[time-nuts] Multiple Time Interval Counters to measure Transients?

Florian Teply usenet at teply.info
Mon Sep 10 19:08:34 UTC 2012


Am Sun, 09 Sep 2012 02:40:23 +0200
schrieb Magnus Danielson <magnus at rubidium.dyndns.org>:

> Hi Florian,
> 
> On 09/08/2012 07:34 PM, Florian Teply wrote:
> > The idea I have right now is employing something on the order of
> > three to five comparators per output, fed with different trigger
> > levels. That way I should be able to get some information on the
> > transient shape as well. But then I'll have to throw a few hundred
> > Time Interval Counters at the problem in order to get the
> > information on the duration of the transients.  So in general,
> > amplitude  information comes from the comparator trigger levels,
> > time information from the TICs.
> >
> > What I expect from the DUTs is transients in the range between 1 and
> > maybe 50 nanoseconds duration, but on some circuits they may be a
> > lot quicker as the bipolars are wicked fast (about 3-5 ps gate
> > delay in ECL inverters).
> >
> > What do you guys think, would a truckload of TICs do the job? Maybe
> > not on the Bipolars, but at the plain CMOS this should do.
> >
> > Any hints?
> 
> Check out Agilents Acquiris products, in particular the U1050A-002:
> http://www.home.agilent.com/agilent/product.jspx?nid=-536902438.733419.00&cc=SE&lc=eng
> 
This indeed is interesting. Now I can at least put some price tag to
the setup I had in mind. The unit you refer to goes for a bit more than
10k for 12 channels, so including a cPCI crate I'd have to find some
80k$ for all the outputs of a single chip. There I'll definitely have
to trade channels for measurement time, as I'll probably use 8 to 10
hours of beam time per run, going at 600-800 euros/h. So it'll be
definitely less expensive to just test one chip at a time...

Apart from that, I'll also check with ACAM in Germany as they have
ready-made chips that would do that, and 65 to 120 ps RMS accuracy is
okay for the CMOS stuff. Maybe they sell their chips for only a few
hundred euros each... ;-)

Best regards,
Florian



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