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Old 19th November 2011, 10:23 PM   #18121
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PMA, increase the rep-rate by two or more. Make it 500ns, or even less. Magnify the vertical. I am only remembering this from the article done by TEK about 35 years ago.
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Old 19th November 2011, 11:26 PM   #18122
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Quote:
Originally Posted by PMA View Post
I am not sure if I understand the word 'hook' regarding the plot.

PMA - I've completely lost the drift here, are you saying this has nothing to do with DA, series inductance, or what?
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Old 19th November 2011, 11:33 PM   #18123
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Perhaps I went in the wrong direction. PMA, please slow the rep speed and 'contain' the overshoot so that it sort of looks like a 'hook'.
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Old 20th November 2011, 04:46 AM   #18124
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Let me try to explain what is being discussed here. About 35 years ago, a Tektronix engineer or two wrote an article on 'CIRCUIT HOOK' (as far as I can distinctly remember) which is a rather strange characterization of a circuit 'glitch'. They were designing attenuators, and they found a problem. Guess what? It was the SAME problem that PMA has just found and fixed! It was due to DA in the system, in the circuit board in Tek's case, and in the poly cap, in YBA's case.
Now why did they call it HOOK?
If YBA can remeasure the problem and EXAGGERATE the problem, so that the DIFFERENCE between ideal and the problem is easy to see, then you can sort of see a HOOK in the ERROR difference. I hope that this helps. I am not trying to talk in code, or anything, but to point out that YBA is not alone with his discovery, and it should be noted by virtually anyone making attenuators, if they really care about optimum performance.
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Old 20th November 2011, 06:33 AM   #18125
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Quote:
Originally Posted by john curl View Post
Perhaps I went in the wrong direction. PMA, please slow the rep speed and 'contain' the overshoot so that it sort of looks like a 'hook'.
The measurements I am showing are 1 year old. I can add a couple of measurements in a different time axis resolution, but with same circuit, signal and phenomenon. I hope it helps, at least a little.
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Old 20th November 2011, 06:39 AM   #18126
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PMA, it doesn't look that you have enough resolution to show it properly.
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Old 20th November 2011, 07:16 AM   #18127
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The plots are 1 year old and I have no other plots with me.

We have the data with enough resolution (12-bit A/D) captured at the site, but I have no access to them at the moment.

But IMO you can easily see it even in these low resolution plots.
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Last edited by PMA; 20th November 2011 at 07:28 AM.
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Old 20th November 2011, 07:42 AM   #18128
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Yes, it is enough to demonstrate the problem.
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Old 20th November 2011, 08:19 AM   #18129
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> .... an article from either the IRT (IRT :: Home) or the VDT (http://www.tonmeister.de) Journal quite a few years back ....
> ... the VDT and IRT sites are goldmines of information, ....

Thorsten,

Where can I find their publications or articles ?
Could you kindly post a link ?


Thanks,
Patrick
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Old 20th November 2011, 08:45 AM   #18130
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Hi,

Quote:
Originally Posted by EUVL View Post
Where can I find their publications or articles ?
Could you kindly post a link ?
I have not found an obvious index, such as for the old technical bulletins of the Beep on their site (Beep = UK Slang for BBC). So for my article I have to get to the paper, for anything else, just snoop around. There is plenty of acoustical stuff...

Ciao T
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