Re: Why no delayed trigger on newer DSOs?

Fred Bartoli wrote:

Le Wed, 15 Aug 2007 07:13:09 +0000, Joerg a écrit:


Rich Grise wrote:


On Mon, 13 Aug 2007 12:19:48 -0700, Joerg wrote:



Hello Folks,

Question: It seems that most portable DSOs in the 200MHz/1GSPS class
don't offer delayed trigger anymore which makes pulse-echo measurements
a real pain. Why don't they?

After all it's just a simple counter that is needed. Same for hold-off
which typically ain't there either :-(

Beats me but IIRC I used delayed trigger on a lower end TDS220 although
its data *** said that it could not do it. However, that scope had
some other serious issues (noise) so I asked the client to obtain a
used 2265. Old Faithful, of course, always has delayed trigger but sure
enough the plastic clutch for that function fell apart right away.
Designing a trigger delay into an analog scope is no small feat but for
a DSO it should be really easy.


But, if it's a digital storage scope, why can't you just trigger it at
the beginning of the test and "zoom in" to the part you're interested
in seeing delayed?



Because the Instek runs out of memory after 25usec. Similarly priced HPs
run out in under 5usec and the Teks run out even earlier :-(



Right now, I have to do some really accurate compensation to a system's step response. From the 10ns scale, down to the 100ms scale. What would really be handy is a logarithmic sweep. That could easily be implemented with say a sampling rate scaling down by a two factor while time rises by a two factor.
Well, with GPIB and some post-processing it works, but it's much longer and a bit... bulky.


The newer scopes such as this Instek allow data dumps via USB into the PC at an amazing clip. Not realtime but close. When I want to do something unusual with the data I use the CSV import into Excel. However, I am not an expert (yet) in VBA so I can't do any processing on-the-fly. But I'll learn it. Was hoping it was C and not Basic but, oh well, I guess that was Bill Gates' decision.

--
Regards, Joerg

http://www.analogconsultants.com
.

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