Re: RE: Re: Fine Tuning Shifting

On 8/15/2024 1:08 PM, cyclintom wrote:

On Wed Aug 14 19:22:06 2024 zen cycle  wrote:

On 8/14/2024 3:35 PM, cyclintom wrote:

>
>
Flunky just talks ahbout crap that he doesn't know about. Notice how
he could not answer how you measure the length of a wire
electronically? That's because he personally doesn't know how to use
an oscilloscope. Which comes as no

>
Or, It could be because Jeff answered it as well as I could so I didn't
feel it was worth commenting, but since you insist, here's how you test
cable length with _out_ using dedicated TDR equipment:
>
- Connect a pulse generator, an oscilloscope, and the cable under test
together with a T connector (Typically BNC, but adaptors may be required
depending on the equipment.
- set up a pulse generator to single pulse, starting with a 1 nS width,
5 V P-P.
- Set up the scope to trigger on the single pulse from the generator,
with the pulse from the generator being displayed at the extreme left of
the display.
- Adjust the time base of the oscilloscope until the reflected pulse
appears on the right side of the display while manually initiating the
pulse on the generator.*
- Longer cable lengths may make the returned pulse not quite
discernible. When the trigger pulse is no longer visible, increase the
pulse width until it is visible, then begin adjusting the time base
again until the reflected pules is visible (It may also be necessary to
increase the pulse amplitude).
- Once the reflected pulse is visible, measure the distance between the
trigger pulse and the reflected pulse on the scope as time delay (Hence
the term Time Domain Reflectometry).
- PLug this delay into the propagation delay value for the cable under
test, and do the math.
>
* setting up the generator to a repetitive pulse could prove problematic
in that the trigger pulse period my be shorter than the propagation
delay of the cable under test giving a confusing display. A competent
technician could manage it, but given the bizarre and completely
non-nonsensical method you described, it's well beyond your comprehension.

    I particularly liked the part about "BNC" because as we all know the connector type is important

It can be, depending on the application. When would you need an N-type? or an F-type? Be specific.

Because you don't know how to use an oscilloscope you can pretend that anyone wouldn't use repetitive pulses

Pay attention sparky, I didn't write anyone "wouldn't use repetitive pulses". I wrote "a repetitive pulse could prove problematic
 >> in that the trigger pulse period my be shorter than the propagation
 >> delay of the cable under test". In a manual set-up they wouldn't unless they already had an idea of how long the cable under test was. A repetitive pulse isn't require in any case. Is this why you were never able to hold a job for more than a year?

or that the actual pulse with (1 ns?) is important.

I didn't say it was. I selected 1 nS as a matter of convenience. For extremely long cables a 1 uS width is more advisable. The important point is to have the pulse narrow enough such that the reflection isn't obscured by the high level of the pulse.

It is no surprise that you never got a real job.

Says the guy who never had a job that lasted more than a year. Meanwhile my resume includes ten years at HP/Agilent, ten years at Schneider Electric, and ten years at my current position.
Still wanna play, sparky?
--
Add xx to reply