probably be better.

REmember Jeff, tommy is the one that thinks one can use Pulse Width Modulation to "to achieve time delay reflection"
https://groups.google.com/g/rec.bicycles.tech/c/f_tByXh5jXo/m/9Y4EzuUJCAAJ

  

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