Instrument Amp and C-load

On a sunny day (Fri, 2 Jun 2017 15:08:25 +1000) it happened Chris Jones wrote in :

That is all true, but there are more aspects, like I mentioned reflections, for example try analog video over a 200 feet coax that is not properly terminated, for speed of light 1 foot per nano-second a 200 feet cable gives 200 ns, so .2 us delay For a horizontal scan time (old NTSC / PAL) of about 60 us and a 60 cm wide screen, that amounts to (.2/60)*60 = .2cm shifted to the right ghost image.

In fact it is worse the speed of the signal in the cable is slower than light, but just using feet etc for simplicity.

For the audio guys it is disappointing that in spite of them having spend $$$$$$$++ on oxygen free gold speaker cables, the harmonics of their 3 kHz square wave are no longer at the amplitude those should be, the precious waveform will be distorted. the clear highs will be gone, and the mosquito landing on the bass players mike can no longer be heard telling its tale.

Just imagine our Nobel prize winner Bob Dylan's

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locusts's song being mutilated!

And that is not even counting the oscillations that started this subject.

ANY coax is a transmission line, and should be treated as such. There DO exists special cable driver chips, and maybe one should read the app notes of those.

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see figure 1, THAT is what I was referring to.

On top of that these day where we go digital every signal is wide band.

Reply to
Jan Panteltje
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On a sunny day (Thu, 01 Jun 2017 11:33:14 -0700) it happened John Larkin wrote in :

See my other reply, or use a real cable driver:

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Reply to
Jan Panteltje

Vos (max) = 5 mV. (Sometimes I'm sending ~10mV level signals around.)

George h.

Reply to
George Herold

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